summaryrefslogtreecommitdiffstats
path: root/generic/tkTextDisp.c
blob: a63c9bc53ab89c6c9a2cc4124399d699f6fd55dd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
5642
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
5658
5659
5660
5661
5662
5663
5664
5665
5666
5667
5668
5669
5670
5671
5672
5673
5674
5675
5676
5677
5678
5679
5680
5681
5682
5683
5684
5685
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
5709
5710
5711
5712
5713
5714
5715
5716
5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
5740
5741
5742
5743
5744
5745
5746
5747
5748
5749
5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872
5873
5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948
5949
5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
5988
5989
5990
5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479
6480
6481
6482
6483
6484
6485
6486
6487
6488
6489
6490
6491
6492
6493
6494
6495
6496
6497
6498
6499
6500
6501
6502
6503
6504
6505
6506
6507
6508
6509
6510
6511
6512
6513
6514
6515
6516
6517
6518
6519
6520
6521
6522
6523
6524
6525
6526
6527
6528
6529
6530
6531
6532
6533
6534
6535
6536
6537
6538
6539
6540
6541
6542
6543
6544
6545
6546
6547
6548
6549
6550
6551
6552
6553
6554
6555
6556
6557
6558
6559
6560
6561
6562
6563
6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593
6594
6595
6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
6614
6615
6616
6617
6618
6619
6620
6621
6622
6623
6624
6625
6626
6627
6628
6629
6630
6631
6632
6633
6634
6635
6636
6637
6638
6639
6640
6641
6642
6643
6644
6645
6646
6647
6648
6649
6650
6651
6652
6653
6654
6655
6656
6657
6658
6659
6660
6661
6662
6663
6664
6665
6666
6667
6668
6669
6670
6671
6672
6673
6674
6675
6676
6677
6678
6679
6680
6681
6682
6683
6684
6685
6686
6687
6688
6689
6690
6691
6692
6693
6694
6695
6696
6697
6698
6699
6700
6701
6702
6703
6704
6705
6706
6707
6708
6709
6710
6711
6712
6713
6714
6715
6716
6717
6718
6719
6720
6721
6722
6723
6724
6725
6726
6727
6728
6729
6730
6731
6732
6733
6734
6735
6736
6737
6738
6739
6740
6741
6742
6743
6744
6745
6746
6747
6748
6749
6750
6751
6752
6753
6754
6755
6756
6757
6758
6759
6760
6761
6762
6763
6764
6765
6766
6767
6768
6769
6770
6771
6772
6773
6774
6775
6776
6777
6778
6779
6780
6781
6782
6783
6784
6785
6786
6787
6788
6789
6790
6791
6792
6793
6794
6795
6796
6797
6798
6799
6800
6801
6802
6803
6804
6805
6806
6807
6808
6809
6810
6811
6812
6813
6814
6815
6816
6817
6818
6819
6820
6821
6822
6823
6824
6825
6826
6827
6828
6829
6830
6831
6832
6833
6834
6835
6836
6837
6838
6839
6840
6841
6842
6843
6844
6845
6846
6847
6848
6849
6850
6851
6852
6853
6854
6855
6856
6857
6858
6859
6860
6861
6862
6863
6864
6865
6866
6867
6868
6869
6870
6871
6872
6873
6874
6875
6876
6877
6878
6879
6880
6881
6882
6883
6884
6885
6886
6887
6888
6889
6890
6891
6892
6893
6894
6895
6896
6897
6898
6899
6900
6901
6902
6903
6904
6905
6906
6907
6908
6909
6910
6911
6912
6913
6914
6915
6916
6917
6918
6919
6920
6921
6922
6923
6924
6925
6926
6927
6928
6929
6930
6931
6932
6933
6934
6935
6936
6937
6938
6939
6940
6941
6942
6943
6944
6945
6946
6947
6948
6949
6950
6951
6952
6953
6954
6955
6956
6957
6958
6959
6960
6961
6962
6963
6964
6965
6966
6967
6968
6969
6970
6971
6972
6973
6974
6975
6976
6977
6978
6979
6980
6981
6982
6983
6984
6985
6986
6987
6988
6989
6990
6991
6992
6993
6994
6995
6996
6997
6998
6999
7000
7001
7002
7003
7004
7005
7006
7007
7008
7009
7010
7011
7012
7013
7014
7015
7016
7017
7018
7019
7020
7021
7022
7023
7024
7025
7026
7027
7028
7029
7030
7031
7032
7033
7034
7035
7036
7037
7038
7039
7040
7041
7042
7043
7044
7045
7046
7047
7048
7049
7050
7051
7052
7053
7054
7055
7056
7057
7058
7059
7060
7061
7062
7063
7064
7065
7066
7067
7068
7069
7070
7071
7072
7073
7074
7075
7076
7077
7078
7079
7080
7081
7082
7083
7084
7085
7086
7087
7088
7089
7090
7091
7092
7093
7094
7095
7096
7097
7098
7099
7100
7101
7102
7103
7104
7105
7106
7107
7108
7109
7110
7111
7112
7113
7114
7115
7116
7117
7118
7119
7120
7121
7122
7123
7124
7125
7126
7127
7128
7129
7130
7131
7132
7133
7134
7135
7136
7137
7138
7139
7140
7141
7142
7143
7144
7145
7146
7147
7148
7149
7150
7151
7152
7153
7154
7155
7156
7157
7158
7159
7160
7161
7162
7163
7164
7165
7166
7167
7168
7169
7170
7171
7172
7173
7174
7175
7176
7177
7178
7179
7180
7181
7182
7183
7184
7185
7186
7187
7188
7189
7190
7191
7192
7193
7194
7195
7196
7197
7198
7199
7200
7201
7202
7203
7204
7205
7206
7207
7208
7209
7210
7211
7212
7213
7214
7215
7216
7217
7218
7219
7220
7221
7222
7223
7224
7225
7226
7227
7228
7229
7230
7231
7232
7233
7234
7235
7236
7237
7238
7239
7240
7241
7242
7243
7244
7245
7246
7247
7248
7249
7250
7251
7252
7253
7254
7255
7256
7257
7258
7259
7260
7261
7262
7263
7264
7265
7266
7267
7268
7269
7270
7271
7272
7273
7274
7275
7276
7277
7278
7279
7280
7281
7282
7283
7284
7285
7286
7287
7288
7289
7290
7291
7292
7293
7294
7295
7296
7297
7298
7299
7300
7301
7302
7303
7304
7305
7306
7307
7308
7309
7310
7311
7312
7313
7314
7315
7316
7317
7318
7319
7320
7321
7322
7323
7324
7325
7326
7327
7328
7329
7330
7331
7332
7333
7334
7335
7336
7337
7338
7339
7340
7341
7342
7343
7344
7345
7346
7347
7348
7349
7350
7351
7352
7353
7354
7355
7356
7357
7358
7359
7360
7361
7362
7363
7364
7365
7366
7367
7368
7369
7370
7371
7372
7373
7374
7375
7376
7377
7378
7379
7380
7381
7382
7383
7384
7385
7386
7387
7388
7389
7390
7391
7392
7393
7394
7395
7396
7397
7398
7399
7400
7401
7402
7403
7404
7405
7406
7407
7408
7409
7410
7411
7412
7413
7414
7415
7416
7417
7418
7419
7420
7421
7422
7423
7424
7425
7426
7427
7428
7429
7430
7431
7432
7433
7434
7435
7436
7437
7438
7439
7440
7441
7442
7443
7444
7445
7446
7447
7448
7449
7450
7451
7452
7453
7454
7455
7456
7457
7458
7459
7460
7461
7462
7463
7464
7465
7466
7467
7468
7469
7470
7471
7472
7473
7474
7475
7476
7477
7478
7479
7480
7481
7482
7483
7484
7485
7486
7487
7488
7489
7490
7491
7492
7493
7494
7495
7496
7497
7498
7499
7500
7501
7502
7503
7504
7505
7506
7507
7508
7509
7510
7511
7512
7513
7514
7515
7516
7517
7518
7519
7520
7521
7522
7523
7524
7525
7526
7527
7528
7529
7530
7531
7532
7533
7534
7535
7536
7537
7538
7539
7540
7541
7542
7543
7544
7545
7546
7547
7548
7549
7550
7551
7552
7553
7554
7555
7556
7557
7558
7559
7560
7561
7562
7563
7564
7565
7566
7567
7568
7569
7570
7571
7572
7573
7574
7575
7576
7577
7578
7579
7580
7581
7582
7583
7584
7585
7586
7587
7588
7589
7590
7591
7592
7593
7594
7595
7596
7597
7598
7599
7600
7601
7602
7603
7604
7605
7606
7607
7608
7609
7610
7611
7612
7613
7614
7615
7616
7617
7618
7619
7620
7621
7622
7623
7624
7625
7626
7627
7628
7629
7630
7631
7632
7633
7634
7635
7636
7637
7638
7639
7640
7641
7642
7643
7644
7645
7646
7647
7648
7649
7650
7651
7652
7653
7654
7655
7656
7657
7658
7659
7660
7661
7662
7663
7664
7665
7666
7667
7668
7669
7670
7671
7672
7673
7674
7675
7676
7677
7678
7679
7680
7681
7682
7683
7684
7685
7686
7687
7688
7689
7690
7691
7692
7693
7694
7695
7696
7697
7698
7699
7700
7701
7702
7703
7704
7705
7706
7707
7708
7709
7710
7711
7712
7713
7714
7715
7716
7717
7718
7719
7720
7721
7722
7723
7724
7725
7726
7727
7728
7729
7730
7731
7732
7733
7734
7735
7736
7737
7738
7739
7740
7741
7742
7743
7744
7745
7746
7747
7748
7749
7750
7751
7752
7753
7754
7755
7756
7757
7758
7759
7760
7761
7762
7763
7764
7765
7766
7767
7768
7769
7770
7771
7772
7773
7774
7775
7776
7777
7778
7779
7780
7781
7782
7783
7784
7785
7786
7787
7788
7789
7790
7791
7792
7793
7794
7795
7796
7797
7798
7799
7800
7801
7802
7803
7804
7805
7806
7807
7808
7809
7810
7811
7812
7813
7814
7815
7816
7817
7818
7819
7820
7821
7822
7823
7824
7825
7826
7827
7828
7829
7830
7831
7832
7833
7834
7835
7836
7837
7838
7839
7840
7841
7842
7843
7844
7845
7846
7847
7848
7849
7850
7851
7852
7853
7854
7855
7856
7857
7858
7859
7860
7861
7862
7863
7864
7865
7866
7867
7868
7869
7870
7871
7872
7873
7874
7875
7876
7877
7878
7879
7880
7881
7882
7883
7884
7885
7886
7887
7888
7889
7890
7891
7892
7893
7894
7895
7896
7897
7898
7899
7900
7901
7902
7903
7904
7905
7906
7907
7908
7909
7910
7911
7912
7913
7914
7915
7916
7917
7918
7919
7920
7921
7922
7923
7924
7925
7926
7927
7928
7929
7930
7931
7932
7933
7934
7935
7936
7937
7938
7939
7940
7941
7942
7943
7944
7945
7946
7947
7948
7949
7950
7951
7952
7953
7954
7955
7956
7957
7958
7959
7960
7961
7962
7963
7964
7965
7966
7967
7968
7969
7970
7971
7972
7973
7974
7975
7976
7977
7978
7979
7980
7981
7982
7983
7984
7985
7986
7987
7988
7989
7990
7991
7992
7993
7994
7995
7996
7997
7998
7999
8000
8001
8002
8003
8004
8005
8006
8007
8008
8009
8010
8011
8012
8013
8014
8015
8016
8017
8018
8019
8020
8021
8022
8023
8024
8025
8026
8027
8028
8029
8030
8031
8032
8033
8034
8035
8036
8037
8038
8039
8040
8041
8042
8043
8044
8045
8046
8047
8048
8049
8050
8051
8052
8053
8054
8055
8056
8057
8058
8059
8060
8061
8062
8063
8064
8065
8066
8067
8068
8069
8070
8071
8072
8073
8074
8075
8076
8077
8078
8079
8080
8081
8082
8083
8084
8085
8086
8087
8088
8089
8090
8091
8092
8093
8094
8095
8096
8097
8098
8099
8100
8101
8102
8103
8104
8105
8106
8107
8108
8109
8110
8111
8112
8113
8114
8115
8116
8117
8118
8119
8120
8121
8122
8123
8124
8125
8126
8127
8128
8129
8130
8131
8132
8133
8134
8135
8136
8137
8138
8139
8140
8141
8142
8143
8144
8145
8146
8147
8148
8149
8150
8151
8152
8153
8154
8155
8156
8157
8158
8159
8160
8161
8162
8163
8164
8165
8166
8167
8168
8169
8170
8171
8172
8173
8174
8175
8176
8177
8178
8179
8180
8181
8182
8183
8184
8185
8186
8187
8188
8189
8190
8191
8192
8193
8194
8195
8196
8197
8198
8199
8200
8201
8202
8203
8204
8205
8206
8207
8208
8209
8210
8211
8212
8213
8214
8215
8216
8217
8218
8219
8220
8221
8222
8223
8224
8225
8226
8227
8228
8229
8230
8231
8232
8233
8234
8235
8236
8237
8238
8239
8240
8241
8242
8243
8244
8245
8246
8247
8248
8249
8250
8251
8252
8253
8254
8255
8256
8257
8258
8259
8260
8261
8262
8263
8264
8265
8266
8267
8268
8269
8270
8271
8272
8273
8274
8275
8276
8277
8278
8279
8280
8281
8282
8283
8284
8285
8286
8287
8288
8289
8290
8291
8292
8293
8294
8295
8296
8297
8298
8299
8300
8301
8302
8303
8304
8305
8306
8307
8308
8309
8310
8311
8312
8313
8314
8315
8316
8317
8318
8319
8320
8321
8322
8323
8324
8325
8326
8327
8328
8329
8330
8331
8332
8333
8334
8335
8336
8337
8338
8339
8340
8341
8342
8343
8344
8345
8346
8347
8348
8349
8350
8351
8352
8353
8354
8355
8356
8357
8358
8359
8360
8361
8362
8363
8364
8365
8366
8367
8368
8369
8370
8371
8372
8373
8374
8375
8376
8377
8378
8379
8380
8381
8382
8383
8384
8385
8386
8387
8388
8389
8390
8391
8392
8393
8394
8395
8396
8397
8398
8399
8400
8401
8402
8403
8404
8405
8406
8407
8408
8409
8410
8411
8412
8413
8414
8415
8416
8417
8418
8419
8420
8421
8422
8423
8424
8425
8426
8427
8428
8429
8430
8431
8432
8433
8434
8435
8436
8437
8438
8439
8440
8441
8442
8443
8444
8445
8446
8447
8448
8449
8450
8451
8452
8453
8454
8455
8456
8457
8458
8459
8460
8461
8462
8463
8464
8465
8466
8467
8468
8469
8470
8471
8472
8473
8474
8475
8476
8477
8478
8479
8480
8481
8482
8483
8484
8485
8486
8487
8488
8489
8490
8491
8492
8493
8494
8495
8496
8497
8498
8499
8500
8501
8502
8503
8504
8505
8506
8507
8508
8509
8510
8511
8512
8513
8514
8515
8516
8517
8518
8519
8520
8521
8522
8523
8524
8525
8526
8527
8528
8529
8530
8531
8532
8533
8534
8535
8536
8537
8538
8539
8540
8541
8542
8543
8544
8545
8546
8547
8548
8549
8550
8551
8552
8553
8554
8555
8556
8557
8558
8559
8560
8561
8562
8563
8564
8565
8566
8567
8568
8569
8570
8571
8572
8573
8574
8575
8576
8577
8578
8579
8580
8581
8582
8583
8584
8585
8586
8587
8588
8589
8590
8591
8592
8593
8594
8595
8596
8597
8598
8599
8600
8601
8602
8603
8604
8605
8606
8607
8608
8609
8610
8611
8612
8613
8614
8615
8616
8617
8618
8619
8620
8621
8622
8623
8624
8625
8626
8627
8628
8629
8630
8631
8632
8633
8634
8635
8636
8637
8638
8639
8640
8641
8642
8643
8644
8645
8646
8647
8648
8649
8650
8651
8652
8653
8654
8655
8656
8657
8658
8659
8660
8661
8662
8663
8664
8665
8666
8667
8668
8669
8670
8671
8672
8673
8674
8675
8676
8677
8678
8679
8680
8681
8682
8683
8684
8685
8686
8687
8688
8689
8690
8691
8692
8693
8694
8695
8696
8697
8698
8699
8700
8701
8702
8703
/*
 * tkTextDisp.c --
 *
 *	This module provides facilities to display text widgets. It is the
 *	only place where information is kept about the screen layout of text
 *	widgets. (Well, strictly, each TkTextLine and B-tree node caches its
 *	last observed pixel height, but that information originates here).
 *
 * Copyright (c) 1992-1994 The Regents of the University of California.
 * Copyright (c) 1994-1997 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 */

#include "tkInt.h"
#include "tkText.h"

#ifdef __WIN32__
#include "tkWinInt.h"
#elif defined(__CYGWIN__)
#include "tkUnixInt.h"
#endif

#ifdef MAC_OSX_TK
#include "tkMacOSXInt.h"
#endif

/*
 * "Calculations of line pixel heights and the size of the vertical
 * scrollbar."
 *
 * Given that tag, font and elide changes can happen to large numbers of
 * diverse chunks in a text widget containing megabytes of text, it is not
 * possible to recalculate all affected height information immediately any
 * such change takes place and maintain a responsive user-experience. Yet, for
 * an accurate vertical scrollbar to be drawn, we must know the total number
 * of vertical pixels shown on display versus the number available to be
 * displayed.
 *
 * The way the text widget solves this problem is by maintaining cached line
 * pixel heights (in the BTree for each logical line), and having asynchronous
 * timer callbacks (i) to iterate through the logical lines recalculating
 * their heights, and (ii) to recalculate the vertical scrollbar's position
 * and size.
 *
 * Typically this works well but there are some situations where the overall
 * functional design of this file causes some problems. These problems can
 * only arise because the calculations used to display lines on screen are not
 * connected to those in the iterating-line- recalculation-process.
 *
 * The reason for this disconnect is that the display calculations operate in
 * display lines, and the iteration and cache operates in logical lines.
 * Given that the display calculations both need not contain complete logical
 * lines (at top or bottom of display), and that they do not actually keep
 * track of logical lines (for simplicity of code and historical design), this
 * means a line may be known and drawn with a different pixel height to that
 * which is cached in the BTree, and this might cause some temporary
 * undesirable mismatch between display and the vertical scrollbar.
 *
 * All such mismatches should be temporary, however, since the asynchronous
 * height calculations will always catch up eventually.
 *
 * For further details see the comments before and within the following
 * functions below: LayoutDLine, AsyncUpdateLineMetrics, GetYView,
 * GetYPixelCount, TkTextUpdateOneLine, TkTextUpdateLineMetrics.
 *
 * For details of the way in which the BTree keeps track of pixel heights, see
 * tkTextBTree.c. Basically the BTree maintains two pieces of information: the
 * logical line indices and the pixel height cache.
 */

/*
 * TK_LAYOUT_WITH_BASE_CHUNKS:
 *
 *	With this macro set, collect all char chunks that have no holes
 *	between them, that are on the same line and use the same font and font
 *	size. Allocate the chars of all these chunks, the so-called "stretch",
 *	in a DString in the first chunk, the so-called "base chunk". Use the
 *	base chunk string for measuring and drawing, so that these actions are
 *	always performed with maximum context.
 *
 *	This is necessary for text rendering engines that provide ligatures
 *	and sub-pixel layout, like ATSU on Mac. If we don't do this, the
 *	measuring will change all the time, leading to an ugly "tremble and
 *	shiver" effect. This is because of the continuous splitting and
 *	re-merging of chunks that goes on in a text widget, when the cursor or
 *	the selection move.
 *
 * Side effects:
 *
 *	Memory management changes. Instead of attaching the character data to
 *	the clientData structures of the char chunks, an additional DString is
 *	used. The collection process will even lead to resizing this DString
 *	for large stretches (> TCL_DSTRING_STATIC_SIZE == 200). We could
 *	reduce the overall memory footprint by copying the result to a plain
 *	char array after the line breaking process, but that would complicate
 *	the code and make performance even worse speedwise. See also TODOs.
 *
 * TODOs:
 *
 *    -	Move the character collection process from the LayoutProc into
 *	LayoutDLine(), so that the collection can be done before actual
 *	layout. In this way measuring can look at the following text, too,
 *	right from the beginning. Memory handling can also be improved with
 *	this. Problem: We don't easily know which chunks are adjacent until
 *	all the other chunks have calculated their width. Apparently marks
 *	would return width==0. A separate char collection loop would have to
 *	know these things.
 *
 *    -	Use a new context parameter to pass the context from LayoutDLine() to
 *	the LayoutProc instead of using a global variable like now. Not
 *	pressing until the previous point gets implemented.
 */

/*
 * The following structure describes how to display a range of characters.
 * The information is generated by scanning all of the tags associated with
 * the characters and combining that with default information for the overall
 * widget. These structures form the hash keys for dInfoPtr->styleTable.
 */

typedef struct StyleValues {
    Tk_3DBorder border;		/* Used for drawing background under text.
				 * NULL means use widget background. */
    int borderWidth;		/* Width of 3-D border for background. */
    int relief;			/* 3-D relief for background. */
    Pixmap bgStipple;		/* Stipple bitmap for background. None means
				 * draw solid. */
    XColor *fgColor;		/* Foreground color for text. */
    Tk_Font tkfont;		/* Font for displaying text. */
    Pixmap fgStipple;		/* Stipple bitmap for text and other
				 * foreground stuff. None means draw solid.*/
    int justify;		/* Justification style for text. */
    int lMargin1;		/* Left margin, in pixels, for first display
				 * line of each text line. */
    int lMargin2;		/* Left margin, in pixels, for second and
				 * later display lines of each text line. */
    int offset;			/* Offset in pixels of baseline, relative to
				 * baseline of line. */
    int overstrike;		/* Non-zero means draw overstrike through
				 * text. */
    int rMargin;		/* Right margin, in pixels. */
    int spacing1;		/* Spacing above first dline in text line. */
    int spacing2;		/* Spacing between lines of dline. */
    int spacing3;		/* Spacing below last dline in text line. */
    TkTextTabArray *tabArrayPtr;/* Locations and types of tab stops (may be
				 * NULL). */
    int tabStyle;		/* One of TABULAR or WORDPROCESSOR. */
    int underline;		/* Non-zero means draw underline underneath
				 * text. */
    int elide;			/* Zero means draw text, otherwise not. */
    TkWrapMode wrapMode;	/* How to handle wrap-around for this tag.
				 * One of TEXT_WRAPMODE_CHAR,
				 * TEXT_WRAPMODE_NONE or TEXT_WRAPMODE_WORD.*/
} StyleValues;

/*
 * The following structure extends the StyleValues structure above with
 * graphics contexts used to actually draw the characters. The entries in
 * dInfoPtr->styleTable point to structures of this type.
 */

typedef struct TextStyle {
    int refCount;		/* Number of times this structure is
				 * referenced in Chunks. */
    GC bgGC;			/* Graphics context for background. None means
				 * use widget background. */
    GC fgGC;			/* Graphics context for foreground. */
    StyleValues *sValuePtr;	/* Raw information from which GCs were
				 * derived. */
    Tcl_HashEntry *hPtr;	/* Pointer to entry in styleTable. Used to
				 * delete entry. */
} TextStyle;

/*
 * The following macro determines whether two styles have the same background
 * so that, for example, no beveled border should be drawn between them.
 */

#define SAME_BACKGROUND(s1, s2) \
    (((s1)->sValuePtr->border == (s2)->sValuePtr->border) \
	&& ((s1)->sValuePtr->borderWidth == (s2)->sValuePtr->borderWidth) \
	&& ((s1)->sValuePtr->relief == (s2)->sValuePtr->relief) \
	&& ((s1)->sValuePtr->bgStipple == (s2)->sValuePtr->bgStipple))

/*
 * The following macro is used to compare two floating-point numbers to within
 * a certain degree of scale. Direct comparison fails on processors where the
 * processor and memory representations of FP numbers of a particular
 * precision is different (e.g. Intel)
 */

#define FP_EQUAL_SCALE(double1, double2, scaleFactor) \
    (fabs((double1)-(double2))*((scaleFactor)+1.0) < 0.3)

/*
 * Macro to make debugging/testing logging a little easier.
 */

#define LOG(toVar,what) \
    Tcl_SetVar2(textPtr->interp, toVar, NULL, (what), \
	    TCL_GLOBAL_ONLY|TCL_APPEND_VALUE|TCL_LIST_ELEMENT)

/*
 * The following structure describes one line of the display, which may be
 * either part or all of one line of the text.
 */

typedef struct DLine {
    TkTextIndex index;		/* Identifies first character in text that is
				 * displayed on this line. */
    int byteCount;		/* Number of bytes accounted for by this
				 * display line, including a trailing space or
				 * newline that isn't actually displayed. */
    int logicalLinesMerged;	/* Number of extra logical lines merged into
				 * this one due to elided newlines. */
    int y;			/* Y-position at which line is supposed to be
				 * drawn (topmost pixel of rectangular area
				 * occupied by line). */
    int oldY;			/* Y-position at which line currently appears
				 * on display. This is used to move lines by
				 * scrolling rather than re-drawing. If
				 * 'flags' have the OLD_Y_INVALID bit set,
				 * then we will never examine this field
				 * (which means line isn't currently visible
				 * on display and must be redrawn). */
    int height;			/* Height of line, in pixels. */
    int baseline;		/* Offset of text baseline from y, in
				 * pixels. */
    int spaceAbove;		/* How much extra space was added to the top
				 * of the line because of spacing options.
				 * This is included in height and baseline. */
    int spaceBelow;		/* How much extra space was added to the
				 * bottom of the line because of spacing
				 * options. This is included in height. */
    int length;			/* Total length of line, in pixels. */
    TkTextDispChunk *chunkPtr;	/* Pointer to first chunk in list of all of
				 * those that are displayed on this line of
				 * the screen. */
    struct DLine *nextPtr;	/* Next in list of all display lines for this
				 * window. The list is sorted in order from
				 * top to bottom. Note: the next DLine doesn't
				 * always correspond to the next line of text:
				 * (a) can have multiple DLines for one text
				 * line (wrapping), (b) can have elided newlines,
				 * and (c) can have gaps where DLine's
				 * have been deleted because they're out of
				 * date. */
    int flags;			/* Various flag bits: see below for values. */
} DLine;

/*
 * Flag bits for DLine structures:
 *
 * HAS_3D_BORDER -		Non-zero means that at least one of the chunks
 *				in this line has a 3D border, so it
 *				potentially interacts with 3D borders in
 *				neighboring lines (see DisplayLineBackground).
 * NEW_LAYOUT -			Non-zero means that the line has been
 *				re-layed out since the last time the display
 *				was updated.
 * TOP_LINE -			Non-zero means that this was the top line in
 *				in the window the last time that the window
 *				was laid out. This is important because a line
 *				may be displayed differently if its at the top
 *				or bottom than if it's in the middle
 *				(e.g. beveled edges aren't displayed for
 *				middle lines if the adjacent line has a
 *				similar background).
 * BOTTOM_LINE -		Non-zero means that this was the bottom line
 *				in the window the last time that the window
 *				was laid out.
 * OLD_Y_INVALID -		The value of oldY in the structure is not
 *				valid or useful and should not be examined.
 *				'oldY' is only useful when the DLine is
 *				currently displayed at a different position
 *				and we wish to re-display it via scrolling, so
 *				this means the DLine needs redrawing.
 */

#define HAS_3D_BORDER	1
#define NEW_LAYOUT	2
#define TOP_LINE	4
#define BOTTOM_LINE	8
#define OLD_Y_INVALID  16

/*
 * Overall display information for a text widget:
 */

typedef struct TextDInfo {
    Tcl_HashTable styleTable;	/* Hash table that maps from StyleValues to
				 * TextStyles for this widget. */
    DLine *dLinePtr;		/* First in list of all display lines for this
				 * widget, in order from top to bottom. */
    int topPixelOffset;		/* Identifies first pixel in top display line
				 * to display in window. */
    int newTopPixelOffset;	/* Desired first pixel in top display line to
				 * display in window. */
    GC copyGC;			/* Graphics context for copying from off-
				 * screen pixmaps onto screen. */
    GC scrollGC;		/* Graphics context for copying from one place
				 * in the window to another (scrolling):
				 * differs from copyGC in that we need to get
				 * GraphicsExpose events. */
    int x;			/* First x-coordinate that may be used for
				 * actually displaying line information.
				 * Leaves space for border, etc. */
    int y;			/* First y-coordinate that may be used for
				 * actually displaying line information.
				 * Leaves space for border, etc. */
    int maxX;			/* First x-coordinate to right of available
				 * space for displaying lines. */
    int maxY;			/* First y-coordinate below available space
				 * for displaying lines. */
    int topOfEof;		/* Top-most pixel (lowest y-value) that has
				 * been drawn in the appropriate fashion for
				 * the portion of the window after the last
				 * line of the text. This field is used to
				 * figure out when to redraw part or all of
				 * the eof field. */

    /*
     * Information used for scrolling:
     */

    int newXPixelOffset;	/* Desired x scroll position, measured as the
				 * number of pixels off-screen to the left for
				 * a line with no left margin. */
    int curXPixelOffset;	/* Actual x scroll position, measured as the
				 * number of pixels off-screen to the left. */
    int maxLength;		/* Length in pixels of longest line that's
				 * visible in window (length may exceed window
				 * size). If there's no wrapping, this will be
				 * zero. */
    double xScrollFirst, xScrollLast;
				/* Most recent values reported to horizontal
				 * scrollbar; used to eliminate unnecessary
				 * reports. */
    double yScrollFirst, yScrollLast;
				/* Most recent values reported to vertical
				 * scrollbar; used to eliminate unnecessary
				 * reports. */

    /*
     * The following information is used to implement scanning:
     */

    int scanMarkXPixel;		/* Pixel index of left edge of the window when
				 * the scan started. */
    int scanMarkX;		/* X-position of mouse at time scan started. */
    int scanTotalYScroll;	/* Total scrolling (in screen pixels) that has
				 * occurred since scanMarkY was set. */
    int scanMarkY;		/* Y-position of mouse at time scan started. */

    /*
     * Miscellaneous information:
     */

    int dLinesInvalidated;	/* This value is set to 1 whenever something
				 * happens that invalidates information in
				 * DLine structures; if a redisplay is in
				 * progress, it will see this and abort the
				 * redisplay. This is needed because, for
				 * example, an embedded window could change
				 * its size when it is first displayed,
				 * invalidating the DLine that is currently
				 * being displayed. If redisplay continues, it
				 * will use freed memory and could dump
				 * core. */
    int flags;			/* Various flag values: see below for
				 * definitions. */
    /*
     * Information used to handle the asynchronous updating of the y-scrollbar
     * and the vertical height calculations:
     */

    int lineMetricUpdateEpoch;	/* Stores a number which is incremented each
				 * time the text widget changes in a
				 * significant way (e.g. resizing or
				 * geometry-influencing tag changes). */
    int currentMetricUpdateLine;/* Stores a counter which is used to iterate
				 * over the logical lines contained in the
				 * widget and update their geometry
				 * calculations, if they are out of date. */
    TkTextIndex metricIndex;	/* If the current metric update line wraps
				 * into very many display lines, then this is
				 * used to keep track of what index we've got
				 * to so far... */
    int metricPixelHeight;	/* ...and this is for the height calculation
				 * so far...*/
    int metricEpoch;		/* ...and this for the epoch of the partial
				 * calculation so it can be cancelled if
				 * things change once more. This field will be
				 * -1 if there is no long-line calculation in
				 * progress, and take a non-negative value if
				 * there is such a calculation in progress. */
    int lastMetricUpdateLine;	/* When the current update line reaches this
				 * line, we are done and should stop the
				 * asychronous callback mechanism. */
    Tcl_TimerToken lineUpdateTimer;
				/* A token pointing to the current line metric
				 * update callback. */
    Tcl_TimerToken scrollbarTimer;
				/* A token pointing to the current scrollbar
				 * update callback. */
} TextDInfo;

/*
 * In TkTextDispChunk structures for character segments, the clientData field
 * points to one of the following structures:
 */

#if !TK_LAYOUT_WITH_BASE_CHUNKS

typedef struct CharInfo {
    int numBytes;		/* Number of bytes to display. */
    char chars[4];		/* UTF characters to display. Actual size will
				 * be numBytes, not 4. THIS MUST BE THE LAST
				 * FIELD IN THE STRUCTURE. */
} CharInfo;

#else /* TK_LAYOUT_WITH_BASE_CHUNKS */

typedef struct CharInfo {
    TkTextDispChunk *baseChunkPtr;
    int baseOffset;		/* Starting offset in base chunk
				 * baseChars. */
    int numBytes;		/* Number of bytes that belong to this
				 * chunk. */
    const char *chars;		/* UTF characters to display. Actually points
				 * into the baseChars of the base chunk. Only
				 * valid after FinalizeBaseChunk(). */
} CharInfo;

/*
 * The BaseCharInfo is a CharInfo with some additional data added.
 */

typedef struct BaseCharInfo {
    CharInfo ci;
    Tcl_DString baseChars;	/* Actual characters for the stretch of text
				 * represented by this base chunk. */
    int width;			/* Width in pixels of the whole string, if
				 * known, else -1. Valid during
				 * LayoutDLine(). */
} BaseCharInfo;

static TkTextDispChunk *baseCharChunkPtr = NULL;

#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */

/*
 * Flag values for TextDInfo structures:
 *
 * DINFO_OUT_OF_DATE:		Non-zero means that the DLine structures for
 *				this window are partially or completely out of
 *				date and need to be recomputed.
 * REDRAW_PENDING:		Means that a when-idle handler has been
 *				scheduled to update the display.
 * REDRAW_BORDERS:		Means window border or pad area has
 *				potentially been damaged and must be redrawn.
 * REPICK_NEEDED:		1 means that the widget has been modified in a
 *				way that could change the current character (a
 *				different character might be under the mouse
 *				cursor now). Need to recompute the current
 *				character before the next redisplay.
 */

#define DINFO_OUT_OF_DATE	1
#define REDRAW_PENDING		2
#define REDRAW_BORDERS		4
#define REPICK_NEEDED		8

/*
 * Action values for FreeDLines:
 *
 * DLINE_FREE:		Free the lines, but no need to unlink them from the
 *			current list of actual display lines.
 * DLINE_UNLINK:	Free and unlink from current display.
 * DLINE_FREE_TEMP:	Free, but don't unlink, and also don't set
 *			'dLinesInvalidated'.
 */

#define DLINE_FREE	  0
#define DLINE_UNLINK	  1
#define DLINE_FREE_TEMP	  2

/*
 * The following counters keep statistics about redisplay that can be checked
 * to see how clever this code is at reducing redisplays.
 */

static int numRedisplays;	/* Number of calls to DisplayText. */
static int linesRedrawn;	/* Number of calls to DisplayDLine. */
static int numCopies;		/* Number of calls to XCopyArea to copy part
				 * of the screen. */
static int lineHeightsRecalculated;
				/* Number of line layouts purely for height
				 * calculation purposes.*/
/*
 * Forward declarations for functions defined later in this file:
 */

static void		AdjustForTab(TkText *textPtr,
			    TkTextTabArray *tabArrayPtr, int index,
			    TkTextDispChunk *chunkPtr);
static void		CharBboxProc(TkText *textPtr,
			    TkTextDispChunk *chunkPtr, int index, int y,
			    int lineHeight, int baseline, int *xPtr,
			    int *yPtr, int *widthPtr, int *heightPtr);
static int		CharChunkMeasureChars(TkTextDispChunk *chunkPtr,
			    const char *chars, int charsLen,
			    int start, int end, int startX, int maxX,
			    int flags, int *nextX);
static void		CharDisplayProc(TkText *textPtr,
			    TkTextDispChunk *chunkPtr, int x, int y,
			    int height, int baseline, Display *display,
			    Drawable dst, int screenY);
static int		CharMeasureProc(TkTextDispChunk *chunkPtr, int x);
static void		CharUndisplayProc(TkText *textPtr,
			    TkTextDispChunk *chunkPtr);
#if TK_LAYOUT_WITH_BASE_CHUNKS
static void		FinalizeBaseChunk(TkTextDispChunk *additionalChunkPtr);
static void		FreeBaseChunk(TkTextDispChunk *baseChunkPtr);
static int		IsSameFGStyle(TextStyle *style1, TextStyle *style2);
static void		RemoveFromBaseChunk(TkTextDispChunk *chunkPtr);
#endif
/*
 * Definitions of elided procs. Compiler can't inline these since we use
 * pointers to these functions. ElideDisplayProc and ElideUndisplayProc are
 * special-cased for speed, as potentially many elided DLine chunks if large,
 * tag toggle-filled elided region.
 */
static void		ElideBboxProc(TkText *textPtr,
			    TkTextDispChunk *chunkPtr, int index, int y,
			    int lineHeight, int baseline, int *xPtr,
			    int *yPtr, int *widthPtr, int *heightPtr);
static int		ElideMeasureProc(TkTextDispChunk *chunkPtr, int x);
static void		DisplayDLine(TkText *textPtr, DLine *dlPtr,
			    DLine *prevPtr, Pixmap pixmap);
static void		DisplayLineBackground(TkText *textPtr, DLine *dlPtr,
			    DLine *prevPtr, Pixmap pixmap);
static void		DisplayText(ClientData clientData);
static DLine *		FindDLine(TkText *textPtr, DLine *dlPtr,
                            CONST TkTextIndex *indexPtr);
static void		FreeDLines(TkText *textPtr, DLine *firstPtr,
			    DLine *lastPtr, int action);
static void		FreeStyle(TkText *textPtr, TextStyle *stylePtr);
static TextStyle *	GetStyle(TkText *textPtr, CONST TkTextIndex *indexPtr);
static void		GetXView(Tcl_Interp *interp, TkText *textPtr,
			    int report);
static void		GetYView(Tcl_Interp *interp, TkText *textPtr,
			    int report);
static int		GetYPixelCount(TkText *textPtr, DLine *dlPtr);
static DLine *		LayoutDLine(TkText *textPtr,
			    CONST TkTextIndex *indexPtr);
static int		MeasureChars(Tk_Font tkfont, CONST char *source,
			    int maxBytes, int rangeStart, int rangeLength,
			    int startX, int maxX, int flags, int *nextXPtr);
static void		MeasureUp(TkText *textPtr,
			    CONST TkTextIndex *srcPtr, int distance,
			    TkTextIndex *dstPtr, int *overlap);
static int		NextTabStop(Tk_Font tkfont, int x, int tabOrigin);
static void		UpdateDisplayInfo(TkText *textPtr);
static void		YScrollByLines(TkText *textPtr, int offset);
static void		YScrollByPixels(TkText *textPtr, int offset);
static int		SizeOfTab(TkText *textPtr, int tabStyle,
			    TkTextTabArray *tabArrayPtr, int *indexPtr, int x,
			    int maxX);
static void		TextChanged(TkText *textPtr,
			    CONST TkTextIndex *index1Ptr,
			    CONST TkTextIndex *index2Ptr);
static void		TextInvalidateRegion(TkText *textPtr, TkRegion region);
static void		TextRedrawTag(TkText *textPtr,
			    TkTextIndex *index1Ptr, TkTextIndex *index2Ptr,
			    TkTextTag *tagPtr, int withTag);
static void		TextInvalidateLineMetrics(TkText *textPtr,
			    TkTextLine *linePtr, int lineCount, int action);
static int		CalculateDisplayLineHeight(TkText *textPtr,
			    CONST TkTextIndex *indexPtr, int *byteCountPtr,
			    int *mergedLinePtr);
static void		DlineIndexOfX(TkText *textPtr,
			    DLine *dlPtr, int x, TkTextIndex *indexPtr);
static int		DlineXOfIndex(TkText *textPtr,
			    DLine *dlPtr, int byteIndex);
static int		TextGetScrollInfoObj(Tcl_Interp *interp,
			    TkText *textPtr, int objc,
			    Tcl_Obj *CONST objv[], double *dblPtr,
			    int *intPtr);
static void		AsyncUpdateLineMetrics(ClientData clientData);
static void		AsyncUpdateYScrollbar(ClientData clientData);

