summaryrefslogtreecommitdiffstats
path: root/doc/text.n
blob: e2871d188d8ec2a632de450b2ca6d7beddb7b6fa (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
'\"
'\" Copyright (c) 1992 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
'\" RCS: @(#) $Id: text.n,v 1.16 2003/05/19 13:04:22 vincentdarley Exp $
'\" 
.so man.macros
.TH text n 8.4 Tk "Tk Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
text, tk_textCopy, tk_textCut, tk_textPaste \- Create and manipulate text widgets
.SH SYNOPSIS
.nf
\fBtext\fR \fIpathName \fR?\fIoptions\fR?
.VS 8.4
\fBtk_textCopy\fR \fIpathName\fR
\fBtk_textCut\fR \fIpathName\fR
\fBtk_textPaste\fR \fIpathName\fR
.VE 8.4
.SO
\-background	\-highlightthickness	\-relief
\-borderwidth	\-insertbackground	\-selectbackground
\-cursor	\-insertborderwidth	\-selectborderwidth
\-exportselection	\-insertofftime	\-selectforeground
\-font	\-insertontime	\-setgrid
\-foreground	\-insertwidth	\-takefocus
\-highlightbackground	\-padx	\-xscrollcommand
\-highlightcolor	\-pady	\-yscrollcommand
.SE
.SH "WIDGET-SPECIFIC OPTIONS"
.OP \-autoseparators autoSeparators AutoSeparators
.VS 8.4
Specifies a boolean that says whether separators are automatically
inserted in the undo stack. Only meaningful when the \fB\-undo\fR
option is true.
.VE 8.4
.OP \-height height Height
Specifies the desired height for the window, in units of characters
in the font given by the \fB\-font\fR option.
Must be at least one.
.OP \-maxundo maxUndo MaxUndo
.VS 8.4
Specifies the maximum number of compound undo actions on the undo
stack. A zero or a negative value imply an unlimited undo stack.
.VE 8.4
.OP \-spacing1 spacing1 Spacing1
Requests additional space above each text line in the widget,
using any of the standard forms for screen distances.
If a line wraps, this option only applies to the first line
on the display.
This option may be overriden with \fB\-spacing1\fR options in
tags.
.OP \-spacing2 spacing2 Spacing2
For lines that wrap (so that they cover more than one line on the
display) this option specifies additional space to provide between
the display lines that represent a single line of text.
The value may have any of the standard forms for screen distances.
This option may be overriden with \fB\-spacing2\fR options in
tags.
.OP \-spacing3 spacing3 Spacing3
Requests additional space below each text line in the widget,
using any of the standard forms for screen distances.
If a line wraps, this option only applies to the last line
on the display.
This option may be overriden with \fB\-spacing3\fR options in
tags.
.OP \-state state State
Specifies one of two states for the text:  \fBnormal\fR or \fBdisabled\fR.
If the text is disabled then characters may not be inserted or deleted
and no insertion cursor will be displayed, even if the input focus is
in the widget.
.OP \-tabs tabs Tabs
Specifies a set of tab stops for the window.  The option's value consists
of a list of screen distances giving the positions of the tab stops.  Each
position may optionally be followed in the next list element
by one of the keywords \fBleft\fR, \fBright\fR, \fBcenter\fR,
or \fBnumeric\fR, which specifies how to justify
text relative to the tab stop.  \fBLeft\fR is the default; it causes
the text following the tab character to be positioned with its left edge
at the tab position.  \fBRight\fR means that the right edge of the text
following the tab character is positioned at the tab position, and
\fBcenter\fR means that the text is centered at the tab position.
\fBNumeric\fR means that the decimal point in the text is positioned
at the tab position;  if there is no decimal point then the least
significant digit of the number is positioned just to the left of the
tab position;  if there is no number in the text then the text is
right-justified at the tab position.
For example, \fB\-tabs {2c left 4c 6c center}\fR creates three
tab stops at two-centimeter intervals;  the first two use left
justification and the third uses center justification.
If the list of tab stops does not have enough elements to cover all
of the tabs in a text line, then Tk extrapolates new tab stops using
the spacing and alignment from the last tab stop in the list.
The value of the \fBtabs\fR option may be overridden by \fB\-tabs\fR
options in tags.
If no \fB\-tabs\fR option is specified, or if it is specified as
an empty list, then Tk uses default tabs spaced every eight
(average size) characters.
.OP \-undo undo Undo
.VS 8.4
Specifies a boolean that says whether the undo mechanism is active or
not.
.VE 8.4
.OP \-width width Width
Specifies the desired width for the window in units of characters
in the font given by the \fB\-font\fR option.
If the font doesn't have a uniform width then the width of the
character ``0'' is used in translating from character units to
screen units.
.OP \-wrap wrap Wrap
Specifies how to handle lines in the text that are too long to be
displayed in a single line of the text's window.
The value must be \fBnone\fR or \fBchar\fR or \fBword\fR.
A wrap mode of \fBnone\fR means that each line of text appears as
exactly one line on the screen;  extra characters that don't fit
on the screen are not displayed.
In the other modes each line of text will be broken up into several
screen lines if necessary to keep all the characters visible.
In \fBchar\fR mode a screen line break may occur after any character;
in \fBword\fR mode a line break will only be made at word boundaries.
.BE

.SH DESCRIPTION
.PP
The \fBtext\fR command creates a new window (given by the
\fIpathName\fR argument) and makes it into a text widget.
Additional
options, described above, may be specified on the command line
or in the option database
to configure aspects of the text such as its default background color
and relief.  The \fBtext\fR command returns the
path name of the new window.
.PP
A text widget displays one or more lines of text and allows that
text to be edited.
Text widgets support four different kinds of annotations on the
text, called tags, marks, embedded windows or embedded images.
Tags allow different portions of the text
to be displayed with different fonts and colors.
In addition, Tcl commands can be associated with tags so
that scripts are invoked when particular actions such as keystrokes
and mouse button presses occur in particular ranges of the text.
See TAGS below for more details.
.PP
The second form of annotation consists of marks, which are floating
markers in the text.
Marks are used to keep track of various interesting positions in the
text as it is edited.
See MARKS below for more details.
.PP
The third form of annotation allows arbitrary windows to be
embedded in a text widget.
See EMBEDDED WINDOWS below for more details.
.PP
The fourth form of annotation allows Tk images to be embedded in a text
widget.
See EMBEDDED IMAGES below for more details.
.PP
.VS 8.4
The text widget also has a built-in undo/redo mechanism.
See UNDO MECHANISM below for more details.
.VE 8.4

.SH INDICES
.PP
Many of the widget commands for texts take one or more indices
as arguments.
An index is a string used to indicate a particular place within
a text, such as a place to insert characters or one endpoint of a
range of characters to delete.
Indices have the syntax
.CS
\fIbase modifier modifier modifier ...\fR
.CE
Where \fIbase\fR gives a starting point and the \fImodifier\fRs
adjust the index from the starting point (e.g. move forward or
backward one character).  Every index must contain a \fIbase\fR,
but the \fImodifier\fRs are optional.
.PP
The \fIbase\fR for an index must have one of the following forms:
.TP 12
\fIline\fB.\fIchar\fR
Indicates \fIchar\fR'th character on line \fIline\fR.
Lines are numbered from 1 for consistency with other UNIX programs
that use this numbering scheme.
Within a line, characters are numbered from 0.
If \fIchar\fR is \fBend\fR then it refers to the newline character
that ends the line.
.TP 12
\fB@\fIx\fB,\fIy\fR
Indicates the character that covers the pixel whose x and y coordinates
within the text's window are \fIx\fR and \fIy\fR.
.TP 12
\fBend\fR
Indicates the end of the text (the character just after the last
newline).
.TP 12
\fImark\fR
Indicates the character just after the mark whose name is \fImark\fR.
.TP 12
\fItag\fB.first\fR
Indicates the first character in the text that has been tagged with
\fItag\fR.
This form generates an error if no characters are currently tagged
with \fItag\fR.
.TP 12
\fItag\fB.last\fR
Indicates the character just after the last one in the text that has
been tagged with \fItag\fR.
This form generates an error if no characters are currently tagged
with \fItag\fR.
.TP 12
\fIpathName\fR
Indicates the position of the embedded window whose name is
\fIpathName\fR.
This form generates an error if there is no embedded window
by the given name.
.TP 12
\fIimageName\fR
Indicates the position of the embedded image whose name is
\fIimageName\fR.
This form generates an error if there is no embedded image
by the given name.
.PP
If the \fIbase\fP could match more than one of the above forms, such
as a \fImark\fP and \fIimageName\fP both having the same value, then
the form earlier in the above list takes precedence.
If modifiers follow the base index, each one of them must have one
of the forms listed below.  Keywords such as \fBchars\fR and \fBwordend\fR
may be abbreviated as long as the abbreviation is unambiguous.
.TP
\fB+ \fIcount\fB chars\fR
Adjust the index forward by \fIcount\fR characters, moving to later
lines in the text if necessary.  If there are fewer than \fIcount\fR
characters in the text after the current index, then set the index
to the last character in the text.
