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1/*
2 * tkCanvText.c --
3 *
4 * This file implements text items for canvas widgets.
5 *
6 * Copyright 1991-1992 Regents of the University of California.
7 * Permission to use, copy, modify, and distribute this
8 * software and its documentation for any purpose and without
9 * fee is hereby granted, provided that the above copyright
10 * notice appear in all copies. The University of California
11 * makes no representations about the suitability of this
12 * software for any purpose. It is provided "as is" without
13 * express or implied warranty.
14 */
15
16#ifndef lint
17static char rcsid[] = "$Header: /user6/ouster/wish/RCS/tkCanvText.c,v 1.12 92/08/19 08:34:12 ouster Exp $ SPRITE (Berkeley)";
18#endif
19
20#include <stdio.h>
21#include "tkint.h"
22#include "tkcanvas.h"
23#include "tkconfig.h"
24
25/*
26 * One of the following structures is kept for each line of text
27 * in a text item. It contains geometry and display information
28 * for that line.
29 */
30
31typedef struct TextLine {
32 char *firstChar; /* Pointer to the first character in this
33 * line (in the "text" field of enclosing
34 * text item). */
35 int numChars; /* Number of characters displayed in this
36 * line. */
37 int totalChars; /* Total number of characters included as
38 * part of this line (may include an extra
39 * space character at the end that isn't
40 * displayed). */
41 int x, y; /* Origin at which to draw line on screen
42 * (in integer pixel units, but in canvas
43 * coordinates, not screen coordinates). */
44 int x1, y1; /* Upper-left pixel that is part of text
45 * line on screen (again, in integer canvas
46 * pixel units). */
47 int x2, y2; /* Lower-left pixel that is part of text
48 * line on screen (again, in integer canvas
49 * pixel units). */
50} TextLine;
51
52/*
53 * The structure below defines the record for each text item.
54 */
55
56typedef struct TextItem {
57 Tk_Item header; /* Generic stuff that's the same for all
58 * types. MUST BE FIRST IN STRUCTURE. */
59 char *text; /* Text for item (malloc-ed). */
60 int numChars; /* Number of non-NULL characters in text. */
61 double x, y; /* Positioning point for text. */
62 Tk_Anchor anchor; /* Where to anchor text relative to (x,y). */
63 int width; /* Width of lines for word-wrap, pixels.
64 * Zero means no word-wrap. */
65 Tk_Justify justify; /* Justification mode for text. */
66 int rightEdge; /* Pixel just to right of right edge of
67 * area of text item. Used for selecting
68 * up to end of line. */
69 XFontStruct *fontPtr; /* Font for drawing text. */
70 XColor *color; /* Color for text. */
71 Pixmap stipple; /* Stipple bitmap for text, or None. */
72 GC gc; /* Graphics context for drawing text. */
73 TextLine *linePtr; /* Pointer to array of structures describing
74 * individual lines of text item (malloc-ed). */
75 int numLines; /* Number of structs at *linePtr. */
76 int cursorPos; /* Insertion cursor is displayed just to left
77 * of character with this index. */
78 GC selTextGC; /* Graphics context for selected text. */
79} TextItem;
80
81/*
82 * Information used for parsing configuration specs:
83 */
84
85static Tk_ConfigSpec configSpecs[] = {
86 {TK_CONFIG_ANCHOR, "-anchor", (char *) NULL, (char *) NULL,
87 "center", Tk_Offset(TextItem, anchor),
88 TK_CONFIG_DONT_SET_DEFAULT},
89 {TK_CONFIG_COLOR, "-fill", (char *) NULL, (char *) NULL,
90 "black", Tk_Offset(TextItem, color), 0},
91 {TK_CONFIG_FONT, "-font", (char *) NULL, (char *) NULL,
92 "-Adobe-Helvetica-Bold-R-Normal-*-120-*",
93 Tk_Offset(TextItem, fontPtr), 0},
94 {TK_CONFIG_JUSTIFY, "-justify", (char *) NULL, (char *) NULL,
95 "left", Tk_Offset(TextItem, justify),
96 TK_CONFIG_DONT_SET_DEFAULT},
97 {TK_CONFIG_BITMAP, "-stipple", (char *) NULL, (char *) NULL,
98 (char *) NULL, Tk_Offset(TextItem, stipple), TK_CONFIG_NULL_OK},
99 {TK_CONFIG_CUSTOM, "-tags", (char *) NULL, (char *) NULL,
100 (char *) NULL, 0, TK_CONFIG_NULL_OK, &tkCanvasTagsOption},
101 {TK_CONFIG_STRING, "-text", (char *) NULL, (char *) NULL,
102 "", Tk_Offset(TextItem, text), 0},
103 {TK_CONFIG_PIXELS, "-width", (char *) NULL, (char *) NULL,
104 "0", Tk_Offset(TextItem, width), TK_CONFIG_DONT_SET_DEFAULT},
105 {TK_CONFIG_END, (char *) NULL, (char *) NULL, (char *) NULL,
106 (char *) NULL, 0, 0}
107};
108
109/*
110 * Prototypes for procedures defined in this file:
111 */
112
113static void ComputeTextBbox _ANSI_ARGS_((Tk_Canvas *canvasPtr,
114 TextItem *textPtr));
115static int ConfigureText _ANSI_ARGS_((
116 Tk_Canvas *canvasPtr, Tk_Item *itemPtr, int argc,
117 char **argv, int flags));
118static int CreateText _ANSI_ARGS_((Tk_Canvas *canvasPtr,
119 struct Tk_Item *itemPtr, int argc, char **argv));
120static void DeleteText _ANSI_ARGS_((Tk_Item *itemPtr));
121static void DisplayText _ANSI_ARGS_((Tk_Canvas *canvasPtr,
122 Tk_Item *itemPtr, Drawable dst));
123static int GetSelText _ANSI_ARGS_((Tk_Canvas *canvasPtr,
124 Tk_Item *itemPtr, int offset, char *buffer,
125 int maxBytes));
126static int GetTextIndex _ANSI_ARGS_((Tk_Canvas *canvasPtr,
127 Tk_Item *itemPtr, char *indexString,
128 int *indexPtr));
129static void ScaleText _ANSI_ARGS_((Tk_Canvas *canvasPtr,
130 Tk_Item *itemPtr, double originX, double originY,
131 double scaleX, double scaleY));
132static void SetTextCursor _ANSI_ARGS_((Tk_Canvas *canvasPtr,
133 Tk_Item *itemPtr, int index));
134static int TextCoords _ANSI_ARGS_((Tk_Canvas *canvasPtr,
135 Tk_Item *itemPtr, int argc, char **argv));
136static int TextDeleteChars _ANSI_ARGS_((Tk_Canvas *canvasPtr,
137 Tk_Item *itemPtr, int first, int last));
138static int TextInsert _ANSI_ARGS_((Tk_Canvas *canvasPtr,
139 Tk_Item *itemPtr, int beforeThis, char *string));
140static int TextToArea _ANSI_ARGS_((Tk_Canvas *canvasPtr,
141 Tk_Item *itemPtr, double *rectPtr));
142static double TextToPoint _ANSI_ARGS_((Tk_Canvas *canvasPtr,
143 Tk_Item *itemPtr, double *pointPtr));
144static void TranslateText _ANSI_ARGS_((Tk_Canvas *canvasPtr,
145 Tk_Item *itemPtr, double deltaX, double deltaY));
146
147/*
148 * The structures below defines the rectangle and oval item types
149 * by means of procedures that can be invoked by generic item code.