/*
 * Result values returned by TextGetScrollInfoObj:
 */

#define TKTEXT_SCROLL_MOVETO	1
#define TKTEXT_SCROLL_PAGES	2
#define TKTEXT_SCROLL_UNITS	3
#define TKTEXT_SCROLL_ERROR	4
#define TKTEXT_SCROLL_PIXELS	5

/*
 *----------------------------------------------------------------------
 *
 * TkTextCreateDInfo --
 *
 *	This function is called when a new text widget is created. Its job is
 *	to set up display-related information for the widget.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	A TextDInfo data structure is allocated and initialized and attached
 *	to textPtr.
 *
 *----------------------------------------------------------------------
 */

void
TkTextCreateDInfo(
    TkText *textPtr)		/* Overall information for text widget. */
{
    register TextDInfo *dInfoPtr;
    XGCValues gcValues;

    dInfoPtr = (TextDInfo *) ckalloc(sizeof(TextDInfo));
    Tcl_InitHashTable(&dInfoPtr->styleTable, sizeof(StyleValues)/sizeof(int));
    dInfoPtr->dLinePtr = NULL;
    dInfoPtr->copyGC = None;
    gcValues.graphics_exposures = True;
    dInfoPtr->scrollGC = Tk_GetGC(textPtr->tkwin, GCGraphicsExposures,
	    &gcValues);
    dInfoPtr->topOfEof = 0;
    dInfoPtr->newXPixelOffset = 0;
    dInfoPtr->curXPixelOffset = 0;
    dInfoPtr->maxLength = 0;
    dInfoPtr->xScrollFirst = -1;
    dInfoPtr->xScrollLast = -1;
    dInfoPtr->yScrollFirst = -1;
    dInfoPtr->yScrollLast = -1;
    dInfoPtr->scanMarkXPixel = 0;
    dInfoPtr->scanMarkX = 0;
    dInfoPtr->scanTotalYScroll = 0;
    dInfoPtr->scanMarkY = 0;
    dInfoPtr->dLinesInvalidated = 0;
    dInfoPtr->flags = DINFO_OUT_OF_DATE;
    dInfoPtr->topPixelOffset = 0;
    dInfoPtr->newTopPixelOffset = 0;
    dInfoPtr->currentMetricUpdateLine = -1;
    dInfoPtr->lastMetricUpdateLine = -1;
    dInfoPtr->lineMetricUpdateEpoch = 1;
    dInfoPtr->metricEpoch = -1;
    dInfoPtr->metricIndex.textPtr = NULL;
    dInfoPtr->metricIndex.linePtr = NULL;

    /*
     * Add a refCount for each of the idle call-backs.
     */

    textPtr->refCount++;
    dInfoPtr->lineUpdateTimer = Tcl_CreateTimerHandler(0,
	    AsyncUpdateLineMetrics, (ClientData) textPtr);
    textPtr->refCount++;
    dInfoPtr->scrollbarTimer = Tcl_CreateTimerHandler(200,
	    AsyncUpdateYScrollbar, (ClientData) textPtr);

    textPtr->dInfoPtr = dInfoPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextFreeDInfo --
 *
 *	This function is called to free up all of the private display
 *	information kept by this file for a text widget.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Lots of resources get freed.
 *
 *----------------------------------------------------------------------
 */

void
TkTextFreeDInfo(
    TkText *textPtr)		/* Overall information for text widget. */
{
    register TextDInfo *dInfoPtr = textPtr->dInfoPtr;

    /*
     * Be careful to free up styleTable *after* freeing up all the DLines, so
     * that the hash table is still intact to free up the style-related
     * information from the lines. Once the lines are all free then styleTable
     * will be empty.
     */

    FreeDLines(textPtr, dInfoPtr->dLinePtr, NULL, DLINE_UNLINK);
    Tcl_DeleteHashTable(&dInfoPtr->styleTable);
    if (dInfoPtr->copyGC != None) {
	Tk_FreeGC(textPtr->display, dInfoPtr->copyGC);
    }
    Tk_FreeGC(textPtr->display, dInfoPtr->scrollGC);
    if (dInfoPtr->flags & REDRAW_PENDING) {
	Tcl_CancelIdleCall(DisplayText, (ClientData) textPtr);
    }
    if (dInfoPtr->lineUpdateTimer != NULL) {
	Tcl_DeleteTimerHandler(dInfoPtr->lineUpdateTimer);
	textPtr->refCount--;
	dInfoPtr->lineUpdateTimer = NULL;
    }
    if (dInfoPtr->scrollbarTimer != NULL) {
	Tcl_DeleteTimerHandler(dInfoPtr->scrollbarTimer);
	textPtr->refCount--;
	dInfoPtr->scrollbarTimer = NULL;
    }
    ckfree((char *) dInfoPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * GetStyle --
 *
 *	This function creates all the information needed to display text at a
 *	particular location.
 *
 * Results:
 *	The return value is a pointer to a TextStyle structure that
 *	corresponds to *sValuePtr.
 *
 * Side effects:
 *	A new entry may be created in the style table for the widget.
 *
 *----------------------------------------------------------------------
 */

static TextStyle *
GetStyle(
    TkText *textPtr,		/* Overall information about text widget. */
    CONST TkTextIndex *indexPtr)/* The character in the text for which display
				 * information is wanted. */
{
    TkTextTag **tagPtrs;
    register TkTextTag *tagPtr;
    StyleValues styleValues;
    TextStyle *stylePtr;
    Tcl_HashEntry *hPtr;
    int numTags, isNew, i;
    XGCValues gcValues;
    unsigned long mask;
    /*
     * The variables below keep track of the highest-priority specification
     * that has occurred for each of the various fields of the StyleValues.
     */
    int borderPrio, borderWidthPrio, reliefPrio, bgStipplePrio;
    int fgPrio, fontPrio, fgStipplePrio;
    int underlinePrio, elidePrio, justifyPrio, offsetPrio;
    int lMargin1Prio, lMargin2Prio, rMarginPrio;
    int spacing1Prio, spacing2Prio, spacing3Prio;
    int overstrikePrio, tabPrio, tabStylePrio, wrapPrio;

    /*
     * Find out what tags are present for the character, then compute a
     * StyleValues structure corresponding to those tags (scan through all of
     * the tags, saving information for the highest-priority tag).
     */

    tagPtrs = TkBTreeGetTags(indexPtr, textPtr, &numTags);
    borderPrio = borderWidthPrio = reliefPrio = bgStipplePrio = -1;
    fgPrio = fontPrio = fgStipplePrio = -1;
    underlinePrio = elidePrio = justifyPrio = offsetPrio = -1;
    lMargin1Prio = lMargin2Prio = rMarginPrio = -1;
    spacing1Prio = spacing2Prio = spacing3Prio = -1;
    overstrikePrio = tabPrio = tabStylePrio = wrapPrio = -1;
    memset(&styleValues, 0, sizeof(StyleValues));
    styleValues.relief = TK_RELIEF_FLAT;
    styleValues.fgColor = textPtr->fgColor;
    styleValues.tkfont = textPtr->tkfont;
    styleValues.justify = TK_JUSTIFY_LEFT;
    styleValues.spacing1 = textPtr->spacing1;
    styleValues.spacing2 = textPtr->spacing2;
    styleValues.spacing3 = textPtr->spacing3;
    styleValues.tabArrayPtr = textPtr->tabArrayPtr;
    styleValues.tabStyle = textPtr->tabStyle;
    styleValues.wrapMode = textPtr->wrapMode;
    styleValues.elide = 0;

    for (i = 0 ; i < numTags; i++) {
	Tk_3DBorder border;

	tagPtr = tagPtrs[i];
	border = tagPtr->border;

	/*
	 * If this is the selection tag, and inactiveSelBorder is NULL (the
	 * default on Windows), then we need to skip it if we don't have the
	 * focus.
	 */

	if ((tagPtr == textPtr->selTagPtr) && !(textPtr->flags & GOT_FOCUS)) {
	    if (textPtr->inactiveSelBorder == NULL
#ifdef MAC_OSX_TK
		    /* Don't show inactive selection in disabled widgets. */
		    || textPtr->state == TK_TEXT_STATE_DISABLED
#endif
	    ) {
		continue;
	    }
	    border = textPtr->inactiveSelBorder;
	}

	if ((border != NULL) && (tagPtr->priority > borderPrio)) {
	    styleValues.border = border;
	    borderPrio = tagPtr->priority;
	}
	if ((tagPtr->borderWidthPtr != NULL)
		&& (Tcl_GetString(tagPtr->borderWidthPtr)[0] != '\0')
		&& (tagPtr->priority > borderWidthPrio)) {
	    styleValues.borderWidth = tagPtr->borderWidth;
	    borderWidthPrio = tagPtr->priority;
	}
	if ((tagPtr->reliefString != NULL)
		&& (tagPtr->priority > reliefPrio)) {
	    if (styleValues.border == NULL) {
		styleValues.border = textPtr->border;
	    }
	    styleValues.relief = tagPtr->relief;
	    reliefPrio = tagPtr->priority;
	}
	if ((tagPtr->bgStipple != None)
		&& (tagPtr->priority > bgStipplePrio)) {
	    styleValues.bgStipple = tagPtr->bgStipple;
	    bgStipplePrio = tagPtr->priority;
	}
	if ((tagPtr->fgColor != None) && (tagPtr->priority > fgPrio)) {
	    styleValues.fgColor = tagPtr->fgColor;
	    fgPrio = tagPtr->priority;
	}
	if ((tagPtr->tkfont != None) && (tagPtr->priority > fontPrio)) {
	    styleValues.tkfont = tagPtr->tkfont;
	    fontPrio = tagPtr->priority;
	}
	if ((tagPtr->fgStipple != None)
		&& (tagPtr->priority > fgStipplePrio)) {
	    styleValues.fgStipple = tagPtr->fgStipple;
	    fgStipplePrio = tagPtr->priority;
	}
	if ((tagPtr->justifyString != NULL)
		&& (tagPtr->priority > justifyPrio)) {
	    styleValues.justify = tagPtr->justify;
	    justifyPrio = tagPtr->priority;
	}
	if ((tagPtr->lMargin1String != NULL)
		&& (tagPtr->priority > lMargin1Prio)) {
	    styleValues.lMargin1 = tagPtr->lMargin1;
	    lMargin1Prio = tagPtr->priority;
	}
	if ((tagPtr->lMargin2String != NULL)
		&& (tagPtr->priority > lMargin2Prio)) {
	    styleValues.lMargin2 = tagPtr->lMargin2;
	    lMargin2Prio = tagPtr->priority;
	}
	if ((tagPtr->offsetString != NULL)
		&& (tagPtr->priority > offsetPrio)) {
	    styleValues.offset = tagPtr->offset;
	    offsetPrio = tagPtr->priority;
	}
	if ((tagPtr->overstrikeString != NULL)
		&& (tagPtr->priority > overstrikePrio)) {
	    styleValues.overstrike = tagPtr->overstrike;
	    overstrikePrio = tagPtr->priority;
	}
	if ((tagPtr->rMarginString != NULL)
		&& (tagPtr->priority > rMarginPrio)) {
	    styleValues.rMargin = tagPtr->rMargin;
	    rMarginPrio = tagPtr->priority;
	}
	if ((tagPtr->spacing1String != NULL)
		&& (tagPtr->priority > spacing1Prio)) {
	    styleValues.spacing1 = tagPtr->spacing1;
	    spacing1Prio = tagPtr->priority;
	}
	if ((tagPtr->spacing2String != NULL)
		&& (tagPtr->priority > spacing2Prio)) {
	    styleValues.spacing2 = tagPtr->spacing2;
	    spacing2Prio = tagPtr->priority;
	}
	if ((tagPtr->spacing3String != NULL)
		&& (tagPtr->priority > spacing3Prio)) {
	    styleValues.spacing3 = tagPtr->spacing3;
	    spacing3Prio = tagPtr->priority;
	}
	if ((tagPtr->tabStringPtr != NULL)
		&& (tagPtr->priority > tabPrio)) {
	    styleValues.tabArrayPtr = tagPtr->tabArrayPtr;
	    tabPrio = tagPtr->priority;
	}
	if ((tagPtr->tabStyle != TK_TEXT_TABSTYLE_NONE)
		&& (tagPtr->priority > tabStylePrio)) {
	    styleValues.tabStyle = tagPtr->tabStyle;
	    tabStylePrio = tagPtr->priority;
	}
	if ((tagPtr->underlineString != NULL)
		&& (tagPtr->priority > underlinePrio)) {
	    styleValues.underline = tagPtr->underline;
	    underlinePrio = tagPtr->priority;
	}
	if ((tagPtr->elideString != NULL)
		&& (tagPtr->priority > elidePrio)) {
	    styleValues.elide = tagPtr->elide;
	    elidePrio = tagPtr->priority;
	}
	if ((tagPtr->wrapMode != TEXT_WRAPMODE_NULL)
		&& (tagPtr->priority > wrapPrio)) {
	    styleValues.wrapMode = tagPtr->wrapMode;
	    wrapPrio = tagPtr->priority;
	}
    }
    if (tagPtrs != NULL) {
	ckfree((char *) tagPtrs);
    }

    /*
     * Use an existing style if there's one around that matches.
     */

    hPtr = Tcl_CreateHashEntry(&textPtr->dInfoPtr->styleTable,
	    (char *) &styleValues, &isNew);
    if (!isNew) {
	stylePtr = (TextStyle *) Tcl_GetHashValue(hPtr);
	stylePtr->refCount++;
	return stylePtr;
    }

    /*
     * No existing style matched. Make a new one.
     */

    stylePtr = (TextStyle *) ckalloc(sizeof(TextStyle));
    stylePtr->refCount = 1;
    if (styleValues.border != NULL) {
	gcValues.foreground = Tk_3DBorderColor(styleValues.border)->pixel;
	mask = GCForeground;
	if (styleValues.bgStipple != None) {
	    gcValues.stipple = styleValues.bgStipple;
	    gcValues.fill_style = FillStippled;
	    mask |= GCStipple|GCFillStyle;
	}
	stylePtr->bgGC = Tk_GetGC(textPtr->tkwin, mask, &gcValues);
    } else {
	stylePtr->bgGC = None;
    }
    mask = GCFont;
    gcValues.font = Tk_FontId(styleValues.tkfont);
    mask |= GCForeground;
    gcValues.foreground = styleValues.fgColor->pixel;
    if (styleValues.fgStipple != None) {
	gcValues.stipple = styleValues.fgStipple;
	gcValues.fill_style = FillStippled;
	mask |= GCStipple|GCFillStyle;
    }
    stylePtr->fgGC = Tk_GetGC(textPtr->tkwin, mask, &gcValues);
    stylePtr->sValuePtr = (StyleValues *)
	    Tcl_GetHashKey(&textPtr->dInfoPtr->styleTable, hPtr);
    stylePtr->hPtr = hPtr;
    Tcl_SetHashValue(hPtr, stylePtr);
    return stylePtr;
}

/*
 *----------------------------------------------------------------------
 *
 * FreeStyle --
 *
 *	This function is called when a TextStyle structure is no longer
 *	needed. It decrements the reference count and frees up the space for
 *	the style structure if the reference count is 0.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The storage and other resources associated with the style are freed up
 *	if no-one's still using it.
 *
 *----------------------------------------------------------------------
 */

static void
FreeStyle(
    TkText *textPtr,		/* Information about overall widget. */
    register TextStyle *stylePtr)
				/* Information about style to free. */
{
    stylePtr->refCount--;
    if (stylePtr->refCount == 0) {
	if (stylePtr->bgGC != None) {
	    Tk_FreeGC(textPtr->display, stylePtr->bgGC);
	}
	if (stylePtr->fgGC != None) {
	    Tk_FreeGC(textPtr->display, stylePtr->fgGC);
	}
	Tcl_DeleteHashEntry(stylePtr->hPtr);
	ckfree((char *) stylePtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * LayoutDLine --
 *
 *	This function generates a single DLine structure for a display line
 *	whose leftmost character is given by indexPtr.
 *
 * Results:
 *	The return value is a pointer to a DLine structure describing the
 *	display line. All fields are filled in and correct except for y and
 *	nextPtr.
 *
 * Side effects:
 *	Storage is allocated for the new DLine.
 *
 *	See the comments in 'GetYView' for some thoughts on what the side-
 *	effects of this call (or its callers) should be; the synchronisation
 *	of TkTextLine->pixelHeight with the sum of the results of this
 *	function operating on all display lines within each logical line.
 *	Ideally the code should be refactored to ensure the cached pixel
 *	height is never behind what is known when this function is called
 *	elsewhere.
 *
 *	Unfortunately, this function is currently called from many different
 *	places, not just to layout a display line for actual display, but also
 *	simply to calculate some metric or other of one or more display lines
 *	(typically the height). It would be a good idea to do some profiling
 *	of typical text widget usage and the way in which this is called and
 *	see if some optimization could or should be done.
 *
 *----------------------------------------------------------------------
 */

static DLine *
LayoutDLine(
    TkText *textPtr,		/* Overall information about text widget. */
    CONST TkTextIndex *indexPtr)/* Beginning of display line. May not
				 * necessarily point to a character
				 * segment. */
{
    register DLine *dlPtr;	/* New display line. */
    TkTextSegment *segPtr;	/* Current segment in text. */
    TkTextDispChunk *lastChunkPtr;
				/* Last chunk allocated so far for line. */
    TkTextDispChunk *chunkPtr;	/* Current chunk. */
    TkTextIndex curIndex;
    TkTextDispChunk *breakChunkPtr;
				/* Chunk containing best word break point, if
				 * any. */
    TkTextIndex breakIndex;	/* Index of first character in
				 * breakChunkPtr. */
    int breakByteOffset;	/* Byte offset of character within
				 * breakChunkPtr just to right of best break
				 * point. */
    int noCharsYet;		/* Non-zero means that no characters have been
				 * placed on the line yet. */
    int paragraphStart;		/* Non-zero means that we are on the first
				 * line of a paragraph (used to choose between
				 * lmargin1, lmargin2). */
    int justify;		/* How to justify line: taken from style for
				 * the first character in line. */
    int jIndent;		/* Additional indentation (beyond margins) due
				 * to justification. */
    int rMargin;		/* Right margin width for line. */
    TkWrapMode wrapMode;	/* Wrap mode to use for this line. */
    int x = 0, maxX = 0;	/* Initializations needed only to stop
				 * compiler warnings. */
    int wholeLine;		/* Non-zero means this display line runs to
				 * the end of the text line. */
    int tabIndex;		/* Index of the current tab stop. */
    int gotTab;			/* Non-zero means the current chunk contains a
				 * tab. */
    TkTextDispChunk *tabChunkPtr;
				/* Pointer to the chunk containing the
				 * previous tab stop. */
    int maxBytes;		/* Maximum number of bytes to include in this
				 * chunk. */
    TkTextTabArray *tabArrayPtr;/* Tab stops for line; taken from style for
				 * the first character on line. */
    int tabStyle;		/* One of TABULAR or WORDPROCESSOR. */
    int tabSize;		/* Number of pixels consumed by current tab
				 * stop. */
    TkTextDispChunk *lastCharChunkPtr;
				/* Pointer to last chunk in display lines with
				 * numBytes > 0. Used to drop 0-sized chunks
				 * from the end of the line. */
    int byteOffset, ascent, descent, code, elide, elidesize;
    StyleValues *sValuePtr;
    TkTextElideInfo info;	/* Keep track of elide state. */

    /*
     * Create and initialize a new DLine structure.
     */

    dlPtr = (DLine *) ckalloc(sizeof(DLine));
    dlPtr->index = *indexPtr;
    dlPtr->byteCount = 0;
    dlPtr->y = 0;
    dlPtr->oldY = 0;		/* Only set to avoid compiler warnings. */
    dlPtr->height = 0;
    dlPtr->baseline = 0;
    dlPtr->chunkPtr = NULL;
    dlPtr->nextPtr = NULL;
    dlPtr->flags = NEW_LAYOUT | OLD_Y_INVALID;
    dlPtr->logicalLinesMerged = 0;

    /*
     * This is not necessarily totally correct, where we have merged logical
     * lines. Fixing this would require a quite significant overhaul, though,
     * so currently we make do with this.
     */

    paragraphStart = (indexPtr->byteIndex == 0);

    /*
     * Special case entirely elide line as there may be 1000s or more.
     */

    elide = TkTextIsElided(textPtr, indexPtr, &info);
    if (elide && indexPtr->byteIndex == 0) {
	maxBytes = 0;
	for (segPtr = info.segPtr; segPtr != NULL; segPtr = segPtr->nextPtr) {
	    if (segPtr->size > 0) {
		if (elide == 0) {
		    /*
		     * We toggled a tag and the elide state changed to
		     * visible, and we have something of non-zero size.
		     * Therefore we must bail out.
		     */

		    break;
		}
		maxBytes += segPtr->size;

		/*
		 * Reset tag elide priority, since we're on a new character.
		 */

	    } else if ((segPtr->typePtr == &tkTextToggleOffType)
		    || (segPtr->typePtr == &tkTextToggleOnType)) {
		TkTextTag *tagPtr = segPtr->body.toggle.tagPtr;

		/*
		 * The elide state only changes if this tag is either the
		 * current highest priority tag (and is therefore being
		 * toggled off), or it's a new tag with higher priority.
		 */

		if (tagPtr->elideString != NULL) {
		    info.tagCnts[tagPtr->priority]++;
		    if (info.tagCnts[tagPtr->priority] & 1) {
			info.tagPtrs[tagPtr->priority] = tagPtr;
		    }
		    if (tagPtr->priority >= info.elidePriority) {
			if (segPtr->typePtr == &tkTextToggleOffType) {
			    /*
			     * If it is being toggled off, and it has an elide
			     * string, it must actually be the current highest
			     * priority tag, so this check is redundant:
			     */

			    if (tagPtr->priority != info.elidePriority) {
				Tcl_Panic("Bad tag priority being toggled off");
			    }

			    /*
			     * Find previous elide tag, if any (if not then
			     * elide will be zero, of course).
			     */

			    elide = 0;
			    while (--info.elidePriority > 0) {
				if (info.tagCnts[info.elidePriority] & 1) {
				    elide = info.tagPtrs[info.elidePriority]
					    ->elide;
				    break;
				}
			    }
			} else {
			    elide = tagPtr->elide;
			    info.elidePriority = tagPtr->priority;
			}
		    }
		}
	    }
	}

	if (elide) {
	    dlPtr->byteCount = maxBytes;
	    dlPtr->spaceAbove = dlPtr->spaceBelow = dlPtr->length = 0;
	    if (dlPtr->index.byteIndex == 0) {
		/*
		 * Elided state goes from beginning to end of an entire
		 * logical line. This means we can update the line's pixel
		 * height, and bring its pixel calculation up to date.
		 */

		TkBTreeLinePixelEpoch(textPtr, dlPtr->index.linePtr)
			= textPtr->dInfoPtr->lineMetricUpdateEpoch;

		if (TkBTreeLinePixelCount(textPtr,dlPtr->index.linePtr) != 0) {
		    TkBTreeAdjustPixelHeight(textPtr,
			    dlPtr->index.linePtr, 0, 0);
		}
	    }
	    TkTextFreeElideInfo(&info);
	    return dlPtr;
	}
    }
    TkTextFreeElideInfo(&info);

    /*
     * Each iteration of the loop below creates one TkTextDispChunk for the
     * new display line. The line will always have at least one chunk (for the
     * newline character at the end, if there's nothing else available).
     */

    curIndex = *indexPtr;
    lastChunkPtr = NULL;
    chunkPtr = NULL;
    noCharsYet = 1;
    elide = 0;
    breakChunkPtr = NULL;
    breakByteOffset = 0;
    justify = TK_JUSTIFY_LEFT;
    tabIndex = -1;
    tabChunkPtr = NULL;
    tabArrayPtr = NULL;
    tabStyle = TK_TEXT_TABSTYLE_TABULAR;
    rMargin = 0;
    wrapMode = TEXT_WRAPMODE_CHAR;
    tabSize = 0;
    lastCharChunkPtr = NULL;

    /*
     * Find the first segment to consider for the line. Can't call
     * TkTextIndexToSeg for this because it won't return a segment with zero
     * size (such as the insertion cursor's mark).
     */

  connectNextLogicalLine:
    byteOffset = curIndex.byteIndex;
    segPtr = curIndex.linePtr->segPtr;
    while ((byteOffset > 0) && (byteOffset >= segPtr->size)) {
	byteOffset -= segPtr->size;
	segPtr = segPtr->nextPtr;

	if (segPtr == NULL) {
	    /*
	     * Two logical lines merged into one display line through eliding
	     * of a newline.
	     */

	    TkTextLine *linePtr = TkBTreeNextLine(NULL, curIndex.linePtr);
	    if (linePtr != NULL) {
		dlPtr->logicalLinesMerged++;
		curIndex.byteIndex = 0;
		curIndex.linePtr = linePtr;
		segPtr = curIndex.linePtr->segPtr;
	    } else {
		break;
	    }
	}
    }

    while (segPtr != NULL) {
	/*
	 * Every logical line still gets at least one chunk due to
	 * expectations in the rest of the code, but we are able to skip
	 * elided portions of the line quickly.
	 *
	 * If current chunk is elided and last chunk was too, coalese.
	 *
	 * This also means that each logical line which is entirely elided
	 * still gets laid out into a DLine, but with zero height. This isn't
	 * particularly a problem, but it does seem somewhat unnecessary. We
	 * may wish to redesign the code to remove these zero height DLines in
	 * the future.
	 */

	if (elide && (lastChunkPtr != NULL)
		&& (lastChunkPtr->displayProc == NULL /*ElideDisplayProc*/)) {
	    elidesize = segPtr->size - byteOffset;
	    if (elidesize > 0) {
		curIndex.byteIndex += elidesize;
		lastChunkPtr->numBytes += elidesize;
		breakByteOffset = lastChunkPtr->breakIndex
			= lastChunkPtr->numBytes;

		/*
		 * If have we have a tag toggle, there is a chance that
		 * invisibility state changed, so bail out.
		 */
	    } else if ((segPtr->typePtr == &tkTextToggleOffType)
		    || (segPtr->typePtr == &tkTextToggleOnType)) {
		if (segPtr->body.toggle.tagPtr->elideString != NULL) {
		    elide = (segPtr->typePtr == &tkTextToggleOffType)
			    ^ segPtr->body.toggle.tagPtr->elide;
		}
	    }

	    byteOffset = 0;
	    segPtr = segPtr->nextPtr;

	    if (segPtr == NULL) {
		/*
		 * Two logical lines merged into one display line through
		 * eliding of a newline.
		 */

		TkTextLine *linePtr = TkBTreeNextLine(NULL, curIndex.linePtr);

		if (linePtr != NULL) {
		    dlPtr->logicalLinesMerged++;
		    curIndex.byteIndex = 0;
		    curIndex.linePtr = linePtr;
		    goto connectNextLogicalLine;
		}
	    }

	    /*
	     * Code no longer needed, now that we allow logical lines to merge
	     * into a single display line.
	     *
	    if (segPtr == NULL && chunkPtr != NULL) {
		ckfree((char *) chunkPtr);
		chunkPtr = NULL;
	    }
	     */

	    continue;
	}

	if (segPtr->typePtr->layoutProc == NULL) {
	    segPtr = segPtr->nextPtr;
	    byteOffset = 0;
	    continue;
	}
	if (chunkPtr == NULL) {
	    chunkPtr = (TkTextDispChunk *) ckalloc(sizeof(TkTextDispChunk));
	    chunkPtr->nextPtr = NULL;
	    chunkPtr->clientData = NULL;
	}
	chunkPtr->stylePtr = GetStyle(textPtr, &curIndex);
	elide = chunkPtr->stylePtr->sValuePtr->elide;

	/*
	 * Save style information such as justification and indentation, up
	 * until the first character is encountered, then retain that
	 * information for the rest of the line.
	 */

	if (!elide && noCharsYet) {
	    tabArrayPtr = chunkPtr->stylePtr->sValuePtr->tabArrayPtr;
	    tabStyle = chunkPtr->stylePtr->sValuePtr->tabStyle;
	    justify = chunkPtr->stylePtr->sValuePtr->justify;
	    rMargin = chunkPtr->stylePtr->sValuePtr->rMargin;
	    wrapMode = chunkPtr->stylePtr->sValuePtr->wrapMode;

	    /*
	     * See above - this test may not be entirely correct where we have
	     * partially elided lines (and therefore merged logical lines).
	     * In such a case a byteIndex of zero doesn't necessarily mean the
	     * beginning of a logical line.
	     */

	    if (paragraphStart) {
		/*
		 * Beginning of logical line.
		 */

		x = chunkPtr->stylePtr->sValuePtr->lMargin1;
	    } else {
		/*
		 * Beginning of display line.
		 */

		x = chunkPtr->stylePtr->sValuePtr->lMargin2;
	    }
	    if (wrapMode == TEXT_WRAPMODE_NONE) {
		maxX = -1;
	    } else {
		maxX = textPtr->dInfoPtr->maxX - textPtr->dInfoPtr->x
			- rMargin;
		if (maxX < x) {
		    maxX = x;
		}
	    }
	}

	gotTab = 0;
	maxBytes = segPtr->size - byteOffset;
	if (segPtr->typePtr == &tkTextCharType) {

	    /*
	     * See if there is a tab in the current chunk; if so, only layout
	     * characters up to (and including) the tab.
	     */

	    if (!elide && justify == TK_JUSTIFY_LEFT) {
		char *p;

		for (p = segPtr->body.chars + byteOffset; *p != 0; p++) {
		    if (*p == '\t') {
			maxBytes = (p + 1 - segPtr->body.chars) - byteOffset;
			gotTab = 1;
			break;
		    }
		}
	    }

#if TK_LAYOUT_WITH_BASE_CHUNKS
	    if (baseCharChunkPtr != NULL) {
		int expectedX =
			((BaseCharInfo *) baseCharChunkPtr->clientData)->width
			+ baseCharChunkPtr->x;

		if ((expectedX != x) || !IsSameFGStyle(
			baseCharChunkPtr->stylePtr, chunkPtr->stylePtr)) {
		    FinalizeBaseChunk(NULL);
		}
	    }
#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */
	}
	chunkPtr->x = x;
	if (elide /*&& maxBytes*/) {
	    /*
	     * Don't free style here, as other code expects to be able to do
	     * that.
	     */

	    /* breakByteOffset =*/
	    chunkPtr->breakIndex = chunkPtr->numBytes = maxBytes;
	    chunkPtr->width = 0;
	    chunkPtr->minAscent = chunkPtr->minDescent
		    = chunkPtr->minHeight = 0;

	    /*
	     * Would just like to point to canonical empty chunk.
	     */

	    chunkPtr->displayProc = NULL;
	    chunkPtr->undisplayProc = NULL;
	    chunkPtr->measureProc = ElideMeasureProc;
	    chunkPtr->bboxProc = ElideBboxProc;

	    code = 1;
	} else {
	    code = (*segPtr->typePtr->layoutProc)(textPtr, &curIndex, segPtr,
		    byteOffset, maxX-tabSize, maxBytes, noCharsYet, wrapMode,
		    chunkPtr);
	}
	if (code <= 0) {
	    FreeStyle(textPtr, chunkPtr->stylePtr);
	    if (code < 0) {
		/*
		 * This segment doesn't wish to display itself (e.g. most
		 * marks).
		 */

		segPtr = segPtr->nextPtr;
		byteOffset = 0;
		continue;
	    }

	    /*
	     * No characters from this segment fit in the window: this means
	     * we're at the end of the display line.
	     */

	    if (chunkPtr != NULL) {
		ckfree((char *) chunkPtr);
	    }
	    break;
	}

	/*
	 * We currently say we have some characters (and therefore something
	 * from which to examine tag values for the first character of the
	 * line) even if those characters are actually elided. This behaviour
	 * is not well documented, and it might be more consistent to
	 * completely ignore such elided characters and their tags. To do so
	 * change this to:
	 *
	 * if (!elide && chunkPtr->numBytes > 0).
	 */

	if (!elide && chunkPtr->numBytes > 0) {
	    noCharsYet = 0;
	    lastCharChunkPtr = chunkPtr;
	}
	if (lastChunkPtr == NULL) {
	    dlPtr->chunkPtr = chunkPtr;
	} else {
	    lastChunkPtr->nextPtr = chunkPtr;
	}
	lastChunkPtr = chunkPtr;
	x += chunkPtr->width;
	if (chunkPtr->breakIndex > 0) {
	    breakByteOffset = chunkPtr->breakIndex;
	    breakIndex = curIndex;
	    breakChunkPtr = chunkPtr;
	}
	if (chunkPtr->numBytes != maxBytes) {
	    break;
	}

	/*
	 * If we're at a new tab, adjust the layout for all the chunks
	 * pertaining to the previous tab. Also adjust the amount of space
	 * left in the line to account for space that will be eaten up by the
	 * tab.
	 */

	if (gotTab) {
	    if (tabIndex >= 0) {
		AdjustForTab(textPtr, tabArrayPtr, tabIndex, tabChunkPtr);
		x = chunkPtr->x + chunkPtr->width;
	    }
	    tabChunkPtr = chunkPtr;
	    tabSize = SizeOfTab(textPtr, tabStyle, tabArrayPtr, &tabIndex, x,
		    maxX);
	    if ((maxX >= 0) && (tabSize >= maxX - x)) {
		break;
	    }
	}
	curIndex.byteIndex += chunkPtr->numBytes;
	byteOffset += chunkPtr->numBytes;
	if (byteOffset >= segPtr->size) {
	    byteOffset = 0;
	    segPtr = segPtr->nextPtr;
	    if (elide && segPtr == NULL) {
		/*
		 * An elided section started on this line, and carries on
		 * until the newline. Hence the newline is actually elided,
		 * and we want to merge the display of the next logical line
		 * with this one.
		 */

		TkTextLine *linePtr = TkBTreeNextLine(NULL, curIndex.linePtr);

		if (linePtr != NULL) {
		    dlPtr->logicalLinesMerged++;
		    curIndex.byteIndex = 0;
		    curIndex.linePtr = linePtr;
		    chunkPtr = NULL;
		    goto connectNextLogicalLine;
		}
	    }
	}

	chunkPtr = NULL;
    }
#if TK_LAYOUT_WITH_BASE_CHUNKS
    FinalizeBaseChunk(NULL);
#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */
    if (noCharsYet) {
	dlPtr->spaceAbove = 0;
	dlPtr->spaceBelow = 0;
	dlPtr->length = 0;

	/*
	 * We used to Tcl_Panic here, saying that LayoutDLine couldn't place
	 * any characters on a line, but I believe a more appropriate response
	 * is to return a DLine with zero height. With elided lines, tag
	 * transitions and asynchronous line height calculations, it is hard
	 * to avoid this situation ever arising with the current code design.
	 */

	return dlPtr;
    }
    wholeLine = (segPtr == NULL);

