summaryrefslogtreecommitdiffstats
path: root/src/gui/graphicsview/qgraphicsview.cpp
blob: 5d8bce52e7e9a385e21e89be279f284e2f11bb86 (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
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://www.qtsoftware.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/

static const int QGRAPHICSVIEW_REGION_RECT_THRESHOLD = 50;

static const int QGRAPHICSVIEW_PREALLOC_STYLE_OPTIONS = 503; // largest prime < 2^9

/*!
    \class QGraphicsView
    \brief The QGraphicsView class provides a widget for displaying the
    contents of a QGraphicsScene.
    \since 4.2
    \ingroup multimedia
    \ingroup graphicsview-api
    \mainclass

    QGraphicsView visualizes the contents of a QGraphicsScene in a scrollable
    viewport. To create a scene with geometrical items, see QGraphicsScene's
    documentation. QGraphicsView is part of \l{The Graphics View Framework}.

    To visualize a scene, you start by constructing a QGraphicsView object,
    passing the address of the scene you want to visualize to QGraphicsView's
    constructor. Alternatively, you can call setScene() to set the scene at a
    later point. After you call show(), the view will by default scroll to the
    center of the scene and display any items that are visible at this
    point. For example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsview.cpp 0

    You can explicitly scroll to any position on the scene by using the
    scroll bars, or by calling centerOn(). By passing a point to centerOn(),
    QGraphicsView will scroll its viewport to ensure that the point is
    centered in the view. An overload is provided for scrolling to a
    QGraphicsItem, in which case QGraphicsView will see to that the center of
    the item is centered in the view. If all you want is to ensure that a
    certain area is visible, (but not necessarily centered,) you can call
    ensureVisible() instead.

    QGraphicsView can be used to visualize a whole scene, or only parts of it.
    The visualized area is by default detected automatically when the view is
    displayed for the first time (by calling
    QGraphicsScene::itemsBoundingRect()). To set the visualized area rectangle
    yourself, you can call setSceneRect(). This will adjust the scroll bars'
    ranges appropriately. Note that although the scene supports a virtually
    unlimited size, the range of the scroll bars will never exceed the range of
    an integer (INT_MIN, INT_MAX). When the scene is larger than the scroll
    bars' values, you can choose to use translate() to navigate the scene
    instead.

    QGraphicsView visualizes the scene by calling render(). By default, the
    items are drawn onto the viewport by using a regular QPainter, and using
    default render hints. To change the default render hints that
    QGraphicsView passes to QPainter when painting items, you can call
    setRenderHints().

    By default, QGraphicsView provides a regular QWidget for the viewport
    widget. You can access this widget by calling viewport(), or you can
    replace it by calling setViewport(). To render using OpenGL, simply call
    setViewport(new QGLWidget). QGraphicsView takes ownership of the viewport
    widget.

    QGraphicsView supports affine transformations, using QTransform. You can
    either pass a matrix to setTransform(), or you can call one of the
    convenience functions rotate(), scale(), translate() or shear(). The most
    two common transformations are scaling, which is used to implement
    zooming, and rotation. QGraphicsView keeps the center of the view fixed
    during a transformation.

    You can interact with the items on the scene by using the mouse and
    keyboard. QGraphicsView translates the mouse and key events into \e scene
    events, (events that inherit QGraphicsSceneEvent,), and forward them to
    the visualized scene. In the end, it's the individual item that handles
    the events and reacts to them. For example, if you click on a selectable
    item, the item will typically let the scene know that it has been
    selected, and it will also redraw itself to display a selection
    rectangle. Similiary, if you click and drag the mouse to move a movable
    item, it's the item that handles the mouse moves and moves itself.  Item
    interaction is enabled by default, and you can toggle it by calling
    setInteractive().

    You can also provide your own custom scene interaction, by creating a
    subclass of QGraphicsView, and reimplementing the mouse and key event
    handlers. To simplify how you programmatically interact with items in the
    view, QGraphicsView provides the mapping functions mapToScene() and
    mapFromScene(), and the item accessors items() and itemAt(). These
    functions allow you to map points, rectangles, polygons and paths between
    view coordinates and scene coordinates, and to find items on the scene
    using view coordinates.

    \img graphicsview-view.png

    \sa QGraphicsScene, QGraphicsItem, QGraphicsSceneEvent
*/

/*!
    \enum QGraphicsView::ViewportAnchor

    This enums describe the possible anchors that QGraphicsView can
    use when the user resizes the view or when the view is
    transformed.

    \value NoAnchor No anchor, i.e. the view leaves the scene's
                    position unchanged.
    \value AnchorViewCenter The scene point at the center of the view
                            is used as the anchor.
    \value AnchorUnderMouse The point under the mouse is used as the anchor.

    \sa resizeAnchor, transformationAnchor
*/

/*!
    \enum QGraphicsView::ViewportUpdateMode

    \since 4.3

    This enum describes how QGraphicsView updates its viewport when the scene
    contents change or are exposed.

    \value FullViewportUpdate When any visible part of the scene changes or is
    reexposed, QGraphicsView will update the entire viewport. This approach is
    fastest when QGraphicsView spends more time figuring out what to draw than
    it would spend drawing (e.g., when very many small items are repeatedly
    updated). This is the preferred update mode for viewports that do not
    support partial updates, such as QGLWidget, and for viewports that need to
    disable scroll optimization.

    \value MinimalViewportUpdate QGraphicsView will determine the minimal
    viewport region that requires a redraw, minimizing the time spent drawing
    by avoiding a redraw of areas that have not changed. This is
    QGraphicsView's default mode. Although this approach provides the best
    performance in general, if there are many small visible changes on the
    scene, QGraphicsView might end up spending more time finding the minimal
    approach than it will spend drawing.

    \value SmartViewportUpdate QGraphicsView will attempt to find an optimal
    update mode by analyzing the areas that require a redraw.

    \value BoundingRectViewportUpdate The bounding rectangle of all changes in
    the viewport will be redrawn. This mode has the advantage that
    QGraphicsView searches only one region for changes, minimizing time spent
    determining what needs redrawing. The disadvantage is that areas that have
    not changed also need to be redrawn.

    \value NoViewportUpdate QGraphicsView will never update its viewport when
    the scene changes; the user is expected to control all updates. This mode
    disables all (potentially slow) item visibility testing in QGraphicsView,
    and is suitable for scenes that either require a fixed frame rate, or where
    the viewport is otherwise updated externally.

    \sa viewportUpdateMode
*/

/*!
    \enum QGraphicsView::OptimizationFlag

    \since 4.3

    This enum describes flags that you can enable to improve rendering
    performance in QGraphicsView. By default, none of these flags are set.
    Note that setting a flag usually imposes a side effect, and this effect
    can vary between paint devices and platforms.

    \value DontClipPainter This value is obsolete and has no effect.

    \value DontSavePainterState When rendering, QGraphicsView protects the
    painter state (see QPainter::save()) when rendering the background or
    foreground, and when rendering each item. This allows you to leave the
    painter in an altered state (i.e., you can call QPainter::setPen() or
    QPainter::setBrush() without restoring the state after painting). However,
    if the items consistently do restore the state, you should enable this
    flag to prevent QGraphicsView from doing the same.

    \value DontAdjustForAntialiasing Disables QGraphicsView's antialiasing
    auto-adjustment of exposed areas. Items that render antialiased lines on
    the boundaries of their QGraphicsItem::boundingRect() can end up rendering
    parts of the line outside. To prevent rendering artifacts, QGraphicsView
    expands all exposed regions by 2 pixels in all directions. If you enable
    this flag, QGraphicsView will no longer perform these adjustments,
    minimizing the areas that require redrawing, which improves performance. A
    common side effect is that items that do draw with antialiasing can leave
    painting traces behind on the scene as they are moved.

    \omitvalue IndirectPainting
*/

/*!
    \enum QGraphicsView::CacheModeFlag

    This enum describes the flags that you can set for a QGraphicsView's cache
    mode.

    \value CacheNone All painting is done directly onto the viewport.

    \value CacheBackground The background is cached. This affects both custom
    backgrounds, and backgrounds based on the backgroundBrush property. When
    this flag is enabled, QGraphicsView will allocate one pixmap with the full
    size of the viewport.

    \sa cacheMode
*/

/*!
    \enum QGraphicsView::DragMode

    This enum describes the default action for the view when pressing and
    dragging the mouse over the viewport.

    \value NoDrag Nothing happens; the mouse event is ignored.

    \value ScrollHandDrag The cursor changes into a pointing hand, and
    dragging the mouse around will scroll the scrolbars. This mode works both
    in \l{QGraphicsView::interactive}{interactive} and non-interactive mode.

    \value RubberBandDrag A rubber band will appear. Dragging the mouse will
    set the rubber band geometry, and all items covered by the rubber band are
    selected. This mode is disabled for non-interactive views.

    \sa dragMode, QGraphicsScene::setSelectionArea()
*/

#include "qgraphicsview.h"
#include "qgraphicsview_p.h"

#ifndef QT_NO_GRAPHICSVIEW

#include "qgraphicsitem.h"
#include "qgraphicsitem_p.h"
#include "qgraphicsscene.h"
#include "qgraphicsscene_p.h"
#include "qgraphicssceneevent.h"
#include "qgraphicswidget.h"

#include <QtCore/qdatetime.h>
#include <QtCore/qdebug.h>
#include <QtCore/qmath.h>
#include <QtGui/qapplication.h>
#include <QtGui/qdesktopwidget.h>
#include <QtGui/qevent.h>
#include <QtGui/qlayout.h>
#include <QtGui/qtransform.h>
#include <QtGui/qmatrix.h>
#include <QtGui/qpainter.h>
#include <QtGui/qscrollbar.h>
#include <QtGui/qstyleoption.h>
#include <QtGui/qinputcontext.h>
#ifdef Q_WS_X11
#include <private/qt_x11_p.h>
#endif

#include <private/qevent_p.h>

QT_BEGIN_NAMESPACE

bool qt_sendSpontaneousEvent(QObject *receiver, QEvent *event);

inline int q_round_bound(qreal d) //### (int)(qreal) INT_MAX != INT_MAX for single precision
{
    if (d <= (qreal) INT_MIN)
        return INT_MIN;
    else if (d >= (qreal) INT_MAX)
        return INT_MAX;
    return d >= 0.0 ? int(d + 0.5) : int(d - int(d-1) + 0.5) + int(d-1);
}

void QGraphicsViewPrivate::translateTouchEvent(QGraphicsViewPrivate *d, QTouchEvent *touchEvent)
{
    QList<QTouchEvent::TouchPoint> touchPoints = touchEvent->touchPoints();
    for (int i = 0; i < touchPoints.count(); ++i) {
        QTouchEvent::TouchPoint &touchPoint = touchPoints[i];
        // the scene will set the item local pos, startPos, lastPos, and rect before delivering to
        // an item, but for now those functions are returning the view's local coordinates
        touchPoint.setSceneRect(d->mapToScene(touchPoint.rect()));
        touchPoint.setStartScenePos(d->mapToScene(touchPoint.startPos()));
        touchPoint.setLastScenePos(d->mapToScene(touchPoint.lastPos()));

        // screenPos, startScreenPos, lastScreenPos, and screenRect are already set
    }

    touchEvent->setTouchPoints(touchPoints);
}

/*!
    \internal
*/
QGraphicsViewPrivate::QGraphicsViewPrivate()
    : renderHints(QPainter::TextAntialiasing),
      dragMode(QGraphicsView::NoDrag),
      sceneInteractionAllowed(true), hasSceneRect(false),
      connectedToScene(false),
      mousePressButton(Qt::NoButton),
      identityMatrix(true),
      dirtyScroll(true),
      accelerateScrolling(true),
      leftIndent(0), topIndent(0),
      lastMouseEvent(QEvent::None, QPoint(), Qt::NoButton, 0, 0),
      useLastMouseEvent(false),
      keepLastCenterPoint(true),
      alignment(Qt::AlignCenter),
      transforming(false),
      transformationAnchor(QGraphicsView::AnchorViewCenter), resizeAnchor(QGraphicsView::NoAnchor),
      viewportUpdateMode(QGraphicsView::MinimalViewportUpdate),
      optimizationFlags(0),
      scene(0),
#ifndef QT_NO_RUBBERBAND
      rubberBanding(false),
      rubberBandSelectionMode(Qt::IntersectsItemShape),
#endif
      handScrolling(false), handScrollMotions(0), cacheMode(0),
      mustAllocateStyleOptions(false),
      mustResizeBackgroundPixmap(true),
#ifndef QT_NO_CURSOR
      hasStoredOriginalCursor(false),
#endif
      lastDragDropEvent(0),
      fullUpdatePending(true),
      updateSceneSlotReimplementedChecked(false)
{
    styleOptions.reserve(QGRAPHICSVIEW_PREALLOC_STYLE_OPTIONS);
}

/*!
    \internal
*/
void QGraphicsViewPrivate::recalculateContentSize()
{
    Q_Q(QGraphicsView);

    QSize maxSize = q->maximumViewportSize();
    int width = maxSize.width();
    int height = maxSize.height();
    QRectF viewRect = matrix.mapRect(q->sceneRect());

    bool frameOnlyAround = (q->style()->styleHint(QStyle::SH_ScrollView_FrameOnlyAroundContents, 0, q));
    if (frameOnlyAround) {
        if (hbarpolicy == Qt::ScrollBarAlwaysOn)
            height -= frameWidth * 2;
        if (vbarpolicy == Qt::ScrollBarAlwaysOn)
            width -= frameWidth * 2;
    }

    // Adjust the maximum width and height of the viewport based on the width
    // of visible scroll bars.
    int scrollBarExtent = q->style()->pixelMetric(QStyle::PM_ScrollBarExtent, 0, q);
    if (frameOnlyAround)
        scrollBarExtent += frameWidth * 2;

    bool useHorizontalScrollBar = (viewRect.width() > width) && hbarpolicy != Qt::ScrollBarAlwaysOff;
    bool useVerticalScrollBar = (viewRect.height() > height) && vbarpolicy != Qt::ScrollBarAlwaysOff;
    if (useHorizontalScrollBar && !useVerticalScrollBar) {
        if (viewRect.height() > height - scrollBarExtent)
            useVerticalScrollBar = true;
    }
    if (useVerticalScrollBar && !useHorizontalScrollBar) {
        if (viewRect.width() > width - scrollBarExtent)
            useHorizontalScrollBar = true;
    }
    if (useHorizontalScrollBar && hbarpolicy != Qt::ScrollBarAlwaysOn)
        height -= scrollBarExtent;
    if (useVerticalScrollBar && vbarpolicy != Qt::ScrollBarAlwaysOn)
        width -= scrollBarExtent;

    // Setting the ranges of these scroll bars can/will cause the values to
    // change, and scrollContentsBy() will be called correspondingly. This
    // will reset the last center point.
    QPointF savedLastCenterPoint = lastCenterPoint;

    // Remember the former indent settings
    qreal oldLeftIndent = leftIndent;
    qreal oldTopIndent = topIndent;

    // If the whole scene fits horizontally, we center the scene horizontally,
    // and ignore the horizontal scroll bars.
    int left =  q_round_bound(viewRect.left());
    int right = q_round_bound(viewRect.right() - width);
    if (left >= right) {
        hbar->setRange(0, 0);

        switch (alignment & Qt::AlignHorizontal_Mask) {
        case Qt::AlignLeft:
            leftIndent = -viewRect.left();
            break;
        case Qt::AlignRight:
            leftIndent = width - viewRect.width() - viewRect.left() - 1;
            break;
        case Qt::AlignHCenter:
        default:
            leftIndent = width / 2 - (viewRect.left() + viewRect.right()) / 2;
            break;
        }
    } else {
        hbar->setRange(left, right);
        hbar->setPageStep(width);
        hbar->setSingleStep(width / 20);
        leftIndent = 0;
    }