150 */
151
152Tk_ItemType TkTextType = {
153 "text", /* name */
154 sizeof(TextItem), /* itemSize */
155 CreateText, /* createProc */
156 configSpecs, /* configSpecs */
157 ConfigureText, /* configureProc */
158 TextCoords, /* coordProc */
159 DeleteText, /* deleteProc */
160 DisplayText, /* displayProc */
161 0, /* alwaysRedraw */
162 TextToPoint, /* pointProc */
163 TextToArea, /* areaProc */
164 (Tk_ItemPostscriptProc *) NULL, /* postscriptProc */
165 ScaleText, /* scaleProc */
166 TranslateText, /* translateProc */
167 GetTextIndex, /* indexProc */
168 SetTextCursor, /* cursorProc */
169 GetSelText, /* selectionProc */
170 TextInsert, /* insertProc */
171 TextDeleteChars, /* dTextProc */
172 (Tk_ItemType *) NULL /* nextPtr */
173};
174\f
175/*
176 *--------------------------------------------------------------
177 *
178 * CreateText --
179 *
180 * This procedure is invoked to create a new text item
181 * in a canvas.
182 *
183 * Results:
184 * A standard Tcl return value. If an error occurred in
185 * creating the item then an error message is left in
186 * canvasPtr->interp->result; in this case itemPtr is
187 * left uninitialized so it can be safely freed by the
188 * caller.
189 *
190 * Side effects:
191 * A new text item is created.
192 *
193 *--------------------------------------------------------------
194 */
195
196static int
197CreateText(canvasPtr, itemPtr, argc, argv)
198 register Tk_Canvas *canvasPtr; /* Canvas to hold new item. */
199 Tk_Item *itemPtr; /* Record to hold new item; header
200 * has been initialized by caller. */
201 int argc; /* Number of arguments in argv. */
202 char **argv; /* Arguments describing rectangle. */
203{
204 register TextItem *textPtr = (TextItem *) itemPtr;
205
206 if (argc < 2) {
207 Tcl_AppendResult(canvasPtr->interp, "wrong # args: should be \"",
208 Tk_PathName(canvasPtr->tkwin),
209 "\" create text x y [options]", (char *) NULL);
210 return TCL_ERROR;
211 }
212
213 /*
214 * Carry out initialization that is needed in order to clean
215 * up after errors during the the remainder of this procedure.
216 */
217
218 textPtr->text = NULL;
219 textPtr->anchor = TK_ANCHOR_CENTER;
220 textPtr->width = 0;
221 textPtr->justify = TK_JUSTIFY_LEFT;
222 textPtr->fontPtr = NULL;
223 textPtr->color = NULL;
224 textPtr->stipple = None;
225 textPtr->gc = None;
226 textPtr->linePtr = NULL;
227 textPtr->numLines = 0;
228 textPtr->cursorPos = 0;
229 textPtr->selTextGC = None;
230
231 /*
232 * Process the arguments to fill in the item record.
233 */
234
235 if ((TkGetCanvasCoord(canvasPtr, argv[0], &textPtr->x) != TCL_OK)
236 || (TkGetCanvasCoord(canvasPtr, argv[1], &textPtr->y) != TCL_OK)) {
237 return TCL_ERROR;
238 }
239
240 if (ConfigureText(canvasPtr, itemPtr, argc-2, argv+2, 0) != TCL_OK) {
241 DeleteText(itemPtr);
242 return TCL_ERROR;
243 }
244 return TCL_OK;
245}
246\f
247/*
248 *--------------------------------------------------------------
249 *
250 * TextCoords --
251 *
252 * This procedure is invoked to process the "coords" widget
253 * command on text items. See the user documentation for
254 * details on what it does.
255 *
256 * Results:
257 * Returns TCL_OK or TCL_ERROR, and sets canvasPtr->interp->result.
258 *
259 * Side effects:
260 * The coordinates for the given item may be changed.
261 *
262 *--------------------------------------------------------------
263 */
264
265static int
266TextCoords(canvasPtr, itemPtr, argc, argv)
267 register Tk_Canvas *canvasPtr; /* Canvas containing item. */
268 Tk_Item *itemPtr; /* Item whose coordinates are to be
269 * read or modified. */
270 int argc; /* Number of coordinates supplied in
271 * argv. */
272 char **argv; /* Array of coordinates: x1, y1,
273 * x2, y2, ... */
274{
275 register TextItem *textPtr = (TextItem *) itemPtr;
276
277 if (argc == 0) {
278 sprintf(canvasPtr->interp->result, "%g %g", textPtr->x, textPtr->y);
279 } else if (argc == 2) {
280 if ((TkGetCanvasCoord(canvasPtr, argv[0], &textPtr->x) != TCL_OK)
281 || (TkGetCanvasCoord(canvasPtr, argv[1],
282 &textPtr->y) != TCL_OK)) {
283 return TCL_ERROR;
284 }
285 ComputeTextBbox(canvasPtr, textPtr);
286 } else {
287 sprintf(canvasPtr->interp->result,
288 "wrong # coordinates: expected 0 or 2, got %d",
289 argc);
290 return TCL_ERROR;
291 }
292 return TCL_OK;
293}
294\f
295/*
296 *--------------------------------------------------------------
297 *
298 * ConfigureText --
299 *
300 * This procedure is invoked to configure various aspects
301 * of a text item, such as its border and background colors.