    /*
     * We're at the end of the display line. Throw away everything after the
     * most recent word break, if there is one; this may potentially require
     * the last chunk to be layed out again.
     */

    if (breakChunkPtr == NULL) {
	/*
	 * This code makes sure that we don't accidentally display chunks with
	 * no characters at the end of the line (such as the insertion
	 * cursor). These chunks belong on the next line. So, throw away
	 * everything after the last chunk that has characters in it.
	 */

	breakChunkPtr = lastCharChunkPtr;
	breakByteOffset = breakChunkPtr->numBytes;
    }
    if ((breakChunkPtr != NULL) && ((lastChunkPtr != breakChunkPtr)
	    || (breakByteOffset != lastChunkPtr->numBytes))) {
	while (1) {
	    chunkPtr = breakChunkPtr->nextPtr;
	    if (chunkPtr == NULL) {
		break;
	    }
	    FreeStyle(textPtr, chunkPtr->stylePtr);
	    breakChunkPtr->nextPtr = chunkPtr->nextPtr;
	    if (chunkPtr->undisplayProc != NULL) {
		(*chunkPtr->undisplayProc)(textPtr, chunkPtr);
	    }
	    ckfree((char *) chunkPtr);
	}
	if (breakByteOffset != breakChunkPtr->numBytes) {
	    if (breakChunkPtr->undisplayProc != NULL) {
		(*breakChunkPtr->undisplayProc)(textPtr, breakChunkPtr);
	    }
	    segPtr = TkTextIndexToSeg(&breakIndex, &byteOffset);
	    (*segPtr->typePtr->layoutProc)(textPtr, &breakIndex,
		    segPtr, byteOffset, maxX, breakByteOffset, 0,
		    wrapMode, breakChunkPtr);
#if TK_LAYOUT_WITH_BASE_CHUNKS
	    FinalizeBaseChunk(NULL);
#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */
	}
	lastChunkPtr = breakChunkPtr;
	wholeLine = 0;
    }

    /*
     * Make tab adjustments for the last tab stop, if there is one.
     */

    if ((tabIndex >= 0) && (tabChunkPtr != NULL)) {
	AdjustForTab(textPtr, tabArrayPtr, tabIndex, tabChunkPtr);
    }

    /*
     * Make one more pass over the line to recompute various things like its
     * height, length, and total number of bytes. Also modify the x-locations
     * of chunks to reflect justification. If we're not wrapping, I'm not sure
     * what is the best way to handle left and center justification: should
     * the total length, for purposes of justification, be (a) the window
     * width, (b) the length of the longest line in the window, or (c) the
     * length of the longest line in the text? (c) isn't available, (b) seems
     * weird, since it can change with vertical scrolling, so (a) is what is
     * implemented below.
     */

    if (wrapMode == TEXT_WRAPMODE_NONE) {
	maxX = textPtr->dInfoPtr->maxX - textPtr->dInfoPtr->x - rMargin;
    }
    dlPtr->length = lastChunkPtr->x + lastChunkPtr->width;
    if (justify == TK_JUSTIFY_LEFT) {
	jIndent = 0;
    } else if (justify == TK_JUSTIFY_RIGHT) {
	jIndent = maxX - dlPtr->length;
    } else {
	jIndent = (maxX - dlPtr->length)/2;
    }
    ascent = descent = 0;
    for (chunkPtr = dlPtr->chunkPtr; chunkPtr != NULL;
	    chunkPtr = chunkPtr->nextPtr) {
	chunkPtr->x += jIndent;
	dlPtr->byteCount += chunkPtr->numBytes;
	if (chunkPtr->minAscent > ascent) {
	    ascent = chunkPtr->minAscent;
	}
	if (chunkPtr->minDescent > descent) {
	    descent = chunkPtr->minDescent;
	}
	if (chunkPtr->minHeight > dlPtr->height) {
	    dlPtr->height = chunkPtr->minHeight;
	}
	sValuePtr = chunkPtr->stylePtr->sValuePtr;
	if ((sValuePtr->borderWidth > 0)
		&& (sValuePtr->relief != TK_RELIEF_FLAT)) {
	    dlPtr->flags |= HAS_3D_BORDER;
	}
    }
    if (dlPtr->height < (ascent + descent)) {
	dlPtr->height = ascent + descent;
	dlPtr->baseline = ascent;
    } else {
	dlPtr->baseline = ascent + (dlPtr->height - ascent - descent)/2;
    }
    sValuePtr = dlPtr->chunkPtr->stylePtr->sValuePtr;
    if (dlPtr->index.byteIndex == 0) {
	dlPtr->spaceAbove = sValuePtr->spacing1;
    } else {
	dlPtr->spaceAbove = sValuePtr->spacing2 - sValuePtr->spacing2/2;
    }
    if (wholeLine) {
	dlPtr->spaceBelow = sValuePtr->spacing3;
    } else {
	dlPtr->spaceBelow = sValuePtr->spacing2/2;
    }
    dlPtr->height += dlPtr->spaceAbove + dlPtr->spaceBelow;
    dlPtr->baseline += dlPtr->spaceAbove;

    /*
     * Recompute line length: may have changed because of justification.
     */

    dlPtr->length = lastChunkPtr->x + lastChunkPtr->width;

    return dlPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * UpdateDisplayInfo --
 *
 *	This function is invoked to recompute some or all of the DLine
 *	structures for a text widget. At the time it is called the DLine
 *	structures still left in the widget are guaranteed to be correct
 *	except that (a) the y-coordinates aren't necessarily correct, (b)
 *	there may be missing structures (the DLine structures get removed as
 *	soon as they are potentially out-of-date), and (c) DLine structures
 *	that don't start at the beginning of a line may be incorrect if
 *	previous information in the same line changed size in a way that moved
 *	a line boundary (DLines for any info that changed will have been
 *	deleted, but not DLines for unchanged info in the same text line).
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Upon return, the DLine information for textPtr correctly reflects the
 *	positions where characters will be displayed. However, this function
 *	doesn't actually bring the display up-to-date.
 *
 *----------------------------------------------------------------------
 */

static void
UpdateDisplayInfo(
    TkText *textPtr)		/* Text widget to update. */
{
    register TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    register DLine *dlPtr, *prevPtr;
    TkTextIndex index;
    TkTextLine *lastLinePtr;
    int y, maxY, xPixelOffset, maxOffset, lineHeight;

    if (!(dInfoPtr->flags & DINFO_OUT_OF_DATE)) {
	return;
    }
    dInfoPtr->flags &= ~DINFO_OUT_OF_DATE;

    /*
     * Delete any DLines that are now above the top of the window.
     */

    index = textPtr->topIndex;
    dlPtr = FindDLine(textPtr, dInfoPtr->dLinePtr, &index);
    if ((dlPtr != NULL) && (dlPtr != dInfoPtr->dLinePtr)) {
	FreeDLines(textPtr, dInfoPtr->dLinePtr, dlPtr, DLINE_UNLINK);
    }
    if (index.byteIndex == 0) {
	lineHeight = 0;
    } else {
	lineHeight = -1;
    }

    /*
     * Scan through the contents of the window from top to bottom, recomputing
     * information for lines that are missing.
     */

    lastLinePtr = TkBTreeFindLine(textPtr->sharedTextPtr->tree, textPtr,
	    TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr));
    dlPtr = dInfoPtr->dLinePtr;
    prevPtr = NULL;
    y = dInfoPtr->y - dInfoPtr->newTopPixelOffset;
    maxY = dInfoPtr->maxY;
    while (1) {
	register DLine *newPtr;

	if (index.linePtr == lastLinePtr) {
	    break;
	}

	/*
	 * There are three possibilities right now:
	 * (a) the next DLine (dlPtr) corresponds exactly to the next
	 *     information we want to display: just use it as-is.
	 * (b) the next DLine corresponds to a different line, or to a segment
	 *     that will be coming later in the same line: leave this DLine
	 *     alone in the hopes that we'll be able to use it later, then
	 *     create a new DLine in front of it.
	 * (c) the next DLine corresponds to a segment in the line we want,
	 *     but it's a segment that has already been processed or will
	 *     never be processed. Delete the DLine and try again.
	 *
	 * One other twist on all this. It's possible for 3D borders to
	 * interact between lines (see DisplayLineBackground) so if a line is
	 * relayed out and has styles with 3D borders, its neighbors have to
	 * be redrawn if they have 3D borders too, since the interactions
	 * could have changed (the neighbors don't have to be relayed out,
	 * just redrawn).
	 */

	if ((dlPtr == NULL) || (dlPtr->index.linePtr != index.linePtr)) {
	    /*
	     * Case (b) -- must make new DLine.
	     */

	makeNewDLine:
	    if (tkTextDebug) {
		char string[TK_POS_CHARS];

		/*
		 * Debugging is enabled, so keep a log of all the lines that
		 * were re-layed out. The test suite uses this information.
		 */

		TkTextPrintIndex(textPtr, &index, string);
		LOG("tk_textRelayout", string);
	    }
	    newPtr = LayoutDLine(textPtr, &index);
	    if (prevPtr == NULL) {
		dInfoPtr->dLinePtr = newPtr;
	    } else {
		prevPtr->nextPtr = newPtr;
		if (prevPtr->flags & HAS_3D_BORDER) {
		    prevPtr->flags |= OLD_Y_INVALID;
		}
	    }
	    newPtr->nextPtr = dlPtr;
	    dlPtr = newPtr;
	} else {
	    /*
	     * DlPtr refers to the line we want. Next check the index within
	     * the line.
	     */

	    if (index.byteIndex == dlPtr->index.byteIndex) {
		/*
		 * Case (a) - can use existing display line as-is.
		 */

		if ((dlPtr->flags & HAS_3D_BORDER) && (prevPtr != NULL)
			&& (prevPtr->flags & (NEW_LAYOUT))) {
		    dlPtr->flags |= OLD_Y_INVALID;
		}
		goto lineOK;
	    }
	    if (index.byteIndex < dlPtr->index.byteIndex) {
		goto makeNewDLine;
	    }

	    /*
	     * Case (c) - dlPtr is useless. Discard it and start again with
	     * the next display line.
	     */

	    newPtr = dlPtr->nextPtr;
	    FreeDLines(textPtr, dlPtr, newPtr, DLINE_FREE);
	    dlPtr = newPtr;
	    if (prevPtr != NULL) {
		prevPtr->nextPtr = newPtr;
	    } else {
		dInfoPtr->dLinePtr = newPtr;
	    }
	    continue;
	}

	/*
	 * Advance to the start of the next line.
	 */

    lineOK:
	dlPtr->y = y;
	y += dlPtr->height;
	if (lineHeight != -1) {
	    lineHeight += dlPtr->height;
	}
	TkTextIndexForwBytes(textPtr, &index, dlPtr->byteCount, &index);
	prevPtr = dlPtr;
	dlPtr = dlPtr->nextPtr;

	/*
	 * If we switched text lines, delete any DLines left for the old text
	 * line.
	 */

	if (index.linePtr != prevPtr->index.linePtr) {
	    register DLine *nextPtr;

	    nextPtr = dlPtr;
	    while ((nextPtr != NULL)
		    && (nextPtr->index.linePtr == prevPtr->index.linePtr)) {
		nextPtr = nextPtr->nextPtr;
	    }
	    if (nextPtr != dlPtr) {
		FreeDLines(textPtr, dlPtr, nextPtr, DLINE_FREE);
		prevPtr->nextPtr = nextPtr;
		dlPtr = nextPtr;
	    }

	    if ((lineHeight != -1) && (TkBTreeLinePixelCount(textPtr,
		    prevPtr->index.linePtr) != lineHeight)) {
		/*
		 * The logical line height we just calculated is actually
		 * different to the currently cached height of the text line.
		 * That is fine (the text line heights are only calculated
		 * asynchronously), but we must update the cached height so
		 * that any counts made with DLine pointers are the same as
		 * counts made through the BTree. This helps to ensure that
		 * the scrollbar size corresponds accurately to that displayed
		 * contents, even as the window is re-sized.
		 */

		TkBTreeAdjustPixelHeight(textPtr, prevPtr->index.linePtr,
			lineHeight, 0);

		/*
		 * I believe we can be 100% sure that we started at the
		 * beginning of the logical line, so we can also adjust the
		 * 'pixelCalculationEpoch' to mark it as being up to date.
		 * There is a slight concern that we might not have got this
		 * right for the first line in the re-display.
		 */

		TkBTreeLinePixelEpoch(textPtr, prevPtr->index.linePtr) =
			dInfoPtr->lineMetricUpdateEpoch;
	    }
	    lineHeight = 0;
	}

	/*
	 * It's important to have the following check here rather than in the
	 * while statement for the loop, so that there's always at least one
	 * DLine generated, regardless of how small the window is. This keeps
	 * a lot of other code from breaking.
	 */

	if (y >= maxY) {
	    break;
	}
    }

    /*
     * Delete any DLine structures that don't fit on the screen.
     */

    FreeDLines(textPtr, dlPtr, NULL, DLINE_UNLINK);

    /*
     * If there is extra space at the bottom of the window (because we've hit
     * the end of the text), then bring in more lines at the top of the
     * window, if there are any, to fill in the view.
     *
     * Since the top line may only be partially visible, we try first to
     * simply show more pixels from that line (newTopPixelOffset). If that
     * isn't enough, we have to layout more lines.
     */

    if (y < maxY) {
	/*
	 * This counts how many vertical pixels we have left to fill by
	 * pulling in more display pixels either from the first currently
	 * displayed, or the lines above it.
	 */

	int spaceLeft = maxY - y;

	if (spaceLeft <= dInfoPtr->newTopPixelOffset) {
	    /*
	     * We can fill up all the needed space just by showing more of the
	     * current top line.
	     */

	    dInfoPtr->newTopPixelOffset -= spaceLeft;
	    y += spaceLeft;
	    spaceLeft = 0;
	} else {
	    int lineNum, bytesToCount;
	    DLine *lowestPtr;

	    /*
	     * Add in all of the current top line, which won't be enough to
	     * bring y up to maxY (if it was we would be in the 'if' block
	     * above).
	     */

	    y += dInfoPtr->newTopPixelOffset;
	    dInfoPtr->newTopPixelOffset = 0;

	    /*
	     * Layout an entire text line (potentially > 1 display line), then
	     * link in as many display lines as fit without moving the bottom
	     * line out of the window. Repeat this until all the extra space
	     * has been used up or we've reached the beginning of the text.
	     */

	    spaceLeft = maxY - y;
	    if (dInfoPtr->dLinePtr == NULL) {
		/*
		 * No lines have been laid out. This must be an empty peer
		 * widget.
		 */

                lineNum = TkBTreeNumLines(textPtr->sharedTextPtr->tree,
                        textPtr) - 1;
                bytesToCount = INT_MAX;
	    } else {
		lineNum = TkBTreeLinesTo(textPtr,
			dInfoPtr->dLinePtr->index.linePtr);
		bytesToCount = dInfoPtr->dLinePtr->index.byteIndex;
		if (bytesToCount == 0) {
		    bytesToCount = INT_MAX;
		    lineNum--;
		}
	    }
	    for ( ; (lineNum >= 0) && (spaceLeft > 0); lineNum--) {
		int pixelHeight = 0;

		index.linePtr = TkBTreeFindLine(textPtr->sharedTextPtr->tree,
			textPtr, lineNum);
		index.byteIndex = 0;
		lowestPtr = NULL;

		do {
		    dlPtr = LayoutDLine(textPtr, &index);
		    pixelHeight += dlPtr->height;
		    dlPtr->nextPtr = lowestPtr;
		    lowestPtr = dlPtr;
		    if (dlPtr->length == 0 && dlPtr->height == 0) {
			bytesToCount--;
			break;
		    }	/* elide */
		    TkTextIndexForwBytes(textPtr, &index, dlPtr->byteCount,
			    &index);
		    bytesToCount -= dlPtr->byteCount;
		} while ((bytesToCount > 0)
			&& (index.linePtr == lowestPtr->index.linePtr));

		/*
		 * We may not have examined the entire line (depending on the
		 * value of 'bytesToCount', so we only want to set this if it
		 * is genuinely bigger).
		 */

		if (pixelHeight > TkBTreeLinePixelCount(textPtr,
			lowestPtr->index.linePtr)) {
		    TkBTreeAdjustPixelHeight(textPtr,
			    lowestPtr->index.linePtr, pixelHeight, 0);
		    if (index.linePtr != lowestPtr->index.linePtr) {
			/*
			 * We examined the entire line, so can update the
			 * epoch.
			 */

			TkBTreeLinePixelEpoch(textPtr,
				lowestPtr->index.linePtr) =
				dInfoPtr->lineMetricUpdateEpoch;
		    }
		}

		/*
		 * Scan through the display lines from the bottom one up to
		 * the top one.
		 */

		while (lowestPtr != NULL) {
		    dlPtr = lowestPtr;
		    spaceLeft -= dlPtr->height;
		    lowestPtr = dlPtr->nextPtr;
		    dlPtr->nextPtr = dInfoPtr->dLinePtr;
		    dInfoPtr->dLinePtr = dlPtr;
		    if (tkTextDebug) {
			char string[TK_POS_CHARS];

			TkTextPrintIndex(textPtr, &dlPtr->index, string);
			LOG("tk_textRelayout", string);
		    }
		    if (spaceLeft <= 0) {
			break;
		    }
		}
		FreeDLines(textPtr, lowestPtr, NULL, DLINE_FREE);
		bytesToCount = INT_MAX;
	    }

	    /*
	     * We've either filled in the space we wanted to or we've run out
	     * of display lines at the top of the text. Note that we already
	     * set dInfoPtr->newTopPixelOffset to zero above.
	     */

	    if (spaceLeft < 0) {
		/*
		 * We've laid out a few too many vertical pixels at or above
		 * the first line. Therefore we only want to show part of the
		 * first displayed line, so that the last displayed line just
		 * fits in the window.
		 */

		dInfoPtr->newTopPixelOffset = -spaceLeft;
		if (dInfoPtr->newTopPixelOffset>=dInfoPtr->dLinePtr->height) {
		    /*
		     * Somehow the entire first line we laid out is shorter
		     * than the new offset. This should not occur and would
		     * indicate a bad problem in the logic above.
		     */

		    Tcl_Panic("Error in pixel height consistency while filling in spacesLeft");
		}
	    }
	}

	/*
	 * Now we're all done except that the y-coordinates in all the DLines
	 * are wrong and the top index for the text is wrong. Update them.
	 */

	if (dInfoPtr->dLinePtr != NULL) {
	    textPtr->topIndex = dInfoPtr->dLinePtr->index;
	    y = dInfoPtr->y - dInfoPtr->newTopPixelOffset;
	    for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL;
		    dlPtr = dlPtr->nextPtr) {
		if (y > dInfoPtr->maxY) {
		    Tcl_Panic("Added too many new lines in UpdateDisplayInfo");
		}
		dlPtr->y = y;
		y += dlPtr->height;
	    }
	}
    }

    /*
     * If the old top or bottom line has scrolled elsewhere on the screen, we
     * may not be able to re-use its old contents by copying bits (e.g., a
     * beveled edge that was drawn when it was at the top or bottom won't be
     * drawn when the line is in the middle and its neighbor has a matching
     * background). Similarly, if the new top or bottom line came from
     * somewhere else on the screen, we may not be able to copy the old bits.
     */

    dlPtr = dInfoPtr->dLinePtr;
    if (dlPtr != NULL) {
	if ((dlPtr->flags & HAS_3D_BORDER) && !(dlPtr->flags & TOP_LINE)) {
	    dlPtr->flags |= OLD_Y_INVALID;
	}
	while (1) {
	    if ((dlPtr->flags & TOP_LINE) && (dlPtr != dInfoPtr->dLinePtr)
		    && (dlPtr->flags & HAS_3D_BORDER)) {
		dlPtr->flags |= OLD_Y_INVALID;
	    }

	    /*
	     * If the old top-line was not completely showing (i.e. the
	     * pixelOffset is non-zero) and is no longer the top-line, then we
	     * must re-draw it.
	     */

	    if ((dlPtr->flags & TOP_LINE) &&
		    dInfoPtr->topPixelOffset!=0 && dlPtr!=dInfoPtr->dLinePtr) {
		dlPtr->flags |= OLD_Y_INVALID;
	    }
	    if ((dlPtr->flags & BOTTOM_LINE) && (dlPtr->nextPtr != NULL)
		    && (dlPtr->flags & HAS_3D_BORDER)) {
		dlPtr->flags |= OLD_Y_INVALID;
	    }
	    if (dlPtr->nextPtr == NULL) {
		if ((dlPtr->flags & HAS_3D_BORDER)
			&& !(dlPtr->flags & BOTTOM_LINE)) {
		    dlPtr->flags |= OLD_Y_INVALID;
		}
		dlPtr->flags &= ~TOP_LINE;
		dlPtr->flags |= BOTTOM_LINE;
		break;
	    }
	    dlPtr->flags &= ~(TOP_LINE|BOTTOM_LINE);
	    dlPtr = dlPtr->nextPtr;
	}
	dInfoPtr->dLinePtr->flags |= TOP_LINE;
	dInfoPtr->topPixelOffset = dInfoPtr->newTopPixelOffset;
    }

    /*
     * Arrange for scrollbars to be updated.
     */

    textPtr->flags |= UPDATE_SCROLLBARS;

    /*
     * Deal with horizontal scrolling:
     * 1. If there's empty space to the right of the longest line, shift the
     *	  screen to the right to fill in the empty space.
     * 2. If the desired horizontal scroll position has changed, force a full
     *	  redisplay of all the lines in the widget.
     * 3. If the wrap mode isn't "none" then re-scroll to the base position.
     */

    dInfoPtr->maxLength = 0;
    for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL;
	    dlPtr = dlPtr->nextPtr) {
	if (dlPtr->length > dInfoPtr->maxLength) {
	    dInfoPtr->maxLength = dlPtr->length;
	}
    }
    maxOffset = dInfoPtr->maxLength - (dInfoPtr->maxX - dInfoPtr->x);

    xPixelOffset = dInfoPtr->newXPixelOffset;
    if (xPixelOffset > maxOffset) {
	xPixelOffset = maxOffset;
    }
    if (xPixelOffset < 0) {
	xPixelOffset = 0;
    }

    /*
     * Here's a problem: see the tests textDisp-29.2.1-4
     *
     * If the widget is being created, but has not yet been configured it will
     * have a maxY of 1 above, and we we won't have examined all the lines
     * (just the first line, in fact), and so maxOffset will not be a true
     * reflection of the widget's lines. Therefore we must not overwrite the
     * original newXPixelOffset in this case.
     */

    if (!(((Tk_FakeWin *) (textPtr->tkwin))->flags & TK_NEED_CONFIG_NOTIFY)) {
	dInfoPtr->newXPixelOffset = xPixelOffset;
    }

    if (xPixelOffset != dInfoPtr->curXPixelOffset) {
	dInfoPtr->curXPixelOffset = xPixelOffset;
	for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL;
		dlPtr = dlPtr->nextPtr) {
	    dlPtr->flags |= OLD_Y_INVALID;
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * FreeDLines --
 *
 *	This function is called to free up all of the resources associated
 *	with one or more DLine structures.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Memory gets freed and various other resources are released.
 *
 *----------------------------------------------------------------------
 */

static void
FreeDLines(
    TkText *textPtr,		/* Information about overall text widget. */
    register DLine *firstPtr,	/* Pointer to first DLine to free up. */
    DLine *lastPtr,		/* Pointer to DLine just after last one to
				 * free (NULL means everything starting with
				 * firstPtr). */
    int action)			/* DLINE_UNLINK means DLines are currently
				 * linked into the list rooted at
				 * textPtr->dInfoPtr->dLinePtr and they have
				 * to be unlinked. DLINE_FREE means just free
				 * without unlinking. DLINE_FREE_TEMP means
				 * the DLine given is just a temporary one and
				 * we shouldn't invalidate anything for the
				 * overall widget. */
{
    register TkTextDispChunk *chunkPtr, *nextChunkPtr;
    register DLine *nextDLinePtr;

    if (action == DLINE_FREE_TEMP) {
	lineHeightsRecalculated++;
	if (tkTextDebug) {
	    char string[TK_POS_CHARS];

	    /*
	     * Debugging is enabled, so keep a log of all the lines whose
	     * height was recalculated. The test suite uses this information.
	     */

	    TkTextPrintIndex(textPtr, &firstPtr->index, string);
	    LOG("tk_textHeightCalc", string);
	}
    } else if (action == DLINE_UNLINK) {
	if (textPtr->dInfoPtr->dLinePtr == firstPtr) {
	    textPtr->dInfoPtr->dLinePtr = lastPtr;
	} else {
	    register DLine *prevPtr;

	    for (prevPtr = textPtr->dInfoPtr->dLinePtr;
		    prevPtr->nextPtr != firstPtr; prevPtr = prevPtr->nextPtr) {
		/* Empty loop body. */
	    }
	    prevPtr->nextPtr = lastPtr;
	}
    }
    while (firstPtr != lastPtr) {
	nextDLinePtr = firstPtr->nextPtr;
	for (chunkPtr = firstPtr->chunkPtr; chunkPtr != NULL;
		chunkPtr = nextChunkPtr) {
	    if (chunkPtr->undisplayProc != NULL) {
		(*chunkPtr->undisplayProc)(textPtr, chunkPtr);
	    }
	    FreeStyle(textPtr, chunkPtr->stylePtr);
	    nextChunkPtr = chunkPtr->nextPtr;
	    ckfree((char *) chunkPtr);
	}
	ckfree((char *) firstPtr);
	firstPtr = nextDLinePtr;
    }
    if (action != DLINE_FREE_TEMP) {
	textPtr->dInfoPtr->dLinesInvalidated = 1;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * DisplayDLine --
 *
 *	This function is invoked to draw a single line on the screen.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The line given by dlPtr is drawn at its correct position in textPtr's
 *	window. Note that this is one *display* line, not one *text* line.
 *
 *----------------------------------------------------------------------
 */

static void
DisplayDLine(
    TkText *textPtr,		/* Text widget in which to draw line. */
    register DLine *dlPtr,	/* Information about line to draw. */
    DLine *prevPtr,		/* Line just before one to draw, or NULL if
				 * dlPtr is the top line. */
    Pixmap pixmap)		/* Pixmap to use for double-buffering. Caller
				 * must make sure it's large enough to hold
				 * line. */
{
    register TkTextDispChunk *chunkPtr;
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    Display *display;
    int height, y_off;
#ifndef TK_NO_DOUBLE_BUFFERING
    const int y = 0;
#else
    const int y = dlPtr->y;
#endif /* TK_NO_DOUBLE_BUFFERING */

    if (dlPtr->chunkPtr == NULL) return;

    display = Tk_Display(textPtr->tkwin);

    height = dlPtr->height;
    if ((height + dlPtr->y) > dInfoPtr->maxY) {
	height = dInfoPtr->maxY - dlPtr->y;
    }
    if (dlPtr->y < dInfoPtr->y) {
	y_off = dInfoPtr->y - dlPtr->y;
	height -= y_off;
    } else {
	y_off = 0;
    }

#ifdef TK_NO_DOUBLE_BUFFERING
    TkpClipDrawableToRect(display, pixmap, dInfoPtr->x, y + y_off,
	    dInfoPtr->maxX - dInfoPtr->x, height);
#endif /* TK_NO_DOUBLE_BUFFERING */

    /*
     * First, clear the area of the line to the background color for the text
     * widget.
     */

    Tk_Fill3DRectangle(textPtr->tkwin, pixmap, textPtr->border, 0, y,
	    Tk_Width(textPtr->tkwin), dlPtr->height, 0, TK_RELIEF_FLAT);

    /*
     * Next, draw background information for the whole line.
     */

    DisplayLineBackground(textPtr, dlPtr, prevPtr, pixmap);

    /*
     * Make another pass through all of the chunks to redraw the insertion
     * cursor, if it is visible on this line. Must do it here rather than in
     * the foreground pass below because otherwise a wide insertion cursor
     * will obscure the character to its left.
     */

    if (textPtr->state == TK_TEXT_STATE_NORMAL) {
	for (chunkPtr = dlPtr->chunkPtr; (chunkPtr != NULL);
		chunkPtr = chunkPtr->nextPtr) {
	    if (chunkPtr->displayProc == TkTextInsertDisplayProc) {
		int x = chunkPtr->x + dInfoPtr->x - dInfoPtr->curXPixelOffset;

		(*chunkPtr->displayProc)(textPtr, chunkPtr, x,
			y + dlPtr->spaceAbove,
			dlPtr->height - dlPtr->spaceAbove - dlPtr->spaceBelow,
			dlPtr->baseline - dlPtr->spaceAbove, display, pixmap,
			dlPtr->y + dlPtr->spaceAbove);
	    }
	}
    }

    /*
     * Make yet another pass through all of the chunks to redraw all of
     * foreground information. Note: we have to call the displayProc even for
     * chunks that are off-screen. This is needed, for example, so that
     * embedded windows can be unmapped in this case.
     */

    for (chunkPtr = dlPtr->chunkPtr; (chunkPtr != NULL);
	    chunkPtr = chunkPtr->nextPtr) {
	if (chunkPtr->displayProc == TkTextInsertDisplayProc) {
	    /*
	     * Already displayed the insertion cursor above. Don't do it again
	     * here.
	     */

	    continue;
	}

	/*
	 * Don't call if elide. This tax OK since not very many visible DLines
	 * in an area, but potentially many elide ones.
	 */

	if (chunkPtr->displayProc != NULL) {
	    int x = chunkPtr->x + dInfoPtr->x - dInfoPtr->curXPixelOffset;

	    if ((x + chunkPtr->width <= 0) || (x >= dInfoPtr->maxX)) {
		/*
		 * Note: we have to call the displayProc even for chunks that
		 * are off-screen. This is needed, for example, so that
		 * embedded windows can be unmapped in this case. Display the
		 * chunk at a coordinate that can be clearly identified by the
		 * displayProc as being off-screen to the left (the
		 * displayProc may not be able to tell if something is off to
		 * the right).
		 */

		x = -chunkPtr->width;
	    }
	    (*chunkPtr->displayProc)(textPtr, chunkPtr, x,
		    y + dlPtr->spaceAbove, dlPtr->height - dlPtr->spaceAbove -
		    dlPtr->spaceBelow, dlPtr->baseline - dlPtr->spaceAbove,
		    display, pixmap, dlPtr->y + dlPtr->spaceAbove);
	}

	if (dInfoPtr->dLinesInvalidated) {
	    return;
	}
    }

#ifndef TK_NO_DOUBLE_BUFFERING
    /*
     * Copy the pixmap onto the screen. If this is the first or last line on
     * the screen then copy a piece of the line, so that it doesn't overflow
     * into the border area. Another special trick: copy the padding area to
     * the left of the line; this is because the insertion cursor sometimes
     * overflows onto that area and we want to get as much of the cursor as
     * possible.
     */

    XCopyArea(display, pixmap, Tk_WindowId(textPtr->tkwin), dInfoPtr->copyGC,
	    dInfoPtr->x, y + y_off, (unsigned) (dInfoPtr->maxX - dInfoPtr->x),
	    (unsigned) height, dInfoPtr->x, dlPtr->y + y_off);
#else
    TkpClipDrawableToRect(display, pixmap, 0, 0, -1, -1);
#endif /* TK_NO_DOUBLE_BUFFERING */
    linesRedrawn++;
}

/*
 *--------------------------------------------------------------
 *
 * DisplayLineBackground --
 *
 *	This function is called to fill in the background for a display line.
 *	It draws 3D borders cleverly so that adjacent chunks with the same
 *	style (whether on the same line or different lines) have a single 3D
 *	border around the whole region.
 *
 * Results:
 *	There is no return value. Pixmap is filled in with background
 *	information for dlPtr.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static void
DisplayLineBackground(
    TkText *textPtr,		/* Text widget containing line. */
    register DLine *dlPtr,	/* Information about line to draw. */
    DLine *prevPtr,		/* Line just above dlPtr, or NULL if dlPtr is
				 * the top-most line in the window. */
    Pixmap pixmap)		/* Pixmap to use for double-buffering. Caller
				 * must make sure it's large enough to hold
				 * line. Caller must also have filled it with
				 * the background color for the widget. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    TkTextDispChunk *chunkPtr;	/* Pointer to chunk in the current line. */
    TkTextDispChunk *chunkPtr2;	/* Pointer to chunk in the line above or below
				 * the current one. NULL if we're to the left
				 * of or to the right of the chunks in the
				 * line. */
    TkTextDispChunk *nextPtr2;	/* Next chunk after chunkPtr2 (it's not the
				 * same as chunkPtr2->nextPtr in the case
				 * where chunkPtr2 is NULL because the line is
				 * indented). */
    int leftX;			/* The left edge of the region we're currently
				 * working on. */
    int leftXIn;		/* 1 means beveled edge at leftX slopes right
				 * as it goes down, 0 means it slopes left as
				 * it goes down. */
    int rightX;			/* Right edge of chunkPtr. */
    int rightX2;		/* Right edge of chunkPtr2. */
    int matchLeft;		/* Does the style of this line match that of
				 * its neighbor just to the left of the
				 * current x coordinate? */
    int matchRight;		/* Does line's style match its neighbor just
				 * to the right of the current x-coord? */
    int minX, maxX, xOffset;
    StyleValues *sValuePtr;
    Display *display;
#ifndef TK_NO_DOUBLE_BUFFERING
    const int y = 0;
#else
    const int y = dlPtr->y;
#endif /* TK_NO_DOUBLE_BUFFERING */

    /*
     * Pass 1: scan through dlPtr from left to right. For each range of chunks
     * with the same style, draw the main background for the style plus the
     * vertical parts of the 3D borders (the left and right edges).
     */

    display = Tk_Display(textPtr->tkwin);
    minX = dInfoPtr->curXPixelOffset;
    xOffset = dInfoPtr->x - minX;
    maxX = minX + dInfoPtr->maxX - dInfoPtr->x;
    chunkPtr = dlPtr->chunkPtr;

    /*
     * Note A: in the following statement, and a few others later in this file
     * marked with "See Note A above", the right side of the assignment was
     * replaced with 0 on 6/18/97. This has the effect of highlighting the
     * empty space to the left of a line whenever the leftmost character of
     * the line is highlighted. This way, multi-line highlights always line up
     * along their left edges. However, this may look funny in the case where
     * a single word is highlighted. To undo the change, replace "leftX = 0"
     * with "leftX = chunkPtr->x" and "rightX2 = 0" with "rightX2 =
     * nextPtr2->x" here and at all the marked points below. This restores the
     * old behavior where empty space to the left of a line is not
     * highlighted, leaving a ragged left edge for multi-line highlights.
     */

    leftX = 0;
    for (; leftX < maxX; chunkPtr = chunkPtr->nextPtr) {
	if ((chunkPtr->nextPtr != NULL)
		&& SAME_BACKGROUND(chunkPtr->nextPtr->stylePtr,
		chunkPtr->stylePtr)) {
	    continue;
	}
	sValuePtr = chunkPtr->stylePtr->sValuePtr;
	rightX = chunkPtr->x + chunkPtr->width;
	if ((chunkPtr->nextPtr == NULL) && (rightX < maxX)) {
	    rightX = maxX;
	}
	if (chunkPtr->stylePtr->bgGC != None) {
	    /*
	     * Not visible - bail out now.
	     */

	    if (rightX + xOffset <= 0) {
		leftX = rightX;
		continue;
	    }

	    /*
	     * Trim the start position for drawing to be no further away than
	     * -borderWidth. The reason is that on many X servers drawing from
	     * -32768 (or less) to +something simply does not display
	     * correctly. [Patch #541999]
	     */

	    if ((leftX + xOffset) < -(sValuePtr->borderWidth)) {
		leftX = -sValuePtr->borderWidth - xOffset;
	    }
	    if ((rightX - leftX) > 32767) {
		rightX = leftX + 32767;
	    }

	    XFillRectangle(display, pixmap, chunkPtr->stylePtr->bgGC,
		    leftX + xOffset, y, (unsigned int) (rightX - leftX),
		    (unsigned int) dlPtr->height);
	    if (sValuePtr->relief != TK_RELIEF_FLAT) {
		Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
			leftX + xOffset, y, sValuePtr->borderWidth,
			dlPtr->height, 1, sValuePtr->relief);
		Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
			rightX - sValuePtr->borderWidth + xOffset,
			y, sValuePtr->borderWidth, dlPtr->height, 0,
			sValuePtr->relief);
	    }
	}
	leftX = rightX;
    }

    /*
     * Pass 2: draw the horizontal bevels along the top of the line. To do
     * this, scan through dlPtr from left to right while simultaneously
     * scanning through the line just above dlPtr. ChunkPtr2 and nextPtr2
     * refer to two adjacent chunks in the line above.
     */

    chunkPtr = dlPtr->chunkPtr;
    leftX = 0;				/* See Note A above. */
    leftXIn = 1;
    rightX = chunkPtr->x + chunkPtr->width;
    if ((chunkPtr->nextPtr == NULL) && (rightX < maxX)) {
	rightX = maxX;
    }
    chunkPtr2 = NULL;
    if (prevPtr != NULL && prevPtr->chunkPtr != NULL) {
	/*
	 * Find the chunk in the previous line that covers leftX.
	 */

	nextPtr2 = prevPtr->chunkPtr;
	rightX2 = 0;			/* See Note A above. */
	while (rightX2 <= leftX) {
	    chunkPtr2 = nextPtr2;
	    if (chunkPtr2 == NULL) {
		break;
	    }
	    nextPtr2 = chunkPtr2->nextPtr;
	    rightX2 = chunkPtr2->x + chunkPtr2->width;
	    if (nextPtr2 == NULL) {
		rightX2 = INT_MAX;
	    }
	}
    } else {
	nextPtr2 = NULL;
	rightX2 = INT_MAX;
    }

    while (leftX < maxX) {
	matchLeft = (chunkPtr2 != NULL)
		&& SAME_BACKGROUND(chunkPtr2->stylePtr, chunkPtr->stylePtr);
	sValuePtr = chunkPtr->stylePtr->sValuePtr;
	if (rightX <= rightX2) {
	    /*
	     * The chunk in our line is about to end. If its style changes
	     * then draw the bevel for the current style.
	     */

	    if ((chunkPtr->nextPtr == NULL)
		    || !SAME_BACKGROUND(chunkPtr->stylePtr,
		    chunkPtr->nextPtr->stylePtr)) {
		if (!matchLeft && (sValuePtr->relief != TK_RELIEF_FLAT)) {
		    Tk_3DHorizontalBevel(textPtr->tkwin, pixmap,
			    sValuePtr->border, leftX + xOffset, y,
			    rightX - leftX, sValuePtr->borderWidth, leftXIn,
			    1, 1, sValuePtr->relief);
		}
		leftX = rightX;
		leftXIn = 1;