    // If the whole scene fits vertically, we center the scene vertically, and
    // ignore the vertical scroll bars.
    int top = q_round_bound(viewRect.top());
    int bottom = q_round_bound(viewRect.bottom()  - height);
    if (top >= bottom) {
        vbar->setRange(0, 0);

        switch (alignment & Qt::AlignVertical_Mask) {
        case Qt::AlignTop:
            topIndent = -viewRect.top();
            break;
        case Qt::AlignBottom:
            topIndent = height - viewRect.height() - viewRect.top() - 1;
            break;
        case Qt::AlignVCenter:
        default:
            topIndent = height / 2 - (viewRect.top() + viewRect.bottom()) / 2;
            break;
        }
    } else {
        vbar->setRange(top, bottom);
        vbar->setPageStep(height);
        vbar->setSingleStep(height / 20);
        topIndent = 0;
    }

    // Restorethe center point from before the ranges changed.
    lastCenterPoint = savedLastCenterPoint;

    // Issue a full update if the indents change.
    // ### If the transform is still the same, we can get away with just a
    // scroll instead.
    if (oldLeftIndent != leftIndent || oldTopIndent != topIndent) {
        dirtyScroll = true;
        updateAll();
    } else if (q->isRightToLeft() && !leftIndent) {
        // In reverse mode, the horizontal scroll always changes after the content
        // size has changed, as the scroll is calculated by summing the min and
        // max values of the range and subtracting the current value. In normal
        // mode the scroll remains unchanged unless the indent has changed.
        dirtyScroll = true;
    }

    if (cacheMode & QGraphicsView::CacheBackground) {
        // Invalidate the background pixmap
        mustResizeBackgroundPixmap = true;
    }
}

/*!
    \internal
*/
void QGraphicsViewPrivate::centerView(QGraphicsView::ViewportAnchor anchor)
{
    Q_Q(QGraphicsView);
    switch (anchor) {
    case QGraphicsView::AnchorUnderMouse: {
        if (q->underMouse()) {
            // Last scene pos: lastMouseMoveScenePoint
            // Current mouse pos:
            QPointF transformationDiff = q->mapToScene(viewport->rect().center())
                                         - q->mapToScene(q->mapFromGlobal(QCursor::pos()));
            q->centerOn(lastMouseMoveScenePoint + transformationDiff);;
        } else {
            q->centerOn(lastCenterPoint);
        }
        break;
    }
    case QGraphicsView::AnchorViewCenter:
        q->centerOn(lastCenterPoint);
        break;
    case QGraphicsView::NoAnchor:
        break;
    }
}

/*!
    \internal
*/
void QGraphicsViewPrivate::updateLastCenterPoint()
{
    Q_Q(QGraphicsView);
    lastCenterPoint = q->mapToScene(viewport->rect().center());
}

/*!
    \internal

    Returns the horizontal scroll value (the X value of the left edge of the
    viewport).
*/
qint64 QGraphicsViewPrivate::horizontalScroll() const
{
    if (dirtyScroll)
        const_cast<QGraphicsViewPrivate *>(this)->updateScroll();
    return scrollX;
}

/*!
    \internal

    Returns the vertical scroll value (the X value of the top edge of the
    viewport).
*/
qint64 QGraphicsViewPrivate::verticalScroll() const
{
    if (dirtyScroll)
        const_cast<QGraphicsViewPrivate *>(this)->updateScroll();
    return scrollY;
}

/*!
    \internal
*/
void QGraphicsViewPrivate::updateScroll()
{
    Q_Q(QGraphicsView);
    scrollX = qint64(-leftIndent);
    if (q->isRightToLeft()) {
        if (!leftIndent) {
            scrollX += hbar->minimum();
            scrollX += hbar->maximum();
            scrollX -= hbar->value();
        }
    } else {
        scrollX += hbar->value();
    }

    scrollY = qint64(vbar->value() - topIndent);

    dirtyScroll = false;
}

/*!
    \internal
*/
void QGraphicsViewPrivate::replayLastMouseEvent()
{
    if (!useLastMouseEvent || !scene)
        return;
    mouseMoveEventHandler(&lastMouseEvent);
}

/*!
    \internal
*/
void QGraphicsViewPrivate::storeMouseEvent(QMouseEvent *event)
{
    useLastMouseEvent = true;
    lastMouseEvent = QMouseEvent(QEvent::MouseMove, event->pos(), event->globalPos(),
                                 event->button(), event->buttons(), event->modifiers());
}

void QGraphicsViewPrivate::mouseMoveEventHandler(QMouseEvent *event)
{
    Q_Q(QGraphicsView);

    storeMouseEvent(event);
    lastMouseEvent.setAccepted(false);

    if (!sceneInteractionAllowed)
        return;
    if (handScrolling)
        return;
    if (!scene)
        return;

    QGraphicsSceneMouseEvent mouseEvent(QEvent::GraphicsSceneMouseMove);
    mouseEvent.setWidget(viewport);
    mouseEvent.setButtonDownScenePos(mousePressButton, mousePressScenePoint);
    mouseEvent.setButtonDownScreenPos(mousePressButton, mousePressScreenPoint);
    mouseEvent.setScenePos(q->mapToScene(event->pos()));
    mouseEvent.setScreenPos(event->globalPos());
    mouseEvent.setLastScenePos(lastMouseMoveScenePoint);
    mouseEvent.setLastScreenPos(lastMouseMoveScreenPoint);
    mouseEvent.setButtons(event->buttons());
    mouseEvent.setButton(event->button());
    mouseEvent.setModifiers(event->modifiers());
    lastMouseMoveScenePoint = mouseEvent.scenePos();
    lastMouseMoveScreenPoint = mouseEvent.screenPos();
    mouseEvent.setAccepted(false);
    if (event->spontaneous())
        qt_sendSpontaneousEvent(scene, &mouseEvent);
    else
        QApplication::sendEvent(scene, &mouseEvent);

    // Remember whether the last event was accepted or not.
    lastMouseEvent.setAccepted(mouseEvent.isAccepted());

    if (mouseEvent.isAccepted() && mouseEvent.buttons() != 0) {
        // The event was delivered to a mouse grabber; the press is likely to
        // have set a cursor, and we must not change it.
        return;
    }

#ifndef QT_NO_CURSOR
    // If all the items ignore hover events, we don't look-up any items
    // in QGraphicsScenePrivate::dispatchHoverEvent, hence the
    // cachedItemsUnderMouse list will be empty. We therefore do the look-up
    // for cursor items here if not all items use the default cursor.
    if (scene->d_func()->allItemsIgnoreHoverEvents && !scene->d_func()->allItemsUseDefaultCursor
        && scene->d_func()->cachedItemsUnderMouse.isEmpty()) {
        scene->d_func()->cachedItemsUnderMouse = scene->d_func()->itemsAtPosition(mouseEvent.screenPos(),
                                                                                  mouseEvent.scenePos(),
                                                                                  mouseEvent.widget());
    }
    // Find the topmost item under the mouse with a cursor.
    foreach (QGraphicsItem *item, scene->d_func()->cachedItemsUnderMouse) {
        if (item->hasCursor()) {
            _q_setViewportCursor(item->cursor());
            return;
        }
    }

    // No items with cursors found; revert to the view cursor.
    if (hasStoredOriginalCursor) {
        // Restore the original viewport cursor.
        hasStoredOriginalCursor = false;
        viewport->setCursor(originalCursor);
    }
#endif
}

/*!
    \internal
*/
#ifndef QT_NO_RUBBERBAND
QRegion QGraphicsViewPrivate::rubberBandRegion(const QWidget *widget, const QRect &rect) const
{
    QStyleHintReturnMask mask;
    QStyleOptionRubberBand option;
    option.initFrom(widget);
    option.rect = rect;
    option.opaque = false;
    option.shape = QRubberBand::Rectangle;

    QRegion tmp;
    tmp += rect;
    if (widget->style()->styleHint(QStyle::SH_RubberBand_Mask, &option, widget, &mask))
        tmp &= mask.region;
    return tmp;
}
#endif

/*!
    \internal
*/
#ifndef QT_NO_CURSOR
void QGraphicsViewPrivate::_q_setViewportCursor(const QCursor &cursor)
{
    if (!hasStoredOriginalCursor) {
        hasStoredOriginalCursor = true;
        originalCursor = viewport->cursor();
    }
    viewport->setCursor(cursor);
}
#endif

/*!
    \internal
*/
#ifndef QT_NO_CURSOR
void QGraphicsViewPrivate::_q_unsetViewportCursor()
{
    Q_Q(QGraphicsView);
    foreach (QGraphicsItem *item, q->items(lastMouseEvent.pos())) {
        if (item->hasCursor()) {
            _q_setViewportCursor(item->cursor());
            return;
        }
    }

    // Restore the original viewport cursor.
    hasStoredOriginalCursor = false;
    if (dragMode == QGraphicsView::ScrollHandDrag)
        viewport->setCursor(Qt::OpenHandCursor);
    else
        viewport->setCursor(originalCursor);
}
#endif

/*!
    \internal
*/
void QGraphicsViewPrivate::storeDragDropEvent(const QGraphicsSceneDragDropEvent *event)
{
    delete lastDragDropEvent;
    lastDragDropEvent = new QGraphicsSceneDragDropEvent(event->type());
    lastDragDropEvent->setScenePos(event->scenePos());
    lastDragDropEvent->setScreenPos(event->screenPos());
    lastDragDropEvent->setButtons(event->buttons());
    lastDragDropEvent->setModifiers(event->modifiers());
    lastDragDropEvent->setPossibleActions(event->possibleActions());
    lastDragDropEvent->setProposedAction(event->proposedAction());
    lastDragDropEvent->setDropAction(event->dropAction());
    lastDragDropEvent->setMimeData(event->mimeData());
    lastDragDropEvent->setWidget(event->widget());
    lastDragDropEvent->setSource(event->source());
}

/*!
    \internal
*/
void QGraphicsViewPrivate::populateSceneDragDropEvent(QGraphicsSceneDragDropEvent *dest,
                                                      QDropEvent *source)
{
#ifndef QT_NO_DRAGANDDROP
    Q_Q(QGraphicsView);
    dest->setScenePos(q->mapToScene(source->pos()));
    dest->setScreenPos(q->mapToGlobal(source->pos()));
    dest->setButtons(source->mouseButtons());
    dest->setModifiers(source->keyboardModifiers());
    dest->setPossibleActions(source->possibleActions());
    dest->setProposedAction(source->proposedAction());
    dest->setDropAction(source->dropAction());
    dest->setMimeData(source->mimeData());
    dest->setWidget(viewport);
    dest->setSource(source->source());
#else
    Q_UNUSED(dest)
    Q_UNUSED(source)
#endif
}

/*!
    \internal
*/
QRect QGraphicsViewPrivate::mapToViewRect(const QGraphicsItem *item, const QRectF &rect) const
{
    Q_Q(const QGraphicsView);
    if (dirtyScroll)
        const_cast<QGraphicsViewPrivate *>(this)->updateScroll();

    if (item->d_ptr->itemIsUntransformable()) {
        QTransform itv = item->deviceTransform(q->viewportTransform());
        return itv.mapRect(rect).toAlignedRect();
    }

    // Translate-only
    // COMBINE
    QPointF offset;
    const QGraphicsItem *parentItem = item;
    const QGraphicsItemPrivate *itemd;
    do {
        itemd = parentItem->d_ptr.data();
        if (itemd->transformData)
            break;
        offset += itemd->pos;
    } while ((parentItem = itemd->parent));

    QRectF baseRect = rect.translated(offset.x(), offset.y());
    if (!parentItem) {
        if (identityMatrix) {
            baseRect.translate(-scrollX, -scrollY);
            return baseRect.toAlignedRect();
        }
        return matrix.mapRect(baseRect).translated(-scrollX, -scrollY).toAlignedRect();
    }

    QTransform tr = parentItem->sceneTransform();
    if (!identityMatrix)
        tr *= matrix;
    QRectF r = tr.mapRect(baseRect);
    r.translate(-scrollX, -scrollY);
    return r.toAlignedRect();
}

/*!
    \internal
*/
QRegion QGraphicsViewPrivate::mapToViewRegion(const QGraphicsItem *item, const QRectF &rect) const
{
    Q_Q(const QGraphicsView);
    if (dirtyScroll)
        const_cast<QGraphicsViewPrivate *>(this)->updateScroll();

    // Accurate bounding region
    QTransform itv = item->deviceTransform(q->viewportTransform());
    return item->boundingRegion(itv) & itv.mapRect(rect).toAlignedRect();
}

/*!
    \internal
*/
void QGraphicsViewPrivate::processPendingUpdates()
{
    if (!scene)
        return;

    if (fullUpdatePending) {
        viewport->update();
    } else if (viewportUpdateMode == QGraphicsView::BoundingRectViewportUpdate) {
        if (optimizationFlags & QGraphicsView::DontAdjustForAntialiasing)
            viewport->update(dirtyBoundingRect.adjusted(-1, -1, 1, 1));
        else
            viewport->update(dirtyBoundingRect.adjusted(-2, -2, 2, 2));
    } else {
        viewport->update(dirtyRegion); // Already adjusted in updateRect/Region.
    }

    dirtyBoundingRect = QRect();
    dirtyRegion = QRegion();
}

static inline bool intersectsViewport(const QRect &r, int width, int height)
{ return !(r.left() > width) && !(r.right() < 0) && !(r.top() >= height) && !(r.bottom() < 0); }

static inline bool containsViewport(const QRect &r, int width, int height)
{ return r.left() <= 0 && r.top() <= 0 && r.right() >= width - 1 && r.bottom() >= height - 1; }

static inline void QRect_unite(QRect *rect, const QRect &other)
{
    if (rect->isEmpty()) {
        *rect = other;
    } else {
        rect->setCoords(qMin(rect->left(), other.left()), qMin(rect->top(), other.top()),
                        qMax(rect->right(), other.right()), qMax(rect->bottom(), other.bottom()));
    }
}

bool QGraphicsViewPrivate::updateRegion(const QRegion &r)
{
    if (fullUpdatePending || viewportUpdateMode == QGraphicsView::NoViewportUpdate || r.isEmpty())
        return false;

    const QRect boundingRect = r.boundingRect();
    if (!intersectsViewport(boundingRect, viewport->width(), viewport->height()))
        return false; // Update region outside viewport.