Spaces on either side of \fIcount\fR are optional.
.TP
\fB\- \fIcount\fB chars\fR
Adjust the index backward by \fIcount\fR characters, moving to earlier
lines in the text if necessary.  If there are fewer than \fIcount\fR
characters in the text before the current index, then set the index
to the first character in the text.
Spaces on either side of \fIcount\fR are optional.
.TP
\fB+ \fIcount\fB lines\fR
Adjust the index forward by \fIcount\fR lines, retaining the same
character position within the line.  If there are fewer than \fIcount\fR
lines after the line containing the current index, then set the index
to refer to the same character position on the last line of the text.
Then, if the line is not long enough to contain a character at the indicated
character position, adjust the character position to refer to the last
character of the line (the newline).
Spaces on either side of \fIcount\fR are optional.
.TP
\fB\- \fIcount\fB lines\fR
Adjust the index backward by \fIcount\fR lines, retaining the same
character position within the line.  If there are fewer than \fIcount\fR
lines before the line containing the current index, then set the index
to refer to the same character position on the first line of the text.
Then, if the line is not long enough to contain a character at the indicated
character position, adjust the character position to refer to the last
character of the line (the newline).
Spaces on either side of \fIcount\fR are optional.
.TP
\fBlinestart\fR
Adjust the index to refer to the first character on the line.
.TP
\fBlineend\fR
Adjust the index to refer to the last character on the line (the newline).
.TP
\fBwordstart\fR
Adjust the index to refer to the first character of the word containing
the current index.  A word consists of any number of adjacent characters
that are letters, digits, or underscores, or a single character that
is not one of these.
.TP
\fBwordend\fR
Adjust the index to refer to the character just after the last one of the
word containing the current index.  If the current index refers to the last
character of the text then it is not modified.
.PP
If more than one modifier is present then they are applied in
left-to-right order.  For example, the index ``\fBend \- 1 chars\fR''
refers to the next-to-last character in the text and
``\fBinsert wordstart \- 1 c\fR'' refers to the character just before
the first one in the word containing the insertion cursor.

.SH TAGS
.PP
The first form of annotation in text widgets is a tag.
A tag is a textual string that is associated with some of the characters
in a text.
Tags may contain arbitrary characters, but it is probably best to
avoid using the the characters `` '' (space), \fB+\fR, or \fB\-\fR:
these characters have special meaning in indices, so tags containing
them can't be used as indices.
There may be any number of tags associated with characters in a
text.
Each tag may refer to a single character, a range of characters, or
several ranges of characters.
An individual character may have any number of tags associated with it.
.PP
A priority order is defined among tags, and this order is used in
implementing some of the tag-related functions described below.
When a tag is defined (by associating it with characters or setting
its display options or binding commands to it), it is given
a priority higher than any existing tag.
The priority order of tags may be redefined using the
``\fIpathName \fBtag raise\fR'' and ``\fIpathName \fBtag lower\fR''
widget commands.
.PP
Tags serve three purposes in text widgets.
First, they control the way information is displayed on the screen.
By default, characters are displayed as determined by the
\fBbackground\fR, \fBfont\fR, and \fBforeground\fR options for the
text widget.
However, display options may be associated with individual tags
using the ``\fIpathName \fBtag configure\fR'' widget command.
If a character has been tagged, then the display options associated
with the tag override the default display style.
The following options are currently supported for tags:
.TP
\fB\-background \fIcolor\fR
\fIColor\fR specifies the background color to use for characters
associated with the tag.
It may have any of the forms accepted by \fBTk_GetColor\fR.
.TP
\fB\-bgstipple \fIbitmap\fR
\fIBitmap\fR specifies a bitmap that is used as a stipple pattern
for the background.
It may have any of the forms accepted by \fBTk_GetBitmap\fR.
If \fIbitmap\fR hasn't been specified, or if it is specified
as an empty string, then a solid fill will be used for the
background.
.TP
\fB\-borderwidth \fIpixels\fR
\fIPixels\fR specifies the width of a 3-D border to draw around
the background.
It may have any of the forms accepted by \fBTk_GetPixels\fR.
This option is used in conjunction with the \fB\-relief\fR
option to give a 3-D appearance to the background for characters;
it is ignored unless the \fB\-background\fR option
has been set for the tag.
.TP
\fB\-elide \fIboolean\fR
\fIElide\fR specifies whether the data should be elided.
Elided data is not displayed and takes no space on screen, but further
on behaves just as normal data.
.TP
\fB\-fgstipple \fIbitmap\fR
\fIBitmap\fR specifies a bitmap that is used as a stipple pattern
when drawing text and other foreground information such as
underlines.
It may have any of the forms accepted by \fBTk_GetBitmap\fR.
If \fIbitmap\fR hasn't been specified, or if it is specified
as an empty string, then a solid fill will be used.
.TP
\fB\-font \fIfontName\fR
\fIFontName\fR is the name of a font to use for drawing characters.
It may have any of the forms accepted by \fBTk_GetFont\fR.
.TP
\fB\-foreground \fIcolor\fR
\fIColor\fR specifies the color to use when drawing text and other
foreground information such as underlines.
It may have any of the forms accepted by \fBTk_GetColor\fR.
.TP
\fB\-justify \fIjustify\fR
If the first character of a display line has a tag for which this
option has been specified, then \fIjustify\fR determines how to
justify the line.
It must be one of \fBleft\fR, \fBright\fR, or \fBcenter\fR.
If a line wraps, then the justification for each line on the
display is determined by the first character of that display line.
.TP
\fB\-lmargin1 \fIpixels\fR
If the first character of a text line has a tag for which this
option has been specified, then \fIpixels\fR specifies how
much the line should be indented from the left edge of the
window.
\fIPixels\fR may have any of the standard forms for screen
distances.
If a line of text wraps, this option only applies to the
first line on the display;  the \fB\-lmargin2\fR option controls
the indentation for subsequent lines.
.TP
\fB\-lmargin2 \fIpixels\fR
If the first character of a display line has a tag for which this
option has been specified, and if the display line is not the
first for its text line (i.e., the text line has wrapped), then
\fIpixels\fR specifies how much the line should be indented from
the left edge of the window.
\fIPixels\fR may have any of the standard forms for screen
distances.
This option is only used when wrapping is enabled, and it only
applies to the second and later display lines for a text line.
.TP
\fB\-offset \fIpixels\fR
\fIPixels\fR specifies an amount by which the text's baseline
should be offset vertically from the baseline of the overall
line, in pixels.
For example, a positive offset can be used for superscripts
and a negative offset can be used for subscripts.
\fIPixels\fR may have any of the standard forms for screen
distances.
.TP
\fB\-overstrike \fIboolean\fR
Specifies whether or not to draw a horizontal rule through
the middle of characters.
\fIBoolean\fR may have any of the forms accepted by \fBTk_GetBoolean\fR.
.TP
\fB\-relief \fIrelief\fR
\fIRelief\fR specifies the 3-D relief to use for drawing backgrounds,
in any of the forms accepted by \fBTk_GetRelief\fR.
This option is used in conjunction with the \fB\-borderwidth\fR
option to give a 3-D appearance to the background for characters;
it is ignored unless the \fB\-background\fR option
has been set for the tag.
.TP
\fB\-rmargin \fIpixels\fR
If the first character of a display line has a tag for which this
option has been specified, then \fIpixels\fR specifies how wide
a margin to leave between the end of the line and the right
edge of the window.
\fIPixels\fR may have any of the standard forms for screen
distances.
This option is only used when wrapping is enabled.
If a text line wraps, the right margin for each line on the
display is determined by the first character of that display
line.
.TP
\fB\-spacing1 \fIpixels\fR
\fIPixels\fR specifies how much additional space should be
left above each text line, using any of the standard forms for
screen distances.
If a line wraps, this option only applies to the first
line on the display.
.TP
\fB\-spacing2 \fIpixels\fR
For lines that wrap, this option specifies how much additional
space to leave between the display lines for a single text line.
\fIPixels\fR may have any of the standard forms for screen
distances.
.TP
\fB\-spacing3 \fIpixels\fR
\fIPixels\fR specifies how much additional space should be
left below each text line, using any of the standard forms for
screen distances.
If a line wraps, this option only applies to the last
line on the display.
.TP
\fB\-tabs \fItabList\fR
\fITabList\fR specifies a set of tab stops in the same form
as for the \fB\-tabs\fR option for the text widget.  This
option only applies to a display line if it applies to the
first character on that display line.
If this option is specified as an empty string, it cancels
the option, leaving it unspecified for the tag (the default).
If the option is specified as a non-empty string that is
an empty list, such as \fB\-tags\0{\0}\fR, then it requests
default 8-character tabs as described for the \fBtags\fR
widget option.
.TP
\fB\-underline \fIboolean\fR
\fIBoolean\fR specifies whether or not to draw an underline underneath
characters.
It may have any of the forms accepted by \fBTk_GetBoolean\fR.
.TP
\fB\-wrap \fImode\fR
\fIMode\fR specifies how to handle lines that are wider than the
text's window.