		/*
		 * If the chunk in the line above is also ending at the same
		 * point then advance to the next chunk in that line.
		 */

		if ((rightX == rightX2) && (chunkPtr2 != NULL)) {
		    goto nextChunk2;
		}
	    }
	    chunkPtr = chunkPtr->nextPtr;
	    if (chunkPtr == NULL) {
		break;
	    }
	    rightX = chunkPtr->x + chunkPtr->width;
	    if ((chunkPtr->nextPtr == NULL) && (rightX < maxX)) {
		rightX = maxX;
	    }
	    continue;
	}

	/*
	 * The chunk in the line above is ending at an x-position where there
	 * is no change in the style of the current line. If the style above
	 * matches the current line on one side of the change but not on the
	 * other, we have to draw an L-shaped piece of bevel.
	 */

	matchRight = (nextPtr2 != NULL)
		&& SAME_BACKGROUND(nextPtr2->stylePtr, chunkPtr->stylePtr);
	if (matchLeft && !matchRight) {
	    if (sValuePtr->relief != TK_RELIEF_FLAT) {
		Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
			rightX2 - sValuePtr->borderWidth + xOffset, y,
			sValuePtr->borderWidth, sValuePtr->borderWidth, 0,
			sValuePtr->relief);
	    }
	    leftX = rightX2 - sValuePtr->borderWidth;
	    leftXIn = 0;
	} else if (!matchLeft && matchRight
		&& (sValuePtr->relief != TK_RELIEF_FLAT)) {
	    Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
		    rightX2 + xOffset, y, sValuePtr->borderWidth,
		    sValuePtr->borderWidth, 1, sValuePtr->relief);
	    Tk_3DHorizontalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
		    leftX + xOffset, y, rightX2 + sValuePtr->borderWidth - 
		    leftX, sValuePtr->borderWidth, leftXIn, 0, 1,
		    sValuePtr->relief);
	}

    nextChunk2:
	chunkPtr2 = nextPtr2;
	if (chunkPtr2 == NULL) {
	    rightX2 = INT_MAX;
	} else {
	    nextPtr2 = chunkPtr2->nextPtr;
	    rightX2 = chunkPtr2->x + chunkPtr2->width;
	    if (nextPtr2 == NULL) {
		rightX2 = INT_MAX;
	    }
	}
    }

    /*
     * Pass 3: draw the horizontal bevels along the bottom of the line. This
     * uses the same approach as pass 2.
     */

    chunkPtr = dlPtr->chunkPtr;
    leftX = 0;				/* See Note A above. */
    leftXIn = 0;
    rightX = chunkPtr->x + chunkPtr->width;
    if ((chunkPtr->nextPtr == NULL) && (rightX < maxX)) {
	rightX = maxX;
    }
    chunkPtr2 = NULL;
    if (dlPtr->nextPtr != NULL && dlPtr->nextPtr->chunkPtr != NULL) {
	/*
	 * Find the chunk in the previous line that covers leftX.
	 */

	nextPtr2 = dlPtr->nextPtr->chunkPtr;
	rightX2 = 0;			/* See Note A above. */
	while (rightX2 <= leftX) {
	    chunkPtr2 = nextPtr2;
	    if (chunkPtr2 == NULL) {
		break;
	    }
	    nextPtr2 = chunkPtr2->nextPtr;
	    rightX2 = chunkPtr2->x + chunkPtr2->width;
	    if (nextPtr2 == NULL) {
		rightX2 = INT_MAX;
	    }
	}
    } else {
	nextPtr2 = NULL;
	rightX2 = INT_MAX;
    }

    while (leftX < maxX) {
	matchLeft = (chunkPtr2 != NULL)
		&& SAME_BACKGROUND(chunkPtr2->stylePtr, chunkPtr->stylePtr);
	sValuePtr = chunkPtr->stylePtr->sValuePtr;
	if (rightX <= rightX2) {
	    if ((chunkPtr->nextPtr == NULL)
		    || !SAME_BACKGROUND(chunkPtr->stylePtr,
		    chunkPtr->nextPtr->stylePtr)) {
		if (!matchLeft && (sValuePtr->relief != TK_RELIEF_FLAT)) {
		    Tk_3DHorizontalBevel(textPtr->tkwin, pixmap,
			    sValuePtr->border, leftX + xOffset,
			    y + dlPtr->height - sValuePtr->borderWidth,
			    rightX - leftX, sValuePtr->borderWidth, leftXIn,
			    0, 0, sValuePtr->relief);
		}
		leftX = rightX;
		leftXIn = 0;
		if ((rightX == rightX2) && (chunkPtr2 != NULL)) {
		    goto nextChunk2b;
		}
	    }
	    chunkPtr = chunkPtr->nextPtr;
	    if (chunkPtr == NULL) {
		break;
	    }
	    rightX = chunkPtr->x + chunkPtr->width;
	    if ((chunkPtr->nextPtr == NULL) && (rightX < maxX)) {
		rightX = maxX;
	    }
	    continue;
	}

	matchRight = (nextPtr2 != NULL)
		&& SAME_BACKGROUND(nextPtr2->stylePtr, chunkPtr->stylePtr);
	if (matchLeft && !matchRight) {
	    if (sValuePtr->relief != TK_RELIEF_FLAT) {
		Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
			rightX2 - sValuePtr->borderWidth + xOffset,
			y + dlPtr->height - sValuePtr->borderWidth,
			sValuePtr->borderWidth, sValuePtr->borderWidth, 0,
			sValuePtr->relief);
	    }
	    leftX = rightX2 - sValuePtr->borderWidth;
	    leftXIn = 1;
	} else if (!matchLeft && matchRight
		&& (sValuePtr->relief != TK_RELIEF_FLAT)) {
	    Tk_3DVerticalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
		    rightX2 + xOffset, y + dlPtr->height -
		    sValuePtr->borderWidth, sValuePtr->borderWidth,
		    sValuePtr->borderWidth, 1, sValuePtr->relief);
	    Tk_3DHorizontalBevel(textPtr->tkwin, pixmap, sValuePtr->border,
		    leftX + xOffset, y + dlPtr->height -
		    sValuePtr->borderWidth, rightX2 + sValuePtr->borderWidth -
		    leftX, sValuePtr->borderWidth, leftXIn, 1, 0,
		    sValuePtr->relief);
	}

    nextChunk2b:
	chunkPtr2 = nextPtr2;
	if (chunkPtr2 == NULL) {
	    rightX2 = INT_MAX;
	} else {
	    nextPtr2 = chunkPtr2->nextPtr;
	    rightX2 = chunkPtr2->x + chunkPtr2->width;
	    if (nextPtr2 == NULL) {
		rightX2 = INT_MAX;
	    }
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * AsyncUpdateLineMetrics --
 *
 *	This function is invoked as a background handler to update the pixel-
 *	height calculations of individual lines in an asychronous manner.
 *
 *	Currently a timer-handler is used for this purpose, which continuously
 *	reschedules itself. It may well be better to use some other approach
 *	(e.g., a background thread). We can't use an idle-callback because of
 *	a known bug in Tcl/Tk in which idle callbacks are not allowed to
 *	re-schedule themselves. This just causes an effective infinite loop.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Line heights may be recalculated.
 *
 *----------------------------------------------------------------------
 */

static void
AsyncUpdateLineMetrics(
    ClientData clientData)	/* Information about widget. */
{
    register TkText *textPtr = (TkText *) clientData;
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    int lineNum;

    dInfoPtr->lineUpdateTimer = NULL;

    if ((textPtr->tkwin == NULL) || (textPtr->flags & DESTROYED)) {
	/*
	 * The widget has been deleted. Don't do anything.
	 */

	if (--textPtr->refCount == 0) {
	    ckfree((char *) textPtr);
	}
	return;
    }

    if (dInfoPtr->flags & REDRAW_PENDING) {
	dInfoPtr->lineUpdateTimer = Tcl_CreateTimerHandler(1,
		AsyncUpdateLineMetrics, clientData);
	return;
    }

    lineNum = dInfoPtr->currentMetricUpdateLine;
    if (dInfoPtr->lastMetricUpdateLine == -1) {
	dInfoPtr->lastMetricUpdateLine =
		TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr);
    }

    /*
     * Update the lines in blocks of about 24 recalculations, or 250+ lines
     * examined, so we pass in 256 for 'doThisMuch'.
     */

    lineNum = TkTextUpdateLineMetrics(textPtr, lineNum,
	    dInfoPtr->lastMetricUpdateLine, 256);

    if (tkTextDebug) {
	char buffer[2 * TCL_INTEGER_SPACE + 1];

	sprintf(buffer, "%d %d", lineNum, dInfoPtr->lastMetricUpdateLine);
	LOG("tk_textInvalidateLine", buffer);
    }

    /*
     * If we're not in the middle of a long-line calculation (metricEpoch==-1)
     * and we've reached the last line, then we're done.
     */

    if (dInfoPtr->metricEpoch == -1
	    && lineNum == dInfoPtr->lastMetricUpdateLine) {
	/*
	 * We have looped over all lines, so we're done. We must release our
	 * refCount on the widget (the timer token was already set to NULL
	 * above).
	 */

	textPtr->refCount--;
	if (textPtr->refCount == 0) {
	    ckfree((char *) textPtr);
	}
	return;
    }
    dInfoPtr->currentMetricUpdateLine = lineNum;

    /*
     * Re-arm the timer. We already have a refCount on the text widget so no
     * need to adjust that.
     */

    dInfoPtr->lineUpdateTimer = Tcl_CreateTimerHandler(1,
	    AsyncUpdateLineMetrics, (ClientData) textPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextUpdateLineMetrics --
 *
 *	This function updates the pixel height calculations of a range of
 *	lines in the widget. The range is from lineNum to endLine, but, if
 *	doThisMuch is positive, then the function may return earlier, once a
 *	certain number of lines has been examined. The line counts are from 0.
 *
 *	If doThisMuch is -1, then all lines in the range will be updated. This
 *	will potentially take quite some time for a large text widget.
 *
 *	Note: with bad input for lineNum and endLine, this function can loop
 *	indefinitely.
 *
 * Results:
 *	The index of the last line examined (or -1 if we are about to wrap
 *	around from end to beginning of the widget, and the next line will be
 *	the first line).
 *
 * Side effects:
 *	Line heights may be recalculated.
 *
 *----------------------------------------------------------------------
 */

int
TkTextUpdateLineMetrics(
    TkText *textPtr,		/* Information about widget. */
    int lineNum,		/* Start at this line. */
    int endLine,		/* Go no further than this line. */
    int doThisMuch)		/* How many lines to check, or how many 10s of
				 * lines to recalculate. If '-1' then do
				 * everything in the range (which may take a
				 * while). */
{
    TkTextLine *linePtr = NULL;
    int count = 0;
    int totalLines = TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr);

    if (totalLines == 0) {
	/*
	 * Empty peer widget.
	 */

	return endLine;
    }

    while (1) {
	/*
	 * Get a suitable line.
	 */

	if (lineNum == -1 && linePtr == NULL) {
	    lineNum = 0;
	    linePtr = TkBTreeFindLine(textPtr->sharedTextPtr->tree, textPtr,
		    lineNum);
	} else {
	    if (lineNum == -1 || linePtr == NULL) {
		if (lineNum == -1) {
		    lineNum = 0;
		}
		linePtr = TkBTreeFindLine(textPtr->sharedTextPtr->tree,
			textPtr, lineNum);
	    } else {
		lineNum++;
		linePtr = TkBTreeNextLine(textPtr, linePtr);
	    }

	    /*
	     * If we're in the middle of a partial-line height calculation,
	     * then we can't be done.
	     */

	    if (textPtr->dInfoPtr->metricEpoch == -1 && lineNum == endLine) {
		/*
		 * We have looped over all lines, so we're done.
		 */

		break;
	    }
	}

	if (lineNum < totalLines) {
	    if (tkTextDebug) {
		char buffer[4 * TCL_INTEGER_SPACE + 3];

		sprintf(buffer, "%d %d %d %d",
			lineNum, endLine, totalLines, count);
		LOG("tk_textInvalidateLine", buffer);
	    }

	    /*
	     * Now update the line's metrics if necessary.
	     */

	    if (TkBTreeLinePixelEpoch(textPtr, linePtr)
		!= textPtr->dInfoPtr->lineMetricUpdateEpoch) {
		if (doThisMuch == -1) {
		    count += 8 * TkTextUpdateOneLine(textPtr, linePtr, 0,
			    NULL, 0);
		} else {
		    TkTextIndex index;
		    TkTextIndex *indexPtr;
		    int pixelHeight;

		    /*
		     * If the metric epoch is the same as the widget's epoch,
		     * then we know that indexPtrs are still valid, and if the
		     * cached metricIndex (if any) is for the same line as we
		     * wish to examine, then we are looking at a long line
		     * wrapped many times, which we will examine in pieces.
		     */

		    if (textPtr->dInfoPtr->metricEpoch ==
			    textPtr->sharedTextPtr->stateEpoch &&
			    textPtr->dInfoPtr->metricIndex.linePtr==linePtr) {
			indexPtr = &textPtr->dInfoPtr->metricIndex;
			pixelHeight = textPtr->dInfoPtr->metricPixelHeight;
		    } else {
			/*
			 * We must reset the partial line height calculation
			 * data here, so we don't use it when it is out of
			 * date.
			 */

			textPtr->dInfoPtr->metricEpoch = -1;
			index.tree = textPtr->sharedTextPtr->tree;
			index.linePtr = linePtr;
			index.byteIndex = 0;
			index.textPtr = NULL;
			indexPtr = &index;
			pixelHeight = 0;
		    }

		    /*
		     * Update the line and update the counter, counting 8 for
		     * each display line we actually re-layout.
		     */

		    count += 8 * TkTextUpdateOneLine(textPtr, linePtr,
			    pixelHeight, indexPtr, 1);

		    if (indexPtr->linePtr == linePtr) {
			/*
			 * We didn't complete the logical line, because it
			 * produced very many display lines - it must be a
			 * long line wrapped many times. So we must cache as
			 * far as we got for next time around.
			 */

			if (pixelHeight == 0) {
			    /*
			     * These have already been stored, unless we just
			     * started the new line.
			     */

			    textPtr->dInfoPtr->metricIndex = index;
			    textPtr->dInfoPtr->metricEpoch =
				    textPtr->sharedTextPtr->stateEpoch;
			}
			textPtr->dInfoPtr->metricPixelHeight =
				TkBTreeLinePixelCount(textPtr, linePtr);
			break;
		    } else {
			/*
			 * We're done with this long line.
			 */

			textPtr->dInfoPtr->metricEpoch = -1;
		    }
		}
	    } else {
		/*
		 * This line is already up to date. That means there's nothing
		 * to do here.
		 */
	    }
	} else {
	    /*
	     * We must never recalculate the height of the last artificial
	     * line. It must stay at zero, and if we recalculate it, it will
	     * change.
	     */

	    if (endLine >= totalLines) {
		lineNum = endLine;
		break;
	    }

	    /*
	     * Set things up for the next loop through.
	     */

	    lineNum = -1;
	}
	count++;

	if (doThisMuch != -1 && count >= doThisMuch) {
	    break;
	}
    }
    if (doThisMuch == -1) {
	/*
	 * If we were requested to provide a full update, then also update the
	 * scrollbar.
	 */

	GetYView(textPtr->interp, textPtr, 1);
    }
    return lineNum;
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextInvalidateLineMetrics, TextInvalidateLineMetrics --
 *
 *	Mark a number of text lines as having invalid line metric
 *	calculations. Never call this with linePtr as the last (artificial)
 *	line in the text. Depending on 'action' which indicates whether the
 *	given lines are simply invalid or have been inserted or deleted, the
 *	pre-existing asynchronous line update range may need to be adjusted.
 *
 *	If linePtr is NULL then 'lineCount' and 'action' are ignored and all
 *	lines are invalidated.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	May schedule an asychronous callback.
 *
 *----------------------------------------------------------------------
 */

void
TkTextInvalidateLineMetrics(
    TkSharedText *sharedTextPtr,/* Shared widget section for all peers, or
				 * NULL. */
    TkText *textPtr,		/* Widget record for text widget. */
    TkTextLine *linePtr,	/* Invalidation starts from this line. */
    int lineCount,		/* And includes this many following lines. */
    int action)			/* Indicates what type of invalidation
				 * occurred (insert, delete, or simple). */
{
    if (sharedTextPtr == NULL) {
	TextInvalidateLineMetrics(textPtr, linePtr, lineCount, action);
    } else {
	textPtr = sharedTextPtr->peers;
	while (textPtr != NULL) {
	    TextInvalidateLineMetrics(textPtr, linePtr, lineCount, action);
	    textPtr = textPtr->next;
	}
    }
}

static void
TextInvalidateLineMetrics(
    TkText *textPtr,		/* Widget record for text widget. */
    TkTextLine *linePtr,	/* Invalidation starts from this line. */
    int lineCount,		/* And includes this many following lines. */
    int action)			/* Indicates what type of invalidation
				 * occurred (insert, delete, or simple). */
{
    int fromLine;
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;

    if (linePtr != NULL) {
	int counter = lineCount;

	fromLine = TkBTreeLinesTo(textPtr, linePtr);

	/*
	 * Invalidate the height calculations of each line in the given range.
	 */

	TkBTreeLinePixelEpoch(textPtr, linePtr) = 0;
	while (counter > 0 && linePtr != NULL) {
	    linePtr = TkBTreeNextLine(textPtr, linePtr);
	    if (linePtr != NULL) {
		TkBTreeLinePixelEpoch(textPtr, linePtr) = 0;
	    }
	    counter--;
	}

	/*
	 * Now schedule an examination of each line in the union of the old
	 * and new update ranges, including the (possibly empty) range in
	 * between. If that between range is not-empty, then we are examining
	 * more lines than is strictly necessary (but the examination of the
	 * extra lines should be quick, since their pixelCalculationEpoch will
	 * be up to date). However, to keep track of that would require more
	 * complex record-keeping than what we have.
	 */

	if (dInfoPtr->lineUpdateTimer == NULL) {
	    dInfoPtr->currentMetricUpdateLine = fromLine;
	    if (action == TK_TEXT_INVALIDATE_DELETE) {
		lineCount = 0;
	    }
	    dInfoPtr->lastMetricUpdateLine = fromLine + lineCount + 1;
	} else {
	    int toLine = fromLine + lineCount + 1;

	    if (action == TK_TEXT_INVALIDATE_DELETE) {
		if (toLine <= dInfoPtr->currentMetricUpdateLine) {
		    dInfoPtr->currentMetricUpdateLine = fromLine;
		    if (dInfoPtr->lastMetricUpdateLine != -1) {
			dInfoPtr->lastMetricUpdateLine -= lineCount;
		    }
		} else if (fromLine <= dInfoPtr->currentMetricUpdateLine) {
		    dInfoPtr->currentMetricUpdateLine = fromLine;
		    if (toLine <= dInfoPtr->lastMetricUpdateLine) {
			dInfoPtr->lastMetricUpdateLine -= lineCount;
		    }
		} else {
		    if (dInfoPtr->lastMetricUpdateLine != -1) {
			dInfoPtr->lastMetricUpdateLine = toLine;
		    }
		}
	    } else if (action == TK_TEXT_INVALIDATE_INSERT) {
		if (toLine <= dInfoPtr->currentMetricUpdateLine) {
		    dInfoPtr->currentMetricUpdateLine = fromLine;
		    if (dInfoPtr->lastMetricUpdateLine != -1) {
			dInfoPtr->lastMetricUpdateLine += lineCount;
		    }
		} else if (fromLine <= dInfoPtr->currentMetricUpdateLine) {
		    dInfoPtr->currentMetricUpdateLine = fromLine;
		    if (toLine <= dInfoPtr->lastMetricUpdateLine) {
			dInfoPtr->lastMetricUpdateLine += lineCount;
		    }
		    if (toLine > dInfoPtr->lastMetricUpdateLine) {
			dInfoPtr->lastMetricUpdateLine = toLine;
		    }
		} else {
		    if (dInfoPtr->lastMetricUpdateLine != -1) {
			dInfoPtr->lastMetricUpdateLine = toLine;
		    }
		}
	    } else {
		if (fromLine < dInfoPtr->currentMetricUpdateLine) {
		    dInfoPtr->currentMetricUpdateLine = fromLine;
		}
		if (dInfoPtr->lastMetricUpdateLine != -1
			&& toLine > dInfoPtr->lastMetricUpdateLine) {
		    dInfoPtr->lastMetricUpdateLine = toLine;
		}
	    }
	}
    } else {
	/*
	 * This invalidates the height of all lines in the widget.
	 */

	if ((++dInfoPtr->lineMetricUpdateEpoch) == 0) {
	    dInfoPtr->lineMetricUpdateEpoch++;
	}

	/*
	 * This has the effect of forcing an entire new loop of update checks
	 * on all lines in the widget.
	 */

	if (dInfoPtr->lineUpdateTimer == NULL) {
	    dInfoPtr->currentMetricUpdateLine = -1;
	}
	dInfoPtr->lastMetricUpdateLine = dInfoPtr->currentMetricUpdateLine;
    }

    /*
     * Now re-set the current update calculations.
     */

    if (dInfoPtr->lineUpdateTimer == NULL) {
	textPtr->refCount++;
	dInfoPtr->lineUpdateTimer = Tcl_CreateTimerHandler(1,
		AsyncUpdateLineMetrics, (ClientData) textPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextFindDisplayLineEnd --
 *
 *	This function is invoked to find the index of the beginning or end of
 *	the particular display line on which the given index sits, whether
 *	that line is displayed or not.
 *
 *	If 'end' is zero, we look for the start, and if 'end' is one we look
 *	for the end.
 *
 *	If the beginning of the current display line is elided, and we are
 *	looking for the start of the line, then the returned index will be the
 *	first elided index on the display line.
 *
 *	Similarly if the end of the current display line is elided and we are
 *	looking for the end, then the returned index will be the last elided
 *	index on the display line.
 *
 * Results:
 *	Modifies indexPtr to point to the given end.
 *
 *	If xOffset is non-NULL, it is set to the x-pixel offset of the given
 *	original index within the given display line.
 *
 * Side effects:
 *	The combination of 'LayoutDLine' and 'FreeDLines' seems like a rather
 *	time-consuming way of gathering the information we need, so this would
 *	be a good place to look to speed up the calculations. In particular
 *	these calls will map and unmap embedded windows respectively, which I
 *	would hope isn't exactly necessary!
 *
 *----------------------------------------------------------------------
 */

void
TkTextFindDisplayLineEnd(
    TkText *textPtr,		/* Widget record for text widget. */
    TkTextIndex *indexPtr,	/* Index we will adjust to the display line
				 * start or end. */
    int end,			/* 0 = start, 1 = end. */
    int *xOffset)		/* NULL, or used to store the x-pixel offset
				 * of the original index within its display
				 * line. */
{
    TkTextIndex indexPtr2;
    TkTextIndexBackBytes(textPtr, indexPtr, 1, &indexPtr2);
    if (!end && indexPtr->byteIndex == 0
            && !TkTextIsElided(textPtr, &indexPtr2, NULL)) {
	/*
	 * Nothing to do.
	 */

	if (xOffset != NULL) {
	    *xOffset = 0;
	}
	return;
    } else {
	TkTextIndex index = *indexPtr;

	index.byteIndex = 0;
	index.textPtr = NULL;

	while (1) {
	    TkTextIndex endOfLastLine;

	    if (TkTextIndexBackBytes(textPtr, &index, 1, &endOfLastLine)) {
		/*
		 * Reached beginning of text.
		 */

		break;
	    }

	    if (!TkTextIsElided(textPtr, &endOfLastLine, NULL)) {
		/*
		 * The eol is not elided, so 'index' points to the start of a
		 * display line (as well as logical line).
		 */

		break;
	    }

	    /*
	     * indexPtr's logical line is actually merged with the previous
	     * logical line whose eol is elided. Continue searching back to
	     * get a real line start.
	     */

	    index = endOfLastLine;
	    index.byteIndex = 0;
	}

	while (1) {
	    DLine *dlPtr;
	    int byteCount;
	    TkTextIndex nextLineStart;

	    dlPtr = LayoutDLine(textPtr, &index);
	    byteCount = dlPtr->byteCount;

	    TkTextIndexForwBytes(textPtr, &index, byteCount, &nextLineStart);

	    /*
	     * 'byteCount' goes up to the beginning of the next display line,
	     * so equality here says we need one more line. We try to perform
	     * a quick comparison which is valid for the case where the
	     * logical line is the same, but otherwise fall back on a full
	     * TkTextIndexCmp.
	     */

	    if (((index.linePtr == indexPtr->linePtr)
		    && (index.byteIndex + byteCount > indexPtr->byteIndex))
		    || (dlPtr->logicalLinesMerged > 0
		    && TkTextIndexCmp(&nextLineStart, indexPtr) > 0)) {
		/*
		 * It's on this display line.
		 */

		if (xOffset != NULL) {
		    /*
		     * This call takes a byte index relative to the start of
		     * the current _display_ line, not logical line. We are
		     * about to overwrite indexPtr->byteIndex, so we must do
		     * this now.
		     */

                    *xOffset = DlineXOfIndex(textPtr, dlPtr,
                            TkTextIndexCount(textPtr, &dlPtr->index, indexPtr,
                            COUNT_INDICES));
		}
		if (end) {
		    /*
		     * The index we want is one less than the number of bytes
		     * in the display line.
		     */

		    TkTextIndexBackBytes(textPtr, &nextLineStart, 1, indexPtr);
		} else {
		    *indexPtr = index;
		}
		FreeDLines(textPtr, dlPtr, NULL, DLINE_FREE_TEMP);
		return;
	    }
	    FreeDLines(textPtr, dlPtr, NULL, DLINE_FREE_TEMP);
	    index = nextLineStart;
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * CalculateDisplayLineHeight --
 *
 *	This function is invoked to recalculate the height of the particular
 *	display line which starts with the given index, whether that line is
 *	displayed or not.
 *
 *	This function does not, in itself, update any cached information about
 *	line heights. That should be done, where necessary, by its callers.
 *
 *	The behaviour of this function is _undefined_ if indexPtr is not
 *	currently at the beginning of a display line.
 *
 * Results:
 *	The number of vertical pixels used by the display line.
 *
 *	If 'byteCountPtr' is non-NULL, then returns in that pointer the number
 *	of byte indices on the given display line (which can be used to update
 *	indexPtr in a loop).
 *
 *	If 'mergedLinePtr' is non-NULL, then returns in that pointer the
 *	number of extra logical lines merged into the given display line.
 *
 * Side effects:
 *	The combination of 'LayoutDLine' and 'FreeDLines' seems like a rather
 *	time-consuming way of gathering the information we need, so this would
 *	be a good place to look to speed up the calculations. In particular
 *	these calls will map and unmap embedded windows respectively, which I
 *	would hope isn't exactly necessary!
 *
 *----------------------------------------------------------------------
 */

static int
CalculateDisplayLineHeight(
    TkText *textPtr,		/* Widget record for text widget. */
    CONST TkTextIndex *indexPtr,/* The index at the beginning of the display
				 * line of interest. */
    int *byteCountPtr,		/* NULL or used to return the number of byte
				 * indices on the given display line. */
    int *mergedLinePtr)		/* NULL or used to return if the given display
				 * line merges with a following logical line
				 * (because the eol is elided). */
{
    DLine *dlPtr;
    int pixelHeight;

    if (tkTextDebug) {
        int oldtkTextDebug = tkTextDebug;
        /*
         * Check that the indexPtr we are given really is at the start of a
         * display line. The gymnastics with tkTextDebug is to prevent
         * failure of a test suite test, that checks that lines are rendered
         * exactly once. TkTextFindDisplayLineEnd is used here for checking
         * indexPtr but it calls LayoutDLine/FreeDLine which makes the
         * counting wrong. The debug mode shall threfore be switched off when
         * calling TkTextFindDisplayLineEnd.
         */

        TkTextIndex indexPtr2 = *indexPtr;
        tkTextDebug = 0;
        TkTextFindDisplayLineEnd(textPtr, &indexPtr2, 0, NULL);
        tkTextDebug = oldtkTextDebug;
        if (TkTextIndexCmp(&indexPtr2,indexPtr) != 0) {
            Tcl_Panic("CalculateDisplayLineHeight called with bad indexPtr");
        }
    }

    /*
     * Special case for artificial last line. May be better to move this
     * inside LayoutDLine.
     */

    if (indexPtr->byteIndex == 0
	    && TkBTreeNextLine(textPtr, indexPtr->linePtr) == NULL) {
	if (byteCountPtr != NULL) {
	    *byteCountPtr = 0;
	}
	if (mergedLinePtr != NULL) {
	    *mergedLinePtr = 0;
	}
	return 0;
    }

    /*
     * Layout, find the information we need and then free the display-line we
     * laid-out. We must use 'FreeDLines' because it will actually call the
     * relevant code to unmap any embedded windows which were mapped in the
     * LayoutDLine call!
     */

    dlPtr = LayoutDLine(textPtr, indexPtr);
    pixelHeight = dlPtr->height;
    if (byteCountPtr != NULL) {
	*byteCountPtr = dlPtr->byteCount;
    }
    if (mergedLinePtr != NULL) {
	*mergedLinePtr = dlPtr->logicalLinesMerged;
    }
    FreeDLines(textPtr, dlPtr, NULL, DLINE_FREE_TEMP);

    return pixelHeight;
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextIndexYPixels --
 *
 *	This function is invoked to calculate the number of vertical pixels
 *	between the first index of the text widget and the given index. The
 *	range from first logical line to given logical line is determined
 *	using the cached values, and the range inside the given logical line
 *	is calculated on the fly.
 *
 * Results:
 *	The pixel distance between first pixel in the widget and the
 *	top of the index's current display line (could be zero).
 *
 * Side effects:
 *	Just those of 'CalculateDisplayLineHeight'.
 *
 *----------------------------------------------------------------------
 */

int
TkTextIndexYPixels(
    TkText *textPtr,		/* Widget record for text widget. */
    CONST TkTextIndex *indexPtr)/* The index of which we want the pixel
				 * distance from top of logical line to top of
				 * index. */
{
    int pixelHeight;
    TkTextIndex index;
    int alreadyStartOfLine = 1;

    /*
     * Find the index denoting the closest position being at the same time
     * the start of a logical line above indexPtr and the start of a display
     * line.
     */

    index = *indexPtr;
    while (1) {
        TkTextFindDisplayLineEnd(textPtr, &index, 0, NULL);
        if (index.byteIndex == 0) {
            break;
        }
        TkTextIndexBackBytes(textPtr, &index, 1, &index);
        alreadyStartOfLine = 0;
    }

    pixelHeight = TkBTreePixelsTo(textPtr, index.linePtr);

    /*
     * Shortcut to avoid layout of a superfluous display line. We know there
     * is nothing more to add up to the height since the index we were given
     * was already the start of a logical line.
     */

    if (alreadyStartOfLine) {
        return pixelHeight;
    }

    /*
     * Iterate through display lines, starting at the logical line belonging
     * to index, adding up the pixel height of each such display line as we
     * go along, until we go past 'indexPtr'.
     */

    while (1) {
	int bytes, height, compare;

	/*
	 * Currently this call doesn't have many side-effects. However, if in
	 * the future we change the code so there are side-effects (such as
	 * adjusting linePtr->pixelHeight), then the code might not quite work
	 * as intended, specifically the 'linePtr->pixelHeight == pixelHeight'
	 * test below this while loop.
	 */

	height = CalculateDisplayLineHeight(textPtr, &index, &bytes, NULL);

        TkTextIndexForwBytes(textPtr, &index, bytes, &index);

        compare = TkTextIndexCmp(&index,indexPtr);
        if (compare > 0) {
	    return pixelHeight;
	}

	if (height > 0) {
	    pixelHeight += height;
	}

        if (compare == 0) {
	    return pixelHeight;
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextUpdateOneLine --
 *
 *	This function is invoked to recalculate the height of a particular
 *	logical line, whether that line is displayed or not.
 *
 *	It must NEVER be called for the artificial last TkTextLine which is
 *	used internally for administrative purposes only. That line must
 *	retain its initial height of 0 otherwise the pixel height calculation
 *	maintained by the B-tree will be wrong.
 *
 * Results:
 *	The number of display lines in the logical line. This could be zero if
 *	the line is totally elided.
 *
 * Side effects:
 *	Line heights may be recalculated, and a timer to update the scrollbar
 *	may be installed. Also see the called function
 *	CalculateDisplayLineHeight for its side effects.
 *
 *----------------------------------------------------------------------
 */

int
TkTextUpdateOneLine(
    TkText *textPtr,		/* Widget record for text widget. */
    TkTextLine *linePtr,	/* The line of which to calculate the
				 * height. */
    int pixelHeight,		/* If indexPtr is non-NULL, then this is the
				 * number of pixels in the logical line
				 * linePtr, up to the index which has been
				 * given. */
    TkTextIndex *indexPtr,	/* Either NULL or an index at the start of a
				 * display line belonging to linePtr, at which
				 * we wish to start (e.g. up to which we have
				 * already calculated). On return this will be
				 * set to the first index on the next line. */
    int partialCalc)		/* Set to 1 if we are allowed to do partial
				 * height calculations of long-lines. In this
				 * case we'll only return what we know so
				 * far. */
{
    TkTextIndex index;
    int displayLines;
    int mergedLines;

    if (indexPtr == NULL) {
	index.tree = textPtr->sharedTextPtr->tree;
	index.linePtr = linePtr;
	index.byteIndex = 0;
	index.textPtr = NULL;
	indexPtr = &index;
	pixelHeight = 0;
    }

    /*
     * CalculateDisplayLineHeight _must_ be called (below) with an index at
     * the beginning of a display line. Force this to happen. This is needed
     * when TkTextUpdateOneLine is called with a line that is merged with its
     * previous line: the number of merged logical lines in a display line is
     * calculated correctly only when CalculateDisplayLineHeight receives
     * an index at the beginning of a display line. In turn this causes the
     * merged lines to receive their correct zero pixel height in
     * TkBTreeAdjustPixelHeight.
     */

    TkTextFindDisplayLineEnd(textPtr, indexPtr, 0, NULL);
    linePtr = indexPtr->linePtr;

    /*
     * Iterate through all display-lines corresponding to the single logical
     * line 'linePtr' (and lines merged into this line due to eol elision),
     * adding up the pixel height of each such display line as we go along.
     * The final total is, therefore, the total height of all display lines
     * made up by the logical line 'linePtr' and subsequent logical lines
     * merged into this line.
     */

    displayLines = 0;
    mergedLines = 0;

    while (1) {
	int bytes, height, logicalLines;

	/*
	 * Currently this call doesn't have many side-effects. However, if in
	 * the future we change the code so there are side-effects (such as
	 * adjusting linePtr->pixelHeight), then the code might not quite work
	 * as intended, specifically the 'linePtr->pixelHeight == pixelHeight'
	 * test below this while loop.
	 */

        height = CalculateDisplayLineHeight(textPtr, indexPtr, &bytes,
		&logicalLines);

	if (height > 0) {
	    pixelHeight += height;
	    displayLines++;
	}

	mergedLines += logicalLines;

	if (TkTextIndexForwBytes(textPtr, indexPtr, bytes, indexPtr)) {
	    break;
	}

        if (mergedLines == 0) {
            if (indexPtr->linePtr != linePtr) {
                /*
                 * If we reached the end of the logical line, then either way
                 * we don't have a partial calculation.
                 */

                partialCalc = 0;
                break;
            }
        } else {
            if (indexPtr->byteIndex != 0) {
                /*
                 * We must still be on the same wrapped line, on a new logical
                 * line merged with the logical line 'linePtr'.
                 */
            } else {
                /*
                 * Must check if indexPtr is really a new logical line which is
                 * not merged with the previous line. The only code that would
                 * really know this is LayoutDLine, which doesn't pass the
                 * information on, so we have to check manually here.
                 */

                TkTextIndex idx;

                TkTextIndexBackChars(textPtr, indexPtr, 1, &idx, COUNT_INDICES);
                if (!TkTextIsElided(textPtr, &idx, NULL)) {
                    /*
                     * We've ended a logical line.
                     */

                    partialCalc = 0;
                    break;
                }

                /*
                 * We must still be on the same wrapped line, on a new logical
                 * line merged with the logical line 'linePtr'.
                 */
            }
        }
	if (partialCalc && displayLines > 50 && mergedLines == 0) {
	    /*
	     * Only calculate 50 display lines at a time, to avoid huge
	     * delays. In any case it is very rare that a single line wraps 50
	     * times!
	     *
	     * If we have any merged lines, we must complete the full logical
	     * line layout here and now, because the partial-calculation code
	     * isn't designed to handle merged logical lines. Hence the
	     * 'mergedLines == 0' check.
	     */

	    break;
	}
    }

    if (!partialCalc) {
	int changed = 0;