    switch (viewportUpdateMode) {
    case QGraphicsView::FullViewportUpdate:
        fullUpdatePending = true;
        viewport->update();
        break;
    case QGraphicsView::BoundingRectViewportUpdate:
        QRect_unite(&dirtyBoundingRect, boundingRect);
        if (containsViewport(dirtyBoundingRect, viewport->width(), viewport->height())) {
            fullUpdatePending = true;
            viewport->update();
        }
        break;
    case QGraphicsView::SmartViewportUpdate: // ### DEPRECATE
    case QGraphicsView::MinimalViewportUpdate:
    {
        const QVector<QRect> &rects = r.rects();
        for (int i = 0; i < rects.size(); ++i) {
            if (optimizationFlags & QGraphicsView::DontAdjustForAntialiasing)
                dirtyRegion += rects.at(i).adjusted(-1, -1, 1, 1);
            else
                dirtyRegion += rects.at(i).adjusted(-2, -2, 2, 2);
        }
        break;
    }
    default:
        break;
    }

    return true;
}

bool QGraphicsViewPrivate::updateRect(const QRect &r)
{
    if (fullUpdatePending || viewportUpdateMode == QGraphicsView::NoViewportUpdate
        || !intersectsViewport(r, viewport->width(), viewport->height())) {
        return false;
    }

    switch (viewportUpdateMode) {
    case QGraphicsView::FullViewportUpdate:
        fullUpdatePending = true;
        viewport->update();
        break;
    case QGraphicsView::BoundingRectViewportUpdate:
        QRect_unite(&dirtyBoundingRect, r);
        if (containsViewport(dirtyBoundingRect, viewport->width(), viewport->height())) {
            fullUpdatePending = true;
            viewport->update();
        }
        break;
    case QGraphicsView::SmartViewportUpdate: // ### DEPRECATE
    case QGraphicsView::MinimalViewportUpdate:
        if (optimizationFlags & QGraphicsView::DontAdjustForAntialiasing)
            dirtyRegion += r.adjusted(-1, -1, 1, 1);
        else
            dirtyRegion += r.adjusted(-2, -2, 2, 2);
        break;
    default:
        break;
    }

    return true;
}

QStyleOptionGraphicsItem *QGraphicsViewPrivate::allocStyleOptionsArray(int numItems)
{
    if (mustAllocateStyleOptions || (numItems > styleOptions.capacity()))
        // too many items, let's allocate on-the-fly
        return new QStyleOptionGraphicsItem[numItems];

    // expand only whenever necessary
    if (numItems > styleOptions.size())
        styleOptions.resize(numItems);

    mustAllocateStyleOptions = true;
    return styleOptions.data();
}

void QGraphicsViewPrivate::freeStyleOptionsArray(QStyleOptionGraphicsItem *array)
{
    mustAllocateStyleOptions = false;
    if (array != styleOptions.data())
        delete [] array;
}

extern QPainterPath qt_regionToPath(const QRegion &region);

/*!
    ### Adjustments in findItems: mapToScene(QRect) forces us to adjust the
    input rectangle by (0, 0, 1, 1), because it uses QRect::bottomRight()
    (etc) when mapping the rectangle to a polygon (which is _wrong_). In
    addition, as QGraphicsItem::boundingRect() is defined in logical space,
    but the default pen for QPainter is cosmetic with a width of 0, QPainter
    is at risk of painting 1 pixel outside the bounding rect. Therefore we
    must search for items with an adjustment of (-1, -1, 1, 1).
*/
QList<QGraphicsItem *> QGraphicsViewPrivate::findItems(const QRegion &exposedRegion, bool *allItems,
                                                       const QTransform &viewTransform) const
{
    Q_Q(const QGraphicsView);

    // Step 1) If all items are contained within the expose region, then
    // return a list of all visible items. ### the scene's growing bounding
    // rect does not take into account untransformable items.
    const QRectF exposedRegionSceneBounds = q->mapToScene(exposedRegion.boundingRect().adjusted(-1, -1, 1, 1))
                                            .boundingRect();
    if (exposedRegionSceneBounds.contains(scene->sceneRect())) {
        Q_ASSERT(allItems);
        *allItems = true;

        // All items are guaranteed within the exposed region.
        return scene->items(Qt::DescendingOrder);
    }

    // Step 2) If the expose region is a simple rect and the view is only
    // translated or scaled, search for items using
    // QGraphicsScene::items(QRectF).
    bool simpleRectLookup =  exposedRegion.numRects() == 1 && matrix.type() <= QTransform::TxScale;
    if (simpleRectLookup) {
        return scene->items(exposedRegionSceneBounds,
                            Qt::IntersectsItemBoundingRect,
                            Qt::DescendingOrder, viewTransform);
    }

    // If the region is complex or the view has a complex transform, adjust
    // the expose region, convert it to a path, and then search for items
    // using QGraphicsScene::items(QPainterPath);
    QRegion adjustedRegion;
    foreach (const QRect &r, exposedRegion.rects())
        adjustedRegion += r.adjusted(-1, -1, 1, 1);

    const QPainterPath exposedScenePath(q->mapToScene(qt_regionToPath(adjustedRegion)));
    return scene->items(exposedScenePath, Qt::IntersectsItemBoundingRect,
                        Qt::DescendingOrder, viewTransform);
}

/*!
    \internal

    Enables input methods for the view if and only if the current focus item of
    the scene accepts input methods. Call function whenever that condition has
    potentially changed.
*/
void QGraphicsViewPrivate::updateInputMethodSensitivity()
{
    Q_Q(QGraphicsView);
    q->setAttribute(
        Qt::WA_InputMethodEnabled,
        scene && scene->focusItem()
        && scene->focusItem()->flags() & QGraphicsItem::ItemAcceptsInputMethod);
}

/*!
    Constructs a QGraphicsView. \a parent is passed to QWidget's constructor.
*/
QGraphicsView::QGraphicsView(QWidget *parent)
    : QAbstractScrollArea(*new QGraphicsViewPrivate, parent)
{
    setViewport(0);
    setAcceptDrops(true);
    setBackgroundRole(QPalette::Base);

    // ### Ideally this would be enabled/disabled depending on whether any
    // widgets in the current scene enabled input methods. We could do that
    // using a simple reference count. The same goes for acceptDrops and mouse
    // tracking.
    setAttribute(Qt::WA_InputMethodEnabled);

    // viewport part of the graphics view has to be enabled
    // as well, because when events come this widget is asked
    // for input context and so on
    viewport()->setAttribute(Qt::WA_InputMethodEnabled);
}

/*!
    Constructs a QGraphicsView and sets the visualized scene to \a
    scene. \a parent is passed to QWidget's constructor.
*/
QGraphicsView::QGraphicsView(QGraphicsScene *scene, QWidget *parent)
    : QAbstractScrollArea(*new QGraphicsViewPrivate, parent)
{
    setScene(scene);
    setViewport(0);
    setAcceptDrops(true);
    setBackgroundRole(QPalette::Base);
    setAttribute(Qt::WA_InputMethodEnabled);

    // viewport part of the graphics view has to be enabled
    // as well, because when events come this widget is asked
    // for input context and so on
    viewport()->setAttribute(Qt::WA_InputMethodEnabled);
}

/*!
  \internal
 */
QGraphicsView::QGraphicsView(QGraphicsViewPrivate &dd, QWidget *parent)
  : QAbstractScrollArea(dd, parent)
{
    setViewport(0);
    setAcceptDrops(true);
    setBackgroundRole(QPalette::Base);
    setAttribute(Qt::WA_InputMethodEnabled);

    // viewport part of the graphics view has to be enabled
    // as well, because when events come this widget is asked
    // for input context and so on
    viewport()->setAttribute(Qt::WA_InputMethodEnabled);
}

/*!
    Destructs the QGraphicsView object.
*/
QGraphicsView::~QGraphicsView()
{
    Q_D(QGraphicsView);
    if (d->scene)
        d->scene->d_func()->views.removeAll(this);
    delete d->lastDragDropEvent;
}

/*!
    \reimp
*/
QSize QGraphicsView::sizeHint() const
{
    Q_D(const QGraphicsView);
    if (d->scene) {
        QSizeF baseSize = d->matrix.mapRect(sceneRect()).size();
        baseSize += QSizeF(d->frameWidth * 2, d->frameWidth * 2);
        return baseSize.boundedTo((3 * QApplication::desktop()->size()) / 4).toSize();
    }
    return QAbstractScrollArea::sizeHint();
}

/*!
    \property QGraphicsView::renderHints
    \brief the default render hints for the view

    These hints are
    used to initialize QPainter before each visible item is drawn. QPainter
    uses render hints to toggle rendering features such as antialiasing and
    smooth pixmap transformation.

    QPainter::TextAntialiasing is enabled by default.

    Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsview.cpp 1
*/
QPainter::RenderHints QGraphicsView::renderHints() const
{
    Q_D(const QGraphicsView);
    return d->renderHints;
}
void QGraphicsView::setRenderHints(QPainter::RenderHints hints)
{
    Q_D(QGraphicsView);
    if (hints == d->renderHints)
        return;
    d->renderHints = hints;
    d->updateAll();
}

/*!
    If \a enabled is true, the render hint \a hint is enabled; otherwise it
    is disabled.

    \sa renderHints
*/
void QGraphicsView::setRenderHint(QPainter::RenderHint hint, bool enabled)
{
    Q_D(QGraphicsView);
    QPainter::RenderHints oldHints = d->renderHints;
    if (enabled)
        d->renderHints |= hint;
    else
        d->renderHints &= ~hint;
    if (oldHints != d->renderHints)
        d->updateAll();
}

/*!
    \property QGraphicsView::alignment
    \brief the alignment of the scene in the view when the whole
    scene is visible.

    If the whole scene is visible in the view, (i.e., there are no visible
    scroll bars,) the view's alignment will decide where the scene will be
    rendered in the view. For example, if the alignment is Qt::AlignCenter,
    which is default, the scene will be centered in the view, and if the
    alignment is (Qt::AlignLeft | Qt::AlignTop), the scene will be rendered in
    the top-left corner of the view.
*/
Qt::Alignment QGraphicsView::alignment() const
{
    Q_D(const QGraphicsView);
    return d->alignment;
}
void QGraphicsView::setAlignment(Qt::Alignment alignment)
{
    Q_D(QGraphicsView);
    if (d->alignment != alignment) {
        d->alignment = alignment;
        d->recalculateContentSize();
    }
}

/*!
    \property QGraphicsView::transformationAnchor
    \brief how the view should position the scene during transformations.

    QGraphicsView uses this property to decide how to position the scene in
    the viewport when the transformation matrix changes, and the coordinate
    system of the view is transformed. The default behavior, AnchorViewCenter,
    ensures that the scene point at the center of the view remains unchanged
    during transformations (e.g., when rotating, the scene will appear to
    rotate around the center of the view).

    Note that the effect of this property is noticeable when only a part of the
    scene is visible (i.e., when there are scroll bars). Otherwise, if the
    whole scene fits in the view, QGraphicsScene uses the view \l alignment to
    position the scene in the view.

    \sa alignment, resizeAnchor
*/
QGraphicsView::ViewportAnchor QGraphicsView::transformationAnchor() const
{
    Q_D(const QGraphicsView);
    return d->transformationAnchor;
}
void QGraphicsView::setTransformationAnchor(ViewportAnchor anchor)
{
    Q_D(QGraphicsView);
    d->transformationAnchor = anchor;
}

/*!
    \property QGraphicsView::resizeAnchor
    \brief how the view should position the scene when the view is resized.

    QGraphicsView uses this property to decide how to position the scene in
    the viewport when the viewport widget's size changes. The default
    behavior, NoAnchor, leaves the scene's position unchanged during a resize;
    the top-left corner of the view will appear to be anchored while resizing.

    Note that the effect of this property is noticeable when only a part of the
    scene is visible (i.e., when there are scroll bars). Otherwise, if the
    whole scene fits in the view, QGraphicsScene uses the view \l alignment to
    position the scene in the view.

    \sa alignment, transformationAnchor, Qt::WNorthWestGravity
*/
QGraphicsView::ViewportAnchor QGraphicsView::resizeAnchor() const
{
    Q_D(const QGraphicsView);
    return d->resizeAnchor;
}
void QGraphicsView::setResizeAnchor(ViewportAnchor anchor)
{
    Q_D(QGraphicsView);
    d->resizeAnchor = anchor;
}

/*!
    \property QGraphicsView::viewportUpdateMode
    \brief how the viewport should update its contents.

    \since 4.3

    QGraphicsView uses this property to decide how to update areas of the
    scene that have been reexposed or changed. Usually you do not need to
    modify this property, but there are some cases where doing so can improve
    rendering performance. See the ViewportUpdateMode documentation for
    specific details.

    The default value is MinimalViewportUpdate, where QGraphicsView will
    update as small an area of the viewport as possible when the contents
    change.

    \sa ViewportUpdateMode, cacheMode
*/
QGraphicsView::ViewportUpdateMode QGraphicsView::viewportUpdateMode() const
{
    Q_D(const QGraphicsView);
    return d->viewportUpdateMode;
}
void QGraphicsView::setViewportUpdateMode(ViewportUpdateMode mode)
{
    Q_D(QGraphicsView);
    d->viewportUpdateMode = mode;
}

/*!
    \property QGraphicsView::optimizationFlags
    \brief flags that can be used to tune QGraphicsView's performance.

    \since 4.3

    QGraphicsView uses clipping, extra bounding rect adjustments, and certain
    other aids to improve rendering quality and performance for the common
    case graphics scene. However, depending on the target platform, the scene,
    and the viewport in use, some of these operations can degrade performance.

    The effect varies from flag to flag; see the OptimizationFlags
    documentation for details.

    By default, no optimization flags are enabled.

    \sa setOptimizationFlag()
*/
QGraphicsView::OptimizationFlags QGraphicsView::optimizationFlags() const
{
    Q_D(const QGraphicsView);
    return d->optimizationFlags;
}
void QGraphicsView::setOptimizationFlags(OptimizationFlags flags)
{
    Q_D(QGraphicsView);
    d->optimizationFlags = flags;
}

/*!
    Enables \a flag if \a enabled is true; otherwise disables \a flag.

    \sa optimizationFlags
*/
void QGraphicsView::setOptimizationFlag(OptimizationFlag flag, bool enabled)
{
    Q_D(QGraphicsView);
    if (enabled)
        d->optimizationFlags |= flag;
    else
        d->optimizationFlags &= ~flag;
}

/*!
    \property QGraphicsView::dragMode
    \brief the behavior for dragging the mouse over the scene while
    the left mouse button is pressed.

    This property defines what should happen when the user clicks on the scene
    background and drags the mouse (e.g., scrolling the viewport contents
    using a pointing hand cursor, or selecting multiple items with a rubber
    band). The default value, NoDrag, does nothing.

    This behavior only affects mouse clicks that are not handled by any item.
    You can define a custom behavior by creating a subclass of QGraphicsView
    and reimplementing mouseMoveEvent().
*/
QGraphicsView::DragMode QGraphicsView::dragMode() const
{
    Q_D(const QGraphicsView);
    return d->dragMode;
}
void QGraphicsView::setDragMode(DragMode mode)
{
    Q_D(QGraphicsView);
    if (d->dragMode == mode)
        return;

#ifndef QT_NO_CURSOR
    if (d->dragMode == ScrollHandDrag)
        viewport()->unsetCursor();
#endif

    // If dragMode is unset while dragging, e.g. via a keyEvent, we
    // don't unset the handScrolling state. When enabling scrolling
    // again the mouseMoveEvent will automatically start scrolling,
    // without a mousePress
    if (d->dragMode == ScrollHandDrag && mode == NoDrag && d->handScrolling)
        d->handScrolling = false;

    d->dragMode = mode;

#ifndef QT_NO_CURSOR
    if (d->dragMode == ScrollHandDrag) {
        // Forget the stored viewport cursor when we enter scroll hand drag mode.
        d->hasStoredOriginalCursor = false;
        viewport()->setCursor(Qt::OpenHandCursor);
    }
#endif
}

#ifndef QT_NO_RUBBERBAND
/*!
    \property QGraphicsView::rubberBandSelectionMode
    \brief the behavior for selecting items with a rubber band selection rectangle.
    \since 4.3

    This property defines how items are selected when using the RubberBandDrag
    drag mode.

    The default value is Qt::IntersectsItemShape; all items whose shape
    intersects with or is contained by the rubber band are selected.