It has the same legal values as the \fB\-wrap\fR option
for the text widget:  \fBnone\fR, \fBchar\fR, or \fBword\fR.
If this tag option is specified, it overrides the \fB\-wrap\fR option
for the text widget.
.PP
If a character has several tags associated with it, and if their
display options conflict, then the options of the highest priority
tag are used.
If a particular display option hasn't been specified for a
particular tag, or if it is specified as an empty string, then
that option will never be used;  the next-highest-priority
tag's option will used instead.
If no tag specifies a particular display option, then the default
style for the widget will be used.
.PP
The second purpose for tags is event bindings.
You can associate bindings with a tag in much the same way you can
associate bindings with a widget class:  whenever particular X
events occur on characters with the given tag, a given
Tcl command will be executed.
Tag bindings can be used to give behaviors to ranges of characters;
among other things, this allows hypertext-like
features to be implemented.
For details, see the description of the \fBtag bind\fR widget
command below.
.PP
The third use for tags is in managing the selection.
See THE SELECTION below.

.SH MARKS
.PP
The second form of annotation in text widgets is a mark.
Marks are used for remembering particular places in a text.
They are something like tags, in that they have names and
they refer to places in the file, but a mark isn't associated
with particular characters.
Instead, a mark is associated with the gap between two characters.
Only a single position may be associated with a mark at any given
time.
If the characters around a mark are deleted the mark will still
remain;  it will just have new neighbor characters.
In contrast, if the characters containing a tag are deleted then
the tag will no longer have an association with characters in
the file.
Marks may be manipulated with the ``\fIpathName \fBmark\fR'' widget
command, and their current locations may be determined by using the
mark name as an index in widget commands.
.PP
Each mark also has a \fIgravity\fR, which is either \fBleft\fR or
\fBright\fR.
The gravity for a mark specifies what happens to the mark when
text is inserted at the point of the mark.
If a mark has left gravity, then the mark is treated as if it
were attached to the character on its left, so the mark will
remain to the left of any text inserted at the mark position.
If the mark has right gravity, new text inserted at the mark
position will appear to the left of the mark (so that the mark
remains rightmost).  The gravity for a mark defaults to \fBright\fR.
.PP
The name space for marks is different from that for tags:  the
same name may be used for both a mark and a tag, but they will refer
to different things.
.PP
Two marks have special significance.
First, the mark \fBinsert\fR is associated with the insertion cursor,
as described under THE INSERTION CURSOR below.
Second, the mark \fBcurrent\fR is associated with the character
closest to the mouse and is adjusted automatically to track the
mouse position and any changes to the text in the widget (one
exception:  \fBcurrent\fR is not updated in response to mouse
motions if a mouse button is down;  the update will be deferred
until all mouse buttons have been released).
Neither of these special marks may be deleted.

.SH "EMBEDDED WINDOWS"
.PP
The third form of annotation in text widgets is an embedded window.
Each embedded window annotation causes a window to be displayed
at a particular point in  the text.
There may be any number of embedded windows in a text widget,
and any widget may be used as an embedded window (subject to the
usual rules for geometry management, which require the text window
to be the parent of the embedded window or a descendant of its
parent).
The embedded window's position on the screen will be updated as the
text is modified or scrolled, and it will be mapped and unmapped as
it moves into and out of the visible area of the text widget.
Each embedded window occupies one character's worth of index space
in the text widget, and it may be referred to either by the name
of its embedded window or by its position in the widget's
index space.
If the range of text containing the embedded window is deleted then
the window is destroyed.
.PP
When an embedded window is added to a text widget with the
\fBwindow create\fR widget command, several configuration
options may be associated with it.
These options may be  modified later with the \fBwindow configure\fR
widget command.
The following options are currently supported:
.TP
\fB\-align \fIwhere\fR
If the window is not as tall as the line in which it is displayed,
this option determines where the window is displayed in the line.
\fIWhere\fR must have one of the values \fBtop\fR (align the top of the window
with the top of the line), \fBcenter\fR (center the window
within the range of the line), \fBbottom\fR (align the bottom of the
window with the bottom of the line's area),
or \fBbaseline\fR (align the bottom of the window with the baseline
of the line).
.TP
\fB\-create \fIscript\fR
Specifies a Tcl script that may be evaluated to create the window
for the annotation.
If no \fB\-window\fR option has been specified for the annotation
this script will be evaluated when the annotation is about to
be displayed on the screen.
\fIScript\fR must create a window for the annotation and return
the name of that window as its result.
If the annotation's window should ever be deleted, \fIscript\fR
will be evaluated again the next time the annotation is displayed.
.TP
\fB\-padx \fIpixels\fR
\fIPixels\fR specifies the amount of extra space to leave on
each side of the embedded window.
It may have any of the usual forms defined for a screen distance.
.TP
\fB\-pady \fIpixels\fR
\fIPixels\fR specifies the amount of extra space to leave on
the top and on the bottom of the embedded window.
It may have any of the usual forms defined for a screen distance.
.TP
\fB\-stretch \fIboolean\fR
If the requested height of the embedded window is less than the
height of the line in which it is displayed, this option can be
used to specify whether the window should be stretched vertically
to fill its line.
If the \fB\-pady\fR option has been specified as well, then the
requested padding will be retained even if the window is
stretched.
.TP
\fB\-window \fIpathName\fR
Specifies the name of a window to display in the annotation.

.SH "EMBEDDED IMAGES"
.PP
The final form of annotation in text widgets is an embedded image.
Each embedded image annotation causes an image to be displayed
at a particular point in  the text.
There may be any number of embedded images in a text widget,
and a particular image may be embedded in multiple places in the same
text widget.
The embedded image's position on the screen will be updated as the
text is modified or scrolled.
Each embedded image occupies one character's worth of index space
in the text widget, and it may be referred to either by
its position in the widget's index space, or the name it is assigned
when the image is inserted into the text widget widh \fBimage create\fP.
If the range of text containing the embedded image is deleted then
that copy of the image is removed from the screen.
.PP
When an embedded image is added to a text widget with the \fBimage
create\fR widget command, a name unique to this instance of the image
is returned.  This name may then be used to refer to this image
instance.  The name is taken to be the value of the \fB-name\fP option
(described below).  If the \fB-name\fP option is not provided, the
\fB-image\fP name is used instead.  If the \fIimageName\fP is already
in use in the text widget, then \fB#\fInn\fR is added to the end of the
\fIimageName\fP, where \fInn\fP is an arbitrary integer.  This insures
the \fIimageName\fP is unique.
Once this name is assigned to this instance of the image, it does not 
change, even though the \fB-image\fP or \fB-name\fP values can be changed
with \fBimage configure\fP.
.PP
When an embedded image is added to a text widget with the
\fBimage create\fR widget command, several configuration
options may be associated with it.
These options may be modified later with the \fBimage configure\fR
widget command.
The following options are currently supported:
.TP
\fB\-align \fIwhere\fR
If the image is not as tall as the line in which it is displayed,
this option determines where the image is displayed in the line.
\fIWhere\fR must have one of the values \fBtop\fR (align the top of the image
with the top of the line), \fBcenter\fR (center the image
within the range of the line), \fBbottom\fR (align the bottom of the
image with the bottom of the line's area),
or \fBbaseline\fR (align the bottom of the image with the baseline
of the line).
.TP
\fB\-image \fIimage\fR
Specifies the name of the Tk image to display in the annotation.
If \fIimage\fP is not a valid Tk image, then an error is returned.
.TP
\fB\-name \fIImageName\fR
Specifies the name by which this image instance may be referenced in
the text widget. If \fIImageName\fP is not supplied, then the
name of the Tk image is used instead.
If the \fIimageName\fP is already in use, \fI#nn\fP is appended to
the end of the name as described above.
.TP
\fB\-padx \fIpixels\fR
\fIPixels\fR specifies the amount of extra space to leave on
each side of the embedded image.
It may have any of the usual forms defined for a screen distance.
.TP
\fB\-pady \fIpixels\fR
\fIPixels\fR specifies the amount of extra space to leave on
the top and on the bottom of the embedded image.
It may have any of the usual forms defined for a screen distance.

.SH "THE SELECTION"
.PP
Selection support is implemented via tags.
If the \fBexportSelection\fR option for the text widget is true
then the \fBsel\fR tag will be associated with the selection:
.IP [1]
Whenever characters are tagged with \fBsel\fR the text widget
will claim ownership of the selection.
.IP [2]
Attempts to retrieve the
selection will be serviced by the text widget, returning all the
characters with the \fBsel\fR tag.
.IP [3]
If the selection is claimed away by another application or by another
window within this application, then the \fBsel\fR tag will be removed
from all characters in the text.
.IP [4]
Whenever the \fBsel\fR tag range changes a virtual event 
\fB<<Selection>>\fR is generated.
.PP
The \fBsel\fR tag is automatically defined when a text widget is
created, and it may not be deleted with the ``\fIpathName \fBtag delete\fR''
widget command.  Furthermore, the \fBselectBackground\fR,
\fBselectBorderWidth\fR, and \fBselectForeground\fR options for
the text widget are tied to the \fB\-background\fR,
\fB\-borderwidth\fR, and \fB\-foreground\fR options for the \fBsel\fR
tag:  changes in either will automatically be reflected in the
other.

.SH "THE INSERTION CURSOR"
.PP
The mark named \fBinsert\fR has special significance in text widgets.
It is defined automatically when a text widget is created and it
may not be unset with the ``\fIpathName \fBmark unset\fR'' widget
command.
The \fBinsert\fR mark represents the position of the insertion
cursor, and the insertion cursor will automatically be drawn at
this point whenever the text widget has the input focus.

.SH "THE MODIFIED FLAG"
The text widget can keep track of changes to the content of the widget
by means of the modified flag. Inserting or deleting text will set
this flag. The flag can be queried, set and cleared programatically
as well. Whenever the flag changes state a \fB<<Modified>>\fR virtual 
event is generated. See the \fBedit modified\fR widget command for 
more details.

.SH "THE UNDO MECHANISM"
.PP
.VS 8.4
The text widget has an unlimited undo and redo mechanism (when the
\fB-undo\fR widget option is true) which records every insert and
delete action on a stack.
.PP
Boundaries (called "separators") are inserted between edit actions.
The purpose of these separators is to group inserts and deletes into
one compound edit action.  When undoing a change everything between
two separators will be undone.  The undone changes are then moved to
the redo stack, so that an undone edit can be redone again.  The redo
stack is cleared whenever new edit actions are recorded on the undo
stack.  The undo and redo stacks can be cleared to keep their depth
under control.
.PP
Separators are inserted automatically when the \fB-autoseparators\fR
widget option is true.  You can insert separators programatically as
well.  If a separator is already present at the top of the undo stack
no other will be inserted.  That means that two separators on the undo
stack are always separated by at least one insert or delete action.
.PP
The undo mechanism is also linked to the modified flag.  This means
that undoing or redoing changes can take a modified text widget back
to the unmodified state or vice versa.  The modified flag will be set
automatically to the appropriate state.  This automatic coupling
does not work when the modified flag has been set by the user, until
the flag has been reset again.
.PP
See below for the \fBedit\fR widget command that controls the undo
mechanism.
.VE 8.4

.SH "WIDGET COMMAND"
.PP
The \fBtext\fR command creates a new Tcl command whose
name is the same as the path name of the text's window.  This
command may be used to invoke various
operations on the widget.  It has the following general form:
.CS
\fIpathName option \fR?\fIarg arg ...\fR?
.CE
\fIPathName\fR is the name of the command, which is the same as
the text widget's path name.  \fIOption\fR and the \fIarg\fRs
determine the exact behavior of the command.  The following
commands are possible for text widgets:
.TP
\fIpathName \fBbbox \fIindex\fR
Returns a list of four elements describing the screen area
of the character given by \fIindex\fR.
The first two elements of the list give the x and y coordinates
of the upper-left corner of the area occupied by the
character, and the last two elements give the width and height
of the area.
If the character is only partially visible on the screen, then
the return value reflects just the visible part.
If the character is not visible on the screen then the return
value is an empty list.
.TP
\fIpathName \fBcget\fR \fIoption\fR
Returns the current value of the configuration option given
by \fIoption\fR.
\fIOption\fR may have any of the values accepted by the \fBtext\fR
command.
.TP
\fIpathName \fBcompare\fR \fIindex1 op index2\fR
Compares the indices given by \fIindex1\fR and \fIindex2\fR according
to the relational operator given by \fIop\fR, and returns 1 if
the relationship is satisfied and 0 if it isn't.
\fIOp\fR must be one of the operators <, <=, ==, >=, >, or !=.
If \fIop\fR is == then 1 is returned if the two indices refer to
the same character, if \fIop\fR is < then 1 is returned if \fIindex1\fR
refers to an earlier character in the text than \fIindex2\fR, and
so on.
.TP
\fIpathName \fBconfigure\fR ?\fIoption\fR? \fI?value option value ...\fR?
Query or modify the configuration options of the widget.
If no \fIoption\fR is specified, returns a list describing all of
the available options for \fIpathName\fR (see \fBTk_ConfigureInfo\fR for
information on the format of this list).  If \fIoption\fR is specified
with no \fIvalue\fR, then the command returns a list describing the
one named option (this list will be identical to the corresponding
sublist of the value returned if no \fIoption\fR is specified).  If
one or more \fIoption\-value\fR pairs are specified, then the command
modifies the given widget option(s) to have the given value(s);  in
this case the command returns an empty string.
\fIOption\fR may have any of the values accepted by the \fBtext\fR
command.
.TP
\fIpathName \fBdebug \fR?\fIboolean\fR?
If \fIboolean\fR is specified, then it must have one of the true or
false values accepted by Tcl_GetBoolean.
If the value is a true one then internal consistency checks will be
turned on in the B-tree code associated with text widgets.
If \fIboolean\fR has a false value then the debugging checks will
be turned off.
In either case the command returns an empty string.
If \fIboolean\fR is not specified then the command returns \fBon\fR
or \fBoff\fR to indicate whether or not debugging is turned on.
There is a single debugging switch shared by all text widgets:  turning
debugging on or off in any widget turns it on or off for all widgets.
For widgets with large amounts of text, the consistency checks may
cause a noticeable slow-down.
.PP
.VS 8.4
When debugging is turned on, the drawing routines of the text widget
set the global variables \fBtk_textRedraw\fR and \fBtk_textRelayout\fR
to the lists of indices that are redrawn.  The values of these variables
are tested by Tk's test suite.
.VE 8.4
.TP
\fIpathName \fBdelete \fIindex1 \fR?\fIindex2 ...\fR?
Delete a range of characters from the text.
If both \fIindex1\fR and \fIindex2\fR are specified, then delete
all the characters starting with the one given by \fIindex1\fR
and stopping just before \fIindex2\fR (i.e. the character at
\fIindex2\fR is not deleted).
If \fIindex2\fR doesn't specify a position later in the text
than \fIindex1\fR then no characters are deleted.
If \fIindex2\fR isn't specified then the single character at
\fIindex1\fR is deleted.
It is not allowable to delete characters in a way that would leave
the text without a newline as the last character.
The command returns an empty string.
.VS 8.4
If more indices are given, multiple ranges of text will be deleted.
All indices are first checked for validity before any deletions are made.
They are sorted and the text is removed from the last range to the
first range to deleted text does not cause a undesired index shifting
side-effects.  If multiple ranges with the same start index are given,
then the longest range is used.  If overlapping ranges are given, then
they will be merged into spans that do not cause deletion of text
outside the given ranges due to text shifted during deletion.
.VE 8.4
.TP
\fIpathName \fBdlineinfo \fIindex\fR
Returns a list with five elements describing the area occupied
by the display line containing \fIindex\fR.
The first two elements of the list give the x and y coordinates
of the upper-left corner of the area occupied by the
line, the third and fourth elements give the width and height
of the area, and the fifth element gives the position of the baseline
for the line, measured down from the top of the area.
All of this information is measured in pixels.
If the current wrap mode is \fBnone\fR and the line extends beyond
the boundaries of the window,
the area returned reflects the entire area of the line, including the
portions that are out of the window.
If the line is shorter than the full width of the window then the
area returned reflects just the portion of the line that is occupied
by characters and embedded windows.
If the display line containing \fIindex\fR is not visible on
the screen then the return value is an empty list.
.TP
\fIpathName \fBdump \fR?\fIswitches\fR? \fIindex1 \fR?\fIindex2\fR?
Return the contents of the text widget from \fIindex1\fR up to,
but not including \fIindex2\fR,
including the text and
information about marks, tags, and embedded windows.
If \fIindex2\fR is not specified, then it defaults to
one character past \fIindex1\fR.  The information is returned
in the following format:
.LP
.RS
\fIkey1 value1 index1 key2 value2 index2\fR ...
.LP
The possible \fIkey\fP values are \fBtext\fP, \fBmark\fP,
\fBtagon\fP, \fBtagoff\fP, and \fBwindow\fP.  The corresponding
\fIvalue\fP is the text, mark name, tag name, or window name.
The \fIindex\fP information is the index of the
start of the text, the mark, the tag transition, or the window.
One or more of the following switches (or abbreviations thereof)
may be specified to control the dump:
.TP
\fB\-all\fR
Return information about all elements: text, marks, tags, images and windows.
This is the default.
.TP
\fB\-command \fIcommand\fR
Instead of returning the information as the result of the dump operation,
invoke the \fIcommand\fR on each element of the text widget within the range.
The command has three arguments appended to it before it is evaluated:
the \fIkey\fP, \fIvalue\fP, and \fIindex\fP.
.TP
\fB\-image\fR
Include information about images in the dump results.
.TP
\fB\-mark\fR
Include information about marks in the dump results.
.TP
\fB\-tag\fR
Include information about tag transitions in the dump results. Tag
information is returned as \fBtagon\fP and \fBtagoff\fP elements that
indicate the begin and end of each range of each tag, respectively.
.TP
\fB\-text\fR
Include information about text in the dump results.  The value is the
text up to the next element or the end of range indicated by \fIindex2\fR.
A text element does not span newlines.  A multi-line block of text that
contains no marks or tag transitions will still be dumped as a set
of text seqments that each end with a newline.  The newline is part
of the value.
.TP
\fB\-window\fR
Include information about embedded windows in the dump results.
The value of a window is its Tk pathname, unless the window
has not been created yet.  (It must have a create script.)
In this case an empty string is returned, and you must query the
window by its index position to get more information.
.RE
.TP
\fIpathName \fBedit \fIoption \fR?\fIarg arg ...\fR?
.VS 8.4
This command controls the undo mechanism and the modified flag.  The
exact behavior of the command depends on the \fIoption\fR argument
that follows the \fBedit\fR argument.  The following forms of the
command are currently supported:
.RS
.TP
\fIpathName \fBedit modified ?\fIboolean\fR?
If \fIboolean\fR is not specified, returns the modified flag of the
widget. The insert, delete, edit undo and edit redo commands or the
user can set or clear the modified flag.  If \fIboolean\fR is
specified, sets the modified flag of the widget to \fIboolean\fR.
.TP
\fIpathName \fBedit redo\fR
When the \fB-undo\fR option is true, reapplies the last undone edits
provided no other edits were done since then. Generates an error when
the redo stack is empty.  Does nothing when the \fB-undo\fR option is
false.
.TP
\fIpathName \fBedit reset\fR
Clears the undo and redo stacks.
.TP
\fIpathName \fBedit separator\fR
Inserts a separator (boundary) on the undo stack. Does nothing when
the \fB-undo\fR option is false.
.TP
\fIpathName \fBedit undo\fR
Undoes the last edit action when the \fB-undo\fR option is true.  An
edit action is defined as all the insert and delete commands that are
recorded on the undo stack in between two separators. Generates an
error when the undo stack is empty.  Does nothing when the \fB-undo\fR
option is false.
.RE
.VE 8.4
.TP
\fIpathName \fBget \fIindex1 \fR?\fIindex2 ...\fR?
Return a range of characters from the text.
The return value will be all the characters in the text starting
with the one whose index is \fIindex1\fR and ending just before
the one whose index is \fIindex2\fR (the character at \fIindex2\fR
will not be returned).
If \fIindex2\fR is omitted then the single character at \fIindex1\fR
is returned.
If there are no characters in the specified range (e.g. \fIindex1\fR
is past the end of the file or \fIindex2\fR is less than or equal
to \fIindex1\fR) then an empty string is returned.
If the specified range contains embedded windows, no information
about them is included in the returned string.
.VS 8.4
If multiple index pairs are given, multiple ranges of text will be returned
in a list.  Invalid ranges will not be represented with empty strings in
the list.  The ranges are returned in the order passed to \fBget\fR.
.VE 8.4
.TP
\fIpathName \fBimage \fIoption \fR?\fIarg arg ...\fR?
This command is used to manipulate embedded images.
The behavior of the command depends on the \fIoption\fR argument
that follows the \fBtag\fR argument.
The following forms of the command are currently supported:
.RS
.TP
\fIpathName \fBimage cget\fR \fIindex option\fR
Returns the value of a configuration option for an embedded image.
\fIIndex\fR identifies the embedded image, and \fIoption\fR
specifies a particular configuration option, which must be one of
the ones listed in the section EMBEDDED IMAGES.
.TP
\fIpathName \fBimage configure \fIindex\fR ?\fIoption value ...\fR?
Query or modify the configuration options for an embedded image.
If no \fIoption\fR is specified, returns a list describing all of
the available options for the embedded image at \fIindex\fR
(see \fBTk_ConfigureInfo\fR for information on the format of this list).
If \fIoption\fR is specified with no \fIvalue\fR, then the command
returns a list describing the one named option (this list will be
identical to the corresponding sublist of the value returned if no
\fIoption\fR is specified).
If one or more \fIoption\-value\fR pairs are specified, then the command
modifies the given option(s) to have the given value(s);  in
this case the command returns an empty string.
See EMBEDDED IMAGES for information on the options that
are supported.
.TP
\fIpathName \fBimage create \fIindex\fR ?\fIoption value ...\fR?
This command creates a new image annotation, which will appear
in the text at the position given by \fIindex\fR.
Any number of \fIoption\-value\fR pairs may be specified to
configure the annotation.
Returns a unique identifier that may be used as an index to refer to
this image.
See EMBEDDED IMAGES for information on the options that
are supported, and a description of the identifier returned.
.TP
\fIpathName \fBimage names\fR
Returns a list whose elements are the names of all image instances currently
embedded in \fIwindow\fR.
.RE
.TP
\fIpathName \fBindex \fIindex\fR
Returns the position corresponding to \fIindex\fR in the form
\fIline.char\fR where \fIline\fR is the line number and \fIchar\fR
is the character number.
\fIIndex\fR may have any of the forms described under INDICES above.
.TP
\fIpathName \fBinsert \fIindex chars \fR?\fItagList chars tagList ...\fR?
Inserts all of the \fIchars\fR arguments just before the character at
\fIindex\fR.
If \fIindex\fR refers to the end of the text (the character after
the last newline) then the new text is inserted just before the
last newline instead.
If there is a single \fIchars\fR argument and no \fItagList\fR, then
the new text will receive any tags that are present on both the
character before and the character after the insertion point; if a tag
is present on only one of these characters then it will not be
applied to the new text.
If \fItagList\fR is specified then it consists of a list of
tag names;  the new characters will receive all of the tags in
this list and no others, regardless of the tags present around
the insertion point.
If multiple \fIchars\fR\-\fItagList\fR argument pairs are present,
they produce the same effect as if a separate \fBinsert\fR widget
command had been issued for each pair, in order.
The last \fItagList\fR argument may be omitted.
.TP
\fIpathName \fBmark \fIoption \fR?\fIarg arg ...\fR?
This command is used to manipulate marks.  The exact behavior of
the command depends on the \fIoption\fR argument that follows
the \fBmark\fR argument.  The following forms of the command
are currently supported:
.RS
.TP
\fIpathName \fBmark gravity \fImarkName\fR ?\fIdirection\fR?
If \fIdirection\fR is not specified, returns \fBleft\fR or \fBright\fR
to indicate which of its adjacent characters \fImarkName\fR is attached
to.
If \fIdirection\fR is specified, it must be \fBleft\fR or \fBright\fR;
the gravity of \fImarkName\fR is set to the given value.
.TP
\fIpathName \fBmark names\fR
Returns a list whose elements are the names of all the marks that
are currently set.
.TP
\fIpathName \fBmark next \fIindex\fR
Returns the name of the next mark at or after \fIindex\fR.
If \fIindex\fR is specified in numerical form, then the search for
the next mark begins at that index.
If \fIindex\fR is the name of a mark, then the search for
the next mark begins immediately after that mark.
This can still return a mark at the same position if
there are multiple marks at the same index.
These semantics mean that the \fBmark next\fP operation can be used to
step through all the marks in a text widget in the same order
as the mark information returned by the \fBdump\fP operation.
If a mark has been set to the special \fBend\fP index,
then it appears to be \fIafter\fP \fBend\fP with respect to the \fBmark next\fP operation.
An empty string is returned if there are no marks after \fIindex\fR.
.TP
\fIpathName \fBmark previous \fIindex\fR
Returns the name of the mark at or before \fIindex\fR.
If \fIindex\fR is specified in numerical form, then the search for
the previous mark begins with the character just before that index.
If \fIindex\fR is the name of a mark, then the search for
the next mark begins immediately before that mark.
This can still return a mark at the same position if
there are multiple marks at the same index.
These semantics mean that the \fBmark previous\fP operation can be used to
step through all the marks in a text widget in the reverse order
as the mark information returned by the \fBdump\fP operation.
An empty string is returned if there are no marks before \fIindex\fR.
.TP
\fIpathName \fBmark set \fImarkName index\fR
Sets the mark named \fImarkName\fR to a position just before the
character at \fIindex\fR.
If \fImarkName\fR already exists, it is moved from its old position;
if it doesn't exist, a new mark is created.
This command returns an empty string.
.TP
\fIpathName \fBmark unset \fImarkName \fR?\fImarkName markName ...\fR?
Remove the mark corresponding to each of the \fImarkName\fR arguments.
The removed marks will not be usable in indices and will not be
returned by future calls to ``\fIpathName \fBmark names\fR''.
This command returns an empty string.
.RE
.TP
\fIpathName \fBscan\fR \fIoption args\fR
This command is used to implement scanning on texts.  It has
two forms, depending on \fIoption\fR:
.RS
.TP
\fIpathName \fBscan mark \fIx y\fR
Records \fIx\fR and \fIy\fR and the current view in the text window,
for use in conjunction with later \fBscan dragto\fR commands.
Typically this command is associated with a mouse button press in
the widget.  It returns an empty string.
.TP
\fIpathName \fBscan dragto \fIx y\fR
This command computes the difference between its \fIx\fR and \fIy\fR
arguments and the \fIx\fR and \fIy\fR arguments to the last
\fBscan mark\fR command for the widget.
It then adjusts the view by 10 times the difference in coordinates.
This command is typically associated
with mouse motion events in the widget, to produce the effect of
dragging the text at high speed through the window.  The return
value is an empty string.
.RE
.TP
\fIpathName \fBsearch \fR?\fIswitches\fR? \fIpattern index \fR?\fIstopIndex\fR?
Searches the text in \fIpathName\fR starting at \fIindex\fR for a range
of characters that matches \fIpattern\fR.
If a match is found, the index of the first character in the match is
returned as result;  otherwise an empty string is returned.
One or more of the following switches (or abbreviations thereof)
may be specified to control the search:
.RS
.TP
\fB\-forwards\fR
The search will proceed forward through the text, finding the first
matching range starting at or after the position given by \fIindex\fR.
This is the default.
.TP
\fB\-backwards\fR
The search will proceed backward through the text, finding the
matching range closest to \fIindex\fR whose first character
is before \fIindex\fR.  Note that, for a variety of reasons, backwards
searches can be substantially slower than forwards searches, so it is
recommended that performance-critical code use forward searches.
.TP
\fB\-exact\fR
Use exact matching:  the characters in the matching range must be
identical to those in \fIpattern\fR.
This is the default.
.TP
\fB\-regexp\fR
Treat \fIpattern\fR as a regular expression and match it against
the text using the rules for regular expressions (see the \fBregexp\fR
command for details).  The default matching automatically passes
both the \fB\-lineanchor\fR and \fB\-linestop\fR options 
to the regexp engine (unless \fB\-nolinestop\fR is used), so that
\fI^$\fR match beginning and end of line, and \fI.\fR, \fI[^\fR 
sequences will never match the newline character \fI\n\fR.
.TP
\fB\-nolinestop\fR
This allows 
\fI.\fR and \fI[^\fR sequences to match the newline character \fI\n\fR,
which they will otherwise not do (see the \fBregexp\fR
command for details). This option is only meaningful if \fB\-regexp\fR 
is also given, and an error will be thrown otherwise.
.TP
\fB\-nocase\fR
Ignore case differences between the pattern and the text.
.TP
\fB\-count\fI varName\fR
The argument following \fB\-count\fR gives the name of a variable;
if a match is found, the number of index positions between beginning and
end of the matching range will be stored in the variable.  If there are no
embedded images or windows in the matching range, this is equivalent to the
number of characters matched.  In either case, the range \fImatchIdx\fR to
\fImatchIdx + $count chars\fR will return the entire matched text.
.TP
\fB\-all\fR
Find all matches in the given range and return a list of the indices of
the first character of each match.  If a \fB\-count\fI varName\fR switch is 
given, then \fBvarName\fR is also set to a list containing one element 
for each successful match.  Note that, even for exact searches, the
elements of this list may be different, if there are embedded images,
windows or hidden text. 
.TP
\fB\-elide\fR
Find elidden (hidden) text as well. By default only displayed text is
searched.
.TP
\fB\-\|\-\fR
This switch has no effect except to terminate the list of switches:
the next argument will be treated as \fIpattern\fR even if it starts
with \fB\-\fR.
.LP
The matching range must be entirely within a single line of text.
For regular expression matching the newlines are removed from the ends
of the lines before matching:  use the \fB$\fR feature in regular
expressions to match the end of a line.
For exact matching the newlines are retained.
If \fIstopIndex\fR is specified, the search stops at that index:
for forward searches, no match at or after \fIstopIndex\fR will
be considered;  for backward searches, no match earlier in the
text than \fIstopIndex\fR will be considered.
If \fIstopIndex\fR is omitted, the entire text will be searched:
when the beginning or end of the text is reached, the search
continues at the other end until the starting location is reached
again;  if \fIstopIndex\fR is specified, no wrap-around will occur.
.RE
.TP
\fIpathName \fBsee \fIindex\fR
Adjusts the view in the window so that the character given by \fIindex\fR
is completely visible.
If \fIindex\fR is already visible then the command does nothing.
If \fIindex\fR is a short distance out of view, the command
adjusts the view just enough to make \fIindex\fR visible at the
edge of the window.
If \fIindex\fR is far out of view, then the command centers
\fIindex\fR in the window.
.TP
\fIpathName \fBtag \fIoption \fR?\fIarg arg ...\fR?
This command is used to manipulate tags.  The exact behavior of the
command depends on the \fIoption\fR argument that follows the
\fBtag\fR argument.  The following forms of the command are currently
supported:
.RS
.TP
\fIpathName \fBtag add \fItagName index1 \fR?\fIindex2 index1 index2 ...\fR?
Associate the tag \fItagName\fR with all of the characters starting
with \fIindex1\fR and ending just before
\fIindex2\fR (the character at \fIindex2\fR isn't tagged).
A single command may contain any number of \fIindex1\fR\-\fIindex2\fR
pairs.
If the last \fIindex2\fR is omitted then the single character at
\fIindex1\fR is tagged.
If there are no characters in the specified range (e.g. \fIindex1\fR
is past the end of the file or \fIindex2\fR is less than or equal
to \fIindex1\fR) then the command has no effect.
.TP
\fIpathName \fBtag bind \fItagName\fR ?\fIsequence\fR? ?\fIscript\fR?
This command associates \fIscript\fR with the tag given by
\fItagName\fR.
Whenever the event sequence given by \fIsequence\fR occurs for a
character that has been tagged with \fItagName\fR,
the script will be invoked.
This widget command is similar to the \fBbind\fR command except that
it operates on characters in a text rather than entire widgets.
See the \fBbind\fR manual entry for complete details
on the syntax of \fIsequence\fR and the substitutions performed
on \fIscript\fR before invoking it.
If all arguments are specified then a new binding is created, replacing
any existing binding for the same \fIsequence\fR and \fItagName\fR
(if the first character of \fIscript\fR is ``+'' then \fIscript\fR
augments an existing binding rather than replacing it).
In this case the return value is an empty string.
If \fIscript\fR is omitted then the command returns the \fIscript\fR
associated with \fItagName\fR and \fIsequence\fR (an error occurs
if there is no such binding).
If both \fIscript\fR and \fIsequence\fR are omitted then the command
returns a list of all the sequences for which bindings have been
defined for \fItagName\fR.
.RS
.PP
.VS
The only events for which bindings may be specified are those related
to the mouse and keyboard (such as \fBEnter\fR, \fBLeave\fR, 
\fBButtonPress\fR, \fBMotion\fR, and \fBKeyPress\fR) or virtual events.
Event bindings for a text widget use the \fBcurrent\fR mark described
under MARKS above.  An \fBEnter\fR event triggers for a tag when the tag
first becomes present on the current character, and a \fBLeave\fR event
triggers for a tag when it ceases to be present on the current character.
\fBEnter\fR and \fBLeave\fR events can happen either because the
\fBcurrent\fR mark moved or because the character at that position
changed.  Note that these events are different than \fBEnter\fR and
\fBLeave\fR events for windows.  Mouse and keyboard events are directed
to the current character.  If a virtual event is used in a binding, that
binding can trigger only if the virtual event is defined by an underlying
mouse-related or keyboard-related event.
.VE
.PP
It is possible for the current character to have multiple tags,
and for each of them to have a binding for a particular event
sequence.
When this occurs, one binding is invoked for each tag, in order
from lowest-priority to highest priority.
If there are multiple matching bindings for a single tag, then
the most specific binding is chosen (see the manual entry for
the \fBbind\fR command for details).
\fBcontinue\fR and \fBbreak\fR commands within binding scripts
are processed in the same way as for bindings created with
the \fBbind\fR command.
.PP
If bindings are created for the widget as a whole using the
\fBbind\fR command, then those bindings will supplement the
tag bindings.
The tag bindings will be invoked first, followed by bindings
for the window as a whole.
.RE
.TP
\fIpathName \fBtag cget\fR \fItagName option\fR
This command returns the current value of the option named \fIoption\fR
associated with the tag given by \fItagName\fR.
\fIOption\fR may have any of the values accepted by the \fBtag configure\fR
widget command.
.TP
\fIpathName \fBtag configure \fItagName\fR ?\fIoption\fR? ?\fIvalue\fR? ?\fIoption value ...\fR?
This command is similar to the \fBconfigure\fR widget command except
that it modifies options associated with the tag given by \fItagName\fR
instead of modifying options for the overall text widget.
If no \fIoption\fR is specified, the command returns a list describing
all of the available options for \fItagName\fR (see \fBTk_ConfigureInfo\fR
for information on the format of this list).
If \fIoption\fR is specified with no \fIvalue\fR, then the command returns
a list describing the one named option (this list will be identical to
the corresponding sublist of the value returned if no \fIoption\fR
is specified).
If one or more \fIoption\-value\fR pairs are specified, then the command
modifies the given option(s) to have the given value(s) in \fItagName\fR;
in this case the command returns an empty string.
See TAGS above for details on the options available for tags.
.TP
\fIpathName \fBtag delete \fItagName \fR?\fItagName ...\fR?
Deletes all tag information for each of the \fItagName\fR
arguments.
The command removes the tags from all characters in the file
and also deletes any other information associated with the tags,
such as bindings and display information.
The command returns an empty string.
.TP
\fIpathName\fB tag lower \fItagName \fR?\fIbelowThis\fR?
Changes the priority of tag \fItagName\fR so that it is just lower
in priority than the tag whose name is \fIbelowThis\fR.
If \fIbelowThis\fR is omitted, then \fItagName\fR's priority
is changed to make it lowest priority of all tags.
.TP
\fIpathName \fBtag names \fR?\fIindex\fR?
Returns a list whose elements are the names of all the tags that
are active at the character position given by \fIindex\fR.
If \fIindex\fR is omitted, then the return value will describe
all of the tags that exist for the text (this includes all tags
that have been named in a ``\fIpathName \fBtag\fR'' widget
command but haven't been deleted by a ``\fIpathName \fBtag delete\fR''
widget command, even if no characters are currently marked with
the tag).
The list will be sorted in order from lowest priority to highest
priority.
.TP
\fIpathName \fBtag nextrange \fItagName index1 \fR?\fIindex2\fR?
This command searches the text for a range of characters tagged
with \fItagName\fR where the first character of the range is
no earlier than the character at \fIindex1\fR and no later than
the character just before \fIindex2\fR (a range starting at
\fIindex2\fR will not be considered).
If several matching ranges exist, the first one is chosen.
The command's return value is a list containing
two elements, which are the index of the first character of the
range and the index of the character just after the last one in
the range.
If no matching range is found then the return value is an
empty string.
If \fIindex2\fR is not given then it defaults to the end of the text.
.TP
\fIpathName \fBtag prevrange \fItagName index1 \fR?\fIindex2\fR?
This command searches the text for a range of characters tagged
with \fItagName\fR where the first character of the range is
before the character at \fIindex1\fR and no earlier than
the character at \fIindex2\fR (a range starting at
\fIindex2\fR will be considered).
If several matching ranges exist, the one closest to \fIindex1\fR is chosen.
The command's return value is a list containing
two elements, which are the index of the first character of the
range and the index of the character just after the last one in
the range.
If no matching range is found then the return value is an
empty string.
If \fIindex2\fR is not given then it defaults to the beginning of the text.
.TP
\fIpathName\fB tag raise \fItagName \fR?\fIaboveThis\fR?
Changes the priority of tag \fItagName\fR so that it is just higher
in priority than the tag whose name is \fIaboveThis\fR.
If \fIaboveThis\fR is omitted, then \fItagName\fR's priority
is changed to make it highest priority of all tags.
.TP
\fIpathName \fBtag ranges \fItagName\fR
Returns a list describing all of the ranges of text that have been
tagged with \fItagName\fR.
The first two elements of the list describe the first tagged range
in the text, the next two elements describe the second range, and
so on.
The first element of each pair contains the index of the first
character of the range, and the second element of the pair contains
the index of the character just after the last one in the
range.
If there are no characters tagged with \fItag\fR then an
empty string is returned.
.TP
\fIpathName \fBtag remove \fItagName index1 \fR?\fIindex2 index1 index2 ...\fR?
Remove the tag \fItagName\fR from all of the characters starting
at \fIindex1\fR and ending just before
\fIindex2\fR (the character at \fIindex2\fR isn't affected).
A single command may contain any number of \fIindex1\fR\-\fIindex2\fR
pairs.
If the last \fIindex2\fR is omitted then the single character at
\fIindex1\fR is tagged.
If there are no characters in the specified range (e.g. \fIindex1\fR
is past the end of the file or \fIindex2\fR is less than or equal
to \fIindex1\fR) then the command has no effect.
This command returns an empty string.
.RE
.TP
\fIpathName \fBwindow \fIoption \fR?\fIarg arg ...\fR?
This command is used to manipulate embedded windows.
The behavior of the command depends on the \fIoption\fR argument
that follows the \fBtag\fR argument.
The following forms of the command are currently supported:
.RS
.TP
\fIpathName \fBwindow cget\fR \fIindex option\fR
Returns the value of a configuration option for an embedded window.
\fIIndex\fR identifies the embedded window, and \fIoption\fR
specifies a particular configuration option, which must be one of
the ones listed in the section EMBEDDED WINDOWS.
.TP
\fIpathName \fBwindow configure \fIindex\fR ?\fIoption value ...\fR?
Query or modify the configuration options for an embedded window.
If no \fIoption\fR is specified, returns a list describing all of
the available options for the embedded window at \fIindex\fR
(see \fBTk_ConfigureInfo\fR for information on the format of this list).
If \fIoption\fR is specified with no \fIvalue\fR, then the command
returns a list describing the one named option (this list will be
identical to the corresponding sublist of the value returned if no
\fIoption\fR is specified).
If one or more \fIoption\-value\fR pairs are specified, then the command
modifies the given option(s) to have the given value(s);  in
this case the command returns an empty string.
See EMBEDDED WINDOWS for information on the options that
are supported.
.TP
\fIpathName \fBwindow create \fIindex\fR ?\fIoption value ...\fR?
This command creates a new window annotation, which will appear
in the text at the position given by \fIindex\fR.
Any number of \fIoption\-value\fR pairs may be specified to
configure the annotation.
See EMBEDDED WINDOWS for information on the options that
are supported.
Returns an empty string.
.TP
\fIpathName \fBwindow names\fR
Returns a list whose elements are the names of all windows currently
embedded in \fIwindow\fR.
.RE
.TP
\fIpathName \fBxview \fIoption args\fR
This command is used to query and change the horizontal position of the
text in the widget's window.  It can take any of the following
forms:
.RS
.TP
\fIpathName \fBxview\fR
Returns a list containing two elements.
Each element is a real fraction between 0 and 1;  together they describe
the portion of the document's horizontal span that is visible in
the window.
For example, if the first element is .2 and the second element is .6,
20% of the text is off-screen to the left, the middle 40% is visible
in the window, and 40% of the text is off-screen to the right.
The fractions refer only to the lines that are actually visible in the
window:  if the lines in the window are all very short, so that they
are entirely visible, the returned fractions will be 0 and 1,
even if there are other lines in the text that are
much wider than the window.
These are the same values passed to scrollbars via the \fB\-xscrollcommand\fR
option.
.TP
\fIpathName \fBxview moveto\fI fraction\fR
Adjusts the view in the window so that \fIfraction\fR of the horizontal
span of the text is off-screen to the left.
\fIFraction\fR is a fraction between 0 and 1.
.TP
\fIpathName \fBxview scroll \fInumber what\fR
This command shifts the view in the window left or right according to
\fInumber\fR and \fIwhat\fR.
\fINumber\fR must be an integer.
\fIWhat\fR must be either \fBunits\fR or \fBpages\fR or an abbreviation
of one of these.
If \fIwhat\fR is \fBunits\fR, the view adjusts left or right by
\fInumber\fR average-width characters on the display;  if it is
\fBpages\fR then the view adjusts by \fInumber\fR screenfuls.
If \fInumber\fR is negative then characters farther to the left
become visible;  if it is positive then characters farther to the right
become visible.
.RE
.TP
\fIpathName \fByview \fI?args\fR?
This command is used to query and change the vertical position of the
text in the widget's window.
It can take any of the following forms:
.RS
.TP
\fIpathName \fByview\fR
Returns a list containing two elements, both of which are real fractions
between 0 and 1.
The first element gives the position of the first character in the
top line in the window, relative to the text as a whole (0.5 means
it is halfway through the text, for example).
The second element gives the position of the character just after
the last one in the bottom line of the window,
relative to the text as a whole.
These are the same values passed to scrollbars via the \fB\-yscrollcommand\fR
option.
.TP
\fIpathName \fByview moveto\fI fraction\fR
Adjusts the view in the window so that the character given by \fIfraction\fR
appears on the top line of the window.
\fIFraction\fR is a fraction between 0 and 1;  0 indicates the first
character in the text, 0.33 indicates the character one-third the
way through the text, and so on.
.TP
\fIpathName \fByview scroll \fInumber what\fR
This command adjust the view in the window up or down according to
\fInumber\fR and \fIwhat\fR.
\fINumber\fR must be an integer.
\fIWhat\fR must be either \fBunits\fR or \fBpages\fR.
If \fIwhat\fR is \fBunits\fR, the view adjusts up or down by
\fInumber\fR lines on the display;  if it is \fBpages\fR then
the view adjusts by \fInumber\fR screenfuls.
If \fInumber\fR is negative then earlier positions in the text
become visible;  if it is positive then later positions in the text
become visible.
.TP
\fIpathName \fByview \fR?\fB\-pickplace\fR? \fIindex\fR
Changes the view in the widget's window to make \fIindex\fR visible.
If the \fB\-pickplace\fR option isn't specified then \fIindex\fR will
appear at the top of the window.
If \fB\-pickplace\fR is specified then the widget chooses where
\fIindex\fR appears in the window:
.RS
.IP [1]
If \fIindex\fR is already visible somewhere in the window then the
command does nothing.
.IP [2]
If \fIindex\fR is only a few lines off-screen above the window then
it will be positioned at the top of the window.
.IP [3]
If \fIindex\fR is only a few lines off-screen below the window then
it will be positioned at the bottom of the window.
.IP [4]
Otherwise, \fIindex\fR will be centered in the window.
.LP
The \fB\-pickplace\fR option has been obsoleted by the \fBsee\fR widget
command (\fBsee\fR handles both x- and y-motion to make a location
visible, whereas \fB\-pickplace\fR only handles motion in y).
.RE
.TP
\fIpathName \fByview \fInumber\fR
This command makes the first character on the line after
the one given by \fInumber\fR visible at the top of the window.
\fINumber\fR must be an integer.
This command used to be used for scrolling, but now it is obsolete.
.RE

.SH BINDINGS
.PP
Tk automatically creates class bindings for texts that give them
the following default behavior.
In the descriptions below, ``word'' is dependent on the value of
the \fBtcl_wordchars\fR variable.  See tclvars(n).
.IP [1]
Clicking mouse button 1 positions the insertion cursor
just before the character underneath the mouse cursor, sets the
input focus to this widget, and clears any selection in the widget.
Dragging with mouse button 1 strokes out a selection between
the insertion cursor and the character under the mouse.
.IP [2]
Double-clicking with mouse button 1 selects the word under the mouse
and positions the insertion cursor at the end of the word.
Dragging after a double click will stroke out a selection consisting
of whole words.
.IP [3]
Triple-clicking with mouse button 1 selects the line under the mouse
and positions the insertion cursor at the end of the line.
Dragging after a triple click will stroke out a selection consisting
of whole lines.
.IP [4]
The ends of the selection can be adjusted by dragging with mouse
button 1 while the Shift key is down;  this will adjust the end
of the selection that was nearest to the mouse cursor when button
1 was pressed.
If the button is double-clicked before dragging then the selection
will be adjusted in units of whole words;  if it is triple-clicked
then the selection will be adjusted in units of whole lines.
.IP [5]
Clicking mouse button 1 with the Control key down will reposition the
insertion cursor without affecting the selection.
.IP [6]
If any normal printing characters are typed, they are
inserted at the point of the insertion cursor.
.IP [7]
The view in the widget can be adjusted by dragging with mouse button 2.
If mouse button 2 is clicked without moving the mouse, the selection
is copied into the text at the position of the mouse cursor.
The Insert key also inserts the selection, but at the position of
the insertion cursor.
.IP [8]
If the mouse is dragged out of the widget
while button 1 is pressed, the entry will automatically scroll to
make more text visible (if there is more text off-screen on the side
where the mouse left the window).
.IP [9]
The Left and Right keys move the insertion cursor one character to the
left or right;  they also clear any selection in the text.
If Left or Right is typed with the Shift key down, then the insertion
cursor moves and the selection is extended to include the new character.
Control-Left and Control-Right move the insertion cursor by words, and
Control-Shift-Left and Control-Shift-Right move the insertion cursor
by words and also extend the selection.
Control-b and Control-f behave the same as Left and Right, respectively.
Meta-b and Meta-f behave the same as Control-Left and Control-Right,
respectively.
.IP [10]
The Up and Down keys move the insertion cursor one line up or
down and clear any selection in the text.
If Up or Right is typed with the Shift key down, then the insertion
cursor moves and the selection is extended to include the new character.
Control-Up and Control-Down move the insertion cursor by paragraphs (groups
of lines separated by blank lines), and
Control-Shift-Up and Control-Shift-Down move the insertion cursor
by paragraphs and also extend the selection.
Control-p and Control-n behave the same as Up and Down, respectively.
.IP [11]
The Next and Prior keys move the insertion cursor forward or backwards
by one screenful and clear any selection in the text.
If the Shift key is held down while Next or Prior is typed, then
the selection is extended to include the new character.
Control-v moves the view down one screenful without moving the
insertion cursor or adjusting the selection.
.IP [12]
Control-Next and Control-Prior scroll the view right or left by one page
without moving the insertion cursor or affecting the selection.
.IP [13]
Home and Control-a move the insertion cursor to the
beginning of its line and clear any selection in the widget.
Shift-Home moves the insertion cursor to the beginning of the line
and also extends the selection to that point.
.IP [14]
End and Control-e move the insertion cursor to the
end of the line and clear any selection in the widget.
Shift-End moves the cursor to the end of the line and extends the selection
to that point.
.IP [15]
Control-Home and Meta-< move the insertion cursor to the beginning of
the text and clear any selection in the widget.
Control-Shift-Home moves the insertion cursor to the beginning of the text
and also extends the selection to that point.
.IP [16]
Control-End and Meta-> move the insertion cursor to the end of the
text and clear any selection in the widget.
Control-Shift-End moves the cursor to the end of the text and extends
the selection to that point.
.IP [17]
The Select key and Control-Space set the selection anchor to the position
of the insertion cursor.  They don't affect the current selection.
Shift-Select and Control-Shift-Space adjust the selection to the
current position of the insertion cursor, selecting from the anchor
to the insertion cursor if there was not any selection previously.
.IP [18]
Control-/ selects the entire contents of the widget.
.IP [19]
Control-\e clears any selection in the widget.
.IP [20]
The F16 key (labelled Copy on many Sun workstations) or Meta-w
copies the selection in the widget to the clipboard, if there is a selection.
.VS 8.4
This action is carried out by the command \fBtk_textCopy\fR.
.VE 8.4
.IP [21]
The F20 key (labelled Cut on many Sun workstations) or Control-w
copies the selection in the widget to the clipboard and deletes
the selection.
.VS 8.4
This action is carried out by the command \fBtk_textCut\fR.
.VE 8.4
If there is no selection in the widget then these keys have no effect.
.IP [22]
The F18 key (labelled Paste on many Sun workstations) or Control-y
inserts the contents of the clipboard at the position of the
insertion cursor.
.VS 8.4
This action is carried out by the command \fBtk_textPaste\fR.
.VE 8.4
.IP [23]
The Delete key deletes the selection, if there is one in the widget.
If there is no selection, it deletes the character to the right of
the insertion cursor.
.IP [24]
Backspace and Control-h delete the selection, if there is one
in the widget.
If there is no selection, they delete the character to the left of
the insertion cursor.
.IP [25]
Control-d deletes the character to the right of the insertion cursor.
.IP [26]
Meta-d deletes the word to the right of the insertion cursor.
.IP [27]
Control-k deletes from the insertion cursor to the end of its line;
if the insertion cursor is already at the end of a line, then
Control-k deletes the newline character.
.IP [28]
Control-o opens a new line by inserting a newline character in
front of the insertion cursor without moving the insertion cursor.
.IP [29]
Meta-backspace and Meta-Delete delete the word to the left of the
insertion cursor.
.IP [30]
Control-x deletes whatever is selected in the text widget.
.IP [31]
Control-t reverses the order of the two characters to the right of
the insertion cursor. 
.IP [32]
.VS 8.4
Control-z (and Control-underscore on UNIX when \fBtk_strictMotif\fR is
true) undoes the last edit action if the \fB-undo\fR option is true.
Does nothing otherwise.
.IP [33]
Control-Z (or Control-y on Windows) reapplies the last undone edit
action if the \fB-undo\fR option is true. Does nothing otherwise.
.VE 8.4
.PP
If the widget is disabled using the \fB\-state\fR option, then its
view can still be adjusted and text can still be selected,
but no insertion cursor will be displayed and no text modifications will
take place.
.PP
The behavior of texts can be changed by defining new bindings for
individual widgets or by redefining the class bindings.

.SH "PERFORMANCE ISSUES"
.PP
Text widgets should run efficiently under a variety
of conditions.  The text widget uses about 2-3 bytes of
main memory for each byte of text, so texts containing a megabyte
or more should be practical on most workstations.
Text is represented internally with a modified B-tree structure
that makes operations relatively efficient even with large texts.
Tags are included in the B-tree structure in a way that allows
tags to span large ranges or have many disjoint smaller ranges
without loss of efficiency.
Marks are also implemented in a way that allows large numbers of
marks.
In most cases it is fine to have large numbers of unique tags,
or a tag that has many distinct ranges.
.PP
One performance problem can arise if you have hundreds or thousands
of different tags that all have the following characteristics:
the first and last ranges of each tag are near the beginning and
end of the text, respectively,
or a single tag range covers most of the text widget.
The cost of adding and deleting tags like this is proportional
to the number of other tags with the same properties.
In contrast, there is no problem with having thousands of distinct
tags if their overall ranges are localized and spread uniformly throughout
the text.
.PP
Very long text lines can be expensive,
especially if they have many marks and tags within them.
.PP
The display line with the insert cursor is redrawn each time the
cursor blinks, which causes a steady stream of graphics traffic.
Set the \fBinsertOffTime\fP attribute to 0 avoid this.
.SH KEYWORDS
text, widget, tkvars