	/*
	 * Cancel any partial line height calculation state.
	 */

	textPtr->dInfoPtr->metricEpoch = -1;

	/*
	 * Mark the logical line as being up to date (caution: it isn't yet up
	 * to date, that will happen in TkBTreeAdjustPixelHeight just below).
	 */

	TkBTreeLinePixelEpoch(textPtr, linePtr)
		= textPtr->dInfoPtr->lineMetricUpdateEpoch;
	if (TkBTreeLinePixelCount(textPtr, linePtr) != pixelHeight) {
	    changed = 1;
	}

	if (mergedLines > 0) {
	    int i = mergedLines;
	    TkTextLine *mergedLinePtr;

	    /*
	     * Loop over all merged logical lines, marking them up to date
	     * (again, the pixel count setting will actually happen in
	     * TkBTreeAdjustPixelHeight).
	     */

	    mergedLinePtr = linePtr;
	    while (i-- > 0) {
		mergedLinePtr = TkBTreeNextLine(textPtr, mergedLinePtr);
		TkBTreeLinePixelEpoch(textPtr, mergedLinePtr)
			= textPtr->dInfoPtr->lineMetricUpdateEpoch;
		if (TkBTreeLinePixelCount(textPtr, mergedLinePtr) != 0) {
		    changed = 1;
		}
	    }
	}

	if (!changed) {
	    /*
	     * If there's nothing to change, then we can already return.
	     */

	    return displayLines;
	}
    }

    /*
     * We set the line's height, but the return value is now the height of the
     * entire widget, which may be used just below for reporting/debugging
     * purposes.
     */

    pixelHeight = TkBTreeAdjustPixelHeight(textPtr, linePtr, pixelHeight,
	    mergedLines);

    if (tkTextDebug) {
	char buffer[2 * TCL_INTEGER_SPACE + 1];

	if (TkBTreeNextLine(textPtr, linePtr) == NULL) {
	    Tcl_Panic("Mustn't ever update line height of last artificial line");
	}

	sprintf(buffer, "%d %d", TkBTreeLinesTo(textPtr,linePtr), pixelHeight);
	LOG("tk_textNumPixels", buffer);
    }
    if (textPtr->dInfoPtr->scrollbarTimer == NULL) {
	textPtr->refCount++;
	textPtr->dInfoPtr->scrollbarTimer = Tcl_CreateTimerHandler(200,
		AsyncUpdateYScrollbar, (ClientData) textPtr);
    }
    return displayLines;
}

/*
 *----------------------------------------------------------------------
 *
 * DisplayText --
 *
 *	This function is invoked as a when-idle handler to update the display.
 *	It only redisplays the parts of the text widget that are out of date.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Information is redrawn on the screen.
 *
 *----------------------------------------------------------------------
 */

static void
DisplayText(
    ClientData clientData)	/* Information about widget. */
{
    register TkText *textPtr = (TkText *) clientData;
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    register DLine *dlPtr;
    DLine *prevPtr;
    Pixmap pixmap;
    int maxHeight, borders;
    int bottomY = 0;		/* Initialization needed only to stop compiler
				 * warnings. */
    Tcl_Interp *interp;

    if ((textPtr->tkwin == NULL) || (textPtr->flags & DESTROYED)) {
	/*
	 * The widget has been deleted.	 Don't do anything.
	 */

	return;
    }

    interp = textPtr->interp;
    Tcl_Preserve((ClientData) interp);

    if (tkTextDebug) {
	Tcl_SetVar2(interp, "tk_textRelayout", NULL, "", TCL_GLOBAL_ONLY);
    }

    if ((textPtr->tkwin == NULL) || (textPtr->flags & DESTROYED)) {
	/*
	 * The widget has been deleted.	 Don't do anything.
	 */

	goto end;
    }

    if (!Tk_IsMapped(textPtr->tkwin) || (dInfoPtr->maxX <= dInfoPtr->x)
	    || (dInfoPtr->maxY <= dInfoPtr->y)) {
	UpdateDisplayInfo(textPtr);
	dInfoPtr->flags &= ~REDRAW_PENDING;
	goto doScrollbars;
    }
    numRedisplays++;
    if (tkTextDebug) {
	Tcl_SetVar2(interp, "tk_textRedraw", NULL, "", TCL_GLOBAL_ONLY);
    }

    if ((textPtr->tkwin == NULL) || (textPtr->flags & DESTROYED)) {
	/*
	 * The widget has been deleted. Don't do anything.
	 */

	goto end;
    }

    /*
     * Choose a new current item if that is needed (this could cause event
     * handlers to be invoked, hence the preserve/release calls and the loop,
     * since the handlers could conceivably necessitate yet another current
     * item calculation). The tkwin check is because the whole window could go
     * away in the Tcl_Release call.
     */

    while (dInfoPtr->flags & REPICK_NEEDED) {
	textPtr->refCount++;
	dInfoPtr->flags &= ~REPICK_NEEDED;
	TkTextPickCurrent(textPtr, &textPtr->pickEvent);
	if (--textPtr->refCount == 0) {
	    ckfree((char *) textPtr);
	    goto end;
	}
	if ((textPtr->tkwin == NULL) || (textPtr->flags & DESTROYED)) {
	    goto end;
	}
    }

    /*
     * First recompute what's supposed to be displayed.
     */

    UpdateDisplayInfo(textPtr);
    dInfoPtr->dLinesInvalidated = 0;

#ifdef MAC_OSX_TK
    /*
     * Make sure that unmapped subwindows really have been unmapped.
     * If the unmap request is pending as an idle request, the window
     * can get redrawn on top of the widget.
     */
     while (Tcl_DoOneEvent(TCL_IDLE_EVENTS|TCL_DONT_WAIT)) {}
#endif


    /*
     * See if it's possible to bring some parts of the screen up-to-date by
     * scrolling (copying from other parts of the screen). We have to be
     * particularly careful with the top and bottom lines of the display,
     * since these may only be partially visible and therefore not helpful for
     * some scrolling purposes.
     */

    for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL; dlPtr = dlPtr->nextPtr) {
	register DLine *dlPtr2;
	int offset, height, y, oldY;
	TkRegion damageRgn;

	/*
	 * These tests are, in order:
	 *
	 * 1. If the line is already marked as invalid
	 * 2. If the line hasn't moved
	 * 3. If the line overlaps the bottom of the window and we are
	 *    scrolling up.
	 * 4. If the line overlaps the top of the window and we are scrolling
	 *    down.
	 *
	 * If any of these tests are true, then we can't scroll this line's
	 * part of the display.
	 *
	 * Note that even if tests 3 or 4 aren't true, we may be able to
	 * scroll the line, but we still need to be sure to call embedded
	 * window display procs on top and bottom lines if they have any
	 * portion non-visible (see below).
	 */

	if ((dlPtr->flags & OLD_Y_INVALID)
		|| (dlPtr->y == dlPtr->oldY)
		|| (((dlPtr->oldY + dlPtr->height) > dInfoPtr->maxY)
		    && (dlPtr->y < dlPtr->oldY))
		|| ((dlPtr->oldY < dInfoPtr->y) && (dlPtr->y > dlPtr->oldY))) {
	    continue;
	}

	/*
	 * This line is already drawn somewhere in the window so it only needs
	 * to be copied to its new location. See if there's a group of lines
	 * that can all be copied together.
	 */

	offset = dlPtr->y - dlPtr->oldY;
	height = dlPtr->height;
	y = dlPtr->y;
	for (dlPtr2 = dlPtr->nextPtr; dlPtr2 != NULL;
		dlPtr2 = dlPtr2->nextPtr) {
	    if ((dlPtr2->flags & OLD_Y_INVALID)
		    || ((dlPtr2->oldY + offset) != dlPtr2->y)
		    || ((dlPtr2->oldY + dlPtr2->height) > dInfoPtr->maxY)) {
		break;
	    }
	    height += dlPtr2->height;
	}

	/*
	 * Reduce the height of the area being copied if necessary to avoid
	 * overwriting the border area.
	 */

	if ((y + height) > dInfoPtr->maxY) {
	    height = dInfoPtr->maxY -y;
	}
	oldY = dlPtr->oldY;
	if (y < dInfoPtr->y) {
	    /*
	     * Adjust if the area being copied is going to overwrite the top
	     * border of the window (so the top line is only half onscreen).
	     */

	    int y_off = dInfoPtr->y - dlPtr->y;
	    height -= y_off;
	    oldY += y_off;
	    y = dInfoPtr->y;
	}

	/*
	 * Update the lines we are going to scroll to show that they have been
	 * copied.
	 */

	while (1) {
	    /*
	     * The DLine already has OLD_Y_INVALID cleared.
	     */

	    dlPtr->oldY = dlPtr->y;
	    if (dlPtr->nextPtr == dlPtr2) {
		break;
	    }
	    dlPtr = dlPtr->nextPtr;
	}

	/*
	 * Scan through the lines following the copied ones to see if we are
	 * going to overwrite them with the copy operation. If so, mark them
	 * for redisplay.
	 */

	for ( ; dlPtr2 != NULL; dlPtr2 = dlPtr2->nextPtr) {
	    if ((!(dlPtr2->flags & OLD_Y_INVALID))
		    && ((dlPtr2->oldY + dlPtr2->height) > y)
		    && (dlPtr2->oldY < (y + height))) {
		dlPtr2->flags |= OLD_Y_INVALID;
	    }
	}

	/*
	 * Now scroll the lines. This may generate damage which we handle by
	 * calling TextInvalidateRegion to mark the display blocks as stale.
	 */

	damageRgn = TkCreateRegion();
	if (TkScrollWindow(textPtr->tkwin, dInfoPtr->scrollGC, dInfoPtr->x,
		oldY, dInfoPtr->maxX-dInfoPtr->x, height, 0, y-oldY,
		damageRgn)) {
	    TextInvalidateRegion(textPtr, damageRgn);
	}
	numCopies++;
	TkDestroyRegion(damageRgn);
    }

    /*
     * Clear the REDRAW_PENDING flag here. This is actually pretty tricky. We
     * want to wait until *after* doing the scrolling, since that could
     * generate more areas to redraw and don't want to reschedule a redisplay
     * for them. On the other hand, we can't wait until after all the
     * redisplaying, because the act of redisplaying could actually generate
     * more redisplays (e.g. in the case of a nested window with event
     * bindings triggered by redisplay).
     */

    dInfoPtr->flags &= ~REDRAW_PENDING;

    /*
     * Redraw the borders if that's needed.
     */

    if (dInfoPtr->flags & REDRAW_BORDERS) {
	if (tkTextDebug) {
	    LOG("tk_textRedraw", "borders");
	}

	if (textPtr->tkwin == NULL) {
	    /*
	     * The widget has been deleted. Don't do anything.
	     */

	    goto end;
	}

	Tk_Draw3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
		textPtr->border, textPtr->highlightWidth,
		textPtr->highlightWidth,
		Tk_Width(textPtr->tkwin) - 2*textPtr->highlightWidth,
		Tk_Height(textPtr->tkwin) - 2*textPtr->highlightWidth,
		textPtr->borderWidth, textPtr->relief);
	if (textPtr->highlightWidth != 0) {
	    GC fgGC, bgGC;

	    bgGC = Tk_GCForColor(textPtr->highlightBgColorPtr,
		    Tk_WindowId(textPtr->tkwin));
	    if (textPtr->flags & GOT_FOCUS) {
		fgGC = Tk_GCForColor(textPtr->highlightColorPtr,
			Tk_WindowId(textPtr->tkwin));
		TkpDrawHighlightBorder(textPtr->tkwin, fgGC, bgGC,
			textPtr->highlightWidth, Tk_WindowId(textPtr->tkwin));
	    } else {
		TkpDrawHighlightBorder(textPtr->tkwin, bgGC, bgGC,
			textPtr->highlightWidth, Tk_WindowId(textPtr->tkwin));
	    }
	}
	borders = textPtr->borderWidth + textPtr->highlightWidth;
	if (textPtr->padY > 0) {
	    Tk_Fill3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
		    textPtr->border, borders, borders,
		    Tk_Width(textPtr->tkwin) - 2*borders, textPtr->padY,
		    0, TK_RELIEF_FLAT);
	    Tk_Fill3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
		    textPtr->border, borders,
		    Tk_Height(textPtr->tkwin) - borders - textPtr->padY,
		    Tk_Width(textPtr->tkwin) - 2*borders,
		    textPtr->padY, 0, TK_RELIEF_FLAT);
	}
	if (textPtr->padX > 0) {
	    Tk_Fill3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
		    textPtr->border, borders, borders + textPtr->padY,
		    textPtr->padX,
		    Tk_Height(textPtr->tkwin) - 2*borders -2*textPtr->padY,
		    0, TK_RELIEF_FLAT);
	    Tk_Fill3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
		    textPtr->border,
		    Tk_Width(textPtr->tkwin) - borders - textPtr->padX,
		    borders + textPtr->padY, textPtr->padX,
		    Tk_Height(textPtr->tkwin) - 2*borders -2*textPtr->padY,
		    0, TK_RELIEF_FLAT);
	}
	dInfoPtr->flags &= ~REDRAW_BORDERS;
    }

    /*
     * Now we have to redraw the lines that couldn't be updated by scrolling.
     * First, compute the height of the largest line and allocate an off-
     * screen pixmap to use for double-buffered displays.
     */

    maxHeight = -1;
    for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL;
	    dlPtr = dlPtr->nextPtr) {
	if ((dlPtr->height > maxHeight) &&
		((dlPtr->flags&OLD_Y_INVALID) || (dlPtr->oldY != dlPtr->y))) {
	    maxHeight = dlPtr->height;
	}
	bottomY = dlPtr->y + dlPtr->height;
    }

    /*
     * There used to be a line here which restricted 'maxHeight' to be no
     * larger than 'dInfoPtr->maxY', but this is incorrect for the case where
     * individual lines may be taller than the widget _and_ we have smooth
     * scrolling. What we can do is restrict maxHeight to be no larger than
     * 'dInfoPtr->maxY + dInfoPtr->topPixelOffset'.
     */

    if (maxHeight > (dInfoPtr->maxY + dInfoPtr->topPixelOffset)) {
	maxHeight = (dInfoPtr->maxY + dInfoPtr->topPixelOffset);
    }

    if (maxHeight > 0) {
#ifndef TK_NO_DOUBLE_BUFFERING
	pixmap = Tk_GetPixmap(Tk_Display(textPtr->tkwin),
		Tk_WindowId(textPtr->tkwin), Tk_Width(textPtr->tkwin),
		maxHeight, Tk_Depth(textPtr->tkwin));
#else
	pixmap = Tk_WindowId(textPtr->tkwin);
#endif /* TK_NO_DOUBLE_BUFFERING */
	for (prevPtr = NULL, dlPtr = textPtr->dInfoPtr->dLinePtr;
		(dlPtr != NULL) && (dlPtr->y < dInfoPtr->maxY);
		prevPtr = dlPtr, dlPtr = dlPtr->nextPtr) {
	    if (dlPtr->chunkPtr == NULL) {
		continue;
	    }
	    if ((dlPtr->flags & OLD_Y_INVALID) || dlPtr->oldY != dlPtr->y) {
		if (tkTextDebug) {
		    char string[TK_POS_CHARS];

		    TkTextPrintIndex(textPtr, &dlPtr->index, string);
		    LOG("tk_textRedraw", string);
		}
		DisplayDLine(textPtr, dlPtr, prevPtr, pixmap);
		if (dInfoPtr->dLinesInvalidated) {
#ifndef TK_NO_DOUBLE_BUFFERING
		    Tk_FreePixmap(Tk_Display(textPtr->tkwin), pixmap);
#endif /* TK_NO_DOUBLE_BUFFERING */
		    return;
		}
		dlPtr->oldY = dlPtr->y;
		dlPtr->flags &= ~(NEW_LAYOUT | OLD_Y_INVALID);
	    } else if (dlPtr->chunkPtr != NULL && ((dlPtr->y < 0)
		    || (dlPtr->y + dlPtr->height > dInfoPtr->maxY))) {
		register TkTextDispChunk *chunkPtr;

		/*
		 * It's the first or last DLine which are also overlapping the
		 * top or bottom of the window, but we decided above it wasn't
		 * necessary to display them (we were able to update them by
		 * scrolling). This is fine, except that if the lines contain
		 * any embedded windows, we must still call the display proc
		 * on them because they might need to be unmapped or they
		 * might need to be moved to reflect their new position.
		 * Otherwise, everything else moves, but the embedded window
		 * doesn't!
		 *
		 * So, we loop through all the chunks, calling the display
		 * proc of embedded windows only.
		 */

		for (chunkPtr = dlPtr->chunkPtr; (chunkPtr != NULL);
			chunkPtr = chunkPtr->nextPtr) {
		    int x;
		    if (chunkPtr->displayProc != TkTextEmbWinDisplayProc) {
			continue;
		    }
		    x = chunkPtr->x + dInfoPtr->x - dInfoPtr->curXPixelOffset;
		    if ((x + chunkPtr->width <= 0) || (x >= dInfoPtr->maxX)) {
			/*
			 * Note: we have to call the displayProc even for
			 * chunks that are off-screen. This is needed, for
			 * example, so that embedded windows can be unmapped
			 * in this case. Display the chunk at a coordinate
			 * that can be clearly identified by the displayProc
			 * as being off-screen to the left (the displayProc
			 * may not be able to tell if something is off to the
			 * right).
			 */

			x = -chunkPtr->width;
		    }
		    TkTextEmbWinDisplayProc(textPtr, chunkPtr, x,
			    dlPtr->spaceAbove,
			    dlPtr->height-dlPtr->spaceAbove-dlPtr->spaceBelow,
			    dlPtr->baseline - dlPtr->spaceAbove, NULL,
			    (Drawable) None, dlPtr->y + dlPtr->spaceAbove);
		}

	    }
	}
#ifndef TK_NO_DOUBLE_BUFFERING
	Tk_FreePixmap(Tk_Display(textPtr->tkwin), pixmap);
#endif /* TK_NO_DOUBLE_BUFFERING */
    }

    /*
     * See if we need to refresh the part of the window below the last line of
     * text (if there is any such area). Refresh the padding area on the left
     * too, since the insertion cursor might have been displayed there
     * previously).
     */

    if (dInfoPtr->topOfEof > dInfoPtr->maxY) {
	dInfoPtr->topOfEof = dInfoPtr->maxY;
    }
    if (bottomY < dInfoPtr->topOfEof) {
	if (tkTextDebug) {
	    LOG("tk_textRedraw", "eof");
	}

	if ((textPtr->tkwin == NULL) || (textPtr->flags & DESTROYED)) {
	    /*
	     * The widget has been deleted. Don't do anything.
	     */

	    goto end;
	}

	Tk_Fill3DRectangle(textPtr->tkwin, Tk_WindowId(textPtr->tkwin),
		textPtr->border, dInfoPtr->x - textPtr->padX, bottomY,
		dInfoPtr->maxX - (dInfoPtr->x - textPtr->padX),
		dInfoPtr->topOfEof-bottomY, 0, TK_RELIEF_FLAT);
    }
    dInfoPtr->topOfEof = bottomY;

    /*
     * Update the vertical scrollbar, if there is one. Note: it's important to
     * clear REDRAW_PENDING here, just in case the scroll function does
     * something that requires redisplay.
     */

  doScrollbars:
    if (textPtr->flags & UPDATE_SCROLLBARS) {
	textPtr->flags &= ~UPDATE_SCROLLBARS;
	if (textPtr->yScrollCmd != NULL) {
	    GetYView(textPtr->interp, textPtr, 1);
	}

	if ((textPtr->tkwin == NULL) || (textPtr->flags & DESTROYED)) {
	    /*
	     * The widget has been deleted. Don't do anything.
	     */

	    goto end;
	}

	/*
	 * Update the horizontal scrollbar, if any.
	 */

	if (textPtr->xScrollCmd != NULL) {
	    GetXView(textPtr->interp, textPtr, 1);
	}
    }

  end:
    Tcl_Release((ClientData) interp);
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextEventuallyRepick --
 *
 *	This function is invoked whenever something happens that could change
 *	the current character or the tags associated with it.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	A repick is scheduled as an idle handler.
 *
 *----------------------------------------------------------------------
 */

void
TkTextEventuallyRepick(
    TkText *textPtr)		/* Widget record for text widget. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;

    dInfoPtr->flags |= REPICK_NEEDED;
    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
	dInfoPtr->flags |= REDRAW_PENDING;
	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextRedrawRegion --
 *
 *	This function is invoked to schedule a redisplay for a given region of
 *	a text widget. The redisplay itself may not occur immediately: it's
 *	scheduled as a when-idle handler.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Information will eventually be redrawn on the screen.
 *
 *----------------------------------------------------------------------
 */

void
TkTextRedrawRegion(
    TkText *textPtr,		/* Widget record for text widget. */
    int x, int y,		/* Coordinates of upper-left corner of area to
				 * be redrawn, in pixels relative to textPtr's
				 * window. */
    int width, int height)	/* Width and height of area to be redrawn. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    TkRegion damageRgn = TkCreateRegion();
    XRectangle rect;

    rect.x = x;
    rect.y = y;
    rect.width = width;
    rect.height = height;
    TkUnionRectWithRegion(&rect, damageRgn, damageRgn);

    TextInvalidateRegion(textPtr, damageRgn);

    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
	dInfoPtr->flags |= REDRAW_PENDING;
	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
    }
    TkDestroyRegion(damageRgn);
}

/*
 *----------------------------------------------------------------------
 *
 * TextInvalidateRegion --
 *
 *	Mark a region of text as invalid.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Updates the display information for the text widget.
 *
 *----------------------------------------------------------------------
 */

static void
TextInvalidateRegion(
    TkText *textPtr,		/* Widget record for text widget. */
    TkRegion region)		/* Region of area to redraw. */
{
    register DLine *dlPtr;
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    int maxY, inset;
    XRectangle rect;

    /*
     * Find all lines that overlap the given region and mark them for
     * redisplay.
     */

    TkClipBox(region, &rect);
    maxY = rect.y + rect.height;
    for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL;
	    dlPtr = dlPtr->nextPtr) {
	if ((!(dlPtr->flags & OLD_Y_INVALID))
		&& (TkRectInRegion(region, rect.x, dlPtr->y,
		rect.width, (unsigned int) dlPtr->height) != RectangleOut)) {
	    dlPtr->flags |= OLD_Y_INVALID;
	}
    }
    if (dInfoPtr->topOfEof < maxY) {
	dInfoPtr->topOfEof = maxY;
    }

    /*
     * Schedule the redisplay operation if there isn't one already scheduled.
     */

    inset = textPtr->borderWidth + textPtr->highlightWidth;
    if ((rect.x < (inset + textPtr->padX))
	    || (rect.y < (inset + textPtr->padY))
	    || ((int) (rect.x + rect.width) > (Tk_Width(textPtr->tkwin)
		    - inset - textPtr->padX))
	    || (maxY > (Tk_Height(textPtr->tkwin) - inset - textPtr->padY))) {
	dInfoPtr->flags |= REDRAW_BORDERS;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextChanged, TextChanged --
 *
 *	This function is invoked when info in a text widget is about to be
 *	modified in a way that changes how it is displayed (e.g. characters
 *	were inserted or deleted, or tag information was changed). This
 *	function must be called *before* a change is made, so that indexes in
 *	the display information are still valid.
 *
 *	Note: if the range of indices may change geometry as well as simply
 *	requiring redisplay, then the caller should also call
 *	TkTextInvalidateLineMetrics.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The range of character between index1Ptr (inclusive) and index2Ptr
 *	(exclusive) will be redisplayed at some point in the future (the
 *	actual redisplay is scheduled as a when-idle handler).
 *
 *----------------------------------------------------------------------
 */

void
TkTextChanged(
    TkSharedText *sharedTextPtr,/* Shared widget section, or NULL. */
    TkText *textPtr,		/* Widget record for text widget, or NULL. */
    CONST TkTextIndex*index1Ptr,/* Index of first character to redisplay. */
    CONST TkTextIndex*index2Ptr)/* Index of character just after last one to
				 * redisplay. */
{
    if (sharedTextPtr == NULL) {
	TextChanged(textPtr, index1Ptr, index2Ptr);
    } else {
	textPtr = sharedTextPtr->peers;
	while (textPtr != NULL) {
	    TextChanged(textPtr, index1Ptr, index2Ptr);
	    textPtr = textPtr->next;
	}
    }
}

static void
TextChanged(
    TkText *textPtr,		/* Widget record for text widget, or NULL. */
    CONST TkTextIndex*index1Ptr,/* Index of first character to redisplay. */
    CONST TkTextIndex*index2Ptr)/* Index of character just after last one to
				 * redisplay. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    DLine *firstPtr, *lastPtr;
    TkTextIndex rounded;
    TkTextLine *linePtr;
    int notBegin;

    /*
     * Schedule both a redisplay and a recomputation of display information.
     * It's done here rather than the end of the function for two reasons:
     *
     * 1. If there are no display lines to update we'll want to return
     *	  immediately, well before the end of the function.
     * 2. It's important to arrange for the redisplay BEFORE calling
     *	  FreeDLines. The reason for this is subtle and has to do with
     *	  embedded windows. The chunk delete function for an embedded window
     *	  will schedule an idle handler to unmap the window. However, we want
     *	  the idle handler for redisplay to be called first, so that it can
     *	  put the embedded window back on the screen again (if appropriate).
     *	  This will prevent the window from ever being unmapped, and thereby
     *	  avoid flashing.
     */

    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
    }
    dInfoPtr->flags |= REDRAW_PENDING|DINFO_OUT_OF_DATE|REPICK_NEEDED;

    /*
     * Find the DLines corresponding to index1Ptr and index2Ptr. There is one
     * tricky thing here, which is that we have to relayout in units of whole
     * text lines: This is necessary because the indices stored in the display
     * lines will no longer be valid. It's also needed because any edit could
     * change the way lines wrap.
     * To relayout in units of whole text (logical) lines, round index1Ptr
     * back to the beginning of its text line (or, if this line start is
     * elided, to the beginning of the text line that starts the display line
     * it is included in), and include all the display lines after index2Ptr,
     * up to the end of its text line (or, if this line end is elided, up to
     * the end of the first non elided text line after this line end).
     */

    rounded = *index1Ptr;
    do {
        rounded.byteIndex = 0;
        notBegin = !TkTextIndexBackBytes(textPtr, &rounded, 1, &rounded);
    } while (TkTextIsElided(textPtr, &rounded, NULL) && notBegin);
    if (notBegin) {
        TkTextIndexForwBytes(textPtr, &rounded, 1, &rounded);
    }

    /*
     * 'rounded' now points to the start of a display line as well as the
     * real (non elided) start of a logical line, and this index is the
     * closest before index1Ptr.
     */

    firstPtr = FindDLine(textPtr, dInfoPtr->dLinePtr, &rounded);

    if (firstPtr == NULL) {

        /*
         * index1Ptr pertains to no display line, i.e this index is after
         * the last display line. Since index2Ptr is after index1Ptr, there
         * are no display line to free/redisplay and we can return early.
         */

	return;
    }

    rounded = *index2Ptr;
    linePtr = index2Ptr->linePtr;
    do {
        linePtr = TkBTreeNextLine(textPtr, linePtr);
        if (linePtr == NULL) {
            break;
        }
        rounded.linePtr = linePtr;
        rounded.byteIndex = 0;
        TkTextIndexBackBytes(textPtr, &rounded, 1, &rounded);
    } while (TkTextIsElided(textPtr, &rounded, NULL));

    if (linePtr == NULL) {
        lastPtr = NULL;
    } else {
        TkTextIndexForwBytes(textPtr, &rounded, 1, &rounded);

        /*
         * 'rounded' now points to the start of a display line as well as the
         * real (non elided) start of a logical line, and this index is the
         * closest after index2Ptr.
         */

        lastPtr = FindDLine(textPtr, dInfoPtr->dLinePtr, &rounded);

        /*
         * At least one display line is supposed to change. This makes the
         * redisplay OK in case the display line we expect to get here was
         * unlinked by a previous call to TkTextChanged and the text widget
         * did not update before reaching this point. This happens for
         * instance when moving the cursor up one line.
         * Note that lastPtr != NULL here, otherwise we would have returned
         * earlier when we tested for firstPtr being NULL.
         */
        if (lastPtr == firstPtr) {
            lastPtr = lastPtr->nextPtr;
        }
    }

    /*
     * Delete all the DLines from firstPtr up to but not including lastPtr.
     */

    FreeDLines(textPtr, firstPtr, lastPtr, DLINE_UNLINK);
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextRedrawTag, TextRedrawTag --
 *
 *	This function is invoked to request a redraw of all characters in a
 *	given range that have a particular tag on or off. It's called, for
 *	example, when tag options change.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Information on the screen may be redrawn, and the layout of the screen
 *	may change.
 *
 *----------------------------------------------------------------------
 */

void
TkTextRedrawTag(
    TkSharedText *sharedTextPtr,/* Shared widget section, or NULL. */
    TkText *textPtr,		/* Widget record for text widget. */
    TkTextIndex *index1Ptr,	/* First character in range to consider for
				 * redisplay. NULL means start at beginning of
				 * text. */
    TkTextIndex *index2Ptr,	/* Character just after last one to consider
				 * for redisplay. NULL means process all the
				 * characters in the text. */
    TkTextTag *tagPtr,		/* Information about tag. */
    int withTag)		/* 1 means redraw characters that have the
				 * tag, 0 means redraw those without. */
{
    if (sharedTextPtr == NULL) {
	TextRedrawTag(textPtr, index1Ptr, index2Ptr, tagPtr, withTag);
    } else {
	textPtr = sharedTextPtr->peers;
	while (textPtr != NULL) {
	    TextRedrawTag(textPtr, index1Ptr, index2Ptr, tagPtr, withTag);
	    textPtr = textPtr->next;
	}
    }
}

static void
TextRedrawTag(
    TkText *textPtr,		/* Widget record for text widget. */
    TkTextIndex *index1Ptr,	/* First character in range to consider for
				 * redisplay. NULL means start at beginning of
				 * text. */
    TkTextIndex *index2Ptr,	/* Character just after last one to consider
				 * for redisplay. NULL means process all the
				 * characters in the text. */
    TkTextTag *tagPtr,		/* Information about tag. */
    int withTag)		/* 1 means redraw characters that have the
				 * tag, 0 means redraw those without. */
{
    register DLine *dlPtr;
    DLine *endPtr;
    int tagOn;
    TkTextSearch search;
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    TkTextIndex *curIndexPtr;
    TkTextIndex endOfText, *endIndexPtr;

    /*
     * Invalidate the pixel calculation of all lines in the given range. This
     * may be a bit over-aggressive, so we could consider more subtle
     * techniques here in the future. In particular, when we create a tag for
     * the first time with '.t tag configure foo -font "Arial 20"', say, even
     * though that obviously can't apply to anything at all (the tag didn't
     * exist a moment ago), we invalidate every single line in the widget.
     */

    if (tagPtr->affectsDisplayGeometry) {
	TkTextLine *startLine, *endLine;
	int lineCount;

	if (index2Ptr == NULL) {
	    endLine = NULL;
	    lineCount = TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr);
	} else {
	    endLine = index2Ptr->linePtr;
	    lineCount = TkBTreeLinesTo(textPtr, endLine);
	}
	if (index1Ptr == NULL) {
	    startLine = NULL;
	} else {
	    startLine = index1Ptr->linePtr;
	    lineCount -= TkBTreeLinesTo(textPtr, startLine);
	}
	TkTextInvalidateLineMetrics(NULL, textPtr, startLine, lineCount,
		TK_TEXT_INVALIDATE_ONLY);
    }

    /*
     * Round up the starting position if it's before the first line visible on
     * the screen (we only care about what's on the screen).
     */

    dlPtr = dInfoPtr->dLinePtr;
    if (dlPtr == NULL) {
	return;
    }
    if ((index1Ptr == NULL) || (TkTextIndexCmp(&dlPtr->index, index1Ptr)>0)) {
	index1Ptr = &dlPtr->index;
    }

    /*
     * Set the stopping position if it wasn't specified.
     */

    if (index2Ptr == NULL) {
	int lastLine = TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr);

	index2Ptr = TkTextMakeByteIndex(textPtr->sharedTextPtr->tree, textPtr,
		lastLine, 0, &endOfText);
    }

    /*
     * Initialize a search through all transitions on the tag, starting with
     * the first transition where the tag's current state is different from
     * what it will eventually be.
     */

    TkBTreeStartSearch(index1Ptr, index2Ptr, tagPtr, &search);

    /*
     * Make our own curIndex because at this point search.curIndex may not
     * equal index1Ptr->curIndex in the case the first tag toggle comes after
     * index1Ptr (See the use of FindTagStart in TkBTreeStartSearch).
     */

    curIndexPtr = index1Ptr;
    tagOn = TkBTreeCharTagged(index1Ptr, tagPtr);
    if (tagOn != withTag) {
	if (!TkBTreeNextTag(&search)) {
	    return;
	}
	curIndexPtr = &search.curIndex;
    }

    /*
     * Schedule a redisplay and layout recalculation if they aren't already
     * pending. This has to be done before calling FreeDLines, for the reason
     * given in TkTextChanged.
     */

    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
    }
    dInfoPtr->flags |= REDRAW_PENDING|DINFO_OUT_OF_DATE|REPICK_NEEDED;

    /*
     * Each loop through the loop below is for one range of characters where
     * the tag's current state is different than its eventual state. At the
     * top of the loop, search contains information about the first character
     * in the range.
     */

    while (1) {
	/*
	 * Find the first DLine structure in the range. Note: if the desired
	 * character isn't the first in its text line, then look for the
	 * character just before it instead. This is needed to handle the case
	 * where the first character of a wrapped display line just got
	 * smaller, so that it now fits on the line before: need to relayout
	 * the line containing the previous character.
	 */

	if ((curIndexPtr->byteIndex == 0)
                && !TkTextIsElided(textPtr, curIndexPtr, NULL)) {
	    dlPtr = FindDLine(textPtr, dlPtr, curIndexPtr);
	} else {
	    TkTextIndex tmp;

	    tmp = *curIndexPtr;
	    tmp.byteIndex -= 1;
	    dlPtr = FindDLine(textPtr, dlPtr, &tmp);
	}
	if (dlPtr == NULL) {
	    break;
	}

	/*
	 * Find the first DLine structure that's past the end of the range.
	 */

	if (!TkBTreeNextTag(&search)) {
	    endIndexPtr = index2Ptr;
	} else {
	    curIndexPtr = &search.curIndex;
	    endIndexPtr = curIndexPtr;
	}
	endPtr = FindDLine(textPtr, dlPtr, endIndexPtr);
	if ((endPtr != NULL)
                && (TkTextIndexCmp(&endPtr->index,endIndexPtr) < 0)) {
	    endPtr = endPtr->nextPtr;
	}

	/*
	 * Delete all of the display lines in the range, so that they'll be
	 * re-layed out and redrawn.
	 */

	FreeDLines(textPtr, dlPtr, endPtr, DLINE_UNLINK);
	dlPtr = endPtr;

	/*
	 * Find the first text line in the next range.
	 */

	if (!TkBTreeNextTag(&search)) {
	    break;
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextRelayoutWindow --
 *
 *	This function is called when something has happened that invalidates
 *	the whole layout of characters on the screen, such as a change in a
 *	configuration option for the overall text widget or a change in the
 *	window size. It causes all display information to be recomputed and
 *	the window to be redrawn.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	All the display information will be recomputed for the window and the
 *	window will be redrawn.
 *
 *----------------------------------------------------------------------
 */

void
TkTextRelayoutWindow(
    TkText *textPtr,		/* Widget record for text widget. */
    int mask)			/* OR'd collection of bits showing what has
				 * changed. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    GC newGC;
    XGCValues gcValues;

    /*
     * Schedule the window redisplay. See TkTextChanged for the reason why
     * this has to be done before any calls to FreeDLines.
     */

    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
    }
    dInfoPtr->flags |= REDRAW_PENDING|REDRAW_BORDERS|DINFO_OUT_OF_DATE
	    |REPICK_NEEDED;

    /*
     * (Re-)create the graphics context for drawing the traversal highlight.
     */

    gcValues.graphics_exposures = False;
    newGC = Tk_GetGC(textPtr->tkwin, GCGraphicsExposures, &gcValues);
    if (dInfoPtr->copyGC != None) {
	Tk_FreeGC(textPtr->display, dInfoPtr->copyGC);
    }
    dInfoPtr->copyGC = newGC;

    /*
     * Throw away all the current layout information.
     */

    FreeDLines(textPtr, dInfoPtr->dLinePtr, NULL, DLINE_UNLINK);
    dInfoPtr->dLinePtr = NULL;

    /*
     * Recompute some overall things for the layout. Even if the window gets
     * very small, pretend that there's at least one pixel of drawing space in
     * it.
     */

    if (textPtr->highlightWidth < 0) {
	textPtr->highlightWidth = 0;
    }
    dInfoPtr->x = textPtr->highlightWidth + textPtr->borderWidth
	    + textPtr->padX;
    dInfoPtr->y = textPtr->highlightWidth + textPtr->borderWidth
	    + textPtr->padY;
    dInfoPtr->maxX = Tk_Width(textPtr->tkwin) - textPtr->highlightWidth
	    - textPtr->borderWidth - textPtr->padX;
    if (dInfoPtr->maxX <= dInfoPtr->x) {
	dInfoPtr->maxX = dInfoPtr->x + 1;
    }