    \sa dragMode, items()
*/
Qt::ItemSelectionMode QGraphicsView::rubberBandSelectionMode() const
{
    Q_D(const QGraphicsView);
    return d->rubberBandSelectionMode;
}
void QGraphicsView::setRubberBandSelectionMode(Qt::ItemSelectionMode mode)
{
    Q_D(QGraphicsView);
    d->rubberBandSelectionMode = mode;
}
#endif

/*!
    \property QGraphicsView::cacheMode
    \brief which parts of the view are cached

    QGraphicsView can cache pre-rendered content in a QPixmap, which is then
    drawn onto the viewport. The purpose of such caching is to speed up the
    total rendering time for areas that are slow to render.  Texture, gradient
    and alpha blended backgrounds, for example, can be notibly slow to render;
    especially with a transformed view. The CacheBackground flag enables
    caching of the view's background. For example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsview.cpp 2

    The cache is invalidated every time the view is transformed. However, when
    scrolling, only partial invalidation is required.

    By default, nothing is cached.

    \sa resetCachedContent(), QPixmapCache
*/
QGraphicsView::CacheMode QGraphicsView::cacheMode() const
{
    Q_D(const QGraphicsView);
    return d->cacheMode;
}
void QGraphicsView::setCacheMode(CacheMode mode)
{
    Q_D(QGraphicsView);
    if (mode == d->cacheMode)
        return;
    d->cacheMode = mode;
    resetCachedContent();
}

/*!
    Resets any cached content. Calling this function will clear
    QGraphicsView's cache. If the current cache mode is \l CacheNone, this
    function does nothing.

    This function is called automatically for you when the backgroundBrush or
    QGraphicsScene::backgroundBrush properties change; you only need to call
    this function if you have reimplemented QGraphicsScene::drawBackground()
    or QGraphicsView::drawBackground() to draw a custom background, and need
    to trigger a full redraw.

    \sa cacheMode()
*/
void QGraphicsView::resetCachedContent()
{
    Q_D(QGraphicsView);
    if (d->cacheMode == CacheNone)
        return;

    if (d->cacheMode & CacheBackground) {
        // Background caching is enabled.
        d->mustResizeBackgroundPixmap = true;
        d->updateAll();
    } else if (d->mustResizeBackgroundPixmap) {
        // Background caching is disabled.
        // Cleanup, free some resources.
        d->mustResizeBackgroundPixmap = false;
        d->backgroundPixmap = QPixmap();
        d->backgroundPixmapExposed = QRegion();
    }
}

/*!
    Invalidates and schedules a redraw of \a layers inside \a rect. \a rect is
    in scene coordinates. Any cached content for \a layers inside \a rect is
    unconditionally invalidated and redrawn.

    You can call this function to notify QGraphicsView of changes to the
    background or the foreground of the scene. It is commonly used for scenes
    with tile-based backgrounds to notify changes when QGraphicsView has
    enabled background caching.

    Note that QGraphicsView currently supports background caching only (see
    QGraphicsView::CacheBackground). This function is equivalent to calling update() if any
    layer but QGraphicsScene::BackgroundLayer is passed.

    \sa QGraphicsScene::invalidate(), update()
*/
void QGraphicsView::invalidateScene(const QRectF &rect, QGraphicsScene::SceneLayers layers)
{
    Q_D(QGraphicsView);
    if ((layers & QGraphicsScene::BackgroundLayer) && !d->mustResizeBackgroundPixmap) {
        QRect viewRect = mapFromScene(rect).boundingRect();
        if (viewport()->rect().intersects(viewRect)) {
            // The updated background area is exposed; schedule this area for
            // redrawing.
            d->backgroundPixmapExposed += viewRect;
            if (d->scene)
                d->scene->update(rect);
        }
    }
}

/*!
    \property QGraphicsView::interactive
    \brief whether the view allowed scene interaction.

    If enabled, this view is set to allow scene interaction. Otherwise, this
    view will not allow interaction, and any mouse or key events are ignored
    (i.e., it will act as a read-only view).

    By default, this property is true.
*/
bool QGraphicsView::isInteractive() const
{
    Q_D(const QGraphicsView);
    return d->sceneInteractionAllowed;
}
void QGraphicsView::setInteractive(bool allowed)
{
    Q_D(QGraphicsView);
    d->sceneInteractionAllowed = allowed;
}

/*!
    Returns a pointer to the scene that is currently visualized in the
    view. If no scene is currently visualized, 0 is returned.

    \sa setScene()
*/
QGraphicsScene *QGraphicsView::scene() const
{
    Q_D(const QGraphicsView);
    return d->scene;
}

/*!
    Sets the current scene to \a scene. If \a scene is already being
    viewed, this function does nothing.

    When a scene is set on a view, the QGraphicsScene::changed() signal
    is automatically connected to this view's updateScene() slot, and the
    view's scroll bars are adjusted to fit the size of the scene.
*/
void QGraphicsView::setScene(QGraphicsScene *scene)
{
    Q_D(QGraphicsView);
    if (d->scene == scene)
        return;

    // Always update the viewport when the scene changes.
    d->updateAll();

    // Remove the previously assigned scene.
    if (d->scene) {
        disconnect(d->scene, SIGNAL(changed(QList<QRectF>)),
                   this, SLOT(updateScene(QList<QRectF>)));
        disconnect(d->scene, SIGNAL(sceneRectChanged(QRectF)),
                   this, SLOT(updateSceneRect(QRectF)));
        d->scene->d_func()->removeView(this);
        d->connectedToScene = false;
    }

    // Assign the new scene and update the contents (scrollbars, etc.)).
    if ((d->scene = scene)) {
        connect(d->scene, SIGNAL(sceneRectChanged(QRectF)),
                this, SLOT(updateSceneRect(QRectF)));
        d->updateSceneSlotReimplementedChecked = false;
        d->scene->d_func()->addView(this);
        d->recalculateContentSize();
        d->lastCenterPoint = sceneRect().center();
        d->keepLastCenterPoint = true;
        // We are only interested in mouse tracking if items accept
        // hover events or use non-default cursors.
        if (!d->scene->d_func()->allItemsIgnoreHoverEvents
            || !d->scene->d_func()->allItemsUseDefaultCursor) {
            d->viewport->setMouseTracking(true);
        }

        // enable touch events if any items is interested in them
        if (!d->scene->d_func()->allItemsIgnoreTouchEvents)
            d->viewport->setAttribute(Qt::WA_AcceptTouchEvents);
    } else {
        d->recalculateContentSize();
    }

    d->updateInputMethodSensitivity();
}

/*!
    \property QGraphicsView::sceneRect
    \brief the area of the scene visualized by this view.

    The scene rectangle defines the extent of the scene, and in the view's case,
    this means the area of the scene that you can navigate using the scroll
    bars.

    If unset, or if a null QRectF is set, this property has the same value as
    QGraphicsScene::sceneRect, and it changes with
    QGraphicsScene::sceneRect. Otherwise, the view's scene rect is unaffected
    by the scene.

    Note that, although the scene supports a virtually unlimited size, the
    range of the scroll bars will never exceed the range of an integer
    (INT_MIN, INT_MAX). When the scene is larger than the scroll bars' values,
    you can choose to use translate() to navigate the scene instead.

    By default, this property contains a rectangle at the origin with zero
    width and height.

    \sa QGraphicsScene::sceneRect
*/
QRectF QGraphicsView::sceneRect() const
{
    Q_D(const QGraphicsView);
    if (d->hasSceneRect)
        return d->sceneRect;
    if (d->scene)
        return d->scene->sceneRect();
    return QRectF();
}
void QGraphicsView::setSceneRect(const QRectF &rect)
{
    Q_D(QGraphicsView);
    d->hasSceneRect = !rect.isNull();
    d->sceneRect = rect;
    d->recalculateContentSize();
}

/*!
    Returns the current transformation matrix for the view. If no current
    transformation is set, the identity matrix is returned.

    \sa setMatrix(), transform(), rotate(), scale(), shear(), translate()
*/
QMatrix QGraphicsView::matrix() const
{
    Q_D(const QGraphicsView);
    return d->matrix.toAffine();
}

/*!
    Sets the view's current transformation matrix to \a matrix.

    If \a combine is true, then \a matrix is combined with the current matrix;
    otherwise, \a matrix \e replaces the current matrix. \a combine is false
    by default.

    The transformation matrix tranforms the scene into view coordinates. Using
    the default transformation, provided by the identity matrix, one pixel in
    the view represents one unit in the scene (e.g., a 10x10 rectangular item
    is drawn using 10x10 pixels in the view). If a 2x2 scaling matrix is
    applied, the scene will be drawn in 1:2 (e.g., a 10x10 rectangular item is
    then drawn using 20x20 pixels in the view).

    Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsview.cpp 3

    To simplify interation with items using a transformed view, QGraphicsView
    provides mapTo... and mapFrom... functions that can translate between
    scene and view coordinates. For example, you can call mapToScene() to map
    a view coordinate to a floating point scene coordinate, or mapFromScene()
    to map from floating point scene coordinates to view coordinates.

    \sa matrix(), setTransform(), rotate(), scale(), shear(), translate()
*/
void QGraphicsView::setMatrix(const QMatrix &matrix, bool combine)
{
    setTransform(QTransform(matrix), combine);
}

/*!
    Resets the view transformation matrix to the identity matrix.

    \sa resetTransform()
*/
void QGraphicsView::resetMatrix()
{
    resetTransform();
}

/*!
    Rotates the current view transformation \a angle degrees clockwise.

    \sa setTransform(), transform(), scale(), shear(), translate()
*/
void QGraphicsView::rotate(qreal angle)
{
    Q_D(QGraphicsView);
    QTransform matrix = d->matrix;
    matrix.rotate(angle);
    setTransform(matrix);
}

/*!
    Scales the current view transformation by (\a sx, \a sy).

    \sa setTransform(), transform(), rotate(), shear(), translate()
*/
void QGraphicsView::scale(qreal sx, qreal sy)
{
    Q_D(QGraphicsView);
    QTransform matrix = d->matrix;
    matrix.scale(sx, sy);
    setTransform(matrix);
}

/*!
    Shears the current view transformation by (\a sh, \a sv).

    \sa setTransform(), transform(), rotate(), scale(), translate()
*/
void QGraphicsView::shear(qreal sh, qreal sv)
{
    Q_D(QGraphicsView);
    QTransform matrix = d->matrix;
    matrix.shear(sh, sv);
    setTransform(matrix);
}

/*!
    Translates the current view transformation by (\a dx, \a dy).

    \sa setTransform(), transform(), rotate(), shear()
*/
void QGraphicsView::translate(qreal dx, qreal dy)
{
    Q_D(QGraphicsView);
    QTransform matrix = d->matrix;
    matrix.translate(dx, dy);
    setTransform(matrix);
}

/*!
    Scrolls the contents of the viewport to ensure that the scene
    coordinate \a pos, is centered in the view.

    Because \a pos is a floating point coordinate, and the scroll bars operate
    on integer coordinates, the centering is only an approximation.

    \note If the item is close to or outside the border, it will be visible
    in the view, but not centered.

    \sa ensureVisible()
*/
void QGraphicsView::centerOn(const QPointF &pos)
{
    Q_D(QGraphicsView);
    qreal width = viewport()->width();
    qreal height = viewport()->height();
    QPointF viewPoint = d->matrix.map(pos);
    QPointF oldCenterPoint = pos;

    if (!d->leftIndent) {
        if (isRightToLeft()) {
            qint64 horizontal = 0;
            horizontal += horizontalScrollBar()->minimum();
            horizontal += horizontalScrollBar()->maximum();
            horizontal -= int(viewPoint.x() - width / 2.0);
            horizontalScrollBar()->setValue(horizontal);
        } else {
            horizontalScrollBar()->setValue(int(viewPoint.x() - width / 2.0));
        }
    }
    if (!d->topIndent)
        verticalScrollBar()->setValue(int(viewPoint.y() - height / 2.0));
    d->lastCenterPoint = oldCenterPoint;
}

/*!
    \fn QGraphicsView::centerOn(qreal x, qreal y)
    \overload

    This function is provided for convenience. It's equivalent to calling
    centerOn(QPointF(\a x, \a y)).
*/

/*!
    \overload

    Scrolls the contents of the viewport to ensure that \a item
    is centered in the view.

    \sa ensureVisible()
*/
void QGraphicsView::centerOn(const QGraphicsItem *item)
{
    centerOn(item->sceneBoundingRect().center());
}

/*!
    Scrolls the contents of the viewport so that the scene rectangle \a rect
    is visible, with margins specified in pixels by \a xmargin and \a
    ymargin. If the specified rect cannot be reached, the contents are
    scrolled to the nearest valid position. The default value for both margins
    is 50 pixels.

    \sa centerOn()
*/
void QGraphicsView::ensureVisible(const QRectF &rect, int xmargin, int ymargin)
{
    Q_D(QGraphicsView);
    Q_UNUSED(xmargin);
    Q_UNUSED(ymargin);
    qreal width = viewport()->width();
    qreal height = viewport()->height();
    QRectF viewRect = d->matrix.mapRect(rect);

    qreal left = d->horizontalScroll();
    qreal right = left + width;
    qreal top = d->verticalScroll();
    qreal bottom = top + height;

    if (viewRect.left() <= left + xmargin) {
        // need to scroll from the left
        if (!d->leftIndent)
            horizontalScrollBar()->setValue(int(viewRect.left() - xmargin - 0.5));
    }
    if (viewRect.right() >= right - xmargin) {
        // need to scroll from the right
        if (!d->leftIndent)
            horizontalScrollBar()->setValue(int(viewRect.right() - width + xmargin + 0.5));
    }
    if (viewRect.top() <= top + ymargin) {
        // need to scroll from the top
        if (!d->topIndent)
            verticalScrollBar()->setValue(int(viewRect.top() - ymargin - 0.5));
    }
    if (viewRect.bottom() >= bottom - ymargin) {
        // need to scroll from the bottom
        if (!d->topIndent)
            verticalScrollBar()->setValue(int(viewRect.bottom() - height + ymargin + 0.5));
    }
}

/*!
    \fn QGraphicsView::ensureVisible(qreal x, qreal y, qreal w, qreal h,
    int xmargin, int ymargin)
    \overload

    This function is provided for convenience. It's equivalent to calling
    ensureVisible(QRectF(\a x, \a y, \a w, \a h), \a xmargin, \a ymargin).
*/

/*!
    \overload

    Scrolls the contents of the viewport so that the center of item \a item is
    visible, with margins specified in pixels by \a xmargin and \a ymargin. If
    the specified point cannot be reached, the contents are scrolled to the
    nearest valid position. The default value for both margins is 50 pixels.

    \sa centerOn()
*/
void QGraphicsView::ensureVisible(const QGraphicsItem *item, int xmargin, int ymargin)
{
    ensureVisible(item->sceneBoundingRect(), xmargin, ymargin);
}

/*!
    Scales the view matrix and scrolls the scroll bars to ensure that the
    scene rectangle \a rect fits inside the viewport. \a rect must be inside
    the scene rect; otherwise, fitInView() cannot guarantee that the whole
    rect is visible.

    This function keeps the view's rotation, translation, or shear. The view
    is scaled according to \a aspectRatioMode. \a rect will be centered in the
    view if it does not fit tightly.

    It's common to call fitInView() from inside a reimplementation of
    resizeEvent(), to ensure that the whole scene, or parts of the scene,
    scales automatically to fit the new size of the viewport as the view is
    resized. Note though, that calling fitInView() from inside resizeEvent()
    can lead to unwanted resize recursion, if the new transformation toggles
    the automatic state of the scrollbars. You can toggle the scrollbar
    policies to always on or always off to prevent this (see
    horizontalScrollBarPolicy() and verticalScrollBarPolicy()).

    If \a rect is empty, or if the viewport is too small, this
    function will do nothing.

    \sa setTransform(), ensureVisible(), centerOn()
*/
void QGraphicsView::fitInView(const QRectF &rect, Qt::AspectRatioMode aspectRatioMode)
{
    Q_D(QGraphicsView);
    if (!d->scene || rect.isNull())
        return;

    // Reset the view scale to 1:1.
    QRectF unity = d->matrix.mapRect(QRectF(0, 0, 1, 1));
    if (unity.isEmpty())
        return;
    scale(1 / unity.width(), 1 / unity.height());

    // Find the ideal x / y scaling ratio to fit \a rect in the view.
    int margin = 2;
    QRectF viewRect = viewport()->rect().adjusted(margin, margin, -margin, -margin);
    if (viewRect.isEmpty())
        return;
    QRectF sceneRect = d->matrix.mapRect(rect);
    if (sceneRect.isEmpty())
        return;
    qreal xratio = viewRect.width() / sceneRect.width();
    qreal yratio = viewRect.height() / sceneRect.height();

    // Respect the aspect ratio mode.
    switch (aspectRatioMode) {
    case Qt::KeepAspectRatio:
        xratio = yratio = qMin(xratio, yratio);
        break;
    case Qt::KeepAspectRatioByExpanding:
        xratio = yratio = qMax(xratio, yratio);
        break;
    case Qt::IgnoreAspectRatio:
        break;
    }

    // Scale and center on the center of \a rect.
    scale(xratio, yratio);
    centerOn(rect.center());
}

/*!
    \fn void QGraphicsView::fitInView(qreal x, qreal y, qreal w, qreal h,
    Qt::AspectRatioMode aspectRatioMode = Qt::IgnoreAspectRatio)

    \overload

    This convenience function is equivalent to calling
    fitInView(QRectF(\a x, \a y, \a w, \a h), \a aspectRatioMode).

    \sa ensureVisible(), centerOn()
*/

/*!
    \overload

    Ensures that \a item fits tightly inside the view, scaling the view
    according to \a aspectRatioMode.

    \sa ensureVisible(), centerOn()
*/
void QGraphicsView::fitInView(const QGraphicsItem *item, Qt::AspectRatioMode aspectRatioMode)
{
    QPainterPath path = item->isClipped() ? item->clipPath() : item->shape();
    if (item->d_ptr->hasTranslateOnlySceneTransform()) {
        path.translate(item->d_ptr->sceneTransform.dx(), item->d_ptr->sceneTransform.dy());
        fitInView(path.boundingRect(), aspectRatioMode);
    } else {
        fitInView(item->d_ptr->sceneTransform.map(path).boundingRect(), aspectRatioMode);
    }
}

/*!
    Renders the \a source rect, which is in view coordinates, from the scene
    into \a target, which is in paint device coordinates, using \a
    painter. This function is useful for capturing the contents of the view
    onto a paint device, such as a QImage (e.g., to take a screenshot), or for
    printing to QPrinter. For example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsview.cpp 4

    If \a source is a null rect, this function will use viewport()->rect() to
    determine what to draw. If \a target is a null rect, the full dimensions
    of \a painter's paint device (e.g., for a QPrinter, the page size) will be
    used.

    The source rect contents will be transformed according to \a
    aspectRatioMode to fit into the target rect. By default, the aspect ratio
    is kept, and \a source is scaled to fit in \a target.

    \sa QGraphicsScene::render()
*/
void QGraphicsView::render(QPainter *painter, const QRectF &target, const QRect &source,
                           Qt::AspectRatioMode aspectRatioMode)
{
    // ### Switch to using the recursive rendering algorithm instead.

    Q_D(QGraphicsView);
    if (!d->scene || !(painter && painter->isActive()))
        return;

    // Default source rect = viewport rect
    QRect sourceRect = source;
    if (source.isNull())
        sourceRect = viewport()->rect();

    // Default target rect = device rect
    QRectF targetRect = target;
    if (target.isNull()) {
        if (painter->device()->devType() == QInternal::Picture)
            targetRect = sourceRect;
        else
            targetRect.setRect(0, 0, painter->device()->width(), painter->device()->height());
    }

    // Find the ideal x / y scaling ratio to fit \a source into \a target.
    qreal xratio = targetRect.width() / sourceRect.width();
    qreal yratio = targetRect.height() / sourceRect.height();

    // Scale according to the aspect ratio mode.
    switch (aspectRatioMode) {
    case Qt::KeepAspectRatio:
        xratio = yratio = qMin(xratio, yratio);
        break;
    case Qt::KeepAspectRatioByExpanding:
        xratio = yratio = qMax(xratio, yratio);
        break;
    case Qt::IgnoreAspectRatio:
        break;
    }

    // Find all items to draw, and reverse the list (we want to draw
    // in reverse order).
    QPolygonF sourceScenePoly = mapToScene(sourceRect.adjusted(-1, -1, 1, 1));
    QList<QGraphicsItem *> itemList = d->scene->items(sourceScenePoly,
                                                      Qt::IntersectsItemBoundingRect);
    QGraphicsItem **itemArray = new QGraphicsItem *[itemList.size()];
    int numItems = itemList.size();
    for (int i = 0; i < numItems; ++i)
        itemArray[numItems - i - 1] = itemList.at(i);
    itemList.clear();

    // Setup painter matrix.
    QTransform moveMatrix = QTransform::fromTranslate(-d->horizontalScroll(), -d->verticalScroll());
    QTransform painterMatrix = d->matrix * moveMatrix;
    painterMatrix *= QTransform()
                     .translate(targetRect.left(), targetRect.top())
                     .scale(xratio, yratio)
                     .translate(-sourceRect.left(), -sourceRect.top());

    // Generate the style options
    QStyleOptionGraphicsItem *styleOptionArray = d->allocStyleOptionsArray(numItems);
    for (int i = 0; i < numItems; ++i)
        itemArray[i]->d_ptr->initStyleOption(&styleOptionArray[i], painterMatrix, targetRect.toRect());

    painter->save();

    // Clip in device coordinates to avoid QRegion transformations.
    painter->setClipRect(targetRect);
    QPainterPath path;
    path.addPolygon(sourceScenePoly);
    path.closeSubpath();
    painter->setClipPath(painterMatrix.map(path), Qt::IntersectClip);

    // Transform the painter.
    painter->setTransform(painterMatrix, true);

    // Render the scene.
    QRectF sourceSceneRect = sourceScenePoly.boundingRect();
    drawBackground(painter, sourceSceneRect);
    drawItems(painter, numItems, itemArray, styleOptionArray);
    drawForeground(painter, sourceSceneRect);

    delete [] itemArray;
    d->freeStyleOptionsArray(styleOptionArray);

    painter->restore();
}

/*!
    Returns a list of all the items in the associated scene.

    \sa QGraphicsScene::items()
*/
QList<QGraphicsItem *> QGraphicsView::items() const
{
    Q_D(const QGraphicsView);
    if (!d->scene)
        return QList<QGraphicsItem *>();
    return d->scene->items();
}

/*!
    Returns a list of all the items at the position \a pos in the view. The
    items are listed in descending Z order (i.e., the first item in the list
    is the top-most item, and the last item is the bottom-most item). \a pos
    is in viewport coordinates.

    This function is most commonly called from within mouse event handlers in
    a subclass in QGraphicsView. \a pos is in untransformed viewport
    coordinates, just like QMouseEvent::pos().

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsview.cpp 5

    \sa QGraphicsScene::items(), QGraphicsItem::zValue()
*/
QList<QGraphicsItem *> QGraphicsView::items(const QPoint &pos) const
{
    Q_D(const QGraphicsView);
    if (!d->scene)
        return QList<QGraphicsItem *>();
    // ### Unify these two, and use the items(QPointF) version in
    // QGraphicsScene instead. The scene items function could use the viewport
    // transform to map the point to a rect/polygon.
    if ((d->identityMatrix || d->matrix.type() <= QTransform::TxScale)) {
        // Use the rect version
        QTransform xinv = viewportTransform().inverted();
        return d->scene->items(xinv.mapRect(QRectF(pos.x(), pos.y(), 1, 1)),
                               Qt::IntersectsItemShape,
                               Qt::AscendingOrder,
                               viewportTransform());
    }
    // Use the polygon version
    return d->scene->items(mapToScene(pos.x(), pos.y(), 1, 1),
                           Qt::IntersectsItemShape,
                           Qt::AscendingOrder,
                           viewportTransform());
}

/*!
    \fn QGraphicsView::items(int x, int y) const

    This function is provided for convenience. It's equivalent to calling
    items(QPoint(\a x, \a y)).
*/

/*!
    \overload

    Returns a list of all the items that, depending on \a mode, are either
    contained by or intersect with \a rect. \a rect is in viewport
    coordinates.

    The default value for \a mode is Qt::IntersectsItemShape; all items whose
    exact shape intersects with or is contained by \a rect are returned.

    \sa itemAt(), items(), mapToScene()
*/
QList<QGraphicsItem *> QGraphicsView::items(const QRect &rect, Qt::ItemSelectionMode mode) const
{
    Q_D(const QGraphicsView);
    if (!d->scene)
        return QList<QGraphicsItem *>();
    return d->scene->items(mapToScene(rect), mode, Qt::AscendingOrder, viewportTransform());
}

/*!
    \fn QList<QGraphicsItem *> QGraphicsView::items(int x, int y, int w, int h, Qt::ItemSelectionMode mode) const
    \since 4.3

    This convenience function is equivalent to calling items(QRectF(\a x, \a
    y, \a w, \a h), \a mode).
*/

/*!
    \overload

    Returns a list of all the items that, depending on \a mode, are either
    contained by or intersect with \a polygon. \a polygon is in viewport
    coordinates.

    The default value for \a mode is Qt::IntersectsItemShape; all items whose
    exact shape intersects with or is contained by \a polygon are returned.

    \sa itemAt(), items(), mapToScene()
*/
QList<QGraphicsItem *> QGraphicsView::items(const QPolygon &polygon, Qt::ItemSelectionMode mode) const
{
    Q_D(const QGraphicsView);
    if (!d->scene)
        return QList<QGraphicsItem *>();
    return d->scene->items(mapToScene(polygon), mode, Qt::AscendingOrder, viewportTransform());
}

/*!
    \overload

    Returns a list of all the items that, depending on \a mode, are either
    contained by or intersect with \a path. \a path is in viewport
    coordinates.

    The default value for \a mode is Qt::IntersectsItemShape; all items whose
    exact shape intersects with or is contained by \a path are returned.

    \sa itemAt(), items(), mapToScene()
*/
QList<QGraphicsItem *> QGraphicsView::items(const QPainterPath &path, Qt::ItemSelectionMode mode) const
{
    Q_D(const QGraphicsView);
    if (!d->scene)
        return QList<QGraphicsItem *>();
    return d->scene->items(mapToScene(path), mode, Qt::AscendingOrder, viewportTransform());
}

/*!
    Returns the item at position \a pos, which is in viewport coordinates.
    If there are several items at this position, this function returns
    the topmost item.

    Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsview.cpp 6

    \sa items()
*/
QGraphicsItem *QGraphicsView::itemAt(const QPoint &pos) const
{
    Q_D(const QGraphicsView);
    if (!d->scene)
        return 0;
    QList<QGraphicsItem *> itemsAtPos = items(pos);
    return itemsAtPos.isEmpty() ? 0 : itemsAtPos.first();
}

/*!
    \overload
    \fn QGraphicsItem *QGraphicsView::itemAt(int x, int y) const

    This function is provided for convenience. It's equivalent to
    calling itemAt(QPoint(\a x, \a y)).
*/

/*!
    Returns the viewport coordinate \a point mapped to scene coordinates.

    Note: It can be useful to map the whole rectangle covered by the pixel at
    \a point instead of the point itself. To do this, you can call
    mapToScene(QRect(\a point, QSize(2, 2))).

    \sa mapFromScene()
*/
QPointF QGraphicsView::mapToScene(const QPoint &point) const
{
    Q_D(const QGraphicsView);
    QPointF p = point;
    p.rx() += d->horizontalScroll();
    p.ry() += d->verticalScroll();
    return d->identityMatrix ? p : d->matrix.inverted().map(p);
}

/*!
    \fn QGraphicsView::mapToScene(int x, int y) const

    This function is provided for convenience. It's equivalent to calling
    mapToScene(QPoint(\a x, \a y)).
*/

/*!
    Returns the viewport rectangle \a rect mapped to a scene coordinate
    polygon.

    \sa mapFromScene()
*/
QPolygonF QGraphicsView::mapToScene(const QRect &rect) const
{
    Q_D(const QGraphicsView);
    if (!rect.isValid())
        return QPolygonF();

    QPointF scrollOffset(d->horizontalScroll(), d->verticalScroll());
    QRect r = rect.adjusted(0, 0, 1, 1);
    QPointF tl = scrollOffset + r.topLeft();
    QPointF tr = scrollOffset + r.topRight();
    QPointF br = scrollOffset + r.bottomRight();
    QPointF bl = scrollOffset + r.bottomLeft();

    QPolygonF poly(4);
    if (!d->identityMatrix) {
        QTransform x = d->matrix.inverted();
        poly[0] = x.map(tl);
        poly[1] = x.map(tr);
        poly[2] = x.map(br);
        poly[3] = x.map(bl);
    } else {
        poly[0] = tl;
        poly[1] = tr;
        poly[2] = br;
        poly[3] = bl;
    }
    return poly;
}

/*!
    \fn QGraphicsView::mapToScene(int x, int y, int w, int h) const

    This function is provided for convenience. It's equivalent to calling
    mapToScene(QRect(\a x, \a y, \a w, \a h)).
*/

/*!
    Returns the viewport polygon \a polygon mapped to a scene coordinate
    polygon.

    \sa mapFromScene()
*/
QPolygonF QGraphicsView::mapToScene(const QPolygon &polygon) const
{
    QPolygonF poly;
    foreach (const QPoint &point, polygon)
        poly << mapToScene(point);
    return poly;
}

/*!
    Returns the viewport painter path \a path mapped to a scene coordinate
    painter path.

    \sa mapFromScene()
*/
QPainterPath QGraphicsView::mapToScene(const QPainterPath &path) const
{
    Q_D(const QGraphicsView);
    QTransform matrix = QTransform::fromTranslate(d->horizontalScroll(), d->verticalScroll());
    matrix *= d->matrix.inverted();
    return matrix.map(path);
}

/*!
    Returns the scene coordinate \a point to viewport coordinates.

    \sa mapToScene()
*/
QPoint QGraphicsView::mapFromScene(const QPointF &point) const
{
    Q_D(const QGraphicsView);
    QPointF p = d->identityMatrix ? point : d->matrix.map(point);
    p.rx() -= d->horizontalScroll();
    p.ry() -= d->verticalScroll();
    return p.toPoint();
}

/*!
    \fn QGraphicsView::mapFromScene(qreal x, qreal y) const

    This function is provided for convenience. It's equivalent to
    calling mapFromScene(QPointF(\a x, \a y)).
*/

/*!
    Returns the scene rectangle \a rect to a viewport coordinate
    polygon.

    \sa mapToScene()
*/
QPolygon QGraphicsView::mapFromScene(const QRectF &rect) const
{
    Q_D(const QGraphicsView);
    QPointF tl;
    QPointF tr;
    QPointF br;
    QPointF bl;
    if (!d->identityMatrix) {
        const QTransform &x = d->matrix;
        tl = x.map(rect.topLeft());
        tr = x.map(rect.topRight());
        br = x.map(rect.bottomRight());
        bl = x.map(rect.bottomLeft());
    } else {
        tl = rect.topLeft();
        tr = rect.topRight();
        br = rect.bottomRight();
        bl = rect.bottomLeft();
    }
    QPointF scrollOffset(d->horizontalScroll(), d->verticalScroll());
    tl -= scrollOffset;
    tr -= scrollOffset;
    br -= scrollOffset;
    bl -= scrollOffset;

    QPolygon poly(4);
    poly[0] = tl.toPoint();
    poly[1] = tr.toPoint();
    poly[2] = br.toPoint();
    poly[3] = bl.toPoint();
    return poly;
}

/*!
    \fn QGraphicsView::mapFromScene(qreal x, qreal y, qreal w, qreal h) const

    This function is provided for convenience. It's equivalent to
    calling mapFromScene(QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    Returns the scene coordinate polygon \a polygon to a viewport coordinate
    polygon.

    \sa mapToScene()
*/
QPolygon QGraphicsView::mapFromScene(const QPolygonF &polygon) const
{
    QPolygon poly;
    foreach (const QPointF &point, polygon)
        poly << mapFromScene(point);
    return poly;
}

/*!
    Returns the scene coordinate painter path \a path to a viewport coordinate
    painter path.

    \sa mapToScene()
*/
QPainterPath QGraphicsView::mapFromScene(const QPainterPath &path) const
{
    Q_D(const QGraphicsView);
    QTransform matrix = d->matrix;
    matrix *= QTransform::fromTranslate(-d->horizontalScroll(), -d->verticalScroll());
    return matrix.map(path);
}

/*!
    \reimp
*/
QVariant QGraphicsView::inputMethodQuery(Qt::InputMethodQuery query) const
{
    Q_D(const QGraphicsView);
    if (!d->scene)
        return QVariant();

    QVariant value = d->scene->inputMethodQuery(query);
    if (value.type() == QVariant::RectF)
        value = mapFromScene(value.toRectF()).boundingRect();
    else if (value.type() == QVariant::PointF)
        value = mapFromScene(value.toPointF());
    else if (value.type() == QVariant::Rect)
        value = mapFromScene(value.toRect()).boundingRect();
    else if (value.type() == QVariant::Point)
        value = mapFromScene(value.toPoint());
    return value;
}

/*!
    \property QGraphicsView::backgroundBrush
    \brief the background brush of the scene.

    This property sets the background brush for the scene in this view. It is
    used to override the scene's own background, and defines the behavior of
    drawBackground(). To provide custom background drawing for this view, you
    can reimplement drawBackground() instead.

    By default, this property contains a brush with the Qt::NoBrush pattern.

    \sa QGraphicsScene::backgroundBrush, foregroundBrush
*/
QBrush QGraphicsView::backgroundBrush() const
{
    Q_D(const QGraphicsView);
    return d->backgroundBrush;
}
void QGraphicsView::setBackgroundBrush(const QBrush &brush)
{
    Q_D(QGraphicsView);
    d->backgroundBrush = brush;
    d->updateAll();

    if (d->cacheMode & CacheBackground) {
        // Invalidate the background pixmap
        d->mustResizeBackgroundPixmap = true;
    }
}

/*!
    \property QGraphicsView::foregroundBrush
    \brief the foreground brush of the scene.

    This property sets the foreground brush for the scene in this view. It is
    used to override the scene's own foreground, and defines the behavior of
    drawForeground(). To provide custom foreground drawing for this view, you
    can reimplement drawForeground() instead.

    By default, this property contains a brush with the Qt::NoBrush pattern.

    \sa QGraphicsScene::foregroundBrush, backgroundBrush
*/
QBrush QGraphicsView::foregroundBrush() const
{
    Q_D(const QGraphicsView);
    return d->foregroundBrush;
}
void QGraphicsView::setForegroundBrush(const QBrush &brush)
{
    Q_D(QGraphicsView);
    d->foregroundBrush = brush;
    d->updateAll();
}

/*!
    Schedules an update of the scene rectangles \a rects.

    \sa QGraphicsScene::changed()
*/
void QGraphicsView::updateScene(const QList<QRectF> &rects)
{
    // ### Note: Since 4.5, this slot is only called if the user explicitly
    // establishes a connection between the scene and the view, as the scene
    // and view are no longer connected. We need to keep it working (basically
    // leave it as it is), but the new delivery path is through
    // QGraphicsScenePrivate::itemUpdate().
    Q_D(QGraphicsView);
    if (d->fullUpdatePending || d->viewportUpdateMode == QGraphicsView::NoViewportUpdate)
        return;

    // Extract and reset dirty scene rect info.
    QVector<QRect> dirtyViewportRects;
    const QVector<QRect> &dirtyRects = d->dirtyRegion.rects();
    for (int i = 0; i < dirtyRects.size(); ++i)
        dirtyViewportRects += dirtyRects.at(i);
    d->dirtyRegion = QRegion();
    d->dirtyBoundingRect = QRect();

    bool fullUpdate = !d->accelerateScrolling || d->viewportUpdateMode == QGraphicsView::FullViewportUpdate;
    bool boundingRectUpdate = (d->viewportUpdateMode == QGraphicsView::BoundingRectViewportUpdate)
                              || (d->viewportUpdateMode == QGraphicsView::SmartViewportUpdate
                                  && ((dirtyViewportRects.size() + rects.size()) >= QGRAPHICSVIEW_REGION_RECT_THRESHOLD));

    QRegion updateRegion;
    QRect boundingRect;
    QRect viewportRect = viewport()->rect();
    bool redraw = false;
    QTransform transform = viewportTransform();

    // Convert scene rects to viewport rects.
    foreach (const QRectF &rect, rects) {
        QRect xrect = transform.mapRect(rect).toRect();
        if (!(d->optimizationFlags & DontAdjustForAntialiasing))
            xrect.adjust(-2, -2, 2, 2);
        if (!viewportRect.intersects(xrect))
            continue;
        dirtyViewportRects << xrect;
    }

    foreach (const QRect &rect, dirtyViewportRects) {
        // Add the exposed rect to the update region. In rect update
        // mode, we only count the bounding rect of items.
        if (!boundingRectUpdate) {
            updateRegion += rect;
        } else {
            boundingRect |= rect;
        }
        redraw = true;
        if (fullUpdate) {
            // If fullUpdate is true and we found a visible dirty rect,
            // we're done.
            break;
        }
    }

    if (!redraw)
        return;

    if (fullUpdate)
        viewport()->update();
    else if (boundingRectUpdate)
        viewport()->update(boundingRect);
    else
        viewport()->update(updateRegion);
}

/*!
    Notifies QGraphicsView that the scene's scene rect has changed.  \a rect
    is the new scene rect. If the view already has an explicitly set scene
    rect, this function does nothing.

    \sa sceneRect, QGraphicsScene::sceneRectChanged()
*/
void QGraphicsView::updateSceneRect(const QRectF &rect)
{
    Q_D(QGraphicsView);
    if (!d->hasSceneRect) {
        d->sceneRect = rect;
        d->recalculateContentSize();
    }
}

/*!
    This slot is called by QAbstractScrollArea after setViewport() has been
    called. Reimplement this function in a subclass of QGraphicsView to
    initialize the new viewport \a widget before it is used.

    \sa setViewport()
*/
void QGraphicsView::setupViewport(QWidget *widget)
{
    Q_D(QGraphicsView);

    if (!widget) {
        qWarning("QGraphicsView::setupViewport: cannot initialize null widget");
        return;
    }

    const bool isGLWidget = widget->inherits("QGLWidget");

    d->accelerateScrolling = !(isGLWidget);

    widget->setFocusPolicy(Qt::StrongFocus);

    if (!isGLWidget) {
        // autoFillBackground enables scroll acceleration.
        widget->setAutoFillBackground(true);
    }

    // We are only interested in mouse tracking if items
    // accept hover events or use non-default cursors.
    if (d->scene && (!d->scene->d_func()->allItemsIgnoreHoverEvents
                     || !d->scene->d_func()->allItemsUseDefaultCursor)) {
        widget->setMouseTracking(true);
    }

    // enable touch events if any items is interested in them
    if (d->scene && !d->scene->d_func()->allItemsIgnoreTouchEvents)
        widget->setAttribute(Qt::WA_AcceptTouchEvents);

    widget->setAcceptDrops(acceptDrops());
}

/*!
    \reimp
*/
bool QGraphicsView::event(QEvent *event)
{
    Q_D(QGraphicsView);

    if (d->sceneInteractionAllowed) {
        switch (event->type()) {
        case QEvent::ShortcutOverride:
            if (d->scene)
                return QApplication::sendEvent(d->scene, event);
            break;
        case QEvent::KeyPress:
            if (d->scene) {
                QKeyEvent *k = static_cast<QKeyEvent *>(event);
                if (k->key() == Qt::Key_Tab || k->key() == Qt::Key_Backtab) {
                    // Send the key events to the scene. This will invoke the
                    // scene's tab focus handling, and if the event is
                    // accepted, we return (prevent further event delivery),
                    // and the base implementation will call QGraphicsView's
                    // focusNextPrevChild() function. If the event is ignored,
                    // we fall back to standard tab focus handling.
                    QApplication::sendEvent(d->scene, event);
                    if (event->isAccepted())
                        return true;
                    // Ensure the event doesn't propagate just because the
                    // scene ignored it. If the event propagates, then tab
                    // handling will be called twice (this and parent).
                    event->accept();
                }
            }
            break;
        default:
            break;
        }
    }

    return QAbstractScrollArea::event(event);
}

/*!
    \reimp
*/
bool QGraphicsView::viewportEvent(QEvent *event)
{
    Q_D(QGraphicsView);

    if (!d->scene)
        return QAbstractScrollArea::viewportEvent(event);

    switch (event->type()) {
    case QEvent::Enter:
        QApplication::sendEvent(d->scene, event);
        break;
    case QEvent::WindowActivate:
        QApplication::sendEvent(d->scene, event);
        break;
    case QEvent::WindowDeactivate:
        // ### This is a temporary fix for until we get proper mouse
        // grab events. mouseGrabberItem should be set to 0 if we lose
        // the mouse grab.
        // Remove all popups when the scene loses focus.
        if (!d->scene->d_func()->popupWidgets.isEmpty())
            d->scene->d_func()->removePopup(d->scene->d_func()->popupWidgets.first());
        QApplication::sendEvent(d->scene, event);
        break;
    case QEvent::Leave:
        // ### This is a temporary fix for until we get proper mouse grab
        // events. activeMouseGrabberItem should be set to 0 if we lose the
        // mouse grab.
        if ((QApplication::activePopupWidget() && QApplication::activePopupWidget() != window())
            || (QApplication::activeModalWidget() && QApplication::activeModalWidget() != window())
            || (QApplication::activeWindow() != window())) {
            if (!d->scene->d_func()->popupWidgets.isEmpty())
                d->scene->d_func()->removePopup(d->scene->d_func()->popupWidgets.first());
        }
        d->useLastMouseEvent = false;
        QApplication::sendEvent(d->scene, event);
        break;
#ifndef QT_NO_TOOLTIP
    case QEvent::ToolTip: {
        QHelpEvent *toolTip = static_cast<QHelpEvent *>(event);
        QGraphicsSceneHelpEvent helpEvent(QEvent::GraphicsSceneHelp);
        helpEvent.setWidget(viewport());
        helpEvent.setScreenPos(toolTip->globalPos());
        helpEvent.setScenePos(mapToScene(toolTip->pos()));
        QApplication::sendEvent(d->scene, &helpEvent);
        toolTip->setAccepted(helpEvent.isAccepted());
        return true;
    }
#endif
    case QEvent::Paint:
        // Reset full update
        d->fullUpdatePending = false;
        d->dirtyScrollOffset = QPoint();
        if (d->scene) {
            // Check if this view reimplements the updateScene slot; if it
            // does, we can't do direct update delivery and have to fall back
            // to connecting the changed signal.
            if (!d->updateSceneSlotReimplementedChecked) {
                d->updateSceneSlotReimplementedChecked = true;
                const QMetaObject *mo = metaObject();
                if (mo != &QGraphicsView::staticMetaObject) {
                    if (mo->indexOfSlot("updateScene(QList<QRectF>)")
                        != QGraphicsView::staticMetaObject.indexOfSlot("updateScene(QList<QRectF>)")) {
                        connect(d->scene, SIGNAL(changed(QList<QRectF>)),
                                this, SLOT(updateScene(QList<QRectF>)));
                    }
                }
            }
            d->scene->d_func()->updateAll = false;
        }
        break;
    case QEvent::TouchBegin:
    case QEvent::TouchUpdate:
    case QEvent::TouchEnd:
    {
        if (!isEnabled())
            return false;

        if (d->scene && d->sceneInteractionAllowed) {
            // Convert and deliver the touch event to the scene.
            QTouchEvent *touchEvent = static_cast<QTouchEvent *>(event);
            touchEvent->setWidget(viewport());
            QGraphicsViewPrivate::translateTouchEvent(d, touchEvent);
            (void) QApplication::sendEvent(d->scene, touchEvent);
        }

        return true;
    }
    default:
        break;
    }

    return QAbstractScrollArea::viewportEvent(event);
}

#ifndef QT_NO_CONTEXTMENU
/*!
    \reimp
*/
void QGraphicsView::contextMenuEvent(QContextMenuEvent *event)
{
    Q_D(QGraphicsView);
    if (!d->scene || !d->sceneInteractionAllowed)
        return;

    d->mousePressViewPoint = event->pos();
    d->mousePressScenePoint = mapToScene(d->mousePressViewPoint);
    d->mousePressScreenPoint = event->globalPos();
    d->lastMouseMoveScenePoint = d->mousePressScenePoint;
    d->lastMouseMoveScreenPoint = d->mousePressScreenPoint;

    QGraphicsSceneContextMenuEvent contextEvent(QEvent::GraphicsSceneContextMenu);
    contextEvent.setWidget(viewport());
    contextEvent.setScenePos(d->mousePressScenePoint);
    contextEvent.setScreenPos(d->mousePressScreenPoint);
    contextEvent.setModifiers(event->modifiers());
    contextEvent.setReason((QGraphicsSceneContextMenuEvent::Reason)(event->reason()));
    contextEvent.setAccepted(event->isAccepted());
    QApplication::sendEvent(d->scene, &contextEvent);
    event->setAccepted(contextEvent.isAccepted());
}
#endif // QT_NO_CONTEXTMENU

/*!
    \reimp
*/
void QGraphicsView::dropEvent(QDropEvent *event)
{
#ifndef QT_NO_DRAGANDDROP
    Q_D(QGraphicsView);
    if (!d->scene || !d->sceneInteractionAllowed)
        return;

    // Generate a scene event.
    QGraphicsSceneDragDropEvent sceneEvent(QEvent::GraphicsSceneDrop);
    d->populateSceneDragDropEvent(&sceneEvent, event);

    // Send it to the scene.
    QApplication::sendEvent(d->scene, &sceneEvent);

    // Accept the originating event if the scene accepted the scene event.
    event->setAccepted(sceneEvent.isAccepted());
    if (sceneEvent.isAccepted())
        event->setDropAction(sceneEvent.dropAction());

    delete d->lastDragDropEvent;
    d->lastDragDropEvent = 0;

#else
    Q_UNUSED(event)
#endif
}

/*!
    \reimp
*/
void QGraphicsView::dragEnterEvent(QDragEnterEvent *event)
{
#ifndef QT_NO_DRAGANDDROP
    Q_D(QGraphicsView);
    if (!d->scene || !d->sceneInteractionAllowed)
        return;

    // Disable replaying of mouse move events.
    d->useLastMouseEvent = false;

    // Generate a scene event.
    QGraphicsSceneDragDropEvent sceneEvent(QEvent::GraphicsSceneDragEnter);
    d->populateSceneDragDropEvent(&sceneEvent, event);

    // Store it for later use.
    d->storeDragDropEvent(&sceneEvent);

    // Send it to the scene.
    QApplication::sendEvent(d->scene, &sceneEvent);

    // Accept the originating event if the scene accepted the scene event.
    if (sceneEvent.isAccepted()) {
        event->setAccepted(true);
        event->setDropAction(sceneEvent.dropAction());
    }
#else
    Q_UNUSED(event)
#endif
}

/*!
    \reimp
*/
void QGraphicsView::dragLeaveEvent(QDragLeaveEvent *event)
{
#ifndef QT_NO_DRAGANDDROP
    Q_D(QGraphicsView);
    if (!d->scene || !d->sceneInteractionAllowed)
        return;
    if (!d->lastDragDropEvent) {
        qWarning("QGraphicsView::dragLeaveEvent: drag leave received before drag enter");
        return;
    }

    // Generate a scene event.
    QGraphicsSceneDragDropEvent sceneEvent(QEvent::GraphicsSceneDragLeave);
    sceneEvent.setScenePos(d->lastDragDropEvent->scenePos());
    sceneEvent.setScreenPos(d->lastDragDropEvent->screenPos());
    sceneEvent.setButtons(d->lastDragDropEvent->buttons());
    sceneEvent.setModifiers(d->lastDragDropEvent->modifiers());
    sceneEvent.setPossibleActions(d->lastDragDropEvent->possibleActions());
    sceneEvent.setProposedAction(d->lastDragDropEvent->proposedAction());
    sceneEvent.setDropAction(d->lastDragDropEvent->dropAction());
    sceneEvent.setMimeData(d->lastDragDropEvent->mimeData());
    sceneEvent.setWidget(d->lastDragDropEvent->widget());
    sceneEvent.setSource(d->lastDragDropEvent->source());
    delete d->lastDragDropEvent;
    d->lastDragDropEvent = 0;

    // Send it to the scene.
    QApplication::sendEvent(d->scene, &sceneEvent);

    // Accept the originating event if the scene accepted the scene event.
    if (sceneEvent.isAccepted())
        event->setAccepted(true);
#else
    Q_UNUSED(event)
#endif
}

/*!
    \reimp
*/
void QGraphicsView::dragMoveEvent(QDragMoveEvent *event)
{
#ifndef QT_NO_DRAGANDDROP
    Q_D(QGraphicsView);
    if (!d->scene || !d->sceneInteractionAllowed)
        return;

    // Generate a scene event.
    QGraphicsSceneDragDropEvent sceneEvent(QEvent::GraphicsSceneDragMove);
    d->populateSceneDragDropEvent(&sceneEvent, event);

    // Store it for later use.
    d->storeDragDropEvent(&sceneEvent);

    // Send it to the scene.
    QApplication::sendEvent(d->scene, &sceneEvent);

    // Ignore the originating event if the scene ignored the scene event.
    event->setAccepted(sceneEvent.isAccepted());
    if (sceneEvent.isAccepted())
        event->setDropAction(sceneEvent.dropAction());
#else
    Q_UNUSED(event)
#endif
}

/*!
    \reimp
*/
void QGraphicsView::focusInEvent(QFocusEvent *event)
{
    Q_D(QGraphicsView);
    d->updateInputMethodSensitivity();
    QAbstractScrollArea::focusInEvent(event);
    if (d->scene)
        QApplication::sendEvent(d->scene, event);
    // Pass focus on if the scene cannot accept focus.
    if (!d->scene || !event->isAccepted())
        QAbstractScrollArea::focusInEvent(event);
}

/*!
    \reimp
*/
bool QGraphicsView::focusNextPrevChild(bool next)
{
    return QAbstractScrollArea::focusNextPrevChild(next);
}

/*!
    \reimp
*/
void QGraphicsView::focusOutEvent(QFocusEvent *event)
{
    Q_D(QGraphicsView);
    QAbstractScrollArea::focusOutEvent(event);
    if (d->scene)
        QApplication::sendEvent(d->scene, event);
}

/*!
    \reimp
*/
void QGraphicsView::keyPressEvent(QKeyEvent *event)
{
    Q_D(QGraphicsView);
    if (!d->scene || !d->sceneInteractionAllowed) {
        QAbstractScrollArea::keyPressEvent(event);
        return;
    }
    QApplication::sendEvent(d->scene, event);
    if (!event->isAccepted())
        QAbstractScrollArea::keyPressEvent(event);
}

/*!
    \reimp
*/
void QGraphicsView::keyReleaseEvent(QKeyEvent *event)
{
    Q_D(QGraphicsView);
    if (!d->scene || !d->sceneInteractionAllowed)
        return;
    QApplication::sendEvent(d->scene, event);
    if (!event->isAccepted())
        QAbstractScrollArea::keyReleaseEvent(event);
}

/*!
    \reimp
*/
void QGraphicsView::mouseDoubleClickEvent(QMouseEvent *event)
{
    Q_D(QGraphicsView);
    if (!d->scene || !d->sceneInteractionAllowed)
        return;

    d->storeMouseEvent(event);
    d->mousePressViewPoint = event->pos();
    d->mousePressScenePoint = mapToScene(d->mousePressViewPoint);
    d->mousePressScreenPoint = event->globalPos();
    d->lastMouseMoveScenePoint = d->mousePressScenePoint;
    d->lastMouseMoveScreenPoint = d->mousePressScreenPoint;
    d->mousePressButton = event->button();

    QGraphicsSceneMouseEvent mouseEvent(QEvent::GraphicsSceneMouseDoubleClick);
    mouseEvent.setWidget(viewport());
    mouseEvent.setButtonDownScenePos(d->mousePressButton, d->mousePressScenePoint);
    mouseEvent.setButtonDownScreenPos(d->mousePressButton, d->mousePressScreenPoint);
    mouseEvent.setScenePos(mapToScene(d->mousePressViewPoint));
    mouseEvent.setScreenPos(d->mousePressScreenPoint);
    mouseEvent.setLastScenePos(d->lastMouseMoveScenePoint);
    mouseEvent.setLastScreenPos(d->lastMouseMoveScreenPoint);
    mouseEvent.setButtons(event->buttons());
    mouseEvent.setButtons(event->buttons());
    mouseEvent.setAccepted(false);
    mouseEvent.setButton(event->button());
    mouseEvent.setModifiers(event->modifiers());
    if (event->spontaneous())
        qt_sendSpontaneousEvent(d->scene, &mouseEvent);
    else
        QApplication::sendEvent(d->scene, &mouseEvent);
}

/*!
    \reimp
*/
void QGraphicsView::mousePressEvent(QMouseEvent *event)
{
    Q_D(QGraphicsView);

    // Store this event for replaying, finding deltas, and for
    // scroll-dragging; even in non-interactive mode, scroll hand dragging is
    // allowed, so we store the event at the very top of this function.
    d->storeMouseEvent(event);
    d->lastMouseEvent.setAccepted(false);

    if (d->sceneInteractionAllowed) {
        // Store some of the event's button-down data.
        d->mousePressViewPoint = event->pos();
        d->mousePressScenePoint = mapToScene(d->mousePressViewPoint);
        d->mousePressScreenPoint = event->globalPos();
        d->lastMouseMoveScenePoint = d->mousePressScenePoint;
        d->lastMouseMoveScreenPoint = d->mousePressScreenPoint;
        d->mousePressButton = event->button();

        if (d->scene) {
            // Convert and deliver the mouse event to the scene.
            QGraphicsSceneMouseEvent mouseEvent(QEvent::GraphicsSceneMousePress);
            mouseEvent.setWidget(viewport());
            mouseEvent.setButtonDownScenePos(d->mousePressButton, d->mousePressScenePoint);
            mouseEvent.setButtonDownScreenPos(d->mousePressButton, d->mousePressScreenPoint);
            mouseEvent.setScenePos(d->mousePressScenePoint);
            mouseEvent.setScreenPos(d->mousePressScreenPoint);
            mouseEvent.setLastScenePos(d->lastMouseMoveScenePoint);
            mouseEvent.setLastScreenPos(d->lastMouseMoveScreenPoint);
            mouseEvent.setButtons(event->buttons());
            mouseEvent.setButton(event->button());
            mouseEvent.setModifiers(event->modifiers());
            mouseEvent.setAccepted(false);
            if (event->spontaneous())
                qt_sendSpontaneousEvent(d->scene, &mouseEvent);
            else
                QApplication::sendEvent(d->scene, &mouseEvent);

            // Update the original mouse event accepted state.
            bool isAccepted = mouseEvent.isAccepted();
            event->setAccepted(isAccepted);

            // Update the last mouse event accepted state.
            d->lastMouseEvent.setAccepted(isAccepted);

            if (isAccepted)
                return;
        }
    }

#ifndef QT_NO_RUBBERBAND
    if (d->dragMode == QGraphicsView::RubberBandDrag && !d->rubberBanding) {
        if (d->sceneInteractionAllowed) {
            // Rubberbanding is only allowed in interactive mode.
            event->accept();
            d->rubberBanding = true;
            d->rubberBandRect = QRect();
            if (d->scene) {
                // Initiating a rubber band always clears the selection.
                d->scene->clearSelection();
            }
        }
    } else
#endif
        if (d->dragMode == QGraphicsView::ScrollHandDrag && event->button() == Qt::LeftButton) {
            // Left-button press in scroll hand mode initiates hand scrolling.
            event->accept();
            d->handScrolling = true;
            d->handScrollMotions = 0;
#ifndef QT_NO_CURSOR
            viewport()->setCursor(Qt::ClosedHandCursor);
#endif
        }
}

/*!
    \reimp
*/
void QGraphicsView::mouseMoveEvent(QMouseEvent *event)
{
    Q_D(QGraphicsView);

#ifndef QT_NO_RUBBERBAND
    if (d->dragMode == QGraphicsView::RubberBandDrag && d->sceneInteractionAllowed) {
        d->storeMouseEvent(event);
        if (d->rubberBanding) {
            // Check for enough drag distance
            if ((d->mousePressViewPoint - event->pos()).manhattanLength()
                < QApplication::startDragDistance()) {
                return;
            }

            // Update old rubberband
            if (d->viewportUpdateMode != QGraphicsView::NoViewportUpdate && !d->rubberBandRect.isEmpty()) {
                if (d->viewportUpdateMode != FullViewportUpdate)
                    viewport()->update(d->rubberBandRegion(viewport(), d->rubberBandRect));
                else
                    d->updateAll();
            }

            // Stop rubber banding if the user has let go of all buttons (even
            // if we didn't get the release events).
            if (!event->buttons()) {
                d->rubberBanding = false;
                d->rubberBandRect = QRect();
                return;
            }

            // Update rubberband position
            const QPoint &mp = d->mousePressViewPoint;
            QPoint ep = event->pos();
            d->rubberBandRect = QRect(qMin(mp.x(), ep.x()), qMin(mp.y(), ep.y()),
                                      qAbs(mp.x() - ep.x()) + 1, qAbs(mp.y() - ep.y()) + 1);

            // Update new rubberband
            if (d->viewportUpdateMode != QGraphicsView::NoViewportUpdate){
                if (d->viewportUpdateMode != FullViewportUpdate)
                    viewport()->update(d->rubberBandRegion(viewport(), d->rubberBandRect));
                else
                    d->updateAll();
            }
            // Set the new selection area
            QPainterPath selectionArea;
            selectionArea.addPolygon(mapToScene(d->rubberBandRect));
            selectionArea.closeSubpath();
            if (d->scene)
                d->scene->setSelectionArea(selectionArea, d->rubberBandSelectionMode,
                                           viewportTransform());
            return;
        }
    } else
#endif // QT_NO_RUBBERBAND
    if (d->dragMode == QGraphicsView::ScrollHandDrag) {
        if (d->handScrolling) {
            QScrollBar *hBar = horizontalScrollBar();
            QScrollBar *vBar = verticalScrollBar();
            QPoint delta = event->pos() - d->lastMouseEvent.pos();
            hBar->setValue(hBar->value() + (isRightToLeft() ? delta.x() : -delta.x()));
            vBar->setValue(vBar->value() - delta.y());

            // Detect how much we've scrolled to disambiguate scrolling from
            // clicking.
            ++d->handScrollMotions;
        }
    }

    d->mouseMoveEventHandler(event);
}

/*!
    \reimp
*/
void QGraphicsView::mouseReleaseEvent(QMouseEvent *event)
{
    Q_D(QGraphicsView);

#ifndef QT_NO_RUBBERBAND
    if (d->dragMode == QGraphicsView::RubberBandDrag && d->sceneInteractionAllowed && !event->buttons()) {
        if (d->rubberBanding) {
            if (d->viewportUpdateMode != QGraphicsView::NoViewportUpdate){
                if (d->viewportUpdateMode != FullViewportUpdate)
                    viewport()->update(d->rubberBandRegion(viewport(), d->rubberBandRect));
                else
                    d->updateAll();
            }
            d->rubberBanding = false;
            d->rubberBandRect = QRect();
        }
    } else
#endif
    if (d->dragMode == QGraphicsView::ScrollHandDrag && event->button() == Qt::LeftButton) {
#ifndef QT_NO_CURSOR
        // Restore the open hand cursor. ### There might be items
        // under the mouse that have a valid cursor at this time, so
        // we could repeat the steps from mouseMoveEvent().
        viewport()->setCursor(Qt::OpenHandCursor);
#endif
        d->handScrolling = false;

        if (d->scene && d->sceneInteractionAllowed && !d->lastMouseEvent.isAccepted() && d->handScrollMotions <= 6) {
            // If we've detected very little motion during the hand drag, and
            // no item accepted the last event, we'll interpret that as a
            // click to the scene, and reset the selection.
            d->scene->clearSelection();
        }
    }

    d->storeMouseEvent(event);

    if (!d->sceneInteractionAllowed)
        return;

    if (!d->scene)
        return;

    QGraphicsSceneMouseEvent mouseEvent(QEvent::GraphicsSceneMouseRelease);
    mouseEvent.setWidget(viewport());
    mouseEvent.setButtonDownScenePos(d->mousePressButton, d->mousePressScenePoint);
    mouseEvent.setButtonDownScreenPos(d->mousePressButton, d->mousePressScreenPoint);
    mouseEvent.setScenePos(mapToScene(event->pos()));
    mouseEvent.setScreenPos(event->globalPos());
    mouseEvent.setLastScenePos(d->lastMouseMoveScenePoint);
    mouseEvent.setLastScreenPos(d->lastMouseMoveScreenPoint);
    mouseEvent.setButtons(event->buttons());
    mouseEvent.setButton(event->button());
    mouseEvent.setModifiers(event->modifiers());
    mouseEvent.setAccepted(false);
    if (event->spontaneous())
        qt_sendSpontaneousEvent(d->scene, &mouseEvent);
    else
        QApplication::sendEvent(d->scene, &mouseEvent);

    // Update the last mouse event selected state.
    d->lastMouseEvent.setAccepted(mouseEvent.isAccepted());

#ifndef QT_NO_CURSOR
    if (mouseEvent.isAccepted() && mouseEvent.buttons() == 0 && viewport()->testAttribute(Qt::WA_SetCursor)) {
        // The last mouse release on the viewport will trigger clearing the cursor.
        d->_q_unsetViewportCursor();
    }
#endif
}

#ifndef QT_NO_WHEELEVENT
/*!
    \reimp
*/
void QGraphicsView::wheelEvent(QWheelEvent *event)
{
    Q_D(QGraphicsView);
    if (!d->scene || !d->sceneInteractionAllowed) {
        QAbstractScrollArea::wheelEvent(event);
        return;
    }

    event->ignore();

    QGraphicsSceneWheelEvent wheelEvent(QEvent::GraphicsSceneWheel);
    wheelEvent.setWidget(viewport());
    wheelEvent.setScenePos(mapToScene(event->pos()));
    wheelEvent.setScreenPos(event->globalPos());
    wheelEvent.setButtons(event->buttons());
    wheelEvent.setModifiers(event->modifiers());
    wheelEvent.setDelta(event->delta());
    wheelEvent.setOrientation(event->orientation());
    wheelEvent.setAccepted(false);
    QApplication::sendEvent(d->scene, &wheelEvent);
    event->setAccepted(wheelEvent.isAccepted());
    if (!event->isAccepted())
        QAbstractScrollArea::wheelEvent(event);
}
#endif // QT_NO_WHEELEVENT

/*!
    \reimp
*/
void QGraphicsView::paintEvent(QPaintEvent *event)
{
    Q_D(QGraphicsView);
    if (!d->scene) {
        QAbstractScrollArea::paintEvent(event);
        return;
    }

    // Set up painter state protection.
    d->scene->d_func()->painterStateProtection = !(d->optimizationFlags & DontSavePainterState);

    // Determine the exposed region
    d->exposedRegion = event->region();
    QRectF exposedSceneRect = mapToScene(d->exposedRegion.boundingRect()).boundingRect();

    // Set up the painter
    QPainter painter(viewport());
#ifndef QT_NO_RUBBERBAND
    if (d->rubberBanding && !d->rubberBandRect.isEmpty())
        painter.save();
#endif
    // Set up render hints
    painter.setRenderHints(painter.renderHints(), false);
    painter.setRenderHints(d->renderHints, true);

    // Set up viewport transform
    const bool viewTransformed = isTransformed();
    if (viewTransformed)
        painter.setWorldTransform(viewportTransform());
    const QTransform viewTransform = painter.worldTransform();

    // Draw background
    if ((d->cacheMode & CacheBackground)
#ifdef Q_WS_X11
        && X11->use_xrender
#endif
        ) {
        // Recreate the background pixmap, and flag the whole background as
        // exposed.
        if (d->mustResizeBackgroundPixmap) {
            d->backgroundPixmap = QPixmap(viewport()->size());
            QBrush bgBrush = viewport()->palette().brush(viewport()->backgroundRole());
            if (!bgBrush.isOpaque())
                d->backgroundPixmap.fill(Qt::transparent);
            QPainter p(&d->backgroundPixmap);
            p.fillRect(0, 0, d->backgroundPixmap.width(), d->backgroundPixmap.height(), bgBrush);
            d->backgroundPixmapExposed = QRegion(viewport()->rect());
            d->mustResizeBackgroundPixmap = false;
        }

        // Redraw exposed areas
        if (!d->backgroundPixmapExposed.isEmpty()) {
            QPainter backgroundPainter(&d->backgroundPixmap);
            backgroundPainter.setClipRegion(d->backgroundPixmapExposed, Qt::ReplaceClip);
            if (viewTransformed)
                backgroundPainter.setTransform(viewTransform);
            backgroundPainter.setCompositionMode(QPainter::CompositionMode_Source);
            drawBackground(&backgroundPainter, exposedSceneRect);
            d->backgroundPixmapExposed = QRegion();
        }

        // Blit the background from the background pixmap
        if (viewTransformed) {
            painter.setWorldTransform(QTransform());
            painter.drawPixmap(QPoint(), d->backgroundPixmap);
            painter.setWorldTransform(viewTransform);
        } else {
            painter.drawPixmap(QPoint(), d->backgroundPixmap);
        }
    } else {
        if (!(d->optimizationFlags & DontSavePainterState))
            painter.save();
        drawBackground(&painter, exposedSceneRect);
        if (!(d->optimizationFlags & DontSavePainterState))
            painter.restore();
    }

    // Items
    if (!(d->optimizationFlags & IndirectPainting)) {
        d->scene->d_func()->drawItems(&painter, viewTransformed ? &viewTransform : 0,
                                      &d->exposedRegion, viewport());
    } else {
        // Find all exposed items
        bool allItems = false;
        QList<QGraphicsItem *> itemList = d->findItems(d->exposedRegion, &allItems, viewTransform);
        if (!itemList.isEmpty()) {
            // Generate the style options.
            const int numItems = itemList.size();
            QGraphicsItem **itemArray = &itemList[0]; // Relies on QList internals, but is perfectly valid.
            QStyleOptionGraphicsItem *styleOptionArray = d->allocStyleOptionsArray(numItems);
            for (int i = 0; i < numItems; ++i) {
                itemArray[i]->d_ptr->initStyleOption(&styleOptionArray[i], viewTransform,
                                                     d->exposedRegion, allItems);
            }
            // Draw the items.
            drawItems(&painter, numItems, itemArray, styleOptionArray);
            d->freeStyleOptionsArray(styleOptionArray);
        }
    }

    // Foreground
    drawForeground(&painter, exposedSceneRect);

#ifndef QT_NO_RUBBERBAND
    // Rubberband
    if (d->rubberBanding && !d->rubberBandRect.isEmpty()) {
        painter.restore();
        QStyleOptionRubberBand option;
        option.initFrom(viewport());
        option.rect = d->rubberBandRect;
        option.shape = QRubberBand::Rectangle;

        QStyleHintReturnMask mask;
        if (viewport()->style()->styleHint(QStyle::SH_RubberBand_Mask, &option, viewport(), &mask)) {
            // painter clipping for masked rubberbands
            painter.setClipRegion(mask.region, Qt::IntersectClip);
        }

        viewport()->style()->drawControl(QStyle::CE_RubberBand, &option, &painter, viewport());
    }
#endif

    painter.end();

    // Restore painter state protection.
    d->scene->d_func()->painterStateProtection = true;
}

/*!
    \reimp
*/
void QGraphicsView::resizeEvent(QResizeEvent *event)
{
    Q_D(QGraphicsView);
    // Save the last center point - the resize may scroll the view, which
    // changes the center point.
    QPointF oldLastCenterPoint = d->lastCenterPoint;

    QAbstractScrollArea::resizeEvent(event);
    d->recalculateContentSize();

    // Restore the center point again.
    if (d->resizeAnchor == NoAnchor && !d->keepLastCenterPoint) {
        d->updateLastCenterPoint();
    } else {
        d->lastCenterPoint = oldLastCenterPoint;
    }
    d->centerView(d->resizeAnchor);
    d->keepLastCenterPoint = false;

    if (d->cacheMode & CacheBackground) {
        // Invalidate the background pixmap
        d->mustResizeBackgroundPixmap = true;
    }
}

/*!
    \reimp
*/
void QGraphicsView::scrollContentsBy(int dx, int dy)
{
    Q_D(QGraphicsView);
    d->dirtyScroll = true;
    if (d->transforming)
        return;
    if (isRightToLeft())
        dx = -dx;

    if (d->viewportUpdateMode != QGraphicsView::NoViewportUpdate) {
        if (d->viewportUpdateMode != QGraphicsView::FullViewportUpdate) {
            if (d->accelerateScrolling) {
#ifndef QT_NO_RUBBERBAND
                // Update new and old rubberband regions
                if (!d->rubberBandRect.isEmpty()) {
                    QRegion rubberBandRegion(d->rubberBandRegion(viewport(), d->rubberBandRect));
                    rubberBandRegion += rubberBandRegion.translated(-dx, -dy);
                    viewport()->update(rubberBandRegion);
                }
#endif
                d->dirtyScrollOffset.rx() += dx;
                d->dirtyScrollOffset.ry() += dy;
                d->dirtyRegion.translate(dx, dy);
                viewport()->scroll(dx, dy);
            } else {
                d->updateAll();
            }
        } else {
            d->updateAll();
        }
    }

    d->updateLastCenterPoint();

    if ((d->cacheMode & CacheBackground)
#ifdef Q_WS_X11
        && X11->use_xrender
#endif
        ) {
        // Scroll the background pixmap
        QRegion exposed;
        if (!d->backgroundPixmap.isNull())
            d->backgroundPixmap.scroll(dx, dy, d->backgroundPixmap.rect(), &exposed);

        // Invalidate the background pixmap
        d->backgroundPixmapExposed.translate(dx, dy);
        d->backgroundPixmapExposed += exposed;
    }

    // Always replay on scroll.
    if (d->sceneInteractionAllowed)
        d->replayLastMouseEvent();
}

/*!
    \reimp
*/
void QGraphicsView::showEvent(QShowEvent *event)
{
    Q_D(QGraphicsView);
    d->recalculateContentSize();
    d->centerView(d->transformationAnchor);
    QAbstractScrollArea::showEvent(event);
}

/*!
    \reimp
*/
void QGraphicsView::inputMethodEvent(QInputMethodEvent *event)
{
    Q_D(QGraphicsView);
    if (d->scene)
        QApplication::sendEvent(d->scene, event);
}

/*!
    Draws the background of the scene using \a painter, before any items and
    the foreground are drawn. Reimplement this function to provide a custom
    background for this view.

    If all you want is to define a color, texture or gradient for the
    background, you can call setBackgroundBrush() instead.

    All painting is done in \e scene coordinates. \a rect is the exposed
    rectangle.

    The default implementation fills \a rect using the view's backgroundBrush.
    If no such brush is defined (the default), the scene's drawBackground()
    function is called instead.

    \sa drawForeground(), QGraphicsScene::drawBackground()
*/
void QGraphicsView::drawBackground(QPainter *painter, const QRectF &rect)
{
    Q_D(QGraphicsView);
    if (d->scene && d->backgroundBrush.style() == Qt::NoBrush) {
        d->scene->drawBackground(painter, rect);
        return;
    }

    painter->fillRect(rect, d->backgroundBrush);
}

/*!
    Draws the foreground of the scene using \a painter, after the background
    and all items are drawn. Reimplement this function to provide a custom
    foreground for this view.

    If all you want is to define a color, texture or gradient for the
    foreground, you can call setForegroundBrush() instead.

    All painting is done in \e scene coordinates. \a rect is the exposed
    rectangle.

    The default implementation fills \a rect using the view's foregroundBrush.
    If no such brush is defined (the default), the scene's drawForeground()
    function is called instead.

    \sa drawBackground(), QGraphicsScene::drawForeground()
*/
void QGraphicsView::drawForeground(QPainter *painter, const QRectF &rect)
{
    Q_D(QGraphicsView);
    if (d->scene && d->foregroundBrush.style() == Qt::NoBrush) {
        d->scene->drawForeground(painter, rect);
        return;
    }

    painter->fillRect(rect, d->foregroundBrush);
}

/*!
    Draws the items \a items in the scene using \a painter, after the
    background and before the foreground are drawn. \a numItems is the number
    of items in \a items and options in \a options. \a options is a list of
    styleoptions; one for each item. Reimplement this function to provide
    custom item drawing for this view.

    The default implementation calls the scene's drawItems() function.

    \sa drawForeground(), drawBackground(), QGraphicsScene::drawItems()
*/
void QGraphicsView::drawItems(QPainter *painter, int numItems,
                              QGraphicsItem *items[],
                              const QStyleOptionGraphicsItem options[])
{
    Q_D(QGraphicsView);
    if (d->scene) {
        QWidget *widget = painter->device() == viewport() ? viewport() : 0;
        d->scene->drawItems(painter, numItems, items, options, widget);
    }
}

/*!
    Returns the current transformation matrix for the view. If no current
    transformation is set, the identity matrix is returned.

    \sa setTransform(), rotate(), scale(), shear(), translate()
*/
QTransform QGraphicsView::transform() const
{
    Q_D(const QGraphicsView);
    return d->matrix;
}

/*!
    Returns a matrix that maps viewport coordinates to scene coordinates.

    \sa mapToScene(), mapFromScene()
*/
QTransform QGraphicsView::viewportTransform() const
{
    Q_D(const QGraphicsView);
    QTransform moveMatrix = QTransform::fromTranslate(-d->horizontalScroll(), -d->verticalScroll());
    return d->identityMatrix ? moveMatrix : d->matrix * moveMatrix;
}

/*!
    \since 4.6

    Returns true if the view is transformed (i.e., a non-identity transform
    has been assigned, or the scrollbars are adjusted).

    \sa setTransform(), horizontalScrollBar(), verticalScrollBar()
*/
bool QGraphicsView::isTransformed() const
{
    Q_D(const QGraphicsView);
    return !d->identityMatrix || d->horizontalScroll() || d->verticalScroll();
}

/*!
    Sets the view's current transformation matrix to \a matrix.

    If \a combine is true, then \a matrix is combined with the current matrix;
    otherwise, \a matrix \e replaces the current matrix. \a combine is false
    by default.

    The transformation matrix tranforms the scene into view coordinates. Using
    the default transformation, provided by the identity matrix, one pixel in
    the view represents one unit in the scene (e.g., a 10x10 rectangular item
    is drawn using 10x10 pixels in the view). If a 2x2 scaling matrix is
    applied, the scene will be drawn in 1:2 (e.g., a 10x10 rectangular item is
    then drawn using 20x20 pixels in the view).

    Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsview.cpp 7

    To simplify interation with items using a transformed view, QGraphicsView
    provides mapTo... and mapFrom... functions that can translate between
    scene and view coordinates. For example, you can call mapToScene() to map
    a view coordiate to a floating point scene coordinate, or mapFromScene()
    to map from floating point scene coordinates to view coordinates.

    \sa transform(), rotate(), scale(), shear(), translate()
*/
void QGraphicsView::setTransform(const QTransform &matrix, bool combine )
{
    Q_D(QGraphicsView);
    QTransform oldMatrix = d->matrix;
    if (!combine)
        d->matrix = matrix;
    else
        d->matrix = matrix * d->matrix;
    if (oldMatrix == d->matrix)
        return;

    d->identityMatrix = d->matrix.isIdentity();
    d->transforming = true;
    if (d->scene) {
        d->recalculateContentSize();
        d->centerView(d->transformationAnchor);
    } else {
        d->updateLastCenterPoint();
    }

    if (d->sceneInteractionAllowed)
        d->replayLastMouseEvent();
    d->transforming = false;

    // Any matrix operation requires a full update.
    d->updateAll();
}

/*!
    Resets the view transformation to the identity matrix.

    \sa transform(), setTransform()
*/
void QGraphicsView::resetTransform()
{
    setTransform(QTransform());
}

QPointF QGraphicsViewPrivate::mapToScene(const QPointF &point) const
{
    QPointF p = point;
    p.rx() += horizontalScroll();
    p.ry() += verticalScroll();
    return identityMatrix ? p : matrix.inverted().map(p);
}

QRectF QGraphicsViewPrivate::mapToScene(const QRectF &rect) const
{
    QPointF scrollOffset(horizontalScroll(), verticalScroll());
    QPointF tl = scrollOffset + rect.topLeft();
    QPointF tr = scrollOffset + rect.topRight();
    QPointF br = scrollOffset + rect.bottomRight();
    QPointF bl = scrollOffset + rect.bottomLeft();

    QPolygonF poly(4);
    if (!identityMatrix) {
        QTransform x = matrix.inverted();
        poly[0] = x.map(tl);
        poly[1] = x.map(tr);
        poly[2] = x.map(br);
        poly[3] = x.map(bl);
    } else {
        poly[0] = tl;
        poly[1] = tr;
        poly[2] = br;
        poly[3] = bl;
    }
    return poly.boundingRect();
}

QT_END_NAMESPACE

#include "moc_qgraphicsview.cpp"

#endif // QT_NO_GRAPHICSVIEW