302 *
303 * Results:
304 * A standard Tcl result code. If an error occurs, then
305 * an error message is left in canvasPtr->interp->result.
306 *
307 * Side effects:
308 * Configuration information, such as colors and stipple
309 * patterns, may be set for itemPtr.
310 *
311 *--------------------------------------------------------------
312 */
313
314static int
315ConfigureText(canvasPtr, itemPtr, argc, argv, flags)
316 Tk_Canvas *canvasPtr; /* Canvas containing itemPtr. */
317 Tk_Item *itemPtr; /* Rectangle item to reconfigure. */
318 int argc; /* Number of elements in argv. */
319 char **argv; /* Arguments describing things to configure. */
320 int flags; /* Flags to pass to Tk_ConfigureWidget. */
321{
322 register TextItem *textPtr = (TextItem *) itemPtr;
323 XGCValues gcValues;
324 GC newGC, newSelGC;
325 unsigned long mask;
326
327 if (Tk_ConfigureWidget(canvasPtr->interp, canvasPtr->tkwin,
328 configSpecs, argc, argv, (char *) textPtr, flags) != TCL_OK) {
329 return TCL_ERROR;
330 }
331
332 /*
333 * A few of the options require additional processing, such as
334 * graphics contexts.
335 */
336
337 textPtr->numChars = strlen(textPtr->text);
338 newGC = newSelGC = None;
339 if ((textPtr->color != NULL) && (textPtr->fontPtr != NULL)) {
340 gcValues.foreground = textPtr->color->pixel;
341 gcValues.font = textPtr->fontPtr->fid;
342 mask = GCForeground|GCFont;
343 if (textPtr->stipple != None) {
344 gcValues.stipple = textPtr->stipple;
345 gcValues.fill_style = FillStippled;
346 mask |= GCForeground|GCStipple|GCFillStyle;
347 }
348 newGC = Tk_GetGC(canvasPtr->tkwin, mask, &gcValues);
349 gcValues.foreground = canvasPtr->selFgColorPtr->pixel;
350 newSelGC = Tk_GetGC(canvasPtr->tkwin, mask, &gcValues);
351 }
352 if (textPtr->gc != None) {
353 Tk_FreeGC(textPtr->gc);
354 }
355 textPtr->gc = newGC;
356 if (textPtr->selTextGC != None) {
357 Tk_FreeGC(textPtr->selTextGC);
358 }
359 textPtr->selTextGC = newSelGC;
360
361 /*
362 * If the text was changed, move the selection and insertion indices
363 * to keep them inside the item.
364 */
365
366 if (canvasPtr->selItemPtr == itemPtr) {
367 if (canvasPtr->selectFirst >= textPtr->numChars) {
368 canvasPtr->selItemPtr = NULL;
369 } else {
370 if (canvasPtr->selectLast >= textPtr->numChars) {
371 canvasPtr->selectLast = textPtr->numChars-1;
372 }
373 if ((canvasPtr->anchorItemPtr == itemPtr)
374 && (canvasPtr->selectAnchor >= textPtr->numChars)) {
375 canvasPtr->selectAnchor = textPtr->numChars-1;
376 }
377 }
378 }
379 if (textPtr->cursorPos >= textPtr->numChars) {
380 textPtr->cursorPos = textPtr->numChars;
381 }
382
383 ComputeTextBbox(canvasPtr, textPtr);
384 return TCL_OK;
385}
386\f
387/*
388 *--------------------------------------------------------------
389 *
390 * DeleteText --
391 *
392 * This procedure is called to clean up the data structure
393 * associated with a text item.
394 *
395 * Results:
396 * None.
397 *
398 * Side effects:
399 * Resources associated with itemPtr are released.
400 *
401 *--------------------------------------------------------------
402 */
403
404static void
405DeleteText(itemPtr)
406 Tk_Item *itemPtr; /* Item that is being deleted. */
407{
408 register TextItem *textPtr = (TextItem *) itemPtr;
409
410 if (textPtr->text != NULL) {
411 ckfree(textPtr->text);
412 }
413 if (textPtr->fontPtr != NULL) {
414 Tk_FreeFontStruct(textPtr->fontPtr);
415 }
416 if (textPtr->color != NULL) {
417 Tk_FreeColor(textPtr->color);
418 }
419 if (textPtr->stipple != None) {
420 Tk_FreeBitmap(textPtr->stipple);
421 }
422 if (textPtr->gc != None) {
423 Tk_FreeGC(textPtr->gc);
424 }
425 if (textPtr->linePtr != NULL) {
426 ckfree((char *) textPtr->linePtr);
427 }
428 if (textPtr->selTextGC != None) {
429 Tk_FreeGC(textPtr->selTextGC);
430 }
431}
432\f
433/*
434 *--------------------------------------------------------------
435 *
436 * ComputeTextBbox --
437 *
438 * This procedure is invoked to compute the bounding box of
439 * all the pixels that may be drawn as part of a text item.
440 * In addition, it recomputes all of the geometry information
441 * used to display a text item or check for mouse hits.
442 *
443 * Results:
444 * None.
445 *
446 * Side effects:
447 * The fields x1, y1, x2, and y2 are updated in the header
448 * for itemPtr, and the linePtr structure is regenerated
449 * for itemPtr.
450 *
451 *--------------------------------------------------------------
452 */
453
454static void
455ComputeTextBbox(canvasPtr, textPtr)
456 register Tk_Canvas *canvasPtr; /* Canvas that contains item. */
457 register TextItem *textPtr; /* Item whose bbos is to be
458 * recomputed. */
459{
460 register TextLine *linePtr;
461#define MAX_LINES 100
462 char *lineStart[MAX_LINES];
463 int lineChars[MAX_LINES];
464 int linePixels[MAX_LINES];
465 int numLines, wrapPixels, maxLinePixels, leftX, topY, y;
466 int lineHeight, i, fudge;
467 char *p;
468 XCharStruct *maxBoundsPtr = &textPtr->fontPtr->max_bounds;
469
470 if (textPtr->linePtr != NULL) {
471 ckfree((char *) textPtr->linePtr);
472 textPtr->linePtr = NULL;
473 }
474
475 /*
476 * Work through the text computing the starting point, number of
477 * characters, and number of pixels in each line.
478 */
479
480 p = textPtr->text;
481 if (textPtr->width > 0) {
482 wrapPixels = maxLinePixels = textPtr->width;
483 } else {
484 wrapPixels = 10000000;
485 maxLinePixels = 0;
486 }
487 for (numLines = 0; (numLines < MAX_LINES) && (*p != 0);
488 numLines++) {
489 int numChars, numPixels;
490 numChars = TkMeasureChars(textPtr->fontPtr, p,
491 (textPtr->text + textPtr->numChars) - p, 0,
492 wrapPixels, TK_WHOLE_WORDS|TK_AT_LEAST_ONE, &numPixels);
493 if (numPixels > maxLinePixels) {
494 maxLinePixels = numPixels;
495 }
496 lineStart[numLines] = p;
497 lineChars[numLines] = numChars;
498 linePixels[numLines] = numPixels;
499 p += numChars;
500
501 /*
502 * Skip space character that terminates a line, if there is one.
503 * In the case of multiple spaces, all but one will be displayed.
504 * This is important to make sure the insertion cursor gets
505 * displayed when it is in the middle of a multi-space.
506 */
507
508 if (isspace(*p)) {
509 p++;
510 }
511 }
512
513 /*
514 * Use overall geometry information to compute the top-left corner
515 * of the bounding box for the text item.
516 */
517
518 leftX = textPtr->x + 0.5;
519 topY = textPtr->y + 0.5;
520 lineHeight = textPtr->fontPtr->ascent + textPtr->fontPtr->descent;
521 switch (textPtr->anchor) {
522 case TK_ANCHOR_NW:
523 case TK_ANCHOR_N:
524 case TK_ANCHOR_NE:
525 break;
526
527 case TK_ANCHOR_W:
528 case TK_ANCHOR_CENTER:
529 case TK_ANCHOR_E:
530 topY -= (lineHeight * numLines)/2;
531 break;
532
533 case TK_ANCHOR_SW:
534 case TK_ANCHOR_S:
535 case TK_ANCHOR_SE:
536 topY -= lineHeight * numLines;
537 break;
538 }
539 switch (textPtr->anchor) {
540 case TK_ANCHOR_NW:
541 case TK_ANCHOR_W:
542 case TK_ANCHOR_SW:
543 break;
544
545 case TK_ANCHOR_N:
546 case TK_ANCHOR_CENTER:
547 case TK_ANCHOR_S:
548 leftX -= maxLinePixels/2;
549 break;
550
551 case TK_ANCHOR_NE:
552 case TK_ANCHOR_E:
553 case TK_ANCHOR_SE:
554 leftX -= maxLinePixels;
555 break;
556 }
557 textPtr->rightEdge = leftX + maxLinePixels;
558
559 /*
560 * Create the new TextLine array and fill it in using the geometry
561 * information gathered already.
562 */
563
564 if (numLines > 0) {
565 textPtr->linePtr = (TextLine *) ckalloc((unsigned)
566 (numLines * sizeof(TextLine)));
567 } else {
568 textPtr->linePtr = NULL;
569 }
570 textPtr->numLines = numLines;
571 for (i = 0, linePtr = textPtr->linePtr, y = topY;
572 i < numLines; i++, linePtr++, y += lineHeight) {
573 linePtr->firstChar = lineStart[i];
574 linePtr->numChars = lineChars[i];
575 if (i == (numLines-1)) {
576 linePtr->totalChars = linePtr->numChars;
577 } else {
578 linePtr->totalChars = lineStart[i+1] - lineStart[i];
579 }
580 switch (textPtr->justify) {
581 case TK_JUSTIFY_LEFT:
582 case TK_JUSTIFY_FILL:
583 linePtr->x = leftX;
584 break;
585 case TK_JUSTIFY_CENTER:
586 linePtr->x = leftX + maxLinePixels/2 - linePixels[i]/2;
587 break;
588 case TK_JUSTIFY_RIGHT:
589 linePtr->x = leftX + maxLinePixels - linePixels[i];
590 break;
591 }
592 linePtr->y = y + textPtr->fontPtr->ascent;
593 linePtr->x1 = linePtr->x - maxBoundsPtr->lbearing;
594 linePtr->y1 = y;
595 linePtr->x2 = linePtr->x + linePixels[i] + maxBoundsPtr->rbearing
596 - textPtr->fontPtr->min_bounds.rbearing;
597 linePtr->y2 = linePtr->y + textPtr->fontPtr->descent - 1;
598 }
599
600 /*
601 * Last of all, update the bounding box for the item. The item's
602 * bounding box includes the bounding box of all its lines, plus
603 * an extra fudge factor for the cursor border (which could
604 * potentially be quite large).
605 */
606
607 linePtr = textPtr->linePtr;
608 textPtr->header.x1 = textPtr->header.x2 = leftX;
609 textPtr->header.y1 = topY;
610 textPtr->header.y2 = topY + numLines*lineHeight;
611 for (linePtr = textPtr->linePtr, i = textPtr->numLines; i > 0;
612 i--, linePtr++) {
613 if (linePtr->x1 < textPtr->header.x1) {
614 textPtr->header.x1 = linePtr->x1;
615 }
616 if (linePtr->x2 >= textPtr->header.x2) {
617 textPtr->header.x2 = linePtr->x2 + 1;
618 }
619 }
620
621 fudge = canvasPtr->cursorWidth/2;
622 if (canvasPtr->selBorderWidth > fudge) {
623 fudge = canvasPtr->selBorderWidth;
624 }
625 textPtr->header.x1 -= fudge;
626 textPtr->header.x2 += fudge;
627}
628\f
629/*
630 *--------------------------------------------------------------
631 *
632 * DisplayText --
633 *
634 * This procedure is invoked to draw a text item in a given
635 * drawable.
636 *
637 * Results:
638 * None.
639 *
640 * Side effects:
641 * ItemPtr is drawn in drawable using the transformation
642 * information in canvasPtr.
643 *
644 *--------------------------------------------------------------
645 */
646
647static void
648DisplayText(canvasPtr, itemPtr, drawable)
649 register Tk_Canvas *canvasPtr; /* Canvas that contains item. */
650 Tk_Item *itemPtr; /* Item to be displayed. */
651 Drawable drawable; /* Pixmap or window in which to draw
652 * item. */
653{
654 register TextItem *textPtr = (TextItem *) itemPtr;
655 Display *display = Tk_Display(canvasPtr->tkwin);
656 register TextLine *linePtr;
657 int i, focusHere, cursorX, cursorIndex, lineIndex;
658 int beforeSelect, inSelect, afterSelect, selStartX, selEndX;
659
660 if (textPtr->gc == None) {
661 return;
662 }
663 focusHere = (canvasPtr->focusItemPtr == itemPtr) &&
664 (canvasPtr->flags & GOT_FOCUS);
665 for (linePtr = textPtr->linePtr, i = textPtr->numLines;
666 i > 0; linePtr++, i--) {
667
668 /*
669 * If part or all of this line is selected, then draw a special
670 * background under the selected part of the line.
671 */
672
673 lineIndex = linePtr->firstChar - textPtr->text;
674 if ((canvasPtr->selItemPtr != itemPtr)
675 || (canvasPtr->selectLast < lineIndex)
676 || (canvasPtr->selectFirst >= (lineIndex
677 + linePtr->totalChars))) {
678 beforeSelect = linePtr->numChars;
679 inSelect = 0;
680 } else {
681 beforeSelect = canvasPtr->selectFirst - lineIndex;
682 if (beforeSelect <= 0) {
683 beforeSelect = 0;
684 selStartX = linePtr->x;
685 } else {
686 (void) TkMeasureChars(textPtr->fontPtr,
687 linePtr->firstChar, beforeSelect, 0,
688 (int) 1000000, TK_PARTIAL_OK, &selStartX);
689 selStartX += linePtr->x;
690 }
691 inSelect = canvasPtr->selectLast + 1 - (lineIndex + beforeSelect);
692
693 /*
694 * If the selection spans the end of this line, then display
695 * selection background all the way to the end of the line.
696 * However, for the last line we only want to display up to
697 * the last character, not the end of the line, hence the
698 * "i != 1" check.
699 */
700
701 if (inSelect >= (linePtr->totalChars - beforeSelect)) {
702 inSelect = linePtr->numChars - beforeSelect;
703 if (i != 1) {
704 selEndX = textPtr->rightEdge;
705 goto fillSelectBackground;
706 }
707 }
708 (void) TkMeasureChars(textPtr->fontPtr,
709 linePtr->firstChar + beforeSelect, inSelect,
710 selStartX-linePtr->x, (int) 1000000, TK_PARTIAL_OK,
711 &selEndX);
712 selEndX += linePtr->x;
713 fillSelectBackground:
714 Tk_Fill3DRectangle(display, drawable, canvasPtr->selBorder,
715 selStartX - canvasPtr->drawableXOrigin
716 - canvasPtr->selBorderWidth,
717 linePtr->y - canvasPtr->drawableYOrigin
718 - textPtr->fontPtr->ascent,
719 selEndX - selStartX + 2*canvasPtr->selBorderWidth,
720 textPtr->fontPtr->ascent + textPtr->fontPtr->descent,
721 canvasPtr->selBorderWidth, TK_RELIEF_RAISED);
722 }
723
724 /*
725 * If the insertion cursor is in this line, then draw a special
726 * background for the cursor before drawing the text. Note:
727 * if we're the cursor item but the cursor is turned off, then
728 * redraw background over the area of the cursor. This guarantees
729 * that the selection won't make the cursor invisible on mono
730 * displays, where both are drawn in the same color.
731 */
732
733 if (focusHere) {
734 cursorIndex = textPtr->cursorPos
735 - (linePtr->firstChar - textPtr->text);
736 if ((cursorIndex >= 0) && (cursorIndex <= linePtr->numChars)) {
737 (void) TkMeasureChars(textPtr->fontPtr, linePtr->firstChar,
738 cursorIndex, 0, (int) 1000000, TK_PARTIAL_OK, &cursorX);
739 if (canvasPtr->flags & CURSOR_ON) {
740 Tk_Fill3DRectangle(display, drawable,
741 canvasPtr->cursorBorder,
742 linePtr->x - canvasPtr->drawableXOrigin
743 + cursorX - (canvasPtr->cursorWidth)/2,
744 linePtr->y - canvasPtr->drawableYOrigin
745 - textPtr->fontPtr->ascent,
746 canvasPtr->cursorWidth,
747 textPtr->fontPtr->ascent
748 + textPtr->fontPtr->descent,
749 canvasPtr->cursorBorderWidth, TK_RELIEF_RAISED);
750 } else if (Tk_DefaultDepth(
751 Tk_Screen(canvasPtr->tkwin)) == 1){
752 Tk_Fill3DRectangle(display, drawable,
753 canvasPtr->bgBorder,
754 linePtr->x - canvasPtr->drawableXOrigin
755 + cursorX - (canvasPtr->cursorWidth)/2,
756 linePtr->y - canvasPtr->drawableYOrigin
757 - textPtr->fontPtr->ascent,
758 canvasPtr->cursorWidth,
759 textPtr->fontPtr->ascent
760 + textPtr->fontPtr->descent,
761 0, TK_RELIEF_FLAT);
762 }
763 }
764 }
765
766 /*
767 * Display the text in three pieces: the part before the
768 * selection, the selected part (which needs a different graphics
769 * context), and the part after the selection.
770 */
771
772 if (beforeSelect != 0) {
773 TkDisplayChars(display, drawable, textPtr->gc, textPtr->fontPtr,
774 linePtr->firstChar, beforeSelect,
775 linePtr->x - canvasPtr->drawableXOrigin,
776 linePtr->y - canvasPtr->drawableYOrigin, 0);
777 }
778 if (inSelect != 0) {
779 TkDisplayChars(display, drawable, textPtr->selTextGC,
780 textPtr->fontPtr, linePtr->firstChar + beforeSelect,
781 inSelect, selStartX - canvasPtr->drawableXOrigin,
782 linePtr->y - canvasPtr->drawableYOrigin, 0);
783 }
784 afterSelect = linePtr->numChars - beforeSelect - inSelect;
785 if (afterSelect > 0) {
786 TkDisplayChars(display, drawable, textPtr->gc, textPtr->fontPtr,
787 linePtr->firstChar + beforeSelect + inSelect,
788 afterSelect, selEndX - canvasPtr->drawableXOrigin,
789 linePtr->y - canvasPtr->drawableYOrigin, 0);
790 }
791 }
792}
793\f
794/*
795 *--------------------------------------------------------------
796 *
797 * TextInsert --
798 *
799 * Insert characters into a text item at a given position.
800 *
801 * Results:
802 * Always returns TCL_OK.
803 *
804 * Side effects:
805 * The text in the given item is modified. The cursor and
806 * selection positions are also modified to reflect the
807 * insertion.
808 *
809 *--------------------------------------------------------------
810 */
811
812static int
813TextInsert(canvasPtr, itemPtr, beforeThis, string)
814 Tk_Canvas *canvasPtr; /* Canvas containing text item. */
815 Tk_Item *itemPtr; /* Text item to be modified. */
816 int beforeThis; /* Index of character before which text is
817 * to be inserted. */
818 char *string; /* New characters to be inserted. */
819{
820 register TextItem *textPtr = (TextItem *) itemPtr;
821 int length;
822 char *new;
823
824 length = strlen(string);
825 if (length == 0) {
826 return TCL_OK;
827 }
828 if (beforeThis < 0) {
829 beforeThis = 0;
830 }
831 if (beforeThis > textPtr->numChars) {
832 beforeThis = textPtr->numChars;
833 }
834
835 new = (char *) ckalloc((unsigned) (textPtr->numChars + length + 1));
836 strncpy(new, textPtr->text, beforeThis);
837 strcpy(new+beforeThis, string);
838 strcpy(new+beforeThis+length, textPtr->text+beforeThis);
839 ckfree(textPtr->text);
840 textPtr->text = new;
841 textPtr->numChars += length;
842
843 /*
844 * Inserting characters invalidates indices such as those for the
845 * selection and cursor. Update the indices appropriately.
846 */
847
848 if (canvasPtr->selItemPtr == itemPtr) {
849 if (canvasPtr->selectFirst >= beforeThis) {
850 canvasPtr->selectFirst += length;
851 }
852 if (canvasPtr->selectLast >= beforeThis) {
853 canvasPtr->selectLast += length;
854 }
855 if ((canvasPtr->anchorItemPtr == itemPtr)
856 && (canvasPtr->selectAnchor >= beforeThis)) {
857 canvasPtr->selectAnchor += length;
858 }
859 }
860 if (textPtr->cursorPos >= beforeThis) {
861 textPtr->cursorPos += length;
862 }
863 ComputeTextBbox(canvasPtr, textPtr);
864 return TCL_OK;
865}
866\f
867/*
868 *--------------------------------------------------------------
869 *
870 * TextDeleteChars --
871 *
872 * Delete one or more characters from a text item.
873 *
874 * Results:
875 * Always returns TCL_OK.
876 *
877 * Side effects:
878 * Characters between "first" and "last", inclusive, get
879 * deleted from itemPtr, and things like the selection
880 * position get updated.
881 *
882 *--------------------------------------------------------------
883 */
884
885static int
886TextDeleteChars(canvasPtr, itemPtr, first, last)
887 Tk_Canvas *canvasPtr; /* Canvas containing itemPtr. */
888 Tk_Item *itemPtr; /* Item in which to delete characters. */
889 int first; /* Index of first character to delete. */
890 int last; /* Index of last character to delete. */
891{
892 register TextItem *textPtr = (TextItem *) itemPtr;
893 int count;
894 char *new;
895
896 if (first < 0) {
897 first = 0;
898 }
899 if (last >= textPtr->numChars) {
900 last = textPtr->numChars-1;
901 }
902 if (first > last) {
903 return TCL_OK;
904 }
905 count = last + 1 - first;
906
907 new = ckalloc((unsigned) (textPtr->numChars + 1 - count));
908 strncpy(new, textPtr->text, first);
909 strcpy(new+first, textPtr->text+last+1);
910 ckfree(textPtr->text);
911 textPtr->text = new;
912 textPtr->numChars -= count;
913
914 /*
915 * Update indexes for the selection and cursor to reflect the
916 * renumbering of the remaining characters.
917 */
918
919 if (canvasPtr->selItemPtr == itemPtr) {
920 if (canvasPtr->selectFirst > first) {
921 canvasPtr->selectFirst -= count;
922 if (canvasPtr->selectFirst < first) {
923 canvasPtr->selectFirst = first;
924 }
925 }
926 if (canvasPtr->selectLast >= first) {
927 canvasPtr->selectLast -= count;
928 if (canvasPtr->selectLast < (first-1)) {
929 canvasPtr->selectLast = (first-1);
930 }
931 }
932 if (canvasPtr->selectFirst > canvasPtr->selectLast) {
933 canvasPtr->selItemPtr = NULL;
934 }
935 if ((canvasPtr->anchorItemPtr == itemPtr)
936 && (canvasPtr->selectAnchor > first)) {
937 canvasPtr->selectAnchor -= count;
938 if (canvasPtr->selectAnchor < first) {
939 canvasPtr->selectAnchor = first;
940 }
941 }
942 }
943 if (textPtr->cursorPos > first) {
944 textPtr->cursorPos -= count;
945 if (textPtr->cursorPos < first) {
946 textPtr->cursorPos = first;
947 }
948 }
949 ComputeTextBbox(canvasPtr, textPtr);
950 return TCL_OK;
951}
952\f
953/*
954 *--------------------------------------------------------------
955 *
956 * TextToPoint --
957 *
958 * Computes the distance from a given point to a given
959 * text item, in canvas units.
960 *
961 * Results:
962 * The return value is 0 if the point whose x and y coordinates
963 * are pointPtr[0] and pointPtr[1] is inside the arc. If the
964 * point isn't inside the arc then the return value is the
965 * distance from the point to the arc.
966 *
967 * Side effects:
968 * None.
969 *
970 *--------------------------------------------------------------
971 */
972
973 /* ARGSUSED */
974static double
975TextToPoint(canvasPtr, itemPtr, pointPtr)
976 Tk_Canvas *canvasPtr; /* Canvas containing itemPtr. */
977 Tk_Item *itemPtr; /* Item to check against point. */
978 double *pointPtr; /* Pointer to x and y coordinates. */
979{
980 TextItem *textPtr = (TextItem *) itemPtr;
981 register TextLine *linePtr;
982 int i;
983 double xDiff, yDiff, dist, minDist;
984
985 /*
986 * Treat each line in the text item as a rectangle, compute the
987 * distance to that rectangle, and take the minimum of these
988 * distances. Perform most of the calculations in integer pixel
989 * units, since that's how the dimensions of the text are defined.
990 */
991
992 minDist = -1.0;
993 for (linePtr = textPtr->linePtr, i = textPtr->numLines;
994 i > 0; linePtr++, i--) {
995
996 /*
997 * If the point is inside the line's rectangle, then can
998 * return immediately.
999 */
1000
1001 if ((pointPtr[0] >= linePtr->x1)
1002 && (pointPtr[0] <= linePtr->x2)
1003 && (pointPtr[1] >= linePtr->y1)
1004 && (pointPtr[1] <= linePtr->y2)) {
1005 return 0.0;
1006 }
1007
1008 /*
1009 * Point is outside line's rectangle; compute distance to nearest
1010 * side.
1011 */
1012
1013 if (pointPtr[0] < linePtr->x1) {
1014 xDiff = linePtr->x1 - pointPtr[0];
1015 } else if (pointPtr[0] > linePtr->x2) {
1016 xDiff = pointPtr[0] - linePtr->x2;
1017 } else {
1018 xDiff = 0;
1019 }
1020
1021 if (pointPtr[1] < linePtr->y1) {
1022 yDiff = linePtr->y1 - pointPtr[1];
1023 } else if (pointPtr[1] > linePtr->y2) {
1024 yDiff = pointPtr[1] - linePtr->y2;
1025 } else {
1026 yDiff = 0;
1027 }
1028
1029 dist = hypot((float) xDiff, (float) yDiff);
1030 if ((dist < minDist) || (minDist < 0.0)) {
1031 minDist = dist;
1032 }
1033 }
1034 return minDist;
1035}
1036\f
1037/*
1038 *--------------------------------------------------------------
1039 *
1040 * TextToArea --
1041 *
1042 * This procedure is called to determine whether an item
1043 * lies entirely inside, entirely outside, or overlapping
1044 * a given rectangle.
1045 *
1046 * Results:
1047 * -1 is returned if the item is entirely outside the area
1048 * given by rectPtr, 0 if it overlaps, and 1 if it is entirely
1049 * inside the given area.
1050 *
1051 * Side effects:
1052 * None.
1053 *
1054 *--------------------------------------------------------------
1055 */
1056
1057 /* ARGSUSED */
1058static int
1059TextToArea(canvasPtr, itemPtr, rectPtr)
1060 Tk_Canvas *canvasPtr; /* Canvas containing itemPtr. */
1061 Tk_Item *itemPtr; /* Item to check against rectangle. */
1062 double *rectPtr; /* Pointer to array of four coordinates
1063 * (x1, y1, x2, y2) describing rectangular
1064 * area. */
1065{
1066 TextItem *textPtr = (TextItem *) itemPtr;
1067 register TextLine *linePtr;
1068 int i, result;
1069
1070 /*
1071 * Scan the lines one at a time, seeing whether each line is
1072 * entirely in, entirely out, or overlapping the rectangle. If
1073 * an overlap is detected, return immediately; otherwise wait
1074 * until all lines have been processed and see if they were all
1075 * inside or all outside.
1076 */
1077
1078 result = 0;
1079 for (linePtr = textPtr->linePtr, i = textPtr->numLines;
1080 i > 0; linePtr++, i--) {
1081 if ((rectPtr[2] < linePtr->x1) || (rectPtr[0] > linePtr->x2)
1082 || (rectPtr[3] < linePtr->y1) || (rectPtr[1] > linePtr->y2)) {
1083 if (result == 1) {
1084 return 0;
1085 }
1086 result = -1;
1087 continue;
1088 }
1089 if ((linePtr->x1 < rectPtr[0]) || (linePtr->x2 > rectPtr[2])
1090 || (linePtr->y1 < rectPtr[1]) || (linePtr->y2 > rectPtr[3])) {
1091 return 0;
1092 }
1093 if (result == -1) {
1094 return 0;
1095 }
1096 result = 1;
1097 }
1098 return result;
1099}
1100\f
1101/*
1102 *--------------------------------------------------------------
1103 *
1104 * ScaleText --
1105 *
1106 * This procedure is invoked to rescale a text item.
1107 *
1108 * Results:
1109 * None.
1110 *
1111 * Side effects:
1112 * Scales the position of the text, but not the size
1113 * of the font for the text.
1114 *
1115 *--------------------------------------------------------------
1116 */
1117
1118 /* ARGSUSED */
1119static void
1120ScaleText(canvasPtr, itemPtr, originX, originY, scaleX, scaleY)
1121 Tk_Canvas *canvasPtr; /* Canvas containing rectangle. */
1122 Tk_Item *itemPtr; /* Rectangle to be scaled. */
1123 double originX, originY; /* Origin about which to scale rect. */
1124 double scaleX; /* Amount to scale in X direction. */
1125 double scaleY; /* Amount to scale in Y direction. */
1126{
1127 register TextItem *textPtr = (TextItem *) itemPtr;
1128
1129 textPtr->x = originX + scaleX*(textPtr->x - originX);
1130 textPtr->y = originY + scaleY*(textPtr->y - originY);
1131 ComputeTextBbox(canvasPtr, textPtr);
1132 return;
1133}
1134\f
1135/*
1136 *--------------------------------------------------------------
1137 *
1138 * TranslateText --
1139 *
1140 * This procedure is called to move a text item by a
1141 * given amount.
1142 *
1143 * Results:
1144 * None.
1145 *
1146 * Side effects:
1147 * The position of the text item is offset by (xDelta, yDelta),
1148 * and the bounding box is updated in the generic part of the
1149 * item structure.
1150 *
1151 *--------------------------------------------------------------
1152 */
1153
1154static void
1155TranslateText(canvasPtr, itemPtr, deltaX, deltaY)
1156 Tk_Canvas *canvasPtr; /* Canvas containing item. */
1157 Tk_Item *itemPtr; /* Item that is being moved. */
1158 double deltaX, deltaY; /* Amount by which item is to be
1159 * moved. */
1160{
1161 register TextItem *textPtr = (TextItem *) itemPtr;
1162
1163 textPtr->x += deltaX;
1164 textPtr->y += deltaY;
1165 ComputeTextBbox(canvasPtr, textPtr);
1166}
1167\f
1168/*
1169 *--------------------------------------------------------------
1170 *
1171 * GetTextIndex --
1172 *
1173 * Parse an index into a text item and return either its value
1174 * or an error.
1175 *
1176 * Results:
1177 * A standard Tcl result. If all went well, then *indexPtr is
1178 * filled in with the index (into itemPtr) corresponding to
1179 * string. Otherwise an error message is left in
1180 * canvasPtr->interp->result.
1181 *
1182 * Side effects:
1183 * None.
1184 *
1185 *--------------------------------------------------------------
1186 */
1187
1188static int
1189GetTextIndex(canvasPtr, itemPtr, string, indexPtr)
1190 Tk_Canvas *canvasPtr; /* Canvas containing item. */
1191 Tk_Item *itemPtr; /* Item for which the index is being
1192 * specified. */
1193 char *string; /* Specification of a particular character
1194 * in itemPtr's text. */
1195 int *indexPtr; /* Where to store converted index. */
1196{
1197 register TextItem *textPtr = (TextItem *) itemPtr;
1198 int length;
1199
1200 length = strlen(string);
1201
1202 if (string[0] == 'e') {
1203 if (strncmp(string, "end", length) == 0) {
1204 *indexPtr = textPtr->numChars;
1205 } else {
1206 badIndex:
1207
1208 /*
1209 * Some of the paths here leave messages in
1210 * canvasPtr->interp->result, so we have to clear it out
1211 * before storing our own message.
1212 */
1213
1214 Tcl_SetResult(canvasPtr->interp, (char *) NULL, TCL_STATIC);
1215 Tcl_AppendResult(canvasPtr->interp, "bad index \"", string,
1216 "\"", (char *) NULL);
1217 return TCL_ERROR;
1218 }
1219 } else if (string[0] == 'c') {
1220 if (strncmp(string, "cursor", length) == 0) {
1221 *indexPtr = textPtr->cursorPos;
1222 } else {
1223 goto badIndex;
1224 }
1225 } else if (string[0] == 's') {
1226 if (canvasPtr->selItemPtr != itemPtr) {
1227 canvasPtr->interp->result = "selection isn't in item";
1228 return TCL_ERROR;
1229 }
1230 if (length < 5) {
1231 goto badIndex;
1232 }
1233 if (strncmp(string, "sel.first", length) == 0) {
1234 *indexPtr = canvasPtr->selectFirst;
1235 } else if (strncmp(string, "sel.last", length) == 0) {
1236 *indexPtr = canvasPtr->selectLast;
1237 } else {
1238 goto badIndex;
1239 }
1240 } else if (string[0] == '@') {
1241 int x, y, dummy, i;
1242 char *end, *p;
1243 register TextLine *linePtr;
1244
1245 p = string+1;
1246 x = strtol(p, &end, 0);
1247 if ((end == p) || (*end != ',')) {
1248 goto badIndex;
1249 }
1250 p = end+1;
1251 y = strtol(p, &end, 0);
1252 if ((end == p) || (*end != 0)) {
1253 goto badIndex;
1254 }
1255 if ((textPtr->numChars == 0) || (y < textPtr->linePtr[0].y1)) {
1256 *indexPtr = 0;
1257 return TCL_OK;
1258 }
1259 for (i = 0, linePtr = textPtr->linePtr; ; i++, linePtr++) {
1260 if (i >= textPtr->numLines) {
1261 *indexPtr = textPtr->numChars;
1262 return TCL_OK;
1263 }
1264 if (y <= linePtr->y2) {
1265 break;
1266 }
1267 }
1268 *indexPtr = TkMeasureChars(textPtr->fontPtr, linePtr->firstChar,
1269 linePtr->numChars, linePtr->x, x, 0, &dummy);
1270 *indexPtr += linePtr->firstChar - textPtr->text;
1271 } else {
1272 if (Tcl_GetInt(canvasPtr->interp, string, indexPtr) != TCL_OK) {
1273 goto badIndex;
1274 }
1275 if (*indexPtr < 0){
1276 *indexPtr = 0;
1277 } else if (*indexPtr > textPtr->numChars) {
1278 *indexPtr = textPtr->numChars;
1279 }
1280 }
1281 return TCL_OK;
1282}
1283\f
1284/*
1285 *--------------------------------------------------------------
1286 *
1287 * SetTextCursor --
1288 *
1289 * Set the position of the insertion cursor in this item.
1290 *
1291 * Results:
1292 * None.
1293 *
1294 * Side effects:
1295 * The cursor position will change.
1296 *
1297 *--------------------------------------------------------------
1298 */
1299
1300 /* ARGSUSED */
1301static void
1302SetTextCursor(canvasPtr, itemPtr, index)
1303 Tk_Canvas *canvasPtr; /* Record describing canvas widget. */
1304 Tk_Item *itemPtr; /* Text item in which cursor position
1305 * is to be set. */
1306 int index; /* Index of character just before which
1307 * cursor is to be positioned. */
1308{
1309 register TextItem *textPtr = (TextItem *) itemPtr;
1310
1311 if (index < 0) {
1312 textPtr->cursorPos = 0;
1313 } else if (index > textPtr->numChars) {
1314 textPtr->cursorPos = textPtr->numChars;
1315 } else {
1316 textPtr->cursorPos = index;
1317 }
1318}
1319\f
1320/*
1321 *--------------------------------------------------------------
1322 *
1323 * GetSelText --
1324 *
1325 * This procedure is invoked to return the selected portion
1326 * of a text item. It is only called when this item has
1327 * the selection.
1328 *
1329 * Results:
1330 * The return value is the number of non-NULL bytes stored
1331 * at buffer. Buffer is filled (or partially filled) with a
1332 * NULL-terminated string containing part or all of the selection,
1333 * as given by offset and maxBytes.
1334 *
1335 * Side effects:
1336 * None.
1337 *
1338 *--------------------------------------------------------------
1339 */
1340
1341static int
1342GetSelText(canvasPtr, itemPtr, offset, buffer, maxBytes)
1343 Tk_Canvas *canvasPtr; /* Canvas containing selection. */
1344 Tk_Item *itemPtr; /* Text item containing selection. */
1345 int offset; /* Offset within selection of first
1346 * character to be returned. */
1347 char *buffer; /* Location in which to place
1348 * selection. */
1349 int maxBytes; /* Maximum number of bytes to place
1350 * at buffer, not including terminating
1351 * NULL character. */
1352{
1353 TextItem *textPtr = (TextItem *) itemPtr;
1354 int count;
1355
1356 count = canvasPtr->selectLast + 1 - canvasPtr->selectFirst - offset;
1357 if (canvasPtr->selectLast == textPtr->numChars) {
1358 count -= 1;
1359 }
1360 if (count > maxBytes) {
1361 count = maxBytes;
1362 }
1363 if (count <= 0) {
1364 return 0;
1365 }
1366 strncpy(buffer, textPtr->text + canvasPtr->selectFirst + offset, count);
1367 buffer[count] = '\0';
1368 return count;
1369}
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