    /*
     * This is the only place where dInfoPtr->maxY is set.
     */

    dInfoPtr->maxY = Tk_Height(textPtr->tkwin) - textPtr->highlightWidth
	    - textPtr->borderWidth - textPtr->padY;
    if (dInfoPtr->maxY <= dInfoPtr->y) {
	dInfoPtr->maxY = dInfoPtr->y + 1;
    }
    dInfoPtr->topOfEof = dInfoPtr->maxY;

    /*
     * If the upper-left character isn't the first in a line, recompute it.
     * This is necessary because a change in the window's size or options
     * could change the way lines wrap.
     */

    if (textPtr->topIndex.byteIndex != 0) {
	TkTextFindDisplayLineEnd(textPtr, &textPtr->topIndex, 0, NULL);
    }

    /*
     * Invalidate cached scrollbar positions, so that scrollbars sliders will
     * be udpated.
     */

    dInfoPtr->xScrollFirst = dInfoPtr->xScrollLast = -1;
    dInfoPtr->yScrollFirst = dInfoPtr->yScrollLast = -1;

    if (mask & TK_TEXT_LINE_GEOMETRY) {
	/*
	 * Set up line metric recalculation.
	 *
	 * Avoid the special zero value, since that is used to mark individual
	 * lines as being out of date.
	 */

	if ((++dInfoPtr->lineMetricUpdateEpoch) == 0) {
	    dInfoPtr->lineMetricUpdateEpoch++;
	}

	dInfoPtr->currentMetricUpdateLine = -1;

	/*
	 * Also cancel any partial line-height calculations (for long-wrapped
	 * lines) in progress.
	 */

	dInfoPtr->metricEpoch = -1;

	if (dInfoPtr->lineUpdateTimer == NULL) {
	    textPtr->refCount++;
	    dInfoPtr->lineUpdateTimer = Tcl_CreateTimerHandler(1,
		    AsyncUpdateLineMetrics, (ClientData) textPtr);
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextSetYView --
 *
 *	This function is called to specify what lines are to be displayed in a
 *	text widget.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The display will (eventually) be updated so that the position given by
 *	"indexPtr" is visible on the screen at the position determined by
 *	"pickPlace".
 *
 *----------------------------------------------------------------------
 */

void
TkTextSetYView(
    TkText *textPtr,		/* Widget record for text widget. */
    TkTextIndex *indexPtr,	/* Position that is to appear somewhere in the
				 * view. */
    int pickPlace)		/* 0 means the given index must appear exactly
				 * at the top of the screen. TK_TEXT_PICKPLACE
				 * (-1) means we get to pick where it appears:
				 * minimize screen motion or else display line
				 * at center of screen. TK_TEXT_NOPIXELADJUST
				 * (-2) indicates to make the given index the
				 * top line, but if it is already the top
				 * line, don't nudge it up or down by a few
				 * pixels just to make sure it is entirely
				 * displayed. Positive numbers indicate the
				 * number of pixels of the index's line which
				 * are to be off the top of the screen. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    register DLine *dlPtr;
    int bottomY, close, lineIndex;
    TkTextIndex tmpIndex, rounded;
    int lineHeight;

    /*
     * If the specified position is the extra line at the end of the text,
     * round it back to the last real line.
     */

    lineIndex = TkBTreeLinesTo(textPtr, indexPtr->linePtr);
    if (lineIndex == TkBTreeNumLines(indexPtr->tree, textPtr)) {
	TkTextIndexBackChars(textPtr, indexPtr, 1, &rounded, COUNT_INDICES);
	indexPtr = &rounded;
    }

    if (pickPlace == TK_TEXT_NOPIXELADJUST) {
	if (textPtr->topIndex.linePtr == indexPtr->linePtr
		&& textPtr->topIndex.byteIndex == indexPtr->byteIndex) {
	    pickPlace = dInfoPtr->topPixelOffset;
	} else {
	    pickPlace = 0;
	}
    }

    if (pickPlace != TK_TEXT_PICKPLACE) {
	/*
	 * The specified position must go at the top of the screen. Just leave
	 * all the DLine's alone: we may be able to reuse some of the
	 * information that's currently on the screen without redisplaying it
	 * all.
	 */

	textPtr->topIndex = *indexPtr;
        if (!(indexPtr->byteIndex == 0
                && !TkTextIsElided(textPtr, indexPtr, NULL))) {
	    TkTextFindDisplayLineEnd(textPtr, &textPtr->topIndex, 0, NULL);
	}
	dInfoPtr->newTopPixelOffset = pickPlace;
	goto scheduleUpdate;
    }

    /*
     * We have to pick where to display the index. First, bring the display
     * information up to date and see if the index will be completely visible
     * in the current screen configuration. If so then there's nothing to do.
     */

    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
	UpdateDisplayInfo(textPtr);
    }
    dlPtr = FindDLine(textPtr, dInfoPtr->dLinePtr, indexPtr);
    if (dlPtr != NULL) {
	if ((dlPtr->y + dlPtr->height) > dInfoPtr->maxY) {
	    /*
	     * Part of the line hangs off the bottom of the screen; pretend
	     * the whole line is off-screen.
	     */

	    dlPtr = NULL;
        } else {
            if (TkTextIndexCmp(&dlPtr->index, indexPtr) <= 0) {
                if (dInfoPtr->dLinePtr == dlPtr && dInfoPtr->topPixelOffset != 0) {
                    /*
                     * It is on the top line, but that line is hanging off the top
                     * of the screen. Change the top overlap to zero and update.
                     */

                    dInfoPtr->newTopPixelOffset = 0;
                    goto scheduleUpdate;
	            }
                return;
            }
        }
    }

    /*
     * The desired line isn't already on-screen. Figure out what it means to
     * be "close" to the top or bottom of the screen. Close means within 1/3
     * of the screen height or within three lines, whichever is greater.
     *
     * If the line is not close, place it in the center of the window.
     */

    tmpIndex = *indexPtr;
    TkTextFindDisplayLineEnd(textPtr, &tmpIndex, 0, NULL);
    lineHeight = CalculateDisplayLineHeight(textPtr, &tmpIndex, NULL, NULL);

    /*
     * It would be better if 'bottomY' were calculated using the actual height
     * of the given line, not 'textPtr->charHeight'.
     */

    bottomY = (dInfoPtr->y + dInfoPtr->maxY + lineHeight)/2;
    close = (dInfoPtr->maxY - dInfoPtr->y)/3;
    if (close < 3*textPtr->charHeight) {
	close = 3*textPtr->charHeight;
    }
    if (dlPtr != NULL) {
	int overlap;

	/*
	 * The desired line is above the top of screen. If it is "close" to
	 * the top of the window then make it the top line on the screen.
	 * MeasureUp counts from the bottom of the given index upwards, so we
	 * add an extra half line to be sure we count far enough.
	 */

	MeasureUp(textPtr, &textPtr->topIndex, close + textPtr->charHeight/2,
		&tmpIndex, &overlap);
	if (TkTextIndexCmp(&tmpIndex, indexPtr) <= 0) {
	    textPtr->topIndex = *indexPtr;
	    TkTextFindDisplayLineEnd(textPtr, &textPtr->topIndex, 0, NULL);
	    dInfoPtr->newTopPixelOffset = 0;
	    goto scheduleUpdate;
	}
    } else {
	int overlap;

	/*
	 * The desired line is below the bottom of the screen. If it is
	 * "close" to the bottom of the screen then position it at the bottom
	 * of the screen.
	 */

	MeasureUp(textPtr, indexPtr, close + lineHeight
		- textPtr->charHeight/2, &tmpIndex, &overlap);
	if (FindDLine(textPtr, dInfoPtr->dLinePtr, &tmpIndex) != NULL) {
	    bottomY = dInfoPtr->maxY - dInfoPtr->y;
	}
    }

    /*
     * Our job now is to arrange the display so that indexPtr appears as low
     * on the screen as possible but with its bottom no lower than bottomY.
     * BottomY is the bottom of the window if the desired line is just below
     * the current screen, otherwise it is a half-line lower than the center
     * of the window.
     */

    MeasureUp(textPtr, indexPtr, bottomY, &textPtr->topIndex,
	    &dInfoPtr->newTopPixelOffset);

  scheduleUpdate:
    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
    }
    dInfoPtr->flags |= REDRAW_PENDING|DINFO_OUT_OF_DATE|REPICK_NEEDED;
}

/*
 *--------------------------------------------------------------
 *
 * TkTextMeasureDown --
 *
 *	Given one index, find the index of the first character on the highest
 *	display line that would be displayed no more than "distance" pixels
 *	below the top of the given index.
 *
 * Results:
 *	The srcPtr is manipulated in place to reflect the new position. We
 *	return the number of pixels by which 'distance' overlaps the srcPtr.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

int
TkTextMeasureDown(
    TkText *textPtr,		/* Text widget in which to measure. */
    TkTextIndex *srcPtr,	/* Index of character from which to start
				 * measuring. */
    int distance)		/* Vertical distance in pixels measured from
				 * the top pixel in srcPtr's logical line. */
{
    TkTextLine *lastLinePtr;
    DLine *dlPtr;
    TkTextIndex loop;

    lastLinePtr = TkBTreeFindLine(textPtr->sharedTextPtr->tree, textPtr,
	    TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr));

    do {
	dlPtr = LayoutDLine(textPtr, srcPtr);
	dlPtr->nextPtr = NULL;

	if (distance < dlPtr->height) {
	    FreeDLines(textPtr, dlPtr, NULL, DLINE_FREE_TEMP);
	    break;
	}
	distance -= dlPtr->height;
	TkTextIndexForwBytes(textPtr, srcPtr, dlPtr->byteCount, &loop);
	FreeDLines(textPtr, dlPtr, NULL, DLINE_FREE_TEMP);
	if (loop.linePtr == lastLinePtr) {
	    break;
	}
	*srcPtr = loop;
    } while (distance > 0);

    return distance;
}

/*
 *--------------------------------------------------------------
 *
 * MeasureUp --
 *
 *	Given one index, find the index of the first character on the highest
 *	display line that would be displayed no more than "distance" pixels
 *	above the given index.
 *
 *	If this function is called with distance=0, it simply finds the first
 *	index on the same display line as srcPtr. However, there is a another
 *	function TkTextFindDisplayLineEnd designed just for that task which is
 *	probably better to use.
 *
 * Results:
 *	*dstPtr is filled in with the index of the first character on a
 *	display line. The display line is found by measuring up "distance"
 *	pixels above the pixel just below an imaginary display line that
 *	contains srcPtr. If the display line that covers this coordinate
 *	actually extends above the coordinate, then return any excess pixels
 *	in *overlap, if that is non-NULL.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static void
MeasureUp(
    TkText *textPtr,		/* Text widget in which to measure. */
    CONST TkTextIndex *srcPtr,	/* Index of character from which to start
				 * measuring. */
    int distance,		/* Vertical distance in pixels measured from
				 * the pixel just below the lowest one in
				 * srcPtr's line. */
    TkTextIndex *dstPtr,	/* Index to fill in with result. */
    int *overlap)		/* Used to store how much of the final index
				 * returned was not covered by 'distance'. */
{
    int lineNum;		/* Number of current line. */
    int bytesToCount;		/* Maximum number of bytes to measure in
				 * current line. */
    TkTextIndex index;
    DLine *dlPtr, *lowestPtr;

    bytesToCount = srcPtr->byteIndex + 1;
    index.tree = srcPtr->tree;
    for (lineNum = TkBTreeLinesTo(textPtr, srcPtr->linePtr); lineNum >= 0;
	    lineNum--) {
	/*
	 * Layout an entire text line (potentially > 1 display line).
	 *
	 * For the first line, which contains srcPtr, only layout the part up
	 * through srcPtr (bytesToCount is non-infinite to accomplish this).
	 * Make a list of all the display lines in backwards order (the lowest
	 * DLine on the screen is first in the list).
	 */

	index.linePtr = TkBTreeFindLine(srcPtr->tree, textPtr, lineNum);
	index.byteIndex = 0;
        TkTextFindDisplayLineEnd(textPtr, &index, 0, NULL);
        lineNum = TkBTreeLinesTo(textPtr, index.linePtr);
	lowestPtr = NULL;
	do {
	    dlPtr = LayoutDLine(textPtr, &index);
	    dlPtr->nextPtr = lowestPtr;
	    lowestPtr = dlPtr;
	    TkTextIndexForwBytes(textPtr, &index, dlPtr->byteCount, &index);
	    bytesToCount -= dlPtr->byteCount;
	} while (bytesToCount>0 && index.linePtr==dlPtr->index.linePtr);

	/*
	 * Scan through the display lines to see if we've covered enough
	 * vertical distance. If so, save the starting index for the line at
	 * the desired location. If distance was zero to start with then we
	 * simply get the first index on the same display line as the original
	 * index.
	 */

	for (dlPtr = lowestPtr; dlPtr != NULL; dlPtr = dlPtr->nextPtr) {
	    distance -= dlPtr->height;
	    if (distance <= 0) {
		*dstPtr = dlPtr->index;

                /*
                 * Adjust index to the start of the display line. This is
                 * needed because the start of a logical line is not always
                 * the start of a display line (this is however true if the
                 * eol is not elided).
                 */

                if (TkTextIsElided(textPtr, dstPtr, NULL)) {
                    TkTextFindDisplayLineEnd(textPtr, dstPtr, 0,
                            NULL);
                }
		if (overlap != NULL) {
		    *overlap = -distance;
		}
		break;
	    }
	}

	/*
	 * Discard the display lines, then either return or prepare for the
	 * next display line to lay out.
	 */

	FreeDLines(textPtr, lowestPtr, NULL, DLINE_FREE);
	if (distance <= 0) {
	    return;
	}
	bytesToCount = INT_MAX;		/* Consider all chars. in next line. */
    }

    /*
     * Ran off the beginning of the text. Return the first character in the
     * text.
     */

    TkTextMakeByteIndex(textPtr->sharedTextPtr->tree, textPtr, 0, 0, dstPtr);
    if (overlap != NULL) {
	*overlap = 0;
    }
}

/*
 *--------------------------------------------------------------
 *
 * TkTextSeeCmd --
 *
 *	This function is invoked to process the "see" option for the widget
 *	command for text widgets. See the user documentation for details on
 *	what it does.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *--------------------------------------------------------------
 */

int
TkTextSeeCmd(
    TkText *textPtr,		/* Information about text widget. */
    Tcl_Interp *interp,		/* Current interpreter. */
    int objc,			/* Number of arguments. */
    Tcl_Obj *CONST objv[])	/* Argument objects. Someone else has already
				 * parsed this command enough to know that
				 * objv[1] is "see". */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    TkTextIndex index;
    int x, y, width, height, lineWidth, byteCount, oneThird, delta;
    DLine *dlPtr;
    TkTextDispChunk *chunkPtr;

    if (objc != 3) {
	Tcl_WrongNumArgs(interp, 2, objv, "index");
	return TCL_ERROR;
    }
    if (TkTextGetObjIndex(interp, textPtr, objv[2], &index) != TCL_OK) {
	return TCL_ERROR;
    }

    /*
     * If the specified position is the extra line at the end of the text,
     * round it back to the last real line.
     */

    if (TkBTreeLinesTo(textPtr, index.linePtr)
	    == TkBTreeNumLines(index.tree, textPtr)) {
	TkTextIndexBackChars(textPtr, &index, 1, &index, COUNT_INDICES);
    }

    /*
     * First get the desired position into the vertical range of the window.
     */

    TkTextSetYView(textPtr, &index, TK_TEXT_PICKPLACE);

    /*
     * Now make sure that the character is in view horizontally.
     */

    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
	UpdateDisplayInfo(textPtr);
    }
    lineWidth = dInfoPtr->maxX - dInfoPtr->x;
    if (dInfoPtr->maxLength < lineWidth) {
	return TCL_OK;
    }

    /*
     * Find the display line containing the desired index. dlPtr may be NULL
     * if the widget is not mapped. [Bug #641778]
     */

    dlPtr = FindDLine(textPtr, dInfoPtr->dLinePtr, &index);
    if (dlPtr == NULL) {
	return TCL_OK;
    }

    /*
     * Find the chunk within the display line that contains the desired
     * index. The chunks making the display line are skipped up to but not
     * including the one crossing index. Skipping is done based on a
     * byteCount offset possibly spanning several logical lines in case
     * they are elided.
     */

    byteCount = TkTextIndexCount(textPtr, &dlPtr->index, &index,
            COUNT_INDICES);
    for (chunkPtr = dlPtr->chunkPtr; chunkPtr != NULL ;
	    chunkPtr = chunkPtr->nextPtr) {
	if (byteCount < chunkPtr->numBytes) {
	    break;
	}
	byteCount -= chunkPtr->numBytes;
    }

    /*
     * Call a chunk-specific function to find the horizontal range of the
     * character within the chunk.
     */

    (*chunkPtr->bboxProc)(textPtr, chunkPtr, byteCount,
            dlPtr->y + dlPtr->spaceAbove,
            dlPtr->height - dlPtr->spaceAbove - dlPtr->spaceBelow,
            dlPtr->baseline - dlPtr->spaceAbove, &x, &y, &width,
            &height);
    delta = x - dInfoPtr->curXPixelOffset;
    oneThird = lineWidth/3;
    if (delta < 0) {
        if (delta < -oneThird) {
            dInfoPtr->newXPixelOffset = (x - lineWidth/2);
        } else {
            dInfoPtr->newXPixelOffset -= ((-delta) );
        }
    } else {
        delta -= (lineWidth - width);
        if (delta > 0) {
            if (delta > oneThird) {
                dInfoPtr->newXPixelOffset = (x - lineWidth/2);
            } else {
                dInfoPtr->newXPixelOffset += (delta );
            }
        } else {
            return TCL_OK;
        }
    }
    dInfoPtr->flags |= DINFO_OUT_OF_DATE;
    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
	dInfoPtr->flags |= REDRAW_PENDING;
	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
    }
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * TkTextXviewCmd --
 *
 *	This function is invoked to process the "xview" option for the widget
 *	command for text widgets. See the user documentation for details on
 *	what it does.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *--------------------------------------------------------------
 */

int
TkTextXviewCmd(
    TkText *textPtr,		/* Information about text widget. */
    Tcl_Interp *interp,		/* Current interpreter. */
    int objc,			/* Number of arguments. */
    Tcl_Obj *CONST objv[])	/* Argument objects. Someone else has already
				 * parsed this command enough to know that
				 * objv[1] is "xview". */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    int type, count;
    double fraction;

    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
	UpdateDisplayInfo(textPtr);
    }

    if (objc == 2) {
	GetXView(interp, textPtr, 0);
	return TCL_OK;
    }

    type = TextGetScrollInfoObj(interp, textPtr, objc, objv,
	    &fraction, &count);
    switch (type) {
    case TKTEXT_SCROLL_ERROR:
	return TCL_ERROR;
    case TKTEXT_SCROLL_MOVETO:
	if (fraction > 1.0) {
	    fraction = 1.0;
	}
	if (fraction < 0) {
	    fraction = 0;
	}
	dInfoPtr->newXPixelOffset = (int)
		(fraction * dInfoPtr->maxLength + 0.5);
	break;
    case TKTEXT_SCROLL_PAGES: {
	int pixelsPerPage;

	pixelsPerPage = (dInfoPtr->maxX-dInfoPtr->x) - 2*textPtr->charWidth;
	if (pixelsPerPage < 1) {
	    pixelsPerPage = 1;
	}
	dInfoPtr->newXPixelOffset += pixelsPerPage * count;
	break;
    }
    case TKTEXT_SCROLL_UNITS:
	dInfoPtr->newXPixelOffset += count * textPtr->charWidth;
	break;
    case TKTEXT_SCROLL_PIXELS:
	dInfoPtr->newXPixelOffset += count;
	break;
    }

    dInfoPtr->flags |= DINFO_OUT_OF_DATE;
    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
	dInfoPtr->flags |= REDRAW_PENDING;
	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * YScrollByPixels --
 *
 *	This function is called to scroll a text widget up or down by a given
 *	number of pixels.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The view in textPtr's window changes to reflect the value of "offset".
 *
 *----------------------------------------------------------------------
 */

static void
YScrollByPixels(
    TkText *textPtr,		/* Widget to scroll. */
    int offset)			/* Amount by which to scroll, in pixels.
				 * Positive means that information later in
				 * text becomes visible, negative means that
				 * information earlier in the text becomes
				 * visible. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;

    if (offset < 0) {
	/*
	 * Now we want to measure up this number of pixels from the top of the
	 * screen. But the top line may not be totally visible. Note that
	 * 'count' is negative here.
	 */

	offset -= CalculateDisplayLineHeight(textPtr,
		&textPtr->topIndex, NULL, NULL) - dInfoPtr->topPixelOffset;
	MeasureUp(textPtr, &textPtr->topIndex, -offset,
		&textPtr->topIndex, &dInfoPtr->newTopPixelOffset);
    } else if (offset > 0) {
	DLine *dlPtr;
	TkTextLine *lastLinePtr;
	TkTextIndex newIdx;

	/*
	 * Scrolling down by pixels. Layout lines starting at the top index
	 * and count through the desired vertical distance.
	 */

	lastLinePtr = TkBTreeFindLine(textPtr->sharedTextPtr->tree, textPtr,
		TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr));
	offset += dInfoPtr->topPixelOffset;
	dInfoPtr->newTopPixelOffset = 0;
	while (offset > 0) {
	    dlPtr = LayoutDLine(textPtr, &textPtr->topIndex);
	    dlPtr->nextPtr = NULL;
	    TkTextIndexForwBytes(textPtr, &textPtr->topIndex,
		    dlPtr->byteCount, &newIdx);
	    if (offset <= dlPtr->height) {
		/*
		 * Adjust the top overlap accordingly.
		 */

		dInfoPtr->newTopPixelOffset = offset;
	    }
	    offset -= dlPtr->height;
	    FreeDLines(textPtr, dlPtr, NULL, DLINE_FREE_TEMP);
	    if (newIdx.linePtr == lastLinePtr || offset <= 0) {
		break;
	    }
	    textPtr->topIndex = newIdx;
	}
    } else {
	/*
	 * offset = 0, so no scrolling required.
	 */

	return;
    }
    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
    }
    dInfoPtr->flags |= REDRAW_PENDING|DINFO_OUT_OF_DATE|REPICK_NEEDED;
}

/*
 *----------------------------------------------------------------------
 *
 * YScrollByLines --
 *
 *	This function is called to scroll a text widget up or down by a given
 *	number of lines.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The view in textPtr's window changes to reflect the value of "offset".
 *
 *----------------------------------------------------------------------
 */

static void
YScrollByLines(
    TkText *textPtr,		/* Widget to scroll. */
    int offset)			/* Amount by which to scroll, in display
				 * lines. Positive means that information
				 * later in text becomes visible, negative
				 * means that information earlier in the text
				 * becomes visible. */
{
    int i, bytesToCount, lineNum;
    TkTextIndex newIdx, index;
    TkTextLine *lastLinePtr;
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    DLine *dlPtr, *lowestPtr;

    if (offset < 0) {
	/*
	 * Must scroll up (to show earlier information in the text). The code
	 * below is similar to that in MeasureUp, except that it counts lines
	 * instead of pixels.
	 */

	bytesToCount = textPtr->topIndex.byteIndex + 1;
	index.tree = textPtr->sharedTextPtr->tree;
	offset--;		/* Skip line containing topIndex. */
	for (lineNum = TkBTreeLinesTo(textPtr, textPtr->topIndex.linePtr);
		lineNum >= 0; lineNum--) {
	    index.linePtr = TkBTreeFindLine(textPtr->sharedTextPtr->tree,
		    textPtr, lineNum);
	    index.byteIndex = 0;
	    lowestPtr = NULL;
	    do {
		dlPtr = LayoutDLine(textPtr, &index);
		dlPtr->nextPtr = lowestPtr;
		lowestPtr = dlPtr;
		TkTextIndexForwBytes(textPtr, &index, dlPtr->byteCount,&index);
		bytesToCount -= dlPtr->byteCount;
	    } while ((bytesToCount > 0)
		    && (index.linePtr == dlPtr->index.linePtr));

	    for (dlPtr = lowestPtr; dlPtr != NULL; dlPtr = dlPtr->nextPtr) {
		offset++;
		if (offset == 0) {
		    textPtr->topIndex = dlPtr->index;

                    /*
                     * Adjust index to the start of the display line. This is
                     * needed because the start of a logical line is not
                     * always the start of a display line (this is however
                     * true if the eol is not elided).
                     */

                    if (TkTextIsElided(textPtr, &textPtr->topIndex, NULL)) {
                        TkTextFindDisplayLineEnd(textPtr, &textPtr->topIndex, 0,
                                NULL);
                    }
		    break;
		}
	    }

	    /*
	     * Discard the display lines, then either return or prepare for
	     * the next display line to lay out.
	     */

	    FreeDLines(textPtr, lowestPtr, NULL, DLINE_FREE);
	    if (offset >= 0) {
		goto scheduleUpdate;
	    }
	    bytesToCount = INT_MAX;
	}

	/*
	 * Ran off the beginning of the text. Return the first character in
	 * the text, and make sure we haven't left anything overlapping the
	 * top window border.
	 */

	TkTextMakeByteIndex(textPtr->sharedTextPtr->tree, textPtr, 0, 0,
		&textPtr->topIndex);
	dInfoPtr->newTopPixelOffset = 0;
    } else {
	/*
	 * Scrolling down, to show later information in the text. Just count
	 * lines from the current top of the window.
	 */

	lastLinePtr = TkBTreeFindLine(textPtr->sharedTextPtr->tree, textPtr,
		TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr));
	for (i = 0; i < offset; i++) {
	    dlPtr = LayoutDLine(textPtr, &textPtr->topIndex);
	    if (dlPtr->length == 0 && dlPtr->height == 0) {
		offset++;
	    }
	    dlPtr->nextPtr = NULL;
	    TkTextIndexForwBytes(textPtr, &textPtr->topIndex,
		    dlPtr->byteCount, &newIdx);
	    FreeDLines(textPtr, dlPtr, NULL, DLINE_FREE);
	    if (newIdx.linePtr == lastLinePtr) {
		break;
	    }
	    textPtr->topIndex = newIdx;
	}
    }

  scheduleUpdate:
    if (!(dInfoPtr->flags & REDRAW_PENDING)) {
	Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
    }
    dInfoPtr->flags |= REDRAW_PENDING|DINFO_OUT_OF_DATE|REPICK_NEEDED;
}

/*
 *--------------------------------------------------------------
 *
 * TkTextYviewCmd --
 *
 *	This function is invoked to process the "yview" option for the widget
 *	command for text widgets. See the user documentation for details on
 *	what it does.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *--------------------------------------------------------------
 */

int
TkTextYviewCmd(
    TkText *textPtr,		/* Information about text widget. */
    Tcl_Interp *interp,		/* Current interpreter. */
    int objc,			/* Number of arguments. */
    Tcl_Obj *CONST objv[])	/* Argument objects. Someone else has already
				 * parsed this command enough to know that
				 * objv[1] is "yview". */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    int pickPlace, type;
    int pixels, count;
    int switchLength;
    double fraction;
    TkTextIndex index;

    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
	UpdateDisplayInfo(textPtr);
    }

    if (objc == 2) {
	GetYView(interp, textPtr, 0);
	return TCL_OK;
    }

    /*
     * Next, handle the old syntax: "pathName yview ?-pickplace? where"
     */

    pickPlace = 0;
    if (Tcl_GetString(objv[2])[0] == '-') {
	register CONST char *switchStr =
		Tcl_GetStringFromObj(objv[2], &switchLength);

	if ((switchLength >= 2) && (strncmp(switchStr, "-pickplace",
		(unsigned) switchLength) == 0)) {
	    pickPlace = 1;
	    if (objc != 4) {
		Tcl_WrongNumArgs(interp, 3, objv, "lineNum|index");
		return TCL_ERROR;
	    }
	}
    }
    if ((objc == 3) || pickPlace) {
	int lineNum;

	if (Tcl_GetIntFromObj(interp, objv[2+pickPlace], &lineNum) == TCL_OK) {
	    TkTextMakeByteIndex(textPtr->sharedTextPtr->tree, textPtr,
		    lineNum, 0, &index);
	    TkTextSetYView(textPtr, &index, 0);
	    return TCL_OK;
	}

	/*
	 * The argument must be a regular text index.
	 */

	Tcl_ResetResult(interp);
	if (TkTextGetObjIndex(interp, textPtr, objv[2+pickPlace],
		&index) != TCL_OK) {
	    return TCL_ERROR;
	}
	TkTextSetYView(textPtr, &index, (pickPlace ? TK_TEXT_PICKPLACE : 0));
	return TCL_OK;
    }

    /*
     * New syntax: dispatch based on objv[2].
     */

    type = TextGetScrollInfoObj(interp, textPtr, objc,objv, &fraction, &count);
    switch (type) {
    case TKTEXT_SCROLL_ERROR:
	return TCL_ERROR;
    case TKTEXT_SCROLL_MOVETO: {
	int numPixels = TkBTreeNumPixels(textPtr->sharedTextPtr->tree,
		textPtr);
	int topMostPixel;

	if (numPixels == 0) {
	    /*
	     * If the window is totally empty no scrolling is needed, and the
	     * TkTextMakePixelIndex call below will fail.
	     */

	    break;
	}
	if (fraction > 1.0) {
	    fraction = 1.0;
	}
	if (fraction < 0) {
	    fraction = 0;
	}

	/*
	 * Calculate the pixel count for the new topmost pixel in the topmost
	 * line of the window. Note that the interpretation of 'fraction' is
	 * that it counts from 0 (top pixel in buffer) to 1.0 (one pixel past
	 * the last pixel in buffer).
	 */

	topMostPixel = (int) (0.5 + fraction * numPixels);
	if (topMostPixel >= numPixels) {
	    topMostPixel = numPixels -1;
	}

	/*
	 * This function returns the number of pixels by which the given line
	 * should overlap the top of the visible screen.
	 *
	 * This is then used to provide smooth scrolling.
	 */

	pixels = TkTextMakePixelIndex(textPtr, topMostPixel, &index);
	TkTextSetYView(textPtr, &index, pixels);
	break;
    }
    case TKTEXT_SCROLL_PAGES: {
	/*
	 * Scroll up or down by screenfuls. Actually, use the window height
	 * minus two lines, so that there's some overlap between adjacent
	 * pages.
	 */

	int height = dInfoPtr->maxY - dInfoPtr->y;

	if (textPtr->charHeight * 4 >= height) {
	    /*
	     * A single line is more than a quarter of the display. We choose
	     * to scroll by 3/4 of the height instead.
	     */

	    pixels = 3*height/4;
	    if (pixels < textPtr->charHeight) {
		/*
		 * But, if 3/4 of the height is actually less than a single
		 * typical character height, then scroll by the minimum of the
		 * linespace or the total height.
		 */

		if (textPtr->charHeight < height) {
		    pixels = textPtr->charHeight;
		} else {
		    pixels = height;
		}
	    }
	    pixels *= count;
	} else {
	    pixels = (height - 2*textPtr->charHeight)*count;
	}
	YScrollByPixels(textPtr, pixels);
	break;
    }
    case TKTEXT_SCROLL_PIXELS:
	YScrollByPixels(textPtr, count);
	break;
    case TKTEXT_SCROLL_UNITS:
	YScrollByLines(textPtr, count);
	break;
    }
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * TkTextScanCmd --
 *
 *	This function is invoked to process the "scan" option for the widget
 *	command for text widgets. See the user documentation for details on
 *	what it does.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *--------------------------------------------------------------
 */

int
TkTextScanCmd(
    register TkText *textPtr,	/* Information about text widget. */
    Tcl_Interp *interp,		/* Current interpreter. */
    int objc,			/* Number of arguments. */
    Tcl_Obj *CONST objv[])	/* Argument objects. Someone else has already
				 * parsed this command enough to know that
				 * objv[1] is "scan". */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    TkTextIndex index;
    int c, x, y, totalScroll, gain=10;
    size_t length;

    if ((objc != 5) && (objc != 6)) {
	Tcl_WrongNumArgs(interp, 2, objv, "mark x y");
	Tcl_AppendResult(interp, " or \"", Tcl_GetString(objv[0]),
		" scan dragto x y ?gain?\"", NULL);
	/*
	 * Ought to be:
	 * Tcl_WrongNumArgs(interp, 2, objc, "dragto x y ?gain?");
	 */
	return TCL_ERROR;
    }
    if (Tcl_GetIntFromObj(interp, objv[3], &x) != TCL_OK) {
	return TCL_ERROR;
    }
    if (Tcl_GetIntFromObj(interp, objv[4], &y) != TCL_OK) {
	return TCL_ERROR;
    }
    if ((objc == 6) && (Tcl_GetIntFromObj(interp, objv[5], &gain) != TCL_OK)) {
	return TCL_ERROR;
    }
    c = Tcl_GetString(objv[2])[0];
    length = strlen(Tcl_GetString(objv[2]));
    if (c=='d' && strncmp(Tcl_GetString(objv[2]), "dragto", length)==0) {
	int newX, maxX;

	/*
	 * Amplify the difference between the current position and the mark
	 * position to compute how much the view should shift, then update the
	 * mark position to correspond to the new view. If we run off the edge
	 * of the text, reset the mark point so that the current position
	 * continues to correspond to the edge of the window. This means that
	 * the picture will start dragging as soon as the mouse reverses
	 * direction (without this reset, might have to slide mouse a long
	 * ways back before the picture starts moving again).
	 */

	newX = dInfoPtr->scanMarkXPixel + gain*(dInfoPtr->scanMarkX - x);
	maxX = 1 + dInfoPtr->maxLength - (dInfoPtr->maxX - dInfoPtr->x);
	if (newX < 0) {
	    newX = 0;
	    dInfoPtr->scanMarkXPixel = 0;
	    dInfoPtr->scanMarkX = x;
	} else if (newX > maxX) {
	    newX = maxX;
	    dInfoPtr->scanMarkXPixel = maxX;
	    dInfoPtr->scanMarkX = x;
	}
	dInfoPtr->newXPixelOffset = newX;

	totalScroll = gain*(dInfoPtr->scanMarkY - y);
	if (totalScroll != dInfoPtr->scanTotalYScroll) {
	    index = textPtr->topIndex;
	    YScrollByPixels(textPtr, totalScroll-dInfoPtr->scanTotalYScroll);
	    dInfoPtr->scanTotalYScroll = totalScroll;
	    if ((index.linePtr == textPtr->topIndex.linePtr) &&
		    (index.byteIndex == textPtr->topIndex.byteIndex)) {
		dInfoPtr->scanTotalYScroll = 0;
		dInfoPtr->scanMarkY = y;
	    }
	}
	dInfoPtr->flags |= DINFO_OUT_OF_DATE;
	if (!(dInfoPtr->flags & REDRAW_PENDING)) {
	    dInfoPtr->flags |= REDRAW_PENDING;
	    Tcl_DoWhenIdle(DisplayText, (ClientData) textPtr);
	}
    } else if (c=='m' && strncmp(Tcl_GetString(objv[2]), "mark", length)==0) {
	dInfoPtr->scanMarkXPixel = dInfoPtr->newXPixelOffset;
	dInfoPtr->scanMarkX = x;
	dInfoPtr->scanTotalYScroll = 0;
	dInfoPtr->scanMarkY = y;
    } else {
	Tcl_AppendResult(interp, "bad scan option \"", Tcl_GetString(objv[2]),
		"\": must be mark or dragto", NULL);
	return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * GetXView --
 *
 *	This function computes the fractions that indicate what's visible in a
 *	text window and, optionally, evaluates a Tcl script to report them to
 *	the text's associated scrollbar.
 *
 * Results:
 *	If report is zero, then the interp's result is filled in with two real
 *	numbers separated by a space, giving the position of the left and
 *	right edges of the window as fractions from 0 to 1, where 0 means the
 *	left edge of the text and 1 means the right edge. If report is
 *	non-zero, then the interp's result isn't modified directly, but
 *	instead a script is evaluated in interp to report the new horizontal
 *	scroll position to the scrollbar (if the scroll position hasn't
 *	changed then no script is invoked).
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
GetXView(
    Tcl_Interp *interp,		/* If "report" is FALSE, string describing
				 * visible range gets stored in the interp's
				 * result. */
    TkText *textPtr,		/* Information about text widget. */
    int report)			/* Non-zero means report info to scrollbar if
				 * it has changed. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    double first, last;
    int code;
    Tcl_Obj *listObj;

    if (dInfoPtr->maxLength > 0) {
	first = ((double) dInfoPtr->curXPixelOffset)
		/ dInfoPtr->maxLength;
	last = ((double) (dInfoPtr->curXPixelOffset + dInfoPtr->maxX
		- dInfoPtr->x))/dInfoPtr->maxLength;
	if (last > 1.0) {
	    last = 1.0;
	}
    } else {
	first = 0;
	last = 1.0;
    }
    if (!report) {
	listObj = Tcl_NewListObj(0, NULL);
	Tcl_ListObjAppendElement(interp, listObj, Tcl_NewDoubleObj(first));
	Tcl_ListObjAppendElement(interp, listObj, Tcl_NewDoubleObj(last));
	Tcl_SetObjResult(interp, listObj);
	return;
    }
    if (FP_EQUAL_SCALE(first, dInfoPtr->xScrollFirst, dInfoPtr->maxLength) &&
	    FP_EQUAL_SCALE(last, dInfoPtr->xScrollLast, dInfoPtr->maxLength)) {
	return;
    }
    dInfoPtr->xScrollFirst = first;
    dInfoPtr->xScrollLast = last;
    if (textPtr->xScrollCmd != NULL) {
	char buf1[TCL_DOUBLE_SPACE+1];
	char buf2[TCL_DOUBLE_SPACE+1];

	buf1[0] = ' ';
	buf2[0] = ' ';
	Tcl_PrintDouble(NULL, first, buf1+1);
	Tcl_PrintDouble(NULL, last, buf2+1);
	code = Tcl_VarEval(interp, textPtr->xScrollCmd, buf1, buf2, NULL);
	if (code != TCL_OK) {
	    Tcl_AddErrorInfo(interp,
		    "\n    (horizontal scrolling command executed by text)");
	    Tcl_BackgroundError(interp);
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * GetYPixelCount --
 *
 *	How many pixels are there between the absolute top of the widget and
 *	the top of the given DLine.
 *
 *	While this function will work for any valid DLine, it is only ever
 *	called when dlPtr is the first display line in the widget (by
 *	'GetYView'). This means that usually this function is a very quick
 *	calculation, since it can use the pre-calculated linked-list of DLines
 *	for height information.
 *
 *	The only situation where this breaks down is if dlPtr's logical line
 *	wraps enough times to fill the text widget's current view - in this
 *	case we won't have enough dlPtrs in the linked list to be able to
 *	subtract off what we want.
 *
 * Results:
 *	The number of pixels.
 *
 *	This value has a valid range between '0' (the very top of the widget)
 *	and the number of pixels in the total widget minus the pixel-height of
 *	the last line.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
GetYPixelCount(
    TkText *textPtr,		/* Information about text widget. */
    DLine *dlPtr)		/* Information about the layout of a given
				 * index. */
{
    TkTextLine *linePtr = dlPtr->index.linePtr;
    int count;

    /*
     * Get the pixel count to the top of dlPtr's logical line. The rest of the
     * function is then concerned with updating 'count' for any difference
     * between the top of the logical line and the display line.
     */

    count = TkBTreePixelsTo(textPtr, linePtr);

    /*
     * For the common case where this dlPtr is also the start of the logical
     * line, we can return right away.
     */

    if ((dlPtr->index.byteIndex == 0)
            && !TkTextIsElided(textPtr, &dlPtr->index, NULL)) {
	return count;
    }

    /*
     * Add on the logical line's height to reach one pixel beyond the bottom
     * of the logical line. And then subtract off the heights of all the
     * display lines from dlPtr to the end of its logical line.
     *
     * A different approach would be to lay things out from the start of the
     * logical line until we reach dlPtr, but since none of those are
     * pre-calculated, it'll usually take a lot longer. (But there are cases
     * where it would be more efficient: say if we're on the second of 1000
     * wrapped lines all from a single logical line - but that sort of
     * optimization is left for the future).
     */

    count += TkBTreeLinePixelCount(textPtr, linePtr);

    do {
	count -= dlPtr->height;
	if (dlPtr->nextPtr == NULL) {
	    /*
	     * We've run out of pre-calculated display lines, so we have to
	     * lay them out ourselves until the end of the logical line. Here
	     * is where we could be clever and ask: what's faster, to layout
	     * all lines from here to line-end, or all lines from the original
	     * dlPtr to the line-start? We just assume the former.
	     */

	    TkTextIndex index;
	    int notFirst = 0;

	    while (1) {
		TkTextIndexForwBytes(textPtr, &dlPtr->index,
			dlPtr->byteCount, &index);
		if (notFirst) {
		    FreeDLines(textPtr, dlPtr, NULL, DLINE_FREE_TEMP);
		}
		if (index.linePtr != linePtr) {
		    break;
		}
		dlPtr = LayoutDLine(textPtr, &index);

		if (tkTextDebug) {
		    char string[TK_POS_CHARS];

		    /*
		     * Debugging is enabled, so keep a log of all the lines
		     * whose height was recalculated. The test suite uses this
		     * information.
		     */

		    TkTextPrintIndex(textPtr, &index, string);
		    LOG("tk_textHeightCalc", string);
		}
		count -= dlPtr->height;
		notFirst = 1;
	    }
	    break;
	} else {
	    dlPtr = dlPtr->nextPtr;
	}
    } while (dlPtr->index.linePtr == linePtr);

    return count;
}

/*
 *----------------------------------------------------------------------
 *
 * GetYView --
 *
 *	This function computes the fractions that indicate what's visible in a
 *	text window and, optionally, evaluates a Tcl script to report them to
 *	the text's associated scrollbar.
 *
 * Results:
 *	If report is zero, then the interp's result is filled in with two real
 *	numbers separated by a space, giving the position of the top and
 *	bottom of the window as fractions from 0 to 1, where 0 means the
 *	beginning of the text and 1 means the end. If report is non-zero, then
 *	the interp's result isn't modified directly, but a script is evaluated
 *	in interp to report the new scroll position to the scrollbar (if the
 *	scroll position hasn't changed then no script is invoked).
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
GetYView(
    Tcl_Interp *interp,		/* If "report" is FALSE, string describing
				 * visible range gets stored in the interp's
				 * result. */
    TkText *textPtr,		/* Information about text widget. */
    int report)			/* Non-zero means report info to scrollbar if
				 * it has changed. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    double first, last;
    DLine *dlPtr;
    int totalPixels, code, count;
    Tcl_Obj *listObj;

    dlPtr = dInfoPtr->dLinePtr;

    if (dlPtr == NULL) {
	return;
    }

    totalPixels = TkBTreeNumPixels(textPtr->sharedTextPtr->tree, textPtr);

    if (totalPixels == 0) {
	first = 0.0;
	last = 1.0;
    } else {
	/*
	 * Get the pixel count for the first visible pixel of the first
	 * visible line. If the first visible line is only partially visible,
	 * then we use 'topPixelOffset' to get the difference.
	 */

	count = GetYPixelCount(textPtr, dlPtr);
	first = (count + dInfoPtr->topPixelOffset) / (double) totalPixels;

	/*
	 * Add on the total number of visible pixels to get the count to one
	 * pixel _past_ the last visible pixel. This is how the 'yview'
	 * command is documented, and also explains why we are dividing by
	 * 'totalPixels' and not 'totalPixels-1'.
	 */

	while (1) {
	    int extra;

	    count += dlPtr->height;
	    extra = dlPtr->y + dlPtr->height - dInfoPtr->maxY;
	    if (extra > 0) {
		/*
		 * This much of the last line is not visible, so don't count
		 * these pixels. Since we've reached the bottom of the window,
		 * we break out of the loop.
		 */

		count -= extra;
		break;
	    }
	    if (dlPtr->nextPtr == NULL) {
		break;
	    }
	    dlPtr = dlPtr->nextPtr;
	}

	if (count > totalPixels) {
	    /*
	     * It can be possible, if we do not update each line's pixelHeight
	     * cache when we lay out individual DLines that the count
	     * generated here is more up-to-date than that maintained by the
	     * BTree. In such a case, the best we can do here is to fix up
	     * 'count' and continue, which might result in small, temporary
	     * perturbations to the size of the scrollbar. This is basically
	     * harmless, but in a perfect world we would not have this
	     * problem.
	     *
	     * For debugging purposes, if anyone wishes to improve the text
	     * widget further, the following 'panic' can be activated. In
	     * principle it should be possible to ensure the BTree is always
	     * at least as up to date as the display, so in the future we
	     * might be able to leave the 'panic' in permanently when we
	     * believe we have resolved the cache synchronisation issue.
	     *
	     * However, to achieve that goal would, I think, require a fairly
	     * substantial refactorisation of the code in this file so that
	     * there is much more obvious and explicit coordination between
	     * calls to LayoutDLine and updating of each TkTextLine's
	     * pixelHeight. The complicated bit is that LayoutDLine deals with
	     * individual display lines, but pixelHeight is for a logical
	     * line.
	     */

#if 0
	    Tcl_Panic("Counted more pixels (%d) than expected (%d) total "
		    "pixels in text widget scroll bar calculation.", count,
		    totalPixels);
#endif
	    count = totalPixels;
	}

	last = ((double) count)/((double)totalPixels);
    }

    if (!report) {
	listObj = Tcl_NewListObj(0,NULL);
	Tcl_ListObjAppendElement(interp, listObj, Tcl_NewDoubleObj(first));
	Tcl_ListObjAppendElement(interp, listObj, Tcl_NewDoubleObj(last));
	Tcl_SetObjResult(interp, listObj);
	return;
    }

    if (FP_EQUAL_SCALE(first, dInfoPtr->yScrollFirst, totalPixels) &&
	    FP_EQUAL_SCALE(last, dInfoPtr->yScrollLast, totalPixels)) {
	return;
    }

    dInfoPtr->yScrollFirst = first;
    dInfoPtr->yScrollLast = last;
    if (textPtr->yScrollCmd != NULL) {
	char buf1[TCL_DOUBLE_SPACE+1];
	char buf2[TCL_DOUBLE_SPACE+1];

	buf1[0] = ' ';
	buf2[0] = ' ';
	Tcl_PrintDouble(NULL, first, buf1+1);
	Tcl_PrintDouble(NULL, last, buf2+1);
	code = Tcl_VarEval(interp, textPtr->yScrollCmd, buf1, buf2, NULL);
	if (code != TCL_OK) {
	    Tcl_AddErrorInfo(interp,
		    "\n    (vertical scrolling command executed by text)");
	    Tcl_BackgroundError(interp);
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * AsyncUpdateYScrollbar --
 *
 *	This function is called to update the vertical scrollbar asychronously
 *	as the pixel height calculations progress for lines in the widget.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	See 'GetYView'. In particular the scrollbar position and size may be
 *	changed.
 *
 *----------------------------------------------------------------------
 */

static void
AsyncUpdateYScrollbar(
    ClientData clientData)	/* Information about widget. */
{
    register TkText *textPtr = (TkText *) clientData;

    textPtr->dInfoPtr->scrollbarTimer = NULL;

    if (!(textPtr->flags & DESTROYED)) {
	GetYView(textPtr->interp, textPtr, 1);
    }

    if (--textPtr->refCount == 0) {
	ckfree((char *) textPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * FindDLine --
 *
 *	This function is called to find the DLine corresponding to a given
 *	text index.
 *
 * Results:
 *	The return value is a pointer to the first DLine found in the list
 *	headed by dlPtr that displays information at or after the specified
 *	position. If there is no such line in the list then NULL is returned.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static DLine *
FindDLine(
    TkText *textPtr,		/* Widget record for text widget. */
    register DLine *dlPtr,	/* Pointer to first in list of DLines to
				 * search. */
    CONST TkTextIndex *indexPtr)/* Index of desired character. */
{
    DLine *dlPtrPrev;
    TkTextIndex indexPtr2;

    if (dlPtr == NULL) {
	return NULL;
    }
    if (TkBTreeLinesTo(NULL, indexPtr->linePtr)
	    < TkBTreeLinesTo(NULL, dlPtr->index.linePtr)) {
	/*
	 * The first display line is already past the desired line.
	 */

	return dlPtr;
    }

    /*
     * The display line containing the desired index is such that the index
     * of the first character of this display line is at or before the
     * desired index, and the index of the first character of the next
     * display line is after the desired index.
     */

    while (TkTextIndexCmp(&dlPtr->index,indexPtr) < 0) {
        dlPtrPrev = dlPtr;
        dlPtr = dlPtr->nextPtr;
        if (dlPtr == NULL) {
            /*
             * We're past the last display line, either because the desired
             * index lies past the visible text, or because the desired index
             * is on the last display line showing the last logical line.
             */
            indexPtr2 = dlPtrPrev->index;
            TkTextFindDisplayLineEnd(textPtr, &indexPtr2, 1, NULL);
            if (TkTextIndexCmp(&indexPtr2,indexPtr) >= 0) {
                dlPtr = dlPtrPrev;
                break;
            } else {
                return NULL;
            }
        }
        if (TkTextIndexCmp(&dlPtr->index,indexPtr) > 0) {
            dlPtr = dlPtrPrev;
            break;
        }
    }

    return dlPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextPixelIndex --
 *
 *	Given an (x,y) coordinate on the screen, find the location of the
 *	character closest to that location.
 *
 * Results:
 *	The index at *indexPtr is modified to refer to the character on the
 *	display that is closest to (x,y).
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
TkTextPixelIndex(
    TkText *textPtr,		/* Widget record for text widget. */
    int x, int y,		/* Pixel coordinates of point in widget's
				 * window. */
    TkTextIndex *indexPtr,	/* This index gets filled in with the index of
				 * the character nearest to (x,y). */
    int *nearest)		/* If non-NULL then gets set to 0 if (x,y) is
				 * actually over the returned index, and 1 if
				 * it is just nearby (e.g. if x,y is on the
				 * border of the widget). */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    register DLine *dlPtr, *validDlPtr;
    int nearby = 0;

    /*
     * Make sure that all of the layout information about what's displayed
     * where on the screen is up-to-date.
     */

    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
	UpdateDisplayInfo(textPtr);
    }

    /*
     * If the coordinates are above the top of the window, then adjust them to
     * refer to the upper-right corner of the window. If they're off to one
     * side or the other, then adjust to the closest side.
     */

    if (y < dInfoPtr->y) {
	y = dInfoPtr->y;
	x = dInfoPtr->x;
	nearby = 1;
    }
    if (x >= dInfoPtr->maxX) {
	x = dInfoPtr->maxX - 1;
	nearby = 1;
    }
    if (x < dInfoPtr->x) {
	x = dInfoPtr->x;
	nearby = 1;
    }

    /*
     * Find the display line containing the desired y-coordinate.
     */

    if (dInfoPtr->dLinePtr == NULL) {
	if (nearest != NULL) {
	    *nearest = 1;
	}
	*indexPtr = textPtr->topIndex;
	return;
    } else {
	for (dlPtr = validDlPtr = dInfoPtr->dLinePtr;
		y >= (dlPtr->y + dlPtr->height);
		dlPtr = dlPtr->nextPtr) {
	    if (dlPtr->chunkPtr != NULL) {
		validDlPtr = dlPtr;
	    }
	    if (dlPtr->nextPtr == NULL) {
		/*
		 * Y-coordinate is off the bottom of the displayed text. Use
		 * the last character on the last line.
		 */

		x = dInfoPtr->maxX - 1;
		nearby = 1;
		break;
	    }
	}
	if (dlPtr->chunkPtr == NULL) dlPtr = validDlPtr;
    }

    if (nearest != NULL) {
	*nearest = nearby;
    }

    DlineIndexOfX(textPtr, dlPtr, x, indexPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * DlineIndexOfX --
 *
 *	Given an x coordinate in a display line, find the index of the
 *	character closest to that location.
 *
 *	This is effectively the opposite of DlineXOfIndex.
 *
 * Results:
 *	The index at *indexPtr is modified to refer to the character on the
 *	display line that is closest to x.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
DlineIndexOfX(
    TkText *textPtr,		/* Widget record for text widget. */
    DLine *dlPtr,		/* Display information for this display
				 * line. */
    int x,			/* Pixel x coordinate of point in widget's
				 * window. */
    TkTextIndex *indexPtr)	/* This index gets filled in with the index of
				 * the character nearest to x. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    register TkTextDispChunk *chunkPtr;

    /*
     * Scan through the line's chunks to find the one that contains the
     * desired x-coordinate. Before doing this, translate the x-coordinate
     * from the coordinate system of the window to the coordinate system of
     * the line (to take account of x-scrolling).
     */

    *indexPtr = dlPtr->index;
    x = x - dInfoPtr->x + dInfoPtr->curXPixelOffset;
    chunkPtr = dlPtr->chunkPtr;

    if (chunkPtr == NULL || x == 0) {
	/*
	 * This may occur if everything is elided, or if we're simply already
	 * at the beginning of the line.
	 */

	return;
    }

    while (x >= (chunkPtr->x + chunkPtr->width)) {
	/*
	 * Note that this forward then backward movement of the index can be
	 * problematic at the end of the buffer (we can't move forward, and
	 * then when we move backward, we do, leading to the wrong position).
	 * Hence when x == 0 we take special action above.
	 */

	if (TkTextIndexForwBytes(NULL,indexPtr,chunkPtr->numBytes,indexPtr)) {
	    /*
	     * We've reached the end of the text.
	     */

            TkTextIndexBackChars(NULL, indexPtr, 1, indexPtr, COUNT_INDICES);
	    return;
	}
	if (chunkPtr->nextPtr == NULL) {
	    /*
	     * We've reached the end of the display line.
	     */

            TkTextIndexBackChars(NULL, indexPtr, 1, indexPtr, COUNT_INDICES);
	    return;
	}
	chunkPtr = chunkPtr->nextPtr;
    }

    /*
     * If the chunk has more than one byte in it, ask it which character is at
     * the desired location. In this case we can manipulate
     * 'indexPtr->byteIndex' directly, because we know we're staying inside a
     * single logical line.
     */

    if (chunkPtr->numBytes > 1) {
	indexPtr->byteIndex += (*chunkPtr->measureProc)(chunkPtr, x);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextIndexOfX --
 *
 *	Given a logical x coordinate (i.e. distance in pixels from the
 *	beginning of the display line, not taking into account any information
 *	about the window, scrolling etc.) on the display line starting with
 *	the given index, adjust that index to refer to the object under the x
 *	coordinate.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
TkTextIndexOfX(
    TkText *textPtr,		/* Widget record for text widget. */
    int x,			/* The x coordinate for which we want the
				 * index. */
    TkTextIndex *indexPtr)	/* Index of display line start, which will be
				 * adjusted to the index under the given x
				 * coordinate. */
{
    DLine *dlPtr = LayoutDLine(textPtr, indexPtr);
    DlineIndexOfX(textPtr, dlPtr, x + textPtr->dInfoPtr->x
		- textPtr->dInfoPtr->curXPixelOffset, indexPtr);
    FreeDLines(textPtr, dlPtr, NULL, DLINE_FREE_TEMP);
}

/*
 *----------------------------------------------------------------------
 *
 * DlineXOfIndex --
 *
 *	Given a relative byte index on a given display line (i.e. the number
 *	of byte indices from the beginning of the given display line), find
 *	the x coordinate of that index within the abstract display line,
 *	without adjusting for the x-scroll state of the line.
 *
 *	This is effectively the opposite of DlineIndexOfX.
 *
 *	NB. The 'byteIndex' is relative to the display line, NOT the logical
 *	line.
 *
 * Results:
 *	The x coordinate.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
DlineXOfIndex(
    TkText *textPtr,		/* Widget record for text widget. */
    DLine *dlPtr,		/* Display information for this display
				 * line. */
    int byteIndex)		/* The byte index for which we want the
				 * coordinate. */
{
    register TkTextDispChunk *chunkPtr = dlPtr->chunkPtr;
    int x;

    if (byteIndex == 0 || chunkPtr == NULL) {
	return 0;
    }

    /*
     * Scan through the line's chunks to find the one that contains the
     * desired byte index.
     */

    chunkPtr = dlPtr->chunkPtr;
    while (byteIndex > 0) {
	if (byteIndex < chunkPtr->numBytes) {
	    int y, width, height;

	    (*chunkPtr->bboxProc)(textPtr, chunkPtr, byteIndex,
		    dlPtr->y + dlPtr->spaceAbove,
		    dlPtr->height - dlPtr->spaceAbove - dlPtr->spaceBelow,
		    dlPtr->baseline - dlPtr->spaceAbove, &x, &y, &width,
		    &height);
	    break;
	} else {
	    byteIndex -= chunkPtr->numBytes;
	}
	if (chunkPtr->nextPtr == NULL || byteIndex == 0) {
	    x = chunkPtr->x + chunkPtr->width;
	    break;
	}
	chunkPtr = chunkPtr->nextPtr;
    }

    return x;
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextIndexBbox --
 *
 *	Given an index, find the bounding box of the screen area occupied by
 *	the entity (character, window, image) at that index.
 *
 * Results:
 *	Zero is returned if the index is on the screen. -1 means the index is
 *	not on the screen. If the return value is 0, then the bounding box of
 *	the part of the index that's visible on the screen is returned to
 *	*xPtr, *yPtr, *widthPtr, and *heightPtr.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
TkTextIndexBbox(
    TkText *textPtr,		/* Widget record for text widget. */
    CONST TkTextIndex *indexPtr,/* Index whose bounding box is desired. */
    int *xPtr, int *yPtr,	/* Filled with index's upper-left
				 * coordinate. */
    int *widthPtr, int *heightPtr,
				/* Filled in with index's dimensions. */
    int *charWidthPtr)		/* If the 'index' is at the end of a display
				 * line and therefore takes up a very large
				 * width, this is used to return the smaller
				 * width actually desired by the index. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    DLine *dlPtr;
    register TkTextDispChunk *chunkPtr;
    int byteCount;

    /*
     * Make sure that all of the screen layout information is up to date.
     */

    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
	UpdateDisplayInfo(textPtr);
    }

    /*
     * Find the display line containing the desired index.
     */

    dlPtr = FindDLine(textPtr, dInfoPtr->dLinePtr, indexPtr);

    /* 
     * Two cases shall be trapped here because the logic later really
     * needs dlPtr to be the display line containing indexPtr:
     *   1. if no display line contains the desired index (NULL dlPtr)
     *   2. if indexPtr is before the first display line, in which case
     *      dlPtr currently points to the first display line
     */

    if ((dlPtr == NULL) || (TkTextIndexCmp(&dlPtr->index, indexPtr) > 0)) {
	return -1;
    }

    /*
     * Find the chunk within the display line that contains the desired
     * index. The chunks making the display line are skipped up to but not
     * including the one crossing indexPtr. Skipping is done based on
     * a byteCount offset possibly spanning several logical lines in case
     * they are elided.
     */

    byteCount = TkTextIndexCount(textPtr, &dlPtr->index, indexPtr,
            COUNT_INDICES);
    for (chunkPtr = dlPtr->chunkPtr; ; chunkPtr = chunkPtr->nextPtr) {
	if (chunkPtr == NULL) {
	    return -1;
	}
	if (byteCount < chunkPtr->numBytes) {
	    break;
	}
	byteCount -= chunkPtr->numBytes;
    }

    /*
     * Call a chunk-specific function to find the horizontal range of the
     * character within the chunk, then fill in the vertical range. The
     * x-coordinate returned by bboxProc is a coordinate within a line, not a
     * coordinate on the screen. Translate it to reflect horizontal scrolling.
     */

    (*chunkPtr->bboxProc)(textPtr, chunkPtr, byteCount,
	    dlPtr->y + dlPtr->spaceAbove,
	    dlPtr->height - dlPtr->spaceAbove - dlPtr->spaceBelow,
	    dlPtr->baseline - dlPtr->spaceAbove, xPtr, yPtr, widthPtr,
	    heightPtr);
    *xPtr = *xPtr + dInfoPtr->x - dInfoPtr->curXPixelOffset;
    if ((byteCount == chunkPtr->numBytes-1) && (chunkPtr->nextPtr == NULL)) {
	/*
	 * Last character in display line. Give it all the space up to the
	 * line.
	 */

	if (charWidthPtr != NULL) {
	    *charWidthPtr = dInfoPtr->maxX - *xPtr;
            if (*charWidthPtr > textPtr->charWidth) {
                *charWidthPtr = textPtr->charWidth;
            }
	}
	if (*xPtr > dInfoPtr->maxX) {
	    *xPtr = dInfoPtr->maxX;
	}
	*widthPtr = dInfoPtr->maxX - *xPtr;
    } else {
	if (charWidthPtr != NULL) {
	    *charWidthPtr = *widthPtr;
	}
    }
    if (*widthPtr == 0) {
	/*
	 * With zero width (e.g. elided text) we just need to make sure it is
	 * onscreen, where the '=' case here is ok.
	 */

	if (*xPtr < dInfoPtr->x) {
	    return -1;
	}
    } else {
	if ((*xPtr + *widthPtr) <= dInfoPtr->x) {
	    return -1;
	}
    }
    if ((*xPtr + *widthPtr) > dInfoPtr->maxX) {
	*widthPtr = dInfoPtr->maxX - *xPtr;
	if (*widthPtr <= 0) {
	    return -1;
	}
    }
    if ((*yPtr + *heightPtr) > dInfoPtr->maxY) {
	*heightPtr = dInfoPtr->maxY - *yPtr;
	if (*heightPtr <= 0) {
	    return -1;
	}
    }
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * TkTextDLineInfo --
 *
 *	Given an index, return information about the display line containing
 *	that character.
 *
 * Results:
 *	Zero is returned if the character is on the screen. -1 means the
 *	character isn't on the screen. If the return value is 0, then
 *	information is returned in the variables pointed to by xPtr, yPtr,
 *	widthPtr, heightPtr, and basePtr.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
TkTextDLineInfo(
    TkText *textPtr,		/* Widget record for text widget. */
    CONST TkTextIndex *indexPtr,/* Index of character whose bounding box is
				 * desired. */
    int *xPtr, int *yPtr,	/* Filled with line's upper-left
				 * coordinate. */
    int *widthPtr, int *heightPtr,
				/* Filled in with line's dimensions. */
    int *basePtr)		/* Filled in with the baseline position,
				 * measured as an offset down from *yPtr. */
{
    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
    DLine *dlPtr;
    int dlx;

    /*
     * Make sure that all of the screen layout information is up to date.
     */

    if (dInfoPtr->flags & DINFO_OUT_OF_DATE) {
	UpdateDisplayInfo(textPtr);
    }

    /*
     * Find the display line containing the desired index.
     */

    dlPtr = FindDLine(textPtr, dInfoPtr->dLinePtr, indexPtr);

    /* 
     * Two cases shall be trapped here because the logic later really
     * needs dlPtr to be the display line containing indexPtr:
     *   1. if no display line contains the desired index (NULL dlPtr)
     *   2. if indexPtr is before the first display line, in which case
     *      dlPtr currently points to the first display line
     */

    if ((dlPtr == NULL) || (TkTextIndexCmp(&dlPtr->index, indexPtr) > 0)) {
	return -1;
    }

    dlx = (dlPtr->chunkPtr != NULL? dlPtr->chunkPtr->x: 0);
    *xPtr = dInfoPtr->x - dInfoPtr->curXPixelOffset + dlx;
    *widthPtr = dlPtr->length - dlx;
    *yPtr = dlPtr->y;
    if ((dlPtr->y + dlPtr->height) > dInfoPtr->maxY) {
	*heightPtr = dInfoPtr->maxY - dlPtr->y;
    } else {
	*heightPtr = dlPtr->height;
    }
    *basePtr = dlPtr->baseline;
    return 0;
}

/*
 * Get bounding-box information about an elided chunk.
 */

static void
ElideBboxProc(
    TkText *textPtr,
    TkTextDispChunk *chunkPtr,	/* Chunk containing desired char. */
    int index,			/* Index of desired character within the
				 * chunk. */
    int y,			/* Topmost pixel in area allocated for this
				 * line. */
    int lineHeight,		/* Height of line, in pixels. */
    int baseline,		/* Location of line's baseline, in pixels
				 * measured down from y. */
    int *xPtr, int *yPtr,	/* Gets filled in with coords of character's
				 * upper-left pixel. X-coord is in same
				 * coordinate system as chunkPtr->x. */
    int *widthPtr,		/* Gets filled in with width of character, in
				 * pixels. */
    int *heightPtr)		/* Gets filled in with height of character, in
				 * pixels. */
{
    *xPtr = chunkPtr->x;
    *yPtr = y;
    *widthPtr = *heightPtr = 0;
}

/*
 * Measure an elided chunk.
 */

static int
ElideMeasureProc(
    TkTextDispChunk *chunkPtr,	/* Chunk containing desired coord. */
    int x)			/* X-coordinate, in same coordinate system as
				 * chunkPtr->x. */
{
    return 0 /*chunkPtr->numBytes - 1*/;
}

/*
 *--------------------------------------------------------------
 *
 * TkTextCharLayoutProc --
 *
 *	This function is the "layoutProc" for character segments.
 *
 * Results:
 *	If there is something to display for the chunk then a non-zero value
 *	is returned and the fields of chunkPtr will be filled in (see the
 *	declaration of TkTextDispChunk in tkText.h for details). If zero is
 *	returned it means that no characters from this chunk fit in the
 *	window. If -1 is returned it means that this segment just doesn't need
 *	to be displayed (never happens for text).
 *
 * Side effects:
 *	Memory is allocated to hold additional information about the chunk.
 *
 *--------------------------------------------------------------
 */

int
TkTextCharLayoutProc(
    TkText *textPtr,		/* Text widget being layed out. */
    TkTextIndex *indexPtr,	/* Index of first character to lay out
				 * (corresponds to segPtr and offset). */
    TkTextSegment *segPtr,	/* Segment being layed out. */
    int byteOffset,		/* Byte offset within segment of first
				 * character to consider. */
    int maxX,			/* Chunk must not occupy pixels at this
				 * position or higher. */
    int maxBytes,		/* Chunk must not include more than this many
				 * characters. */
    int noCharsYet,		/* Non-zero means no characters have been
				 * assigned to this display line yet. */
    TkWrapMode wrapMode,	/* How to handle line wrapping:
				 * TEXT_WRAPMODE_CHAR, TEXT_WRAPMODE_NONE, or
				 * TEXT_WRAPMODE_WORD. */
    register TkTextDispChunk *chunkPtr)
				/* Structure to fill in with information about
				 * this chunk. The x field has already been
				 * set by the caller. */
{
    Tk_Font tkfont;
    int nextX, bytesThatFit, count;
    CharInfo *ciPtr;
    char *p;
    TkTextSegment *nextPtr;
    Tk_FontMetrics fm;
#if TK_LAYOUT_WITH_BASE_CHUNKS
    const char *line;
    int lineOffset;
    BaseCharInfo *bciPtr;
    Tcl_DString *baseString;
#endif

    /*
     * Figure out how many characters will fit in the space we've got. Include
     * the next character, even though it won't fit completely, if any of the
     * following is true:
     *	 (a) the chunk contains no characters and the display line contains no
     *	     characters yet (i.e. the line isn't wide enough to hold even a
     *	     single character).
     *	 (b) at least one pixel of the character is visible, we have not
     *	     already exceeded the character limit, and the next character is a
     *	     white space character.
     */

    p = segPtr->body.chars + byteOffset;
    tkfont = chunkPtr->stylePtr->sValuePtr->tkfont;

#if TK_LAYOUT_WITH_BASE_CHUNKS
    if (baseCharChunkPtr == NULL) {
	baseCharChunkPtr = chunkPtr;
	bciPtr = (BaseCharInfo *) ckalloc(sizeof(BaseCharInfo));
	baseString = &bciPtr->baseChars;
	Tcl_DStringInit(baseString);
	bciPtr->width = 0;

	ciPtr = &bciPtr->ci;
    } else {
	bciPtr = (BaseCharInfo *) baseCharChunkPtr->clientData;
	ciPtr = (CharInfo *) ckalloc(sizeof(CharInfo));
	baseString = &bciPtr->baseChars;
    }

    lineOffset = Tcl_DStringLength(baseString);
    line = Tcl_DStringAppend(baseString,p,maxBytes);

    chunkPtr->clientData = (ClientData) ciPtr;
    ciPtr->baseChunkPtr = baseCharChunkPtr;
    ciPtr->baseOffset = lineOffset;
    ciPtr->chars = NULL;
    ciPtr->numBytes = 0;

    bytesThatFit = CharChunkMeasureChars(chunkPtr, line,
	    lineOffset + maxBytes, lineOffset, -1, chunkPtr->x, maxX,
	    TK_ISOLATE_END, &nextX);
#else /* !TK_LAYOUT_WITH_BASE_CHUNKS */
    bytesThatFit = CharChunkMeasureChars(chunkPtr, p, maxBytes, 0, -1,
	    chunkPtr->x, maxX, TK_ISOLATE_END, &nextX);
#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */

    if (bytesThatFit < maxBytes) {
	if ((bytesThatFit == 0) && noCharsYet) {
	    Tcl_UniChar ch;
	    int chLen = Tcl_UtfToUniChar(p, &ch);

#if TK_LAYOUT_WITH_BASE_CHUNKS
	    bytesThatFit = CharChunkMeasureChars(chunkPtr, line,
		    lineOffset+chLen, lineOffset, -1, chunkPtr->x, -1, 0,
		    &nextX);
#else /* !TK_LAYOUT_WITH_BASE_CHUNKS */
	    bytesThatFit = CharChunkMeasureChars(chunkPtr, p, chLen, 0, -1,
		    chunkPtr->x, -1, 0, &nextX);
#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */
	}
	if ((nextX < maxX) && ((p[bytesThatFit] == ' ')
		|| (p[bytesThatFit] == '\t'))) {
	    /*
	     * Space characters are funny, in that they are considered to fit
	     * if there is at least one pixel of space left on the line. Just
	     * give the space character whatever space is left.
	     */

	    nextX = maxX;
	    bytesThatFit++;
	}
	if (p[bytesThatFit] == '\n') {
	    /*
	     * A newline character takes up no space, so if the previous
	     * character fits then so does the newline.
	     */

	    bytesThatFit++;
	}
	if (bytesThatFit == 0) {
#if TK_LAYOUT_WITH_BASE_CHUNKS
	    chunkPtr->clientData = NULL;
	    if (chunkPtr == baseCharChunkPtr) {
		baseCharChunkPtr = NULL;
		Tcl_DStringFree(baseString);
	    } else {
		Tcl_DStringSetLength(baseString,lineOffset);
	    }
	    ckfree((char *) ciPtr);
#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */
	    return 0;
	}
    }

    Tk_GetFontMetrics(tkfont, &fm);

    /*
     * Fill in the chunk structure and allocate and initialize a CharInfo
     * structure. If the last character is a newline then don't bother to
     * display it.
     */

    chunkPtr->displayProc = CharDisplayProc;
    chunkPtr->undisplayProc = CharUndisplayProc;
    chunkPtr->measureProc = CharMeasureProc;
    chunkPtr->bboxProc = CharBboxProc;
    chunkPtr->numBytes = bytesThatFit;
    chunkPtr->minAscent = fm.ascent + chunkPtr->stylePtr->sValuePtr->offset;
    chunkPtr->minDescent = fm.descent - chunkPtr->stylePtr->sValuePtr->offset;
    chunkPtr->minHeight = 0;
    chunkPtr->width = nextX - chunkPtr->x;
    chunkPtr->breakIndex = -1;

#if !TK_LAYOUT_WITH_BASE_CHUNKS
    ciPtr = (CharInfo *)
	    ckalloc((unsigned) bytesThatFit + Tk_Offset(CharInfo, chars) + 1);
    chunkPtr->clientData = (ClientData) ciPtr;
    memcpy(ciPtr->chars, p, (unsigned) bytesThatFit);
#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */

    ciPtr->numBytes = bytesThatFit;
    if (p[bytesThatFit - 1] == '\n') {
	ciPtr->numBytes--;
    }

#if TK_LAYOUT_WITH_BASE_CHUNKS
    /*
     * Final update for the current base chunk data.
     */

    Tcl_DStringSetLength(baseString,lineOffset+ciPtr->numBytes);
    bciPtr->width = nextX - baseCharChunkPtr->x;

    /*
     * Finalize the base chunk if this chunk ends in a tab, which definitly
     * breaks the context and needs to be handled on a higher level.
     */

    if (ciPtr->numBytes > 0 && p[ciPtr->numBytes - 1] == '\t') {
	FinalizeBaseChunk(chunkPtr);
    }
#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */

    /*
     * Compute a break location. If we're in word wrap mode, a break can occur
     * after any space character, or at the end of the chunk if the next
     * segment (ignoring those with zero size) is not a character segment.
     */

    if (wrapMode != TEXT_WRAPMODE_WORD) {
	chunkPtr->breakIndex = chunkPtr->numBytes;
    } else {
	for (count = bytesThatFit, p += bytesThatFit - 1; count > 0;
		count--, p--) {
	    if (UCHAR(*p) < 0x80 && isspace(UCHAR(*p))) {
		chunkPtr->breakIndex = count;
		break;
	    }
	}
	if ((bytesThatFit + byteOffset) == segPtr->size) {
	    for (nextPtr = segPtr->nextPtr; nextPtr != NULL;
		    nextPtr = nextPtr->nextPtr) {
		if (nextPtr->size != 0) {
		    if (nextPtr->typePtr != &tkTextCharType) {
			chunkPtr->breakIndex = chunkPtr->numBytes;
		    }
		    break;
		}
	    }
	}
    }
    return 1;
}

/*
 *---------------------------------------------------------------------------
 *
 * CharChunkMeasureChars --
 *
 *	Determine the number of characters from a char chunk that will fit in
 *	the given horizontal span.
 *
 *	This is the same as MeasureChars (which see), but in the context of a
 *	char chunk, i.e. on a higher level of abstraction. Use this function
 *	whereever possible instead of plain MeasureChars, so that the right
 *	context is used automatically.
 *
 * Results:
 *	The return value is the number of bytes from the range of start to end
 *	in source that fit in the span given by startX and maxX. *nextXPtr is
 *	filled in with the x-coordinate at which the first character that
 *	didn't fit would be drawn, if it were to be drawn.
 *
 * Side effects:
 *	None.
 *--------------------------------------------------------------
 */

static int
CharChunkMeasureChars(
    TkTextDispChunk *chunkPtr,	/* Chunk from which to measure. */
    const char *chars,		/* Chars to use, instead of the chunk's own.
				 * Used by the layoutproc during chunk setup.
				 * All other callers use NULL. Not
				 * NUL-terminated. */
    int charsLen,		/* Length of the "chars" parameter. */
    int start, int end,		/* The range of chars to measure inside the
				 * chunk (or inside the additional chars). */
    int startX,			/* Starting x coordinate where the measured
				 * span will begin. */
    int maxX,			/* Maximum pixel width of the span. May be -1
				 * for unlimited. */
    int flags,			/* Flags to pass to MeasureChars. */
    int *nextXPtr)		/* The function puts the newly calculated
				 * right border x-position of the span
				 * here. */
{
    Tk_Font tkfont = chunkPtr->stylePtr->sValuePtr->tkfont;
    CharInfo *ciPtr = (CharInfo *) chunkPtr->clientData;

#if !TK_LAYOUT_WITH_BASE_CHUNKS
    if (chars == NULL) {
	chars = ciPtr->chars;
	charsLen = ciPtr->numBytes;
    }
    if (end == -1) {
	end = charsLen;
    }

    return MeasureChars(tkfont, chars, charsLen, start, end-start,
	    startX, maxX, flags, nextXPtr);
#else
    {
	int xDisplacement;
	int fit, bstart = start, bend = end;

	if (chars == NULL) {
	    Tcl_DString *baseChars = &((BaseCharInfo *)
		    ciPtr->baseChunkPtr->clientData)->baseChars;

	    chars = Tcl_DStringValue(baseChars);
	    charsLen = Tcl_DStringLength(baseChars);
	    bstart += ciPtr->baseOffset;
	    if (bend == -1) {
		bend = ciPtr->baseOffset + ciPtr->numBytes;
	    } else {
		bend += ciPtr->baseOffset;
	    }
	} else if (bend == -1) {
	    bend = charsLen;
	}

	if (bstart == ciPtr->baseOffset) {
	    xDisplacement = startX - chunkPtr->x;
	} else {
	    int widthUntilStart = 0;

	    MeasureChars(tkfont, chars, charsLen, 0, bstart,
		    0, -1, 0, &widthUntilStart);
	    xDisplacement = startX - widthUntilStart - chunkPtr->x;
	}

	fit = MeasureChars(tkfont, chars, charsLen, 0, bend,
		ciPtr->baseChunkPtr->x + xDisplacement, maxX, flags, nextXPtr);

	if (fit < bstart) {
	    return 0;
	} else {
	    return fit - bstart;
	}
    }
#endif
}

/*
 *--------------------------------------------------------------
 *
 * CharDisplayProc --
 *
 *	This function is called to display a character chunk on the screen or
 *	in an off-screen pixmap.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Graphics are drawn.
 *
 *--------------------------------------------------------------
 */

static void
CharDisplayProc(
    TkText *textPtr,
    TkTextDispChunk *chunkPtr,	/* Chunk that is to be drawn. */
    int x,			/* X-position in dst at which to draw this
				 * chunk (may differ from the x-position in
				 * the chunk because of scrolling). */
    int y,			/* Y-position at which to draw this chunk in
				 * dst. */
    int height,			/* Total height of line. */
    int baseline,		/* Offset of baseline from y. */
    Display *display,		/* Display to use for drawing. */
    Drawable dst,		/* Pixmap or window in which to draw chunk. */
    int screenY)		/* Y-coordinate in text window that
				 * corresponds to y. */
{
    CharInfo *ciPtr = (CharInfo *) chunkPtr->clientData;
    const char *string;
    TextStyle *stylePtr;
    StyleValues *sValuePtr;
    int numBytes, offsetBytes, offsetX;
#if TK_DRAW_IN_CONTEXT
    BaseCharInfo *bciPtr;
#endif /* TK_DRAW_IN_CONTEXT */

    if ((x + chunkPtr->width) <= 0) {
	/*
	 * The chunk is off-screen.
	 */

	return;
    }

#if TK_DRAW_IN_CONTEXT
    bciPtr = (BaseCharInfo *) ciPtr->baseChunkPtr->clientData;
    numBytes = Tcl_DStringLength(&bciPtr->baseChars);
    string = Tcl_DStringValue(&bciPtr->baseChars);

#elif TK_LAYOUT_WITH_BASE_CHUNKS
    if (ciPtr->baseChunkPtr != chunkPtr) {
	/*
	 * Without context drawing only base chunks display their foreground.
	 */

	return;
    }

    numBytes = Tcl_DStringLength(&((BaseCharInfo *) ciPtr)->baseChars);
    string = ciPtr->chars;

#else /* !TK_LAYOUT_WITH_BASE_CHUNKS */
    numBytes = ciPtr->numBytes;
    string = ciPtr->chars;
#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */

    stylePtr = chunkPtr->stylePtr;
    sValuePtr = stylePtr->sValuePtr;

    /*
     * If the text sticks out way to the left of the window, skip over the
     * characters that aren't in the visible part of the window. This is
     * essential if x is very negative (such as less than 32K); otherwise
     * overflow problems will occur in servers that use 16-bit arithmetic,
     * like X.
     */

    offsetX = x;
    offsetBytes = 0;
    if (x < 0) {
	offsetBytes = CharChunkMeasureChars(chunkPtr, NULL, 0, 0, -1,
		x, 0, 0, &offsetX);
    }

    /*
     * Draw the text, underline, and overstrike for this chunk.
     */

    if (!sValuePtr->elide && (numBytes > offsetBytes)
	    && (stylePtr->fgGC != None)) {
#if TK_DRAW_IN_CONTEXT
	int start = ciPtr->baseOffset + offsetBytes;
	int len = ciPtr->numBytes - offsetBytes;
	int xDisplacement = x - chunkPtr->x;

	if ((len > 0) && (string[start + len - 1] == '\t')) {
	    len--;
	}
	if (len <= 0) {
	    return;
	}

	TkpDrawCharsInContext(display, dst, stylePtr->fgGC, sValuePtr->tkfont,
		string, numBytes, start, len,
		ciPtr->baseChunkPtr->x + xDisplacement,
		y + baseline - sValuePtr->offset);

	if (sValuePtr->underline) {
	    TkUnderlineCharsInContext(display, dst, stylePtr->fgGC,
		    sValuePtr->tkfont, string, numBytes,
		    ciPtr->baseChunkPtr->x + xDisplacement,
		    y + baseline - sValuePtr->offset,
		    start, start+len);
	}
	if (sValuePtr->overstrike) {
	    Tk_FontMetrics fm;

	    Tk_GetFontMetrics(sValuePtr->tkfont, &fm);
	    TkUnderlineCharsInContext(display, dst, stylePtr->fgGC,
		    sValuePtr->tkfont, string, numBytes,
		    ciPtr->baseChunkPtr->x + xDisplacement,
		    y + baseline - sValuePtr->offset
			    - fm.descent - (fm.ascent * 3) / 10,
		    start, start+len);
	}
#else /* !TK_DRAW_IN_CONTEXT */
	string += offsetBytes;
	numBytes -= offsetBytes;

	if ((numBytes > 0) && (string[numBytes - 1] == '\t')) {
	    numBytes--;
	}
	Tk_DrawChars(display, dst, stylePtr->fgGC, sValuePtr->tkfont, string,
		numBytes, offsetX, y + baseline - sValuePtr->offset);
	if (sValuePtr->underline) {
	    Tk_UnderlineChars(display, dst, stylePtr->fgGC, sValuePtr->tkfont,
		    string, offsetX,
		    y + baseline - sValuePtr->offset,
		    0, numBytes);

	}
	if (sValuePtr->overstrike) {
	    Tk_FontMetrics fm;

	    Tk_GetFontMetrics(sValuePtr->tkfont, &fm);
	    Tk_UnderlineChars(display, dst, stylePtr->fgGC, sValuePtr->tkfont,
		    string, offsetX,
		    y + baseline - sValuePtr->offset
			    - fm.descent - (fm.ascent * 3) / 10,
		    0, numBytes);
	}
#endif /* TK_DRAW_IN_CONTEXT */
    }
}

/*
 *--------------------------------------------------------------
 *
 * CharUndisplayProc --
 *
 *	This function is called when a character chunk is no longer going to
 *	be displayed. It frees up resources that were allocated to display the
 *	chunk.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Memory and other resources get freed.
 *
 *--------------------------------------------------------------
 */

static void
CharUndisplayProc(
    TkText *textPtr,		/* Overall information about text widget. */
    TkTextDispChunk *chunkPtr)	/* Chunk that is about to be freed. */
{
    CharInfo *ciPtr = (CharInfo *) chunkPtr->clientData;

    if (ciPtr) {
#if TK_LAYOUT_WITH_BASE_CHUNKS
	if (chunkPtr == ciPtr->baseChunkPtr) {
	    /*
	     * Basechunks are undisplayed first, when DLines are freed or
	     * partially freed, so this makes sure we don't access their data
	     * any more.
	     */

	    FreeBaseChunk(chunkPtr);
	} else if (ciPtr->baseChunkPtr != NULL) {
	    /*
	     * When other char chunks are undisplayed, drop their characters
	     * from the base chunk. This usually happens, when they are last
	     * in a line and need to be re-layed out.
	     */

	    RemoveFromBaseChunk(chunkPtr);
	}

	ciPtr->baseChunkPtr = NULL;
	ciPtr->chars = NULL;
	ciPtr->numBytes = 0;
#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */

	ckfree((char *) ciPtr);
	chunkPtr->clientData = NULL;
    }
}

/*
 *--------------------------------------------------------------
 *
 * CharMeasureProc --
 *
 *	This function is called to determine which character in a character
 *	chunk lies over a given x-coordinate.
 *
 * Results:
 *	The return value is the index *within the chunk* of the character that
 *	covers the position given by "x".
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static int
CharMeasureProc(
    TkTextDispChunk *chunkPtr,	/* Chunk containing desired coord. */
    int x)			/* X-coordinate, in same coordinate system as
				 * chunkPtr->x. */
{
    int endX;

    return CharChunkMeasureChars(chunkPtr, NULL, 0, 0, chunkPtr->numBytes-1,
	    chunkPtr->x, x, 0, &endX); /* CHAR OFFSET */
}

/*
 *--------------------------------------------------------------
 *
 * CharBboxProc --
 *
 *	This function is called to compute the bounding box of the area
 *	occupied by a single character.
 *
 * Results:
 *	There is no return value. *xPtr and *yPtr are filled in with the
 *	coordinates of the upper left corner of the character, and *widthPtr
 *	and *heightPtr are filled in with the dimensions of the character in
 *	pixels. Note: not all of the returned bbox is necessarily visible on
 *	the screen (the rightmost part might be off-screen to the right, and
 *	the bottommost part might be off-screen to the bottom).
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static void
CharBboxProc(
    TkText *textPtr,
    TkTextDispChunk *chunkPtr,	/* Chunk containing desired char. */
    int byteIndex,		/* Byte offset of desired character within the
				 * chunk. */
    int y,			/* Topmost pixel in area allocated for this
				 * line. */
    int lineHeight,		/* Height of line, in pixels. */
    int baseline,		/* Location of line's baseline, in pixels
				 * measured down from y. */
    int *xPtr, int *yPtr,	/* Gets filled in with coords of character's
				 * upper-left pixel. X-coord is in same
				 * coordinate system as chunkPtr->x. */
    int *widthPtr,		/* Gets filled in with width of character, in
				 * pixels. */
    int *heightPtr)		/* Gets filled in with height of character, in
				 * pixels. */
{
    CharInfo *ciPtr = (CharInfo *) chunkPtr->clientData;
    int maxX;

    maxX = chunkPtr->width + chunkPtr->x;
    CharChunkMeasureChars(chunkPtr, NULL, 0, 0, byteIndex,
	    chunkPtr->x, -1, 0, xPtr);

    if (byteIndex == ciPtr->numBytes) {
	/*
	 * This situation only happens if the last character in a line is a
	 * space character, in which case it absorbs all of the extra space in
	 * the line (see TkTextCharLayoutProc).
	 */

	*widthPtr = maxX - *xPtr;
    } else if ((ciPtr->chars[byteIndex] == '\t')
	    && (byteIndex == ciPtr->numBytes - 1)) {
	/*
	 * The desired character is a tab character that terminates a chunk;
	 * give it all the space left in the chunk.
	 */

	*widthPtr = maxX - *xPtr;
    } else {
	CharChunkMeasureChars(chunkPtr, NULL, 0, byteIndex, byteIndex+1,
		*xPtr, -1, 0, widthPtr);
	if (*widthPtr > maxX) {
	    *widthPtr = maxX - *xPtr;
	} else {
	    *widthPtr -= *xPtr;
	}
    }
    *yPtr = y + baseline - chunkPtr->minAscent;
    *heightPtr = chunkPtr->minAscent + chunkPtr->minDescent;
}

/*
 *----------------------------------------------------------------------
 *
 * AdjustForTab --
 *
 *	This function is called to move a series of chunks right in order to
 *	align them with a tab stop.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The width of chunkPtr gets adjusted so that it absorbs the extra space
 *	due to the tab. The x locations in all the chunks after chunkPtr are
 *	adjusted rightward to align with the tab stop given by tabArrayPtr and
 *	index.
 *
 *----------------------------------------------------------------------
 */

static void
AdjustForTab(
    TkText *textPtr,		/* Information about the text widget as a
				 * whole. */
    TkTextTabArray *tabArrayPtr,/* Information about the tab stops that apply
				 * to this line. May be NULL to indicate
				 * default tabbing (every 8 chars). */
    int index,			/* Index of current tab stop. */
    TkTextDispChunk *chunkPtr)	/* Chunk whose last character is the tab; the
				 * following chunks contain information to be
				 * shifted right. */
{
    int x, desired, delta, width, decimal, i, gotDigit;
    TkTextDispChunk *chunkPtr2, *decimalChunkPtr;
    CharInfo *ciPtr;
    int tabX, spaceWidth;
    const char *p;
    TkTextTabAlign alignment;

    if (chunkPtr->nextPtr == NULL) {
	/*
	 * Nothing after the actual tab; just return.
	 */

	return;
    }

    x = chunkPtr->nextPtr->x;

    /*
     * If no tab information has been given, assuming tab stops are at 8
     * average-sized characters. Still ensure we respect the tabular versus
     * wordprocessor tab style.
     */

    if ((tabArrayPtr == NULL) || (tabArrayPtr->numTabs == 0)) {
	/*
	 * No tab information has been given, so use the default
	 * interpretation of tabs.
	 */

	if (textPtr->tabStyle == TK_TEXT_TABSTYLE_TABULAR) {
	    int tabWidth = Tk_TextWidth(textPtr->tkfont, "0", 1) * 8;
	    if (tabWidth == 0) {
		tabWidth = 1;
	    }

	    desired = tabWidth * (index + 1);
	} else {
	    desired = NextTabStop(textPtr->tkfont, x, 0);
	}

	goto update;
    }

    if (index < tabArrayPtr->numTabs) {
	alignment = tabArrayPtr->tabs[index].alignment;
	tabX = tabArrayPtr->tabs[index].location;
    } else {
	/*
	 * Ran out of tab stops; compute a tab position by extrapolating from
	 * the last two tab positions.
	 */

	tabX = (int) (tabArrayPtr->lastTab +
		(index + 1 - tabArrayPtr->numTabs)*tabArrayPtr->tabIncrement +
		0.5);
	alignment = tabArrayPtr->tabs[tabArrayPtr->numTabs-1].alignment;
    }

    if (alignment == LEFT) {
	desired = tabX;
	goto update;
    }

    if ((alignment == CENTER) || (alignment == RIGHT)) {
	/*
	 * Compute the width of all the information in the tab group, then use
	 * it to pick a desired location.
	 */

	width = 0;
	for (chunkPtr2 = chunkPtr->nextPtr; chunkPtr2 != NULL;
		chunkPtr2 = chunkPtr2->nextPtr) {
	    width += chunkPtr2->width;
	}
	if (alignment == CENTER) {
	    desired = tabX - width/2;
	} else {
	    desired = tabX - width;
	}
	goto update;
    }

    /*
     * Must be numeric alignment. Search through the text to be tabbed,
     * looking for the last , or . before the first character that isn't a
     * number, comma, period, or sign.
     */

    decimalChunkPtr = NULL;
    decimal = gotDigit = 0;
    for (chunkPtr2 = chunkPtr->nextPtr; chunkPtr2 != NULL;
	    chunkPtr2 = chunkPtr2->nextPtr) {
	if (chunkPtr2->displayProc != CharDisplayProc) {
	    continue;
	}
	ciPtr = (CharInfo *) chunkPtr2->clientData;
	for (p = ciPtr->chars, i = 0; i < ciPtr->numBytes; p++, i++) {
	    if (isdigit(UCHAR(*p))) {
		gotDigit = 1;
	    } else if ((*p == '.') || (*p == ',')) {
		decimal = p-ciPtr->chars;
		decimalChunkPtr = chunkPtr2;
	    } else if (gotDigit) {
		if (decimalChunkPtr == NULL) {
		    decimal = p-ciPtr->chars;
		    decimalChunkPtr = chunkPtr2;
		}
		goto endOfNumber;
	    }
	}
    }

  endOfNumber:
    if (decimalChunkPtr != NULL) {
	int curX;

	ciPtr = (CharInfo *) decimalChunkPtr->clientData;
	CharChunkMeasureChars(decimalChunkPtr, NULL, 0, 0, decimal,
		decimalChunkPtr->x, -1, 0, &curX);
	desired = tabX - (curX - x);
	goto update;
    } else {
	/*
	 * There wasn't a decimal point. Right justify the text.
	 */

	width = 0;
	for (chunkPtr2 = chunkPtr->nextPtr; chunkPtr2 != NULL;
		chunkPtr2 = chunkPtr2->nextPtr) {
	    width += chunkPtr2->width;
	}
	desired = tabX - width;
    }

    /*
     * Shift all of the chunks to the right so that the left edge is at the
     * desired location, then expand the chunk containing the tab. Be sure
     * that the tab occupies at least the width of a space character.
     */

  update:
    delta = desired - x;
    MeasureChars(textPtr->tkfont, " ", 1, 0, 1, 0, -1, 0, &spaceWidth);
    if (delta < spaceWidth) {
	delta = spaceWidth;
    }
    for (chunkPtr2 = chunkPtr->nextPtr; chunkPtr2 != NULL;
	    chunkPtr2 = chunkPtr2->nextPtr) {
	chunkPtr2->x += delta;
    }
    chunkPtr->width += delta;
}

/*
 *----------------------------------------------------------------------
 *
 * SizeOfTab --
 *
 *	This returns an estimate of the amount of white space that will be
 *	consumed by a tab.
 *
 * Results:
 *	The return value is the minimum number of pixels that will be occupied
 *	by the next tab of tabArrayPtr, assuming that the current position on
 *	the line is x and the end of the line is maxX. The 'next tab' is
 *	determined by a combination of the current position (x) which it must
 *	be equal to or beyond, and the tab count in indexPtr.
 *
 *	For numeric tabs, this is a conservative estimate. The return value is
 *	always >= 0.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
SizeOfTab(
    TkText *textPtr,		/* Information about the text widget as a
				 * whole. */
    int tabStyle,		/* One of TK_TEXT_TABSTYLE_TABULAR
				 * or TK_TEXT_TABSTYLE_WORDPROCESSOR. */
    TkTextTabArray *tabArrayPtr,/* Information about the tab stops that apply
				 * to this line. NULL means use default
				 * tabbing (every 8 chars.) */
    int *indexPtr,		/* Contains index of previous tab stop, will
				 * be updated to reflect the number of stops
				 * used. */
    int x,			/* Current x-location in line. */
    int maxX)			/* X-location of pixel just past the right
				 * edge of the line. */
{
    int tabX, result, index, spaceWidth, tabWidth;
    TkTextTabAlign alignment;

    index = *indexPtr;

    if ((tabArrayPtr == NULL) || (tabArrayPtr->numTabs == 0)) {
	/*
	 * We're using a default tab spacing of 8 characters.
	 */

	tabWidth = Tk_TextWidth(textPtr->tkfont, "0", 1) * 8;
	if (tabWidth == 0) {
	    tabWidth = 1;
	}
    } else {
	tabWidth = 0;		/* Avoid compiler error. */
    }

    do {
	/*
	 * We were given the count before this tab, so increment it first.
	 */

	index++;

	if ((tabArrayPtr == NULL) || (tabArrayPtr->numTabs == 0)) {
	    /*
	     * We're using a default tab spacing calculated above.
	     */

	    tabX = tabWidth * (index + 1);
	    alignment = LEFT;
	} else if (index < tabArrayPtr->numTabs) {
	    tabX = tabArrayPtr->tabs[index].location;
	    alignment = tabArrayPtr->tabs[index].alignment;
	} else {
	    /*
	     * Ran out of tab stops; compute a tab position by extrapolating.
	     */

	    tabX = (int) (tabArrayPtr->lastTab
		    + (index + 1 - tabArrayPtr->numTabs)
		    * tabArrayPtr->tabIncrement + 0.5);
	    alignment = tabArrayPtr->tabs[tabArrayPtr->numTabs-1].alignment;
	}

	/*
	 * If this tab stop is before the current x position, then we have two
	 * cases:
	 *
	 * With 'wordprocessor' style tabs, we must obviously continue until
	 * we reach the text tab stop.
	 *
	 * With 'tabular' style tabs, we always use the index'th tab stop.
	 */
    } while (tabX <= x && (tabStyle == TK_TEXT_TABSTYLE_WORDPROCESSOR));

    /*
     * Inform our caller of how many tab stops we've used up.
     */

    *indexPtr = index;

    if (alignment == CENTER) {
	/*
	 * Be very careful in the arithmetic below, because maxX may be the
	 * largest positive number: watch out for integer overflow.
	 */

	if ((maxX-tabX) < (tabX - x)) {
	    result = (maxX - x) - 2*(maxX - tabX);
	} else {
	    result = 0;
	}
	goto done;
    }
    if (alignment == RIGHT) {
	result = 0;
	goto done;
    }

    /*
     * Note: this treats NUMERIC alignment the same as LEFT alignment, which
     * is somewhat conservative. However, it's pretty tricky at this point to
     * figure out exactly where the damn decimal point will be.
     */

    if (tabX > x) {
	result = tabX - x;
    } else {
	result = 0;
    }

  done:
    MeasureChars(textPtr->tkfont, " ", 1, 0, 1, 0, -1, 0, &spaceWidth);
    if (result < spaceWidth) {
	result = spaceWidth;
    }
    return result;
}

/*
 *---------------------------------------------------------------------------
 *
 * NextTabStop --
 *
 *	Given the current position, determine where the next default tab stop
 *	would be located. This function is called when the current chunk in
 *	the text has no tabs defined and so the default tab spacing for the
 *	font should be used, provided we are using wordprocessor style tabs.
 *
 * Results:
 *	The location in pixels of the next tab stop.
 *
 * Side effects:
 *	None.
 *
 *---------------------------------------------------------------------------
 */

static int
NextTabStop(
    Tk_Font tkfont,		/* Font in which chunk that contains tab stop
				 * will be drawn. */
    int x,			/* X-position in pixels where last character
				 * was drawn. The next tab stop occurs
				 * somewhere after this location. */
    int tabOrigin)		/* The origin for tab stops. May be non-zero
				 * if text has been scrolled. */
{
    int tabWidth, rem;

    tabWidth = Tk_TextWidth(tkfont, "0", 1) * 8;
    if (tabWidth == 0) {
	tabWidth = 1;
    }

    x += tabWidth;
    rem = (x - tabOrigin) % tabWidth;
    if (rem < 0) {
	rem += tabWidth;
    }
    x -= rem;
    return x;
}

/*
 *---------------------------------------------------------------------------
 *
 * MeasureChars --
 *
 *	Determine the number of characters from the string that will fit in
 *	the given horizontal span. The measurement is done under the
 *	assumption that Tk_DrawChars will be used to actually display the
 *	characters.
 *
 *	If tabs are encountered in the string, they will be ignored (they
 *	should only occur as last character of the string anyway).
 *
 *	If a newline is encountered in the string, the line will be broken at
 *	that point.
 *
 * Results:
 *	The return value is the number of bytes from the range of start to end
 *	in source that fit in the span given by startX and maxX. *nextXPtr is
 *	filled in with the x-coordinate at which the first character that
 *	didn't fit would be drawn, if it were to be drawn.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static int
MeasureChars(
    Tk_Font tkfont,		/* Font in which to draw characters. */
    CONST char *source,		/* Characters to be displayed. Need not be
				 * NULL-terminated. */
    int maxBytes,		/* Maximum # of bytes to consider from
				 * source. */
    int rangeStart, int rangeLength,
				/* Range of bytes to consider in source.*/
    int startX,			/* X-position at which first character will be
				 * drawn. */
    int maxX,			/* Don't consider any character that would
				 * cross this x-position. */
    int flags,			/* Flags to pass to Tk_MeasureChars. */
    int *nextXPtr)		/* Return x-position of terminating character
				 * here. */
{
    int curX, width, ch;
    CONST char *special, *end, *start;

    ch = 0;			/* lint. */
    curX = startX;
    start = source + rangeStart;
    end = start + rangeLength;
    special = start;
    while (start < end) {
	if (start >= special) {
	    /*
	     * Find the next special character in the string.
	     */

	    for (special = start; special < end; special++) {
		ch = *special;
		if ((ch == '\t') || (ch == '\n')) {
		    break;
		}
	    }
	}

	/*
	 * Special points at the next special character (or the end of the
	 * string). Process characters between start and special.
	 */

	if ((maxX >= 0) && (curX >= maxX)) {
	    break;
	}
#if TK_DRAW_IN_CONTEXT
	start += TkpMeasureCharsInContext(tkfont, source, maxBytes,
		start - source, special - start,
		maxX >= 0 ? maxX - curX : -1, flags, &width);
#else
	(void) maxBytes;
	start += Tk_MeasureChars(tkfont, start, special - start,
		maxX >= 0 ? maxX - curX : -1, flags, &width);
#endif /* TK_DRAW_IN_CONTEXT */
	curX += width;
	if (start < special) {
	    /*
	     * No more chars fit in line.
	     */

	    break;
	}
	if (special < end) {
	    if (ch == '\t') {
		start++;
	    } else {
		break;
	    }
	}
    }

    *nextXPtr = curX;
    return start - (source+rangeStart);
}

/*
 *----------------------------------------------------------------------
 *
 * TextGetScrollInfoObj --
 *
 *	This function is invoked to parse "xview" and "yview" scrolling
 *	commands for text widgets using the new scrolling command syntax
 *	("moveto" or "scroll" options). It extends the public
 *	Tk_GetScrollInfoObj function with the addition of "pixels" as a valid
 *	unit alongside "pages" and "units". It is a shame the core API isn't
 *	more flexible in this regard.
 *
 * Results:
 *	The return value is either TKTEXT_SCROLL_MOVETO, TKTEXT_SCROLL_PAGES,
 *	TKTEXT_SCROLL_UNITS, TKTEXT_SCROLL_PIXELS or TKTEXT_SCROLL_ERROR. This
 *	indicates whether the command was successfully parsed and what form
 *	the command took. If TKTEXT_SCROLL_MOVETO, *dblPtr is filled in with
 *	the desired position; if TKTEXT_SCROLL_PAGES, TKTEXT_SCROLL_PIXELS or
 *	TKTEXT_SCROLL_UNITS, *intPtr is filled in with the number of
 *	pages/pixels/lines to move (may be negative); if TKTEXT_SCROLL_ERROR,
 *	the interp's result contains an error message.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
TextGetScrollInfoObj(
    Tcl_Interp *interp,		/* Used for error reporting. */
    TkText *textPtr,		/* Information about the text widget. */
    int objc,			/* # arguments for command. */
    Tcl_Obj *CONST objv[],	/* Arguments for command. */
    double *dblPtr,		/* Filled in with argument "moveto" option, if
				 * any. */
    int *intPtr)		/* Filled in with number of pages or lines or
				 * pixels to scroll, if any. */
{
    static CONST char *subcommands[] = {
	"moveto", "scroll", NULL
    };
    enum viewSubcmds {
	VIEW_MOVETO, VIEW_SCROLL
    };
    static CONST char *units[] = {
	"units", "pages", "pixels", NULL
    };
    enum viewUnits {
	VIEW_SCROLL_UNITS, VIEW_SCROLL_PAGES, VIEW_SCROLL_PIXELS
    };
    int index;

    if (Tcl_GetIndexFromObj(interp, objv[2], subcommands, "option", 0,
	    &index) != TCL_OK) {
	return TKTEXT_SCROLL_ERROR;
    }

    switch ((enum viewSubcmds) index) {
    case VIEW_MOVETO:
	if (objc != 4) {
	    Tcl_WrongNumArgs(interp, 3, objv, "fraction");
	    return TKTEXT_SCROLL_ERROR;
	}
	if (Tcl_GetDoubleFromObj(interp, objv[3], dblPtr) != TCL_OK) {
	    return TKTEXT_SCROLL_ERROR;
	}
	return TKTEXT_SCROLL_MOVETO;
    case VIEW_SCROLL:
	if (objc != 5) {
	    Tcl_WrongNumArgs(interp, 3, objv, "number units|pages|pixels");
	    return TKTEXT_SCROLL_ERROR;
	}
	if (Tcl_GetIndexFromObj(interp, objv[4], units, "argument", 0,
		&index) != TCL_OK) {
	    return TKTEXT_SCROLL_ERROR;
	}
	switch ((enum viewUnits) index) {
	case VIEW_SCROLL_PAGES:
	    if (Tcl_GetIntFromObj(interp, objv[3], intPtr) != TCL_OK) {
		return TKTEXT_SCROLL_ERROR;
	    }
	    return TKTEXT_SCROLL_PAGES;
	case VIEW_SCROLL_PIXELS:
	    if (Tk_GetPixelsFromObj(interp, textPtr->tkwin, objv[3],
		    intPtr) != TCL_OK) {
		return TKTEXT_SCROLL_ERROR;
	    }
	    return TKTEXT_SCROLL_PIXELS;
	case VIEW_SCROLL_UNITS:
	    if (Tcl_GetIntFromObj(interp, objv[3], intPtr) != TCL_OK) {
		return TKTEXT_SCROLL_ERROR;
	    }
	    return TKTEXT_SCROLL_UNITS;
	}
    }
    Tcl_Panic("unexpected switch fallthrough");
    return TKTEXT_SCROLL_ERROR;
}

#if TK_LAYOUT_WITH_BASE_CHUNKS
/*
 *----------------------------------------------------------------------
 *
 * FinalizeBaseChunk --
 *
 *	This procedure makes sure that all the chunks of the stretch are
 *	up-to-date. It is invoked when the LayoutProc has been called for all
 *	chunks and the base chunk is stable.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The CharInfo.chars of all dependent chunks point into
 *	BaseCharInfo.baseChars for easy access (and compatibility).
 *
 *----------------------------------------------------------------------
 */

static void
FinalizeBaseChunk(
    TkTextDispChunk *addChunkPtr)
				/* An additional chunk to add to the stretch,
				 * even though it may not be in the linked
				 * list yet. Used by the LayoutProc, otherwise
				 * NULL. */
{
    const char *baseChars;
    TkTextDispChunk *chunkPtr;
    CharInfo *ciPtr;
#if TK_DRAW_IN_CONTEXT
    int widthAdjust = 0;
    int newwidth;
#endif /* TK_DRAW_IN_CONTEXT */

    if (baseCharChunkPtr == NULL) {
	return;
    }

    baseChars = Tcl_DStringValue(
	    &((BaseCharInfo *) baseCharChunkPtr->clientData)->baseChars);

    for (chunkPtr = baseCharChunkPtr; chunkPtr != NULL;
	    chunkPtr = chunkPtr->nextPtr) {
#if TK_DRAW_IN_CONTEXT
	chunkPtr->x += widthAdjust;
#endif /* TK_DRAW_IN_CONTEXT */

	if (chunkPtr->displayProc != CharDisplayProc) {
	    continue;
	}
	ciPtr = (CharInfo *)chunkPtr->clientData;
	if (ciPtr->baseChunkPtr != baseCharChunkPtr) {
	    break;
	}
	ciPtr->chars = baseChars + ciPtr->baseOffset;

#if TK_DRAW_IN_CONTEXT
	newwidth = 0;
	CharChunkMeasureChars(chunkPtr, NULL, 0, 0, -1, 0, -1, 0, &newwidth);
	if (newwidth != chunkPtr->width) {
	    widthAdjust += newwidth - chunkPtr->width;
	    chunkPtr->width = newwidth;
	}
#endif /* TK_DRAW_IN_CONTEXT */
    }

    if (addChunkPtr != NULL) {
	ciPtr = (CharInfo *)addChunkPtr->clientData;
	ciPtr->chars = baseChars + ciPtr->baseOffset;

#if TK_DRAW_IN_CONTEXT
	addChunkPtr->x += widthAdjust;
	CharChunkMeasureChars(addChunkPtr, NULL, 0, 0, -1, 0, -1, 0,
		&addChunkPtr->width);
#endif /* TK_DRAW_IN_CONTEXT */
    }

    baseCharChunkPtr = NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * FreeBaseChunk --
 *
 *	This procedure makes sure that all the chunks of the stretch are
 *	disconnected from the base chunk and the base chunk specific data is
 *	freed. It is invoked from the UndisplayProc. The procedure doesn't
 *	ckfree the base chunk clientData itself, that's up to the main
 *	UndisplayProc.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The CharInfo.chars of all dependent chunks are set to NULL. Memory
 *	that belongs specifically to the base chunk is freed.
 *
 *----------------------------------------------------------------------
 */

static void
FreeBaseChunk(
    TkTextDispChunk *baseChunkPtr)
				/* The base chunk of the stretch and head of
				 * the linked list. */
{
    TkTextDispChunk *chunkPtr;
    CharInfo *ciPtr;

    if (baseCharChunkPtr == baseChunkPtr) {
	baseCharChunkPtr = NULL;
    }

    for (chunkPtr=baseChunkPtr; chunkPtr!=NULL; chunkPtr=chunkPtr->nextPtr) {
	if (chunkPtr->undisplayProc != CharUndisplayProc) {
	    continue;
	}
	ciPtr = (CharInfo *) chunkPtr->clientData;
	if (ciPtr->baseChunkPtr != baseChunkPtr) {
	    break;
	}

	ciPtr->baseChunkPtr = NULL;
	ciPtr->chars = NULL;
    }

    Tcl_DStringFree(&((BaseCharInfo *) baseChunkPtr->clientData)->baseChars);
}

/*
 *----------------------------------------------------------------------
 *
 * IsSameFGStyle --
 *
 *	Compare the foreground attributes of two styles. Specifically must
 *	consider: foreground color, font, font style and font decorations,
 *	elide, "offset" and foreground stipple. Do *not* consider: background
 *	color, border, relief or background stipple.
 *
 *	If we use TkpDrawCharsInContext(), we also don't need to check
 *	foreground color, font decorations, elide, offset and foreground
 *	stipple, so all that is left is font (including font size and font
 *	style) and "offset".
 *
 * Results:
 *	1 if the two styles match, 0 otherwise.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
IsSameFGStyle(
    TextStyle *style1,
    TextStyle *style2)
{
    StyleValues *sv1;
    StyleValues *sv2;

    if (style1 == style2) {
	return 1;
    }

#if !TK_DRAW_IN_CONTEXT
    if (
#ifdef MAC_OSX_TK
	    !TkMacOSXCompareColors(style1->fgGC->foreground,
		    style2->fgGC->foreground)
#else
	    style1->fgGC->foreground != style2->fgGC->foreground
#endif
	    ) {
	return 0;
    }
#endif /* !TK_DRAW_IN_CONTEXT */

    sv1 = style1->sValuePtr;
    sv2 = style2->sValuePtr;

#if TK_DRAW_IN_CONTEXT
    return sv1->tkfont == sv2->tkfont && sv1->offset == sv2->offset;
#else
    return sv1->tkfont == sv2->tkfont
	    && sv1->underline == sv2->underline
	    && sv1->overstrike == sv2->overstrike
	    && sv1->elide == sv2->elide
	    && sv1->offset == sv2->offset
	    && sv1->fgStipple == sv1->fgStipple;
#endif /* TK_DRAW_IN_CONTEXT */
}

/*
 *----------------------------------------------------------------------
 *
 * RemoveFromBaseChunk --
 *
 *	This procedure removes a chunk from the stretch as a result of
 *	UndisplayProc. The chunk in question should be the last in a stretch.
 *	This happens during re-layouting of the break position.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The characters that belong to this chunk are removed from the base
 *	chunk. It is assumed that LayoutProc and FinalizeBaseChunk are called
 *	next to repair any damage that this causes to the integrity of the
 *	stretch and the other chunks. For that reason the base chunk is also
 *	put into baseCharChunkPtr automatically, so that LayoutProc can resume
 *	correctly.
 *
 *----------------------------------------------------------------------
 */

static void
RemoveFromBaseChunk(
    TkTextDispChunk *chunkPtr)	/* The chunk to remove from the end of the
				 * stretch. */
{
    CharInfo *ciPtr;
    BaseCharInfo *bciPtr;

    if (chunkPtr->displayProc != CharDisplayProc) {
#ifdef DEBUG_LAYOUT_WITH_BASE_CHUNKS
	fprintf(stderr,"RemoveFromBaseChunk called with wrong chunk type\n");
#endif
	return;
    }

    /*
     * Reinstitute this base chunk for re-layout.
     */

    ciPtr = (CharInfo *) chunkPtr->clientData;
    baseCharChunkPtr = ciPtr->baseChunkPtr;

    /*
     * Remove the chunk data from the base chunk data.
     */

    bciPtr = (BaseCharInfo *) baseCharChunkPtr->clientData;

    if ((ciPtr->baseOffset + ciPtr->numBytes)
	    != Tcl_DStringLength(&bciPtr->baseChars)) {
#ifdef DEBUG_LAYOUT_WITH_BASE_CHUNKS
	fprintf(stderr,"RemoveFromBaseChunk called with wrong chunk "
		"(not last)\n");
#endif
    }

    Tcl_DStringSetLength(&bciPtr->baseChars, ciPtr->baseOffset);

    /*
     * Invalidate the stored pixel width of the base chunk.
     */

    bciPtr->width = -1;
}
#endif /* TK_LAYOUT_WITH_BASE_CHUNKS */

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */