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1.1 root 1: /*
2: * tkCanvLine.c --
3: *
4: * This file implements line 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
17: static char rcsid[] = "$Header: /user6/ouster/wish/RCS/tkCanvLine.c,v 1.7 92/07/28 15:40:08 ouster Exp $ SPRITE (Berkeley)";
18: #endif
19:
20: #include <stdio.h>
21: #include <math.h>
22: #include "tkint.h"
23: #include "tkcanvas.h"
24: #include "tkconfig.h"
25:
26: /*
27: * The structure below defines the record for each line item.
28: */
29:
30: typedef struct LineItem {
31: Tk_Item header; /* Generic stuff that's the same for all
32: * types. MUST BE FIRST IN STRUCTURE. */
33: Tk_Canvas *canvasPtr; /* Canvas containing item. Needed for
34: * parsing arrow shapes. */
35: int numPoints; /* Number of points in line (always >= 2). */
36: double *coordPtr; /* Pointer to malloc-ed array containing
37: * x- and y-coords of all points in line.
38: * X-coords are even-valued indices, y-coords
39: * are corresponding odd-valued indices. */
40: int width; /* Width of line. */
41: XColor *fg; /* Foreground color for line. */
42: Pixmap fillStipple; /* Stipple bitmap for filling line. */
43: int capStyle; /* Cap style for line. */
44: int joinStyle; /* Join style for line. */
45: GC gc; /* Graphics context for filling line. */
46: Tk_Uid arrow; /* Indicates whether or not to draw arrowheads:
47: * "none", "first", "last", or "both". */
48: float arrowShapeA; /* Distance from tip of arrowhead to center. */
49: float arrowShapeB; /* Distance from tip of arrowhead to trailing
50: * point, measured along shaft. */
51: float arrowShapeC; /* Distance of trailing points from outside
52: * edge of shaft. */
53: double *firstArrowPtr; /* Points to array of 5 points describing
54: * polygon for arrowhead at first point in
55: * line. First point of arrowhead is tip.
56: * Malloc'ed. NULL means no arrowhead at
57: * first point. */
58: double *lastArrowPtr; /* Points to polygon for arrowhead at last
59: * point in line (5 points, first of which
60: * is tip). Malloc'ed. NULL means no
61: * arrowhead at last point. */
62: int smooth; /* Non-zero means draw line smoothed (i.e.
63: * with Bezier splines). */
64: int splineSteps; /* Number of steps in each spline segment. */
65: } LineItem;
66:
67: /*
68: * Number of points in an arrowHead:
69: */
70:
71: #define PTS_IN_ARROW 6
72:
73: /*
74: * Prototypes for procedures defined in this file:
75: */
76:
77: static void ComputeLineBbox _ANSI_ARGS_((Tk_Canvas *canvasPtr,
78: LineItem *linePtr));
79: static int ConfigureLine _ANSI_ARGS_((
80: Tk_Canvas *canvasPtr, Tk_Item *itemPtr, int argc,
81: char **argv, int flags));
82: static int ConfigureArrows _ANSI_ARGS_((Tk_Canvas *canvasPtr,
83: LineItem *linePtr));
84: static int CreateLine _ANSI_ARGS_((Tk_Canvas *canvasPtr,
85: struct Tk_Item *itemPtr, int argc, char **argv));
86: static void DeleteLine _ANSI_ARGS_((Tk_Item *itemPtr));
87: static void DisplayLine _ANSI_ARGS_((Tk_Canvas *canvasPtr,
88: Tk_Item *itemPtr, Drawable dst));
89: static int LineCoords _ANSI_ARGS_((Tk_Canvas *canvasPtr,
90: Tk_Item *itemPtr, int argc, char **argv));
91: static int LineToArea _ANSI_ARGS_((Tk_Canvas *canvasPtr,
92: Tk_Item *itemPtr, double *rectPtr));
93: static double LineToPoint _ANSI_ARGS_((Tk_Canvas *canvasPtr,
94: Tk_Item *itemPtr, double *coordPtr));
95: static int ParseArrowShape _ANSI_ARGS_((ClientData clientData,
96: Tcl_Interp *interp, Tk_Window tkwin, char *value,
97: char *recordPtr, int offset));
98: static char * PrintArrowShape _ANSI_ARGS_((ClientData clientData,
99: Tk_Window tkwin, char *recordPtr, int offset,
100: Tcl_FreeProc **freeProcPtr));
101: static void ScaleLine _ANSI_ARGS_((Tk_Canvas *canvasPtr,
102: Tk_Item *itemPtr, double originX, double originY,
103: double scaleX, double scaleY));
104: static void TranslateLine _ANSI_ARGS_((Tk_Canvas *canvasPtr,
105: Tk_Item *itemPtr, double deltaX, double deltaY));
106:
107: /*
108: * Information used for parsing configuration specs. If you change any
109: * of the default strings, be sure to change the corresponding default
110: * values in CreateLine.
111: */
112:
113: static Tk_CustomOption arrowShapeOption = {ParseArrowShape,
114: PrintArrowShape, (ClientData) NULL};
115:
116: static Tk_ConfigSpec configSpecs[] = {
117: {TK_CONFIG_UID, "-arrow", (char *) NULL, (char *) NULL,
118: "none", Tk_Offset(LineItem, arrow), TK_CONFIG_DONT_SET_DEFAULT},
119: {TK_CONFIG_CUSTOM, "-arrowshape", (char *) NULL, (char *) NULL,
120: "8 10 3", Tk_Offset(LineItem, arrowShapeA),
121: TK_CONFIG_DONT_SET_DEFAULT, &arrowShapeOption},
122: {TK_CONFIG_CAP_STYLE, "-capstyle", (char *) NULL, (char *) NULL,
123: "butt", Tk_Offset(LineItem, capStyle), TK_CONFIG_DONT_SET_DEFAULT},
124: {TK_CONFIG_COLOR, "-fill", (char *) NULL, (char *) NULL,
125: "black", Tk_Offset(LineItem, fg), 0},
126: {TK_CONFIG_JOIN_STYLE, "-joinstyle", (char *) NULL, (char *) NULL,
127: "round", Tk_Offset(LineItem, joinStyle), TK_CONFIG_DONT_SET_DEFAULT},
128: {TK_CONFIG_BOOLEAN, "-smooth", (char *) NULL, (char *) NULL,
129: "no", Tk_Offset(LineItem, smooth), TK_CONFIG_DONT_SET_DEFAULT},
130: {TK_CONFIG_INT, "-splinesteps", (char *) NULL, (char *) NULL,
131: "12", Tk_Offset(LineItem, splineSteps), TK_CONFIG_DONT_SET_DEFAULT},
132: {TK_CONFIG_BITMAP, "-stipple", (char *) NULL, (char *) NULL,
133: (char *) NULL, Tk_Offset(LineItem, fillStipple), TK_CONFIG_NULL_OK},
134: {TK_CONFIG_CUSTOM, "-tags", (char *) NULL, (char *) NULL,
135: (char *) NULL, 0, TK_CONFIG_NULL_OK, &tkCanvasTagsOption},
136: {TK_CONFIG_PIXELS, "-width", (char *) NULL, (char *) NULL,
137: "1", Tk_Offset(LineItem, width), TK_CONFIG_DONT_SET_DEFAULT},
138: {TK_CONFIG_END, (char *) NULL, (char *) NULL, (char *) NULL,
139: (char *) NULL, 0, 0}
140: };
141:
142: /*
143: * The structures below defines the line item type by means
144: * of procedures that can be invoked by generic item code.
145: */
146:
147: Tk_ItemType TkLineType = {
148: "line", /* name */
149: sizeof(LineItem), /* itemSize */
150: CreateLine, /* createProc */
151: configSpecs, /* configSpecs */
152: ConfigureLine, /* configureProc */
153: LineCoords, /* coordProc */
154: DeleteLine, /* deleteProc */
155: DisplayLine, /* displayProc */
156: 0, /* alwaysRedraw */
157: LineToPoint, /* pointProc */
158: LineToArea, /* areaProc */
159: (Tk_ItemPostscriptProc *) NULL, /* postscriptProc */
160: ScaleLine, /* scaleProc */
161: TranslateLine, /* translateProc */
162: (Tk_ItemIndexProc *) NULL, /* indexProc */
163: (Tk_ItemCursorProc *) NULL, /* cursorProc */
164: (Tk_ItemSelectionProc *) NULL, /* selectionProc */
165: (Tk_ItemInsertProc *) NULL, /* insertProc */
166: (Tk_ItemDCharsProc *) NULL, /* dTextProc */
167: (Tk_ItemType *) NULL /* nextPtr */
168: };
169:
170: /*
171: * The Tk_Uid's below refer to uids for the various arrow types:
172: */
173:
174: static Tk_Uid noneUid = NULL;
175: static Tk_Uid firstUid = NULL;
176: static Tk_Uid lastUid = NULL;
177: static Tk_Uid bothUid = NULL;
178:
179: /*
180: * The definition below determines how large are static arrays
181: * used to hold spline points (splines larger than this have to
182: * have their arrays malloc-ed).
183: */
184:
185: #define MAX_STATIC_POINTS 200
186:
187: /*
188: *--------------------------------------------------------------
189: *
190: * CreateLine --
191: *
192: * This procedure is invoked to create a new line item in
193: * a canvas.
194: *
195: * Results:
196: * A standard Tcl return value. If an error occurred in
197: * creating the item, then an error message is left in
198: * canvasPtr->interp->result; in this case itemPtr is
199: * left uninitialized, so it can be safely freed by the
200: * caller.
201: *
202: * Side effects:
203: * A new line item is created.
204: *
205: *--------------------------------------------------------------
206: */
207:
208: static int
209: CreateLine(canvasPtr, itemPtr, argc, argv)
210: register Tk_Canvas *canvasPtr; /* Canvas to hold new item. */
211: Tk_Item *itemPtr; /* Record to hold new item; header
212: * has been initialized by caller. */
213: int argc; /* Number of arguments in argv. */
214: char **argv; /* Arguments describing line. */
215: {
216: register LineItem *linePtr = (LineItem *) itemPtr;
217: int i;
218:
219: if (argc < 4) {
220: Tcl_AppendResult(canvasPtr->interp, "wrong # args: should be \"",
221: Tk_PathName(canvasPtr->tkwin),
222: "\" create x1 y1 x2 y2 ?x3 y3 ...? ?options?",
223: (char *) NULL);
224: return TCL_ERROR;
225: }
226:
227: /*
228: * Carry out initialization that is needed to set defaults and to
229: * allow proper cleanup after errors during the the remainder of
230: * this procedure.
231: */
232:
233: linePtr->canvasPtr = canvasPtr;
234: linePtr->numPoints = 0;
235: linePtr->coordPtr = NULL;
236: linePtr->width = 1;
237: linePtr->fg = None;
238: linePtr->fillStipple = None;
239: linePtr->capStyle = CapButt;
240: linePtr->joinStyle = JoinRound;
241: linePtr->gc = None;
242: if (noneUid == NULL) {
243: noneUid = Tk_GetUid("none");
244: firstUid = Tk_GetUid("first");
245: lastUid = Tk_GetUid("last");
246: bothUid = Tk_GetUid("both");
247: }
248: linePtr->arrow = noneUid;
249: linePtr->arrowShapeA = 8.0;
250: linePtr->arrowShapeB = 10.0;
251: linePtr->arrowShapeC = 3.0;
252: linePtr->firstArrowPtr = NULL;
253: linePtr->lastArrowPtr = NULL;
254: linePtr->smooth = 0;
255: linePtr->splineSteps = 12;
256:
257: /*
258: * Count the number of points and then parse them into a point
259: * array. Leading arguments are assumed to be points if they
260: * start with a digit or a minus sign followed by a digit.
261: */
262:
263: for (i = 4; i < (argc-1); i+=2) {
264: if ((!isdigit(argv[i][0])) &&
265: ((argv[i][0] != '-') || (!isdigit(argv[i][1])))) {
266: break;
267: }
268: }
269: if (LineCoords(canvasPtr, itemPtr, i, argv) != TCL_OK) {
270: goto error;
271: }
272: if (ConfigureLine(canvasPtr, itemPtr, argc-i, argv+i, 0) == TCL_OK) {
273: return TCL_OK;
274: }
275:
276: error:
277: DeleteLine(itemPtr);
278: return TCL_ERROR;
279: }
280:
281: /*
282: *--------------------------------------------------------------
283: *
284: * LineCoords --
285: *
286: * This procedure is invoked to process the "coords" widget
287: * command on lines. See the user documentation for details
288: * on what it does.
289: *
290: * Results:
291: * Returns TCL_OK or TCL_ERROR, and sets canvasPtr->interp->result.
292: *
293: * Side effects:
294: * The coordinates for the given item may be changed.
295: *
296: *--------------------------------------------------------------
297: */
298:
299: static int
300: LineCoords(canvasPtr, itemPtr, argc, argv)
301: register Tk_Canvas *canvasPtr; /* Canvas containing item. */
302: Tk_Item *itemPtr; /* Item whose coordinates are to be
303: * read or modified. */
304: int argc; /* Number of coordinates supplied in
305: * argv. */
306: char **argv; /* Array of coordinates: x1, y1,
307: * x2, y2, ... */
308: {
309: register LineItem *linePtr = (LineItem *) itemPtr;
310: char buffer[300];
311: int i, numPoints;
312:
313: if (argc == 0) {
314: for (i = 0; i < 2*linePtr->numPoints; i++) {
315: sprintf(buffer, "%g", linePtr->coordPtr[i]);
316: Tcl_AppendElement(canvasPtr->interp, buffer, 0);
317: }
318: } else if (argc < 4) {
319: Tcl_AppendResult(canvasPtr->interp,
320: "too few coordinates for line: must have at least 4",
321: (char *) NULL);
322: return TCL_ERROR;
323: } else if (argc & 1) {
324: Tcl_AppendResult(canvasPtr->interp,
325: "odd number of coordinates specified for line",
326: (char *) NULL);
327: return TCL_ERROR;
328: } else {
329: numPoints = argc/2;
330: if (linePtr->numPoints != numPoints) {
331: if (linePtr->coordPtr != NULL) {
332: ckfree((char *) linePtr->coordPtr);
333: }
334: linePtr->coordPtr = (double *) ckalloc((unsigned)
335: (sizeof(double) * argc));
336: linePtr->numPoints = numPoints;
337: }
338: for (i = argc-1; i >= 0; i--) {
339: if (TkGetCanvasCoord(canvasPtr, argv[i], &linePtr->coordPtr[i])
340: != TCL_OK) {
341: return TCL_ERROR;
342: }
343: }
344: ComputeLineBbox(canvasPtr, linePtr);
345: }
346: return TCL_OK;
347: }
348:
349: /*
350: *--------------------------------------------------------------
351: *
352: * ConfigureLine --
353: *
354: * This procedure is invoked to configure various aspects
355: * of a line item such as its background color.
356: *
357: * Results:
358: * A standard Tcl result code. If an error occurs, then
359: * an error message is left in canvasPtr->interp->result.
360: *
361: * Side effects:
362: * Configuration information, such as colors and stipple
363: * patterns, may be set for itemPtr.
364: *
365: *--------------------------------------------------------------
366: */
367:
368: static int
369: ConfigureLine(canvasPtr, itemPtr, argc, argv, flags)
370: Tk_Canvas *canvasPtr; /* Canvas containing itemPtr. */
371: Tk_Item *itemPtr; /* Line item to reconfigure. */
372: int argc; /* Number of elements in argv. */
373: char **argv; /* Arguments describing things to configure. */
374: int flags; /* Flags to pass to Tk_ConfigureWidget. */
375: {
376: register LineItem *linePtr = (LineItem *) itemPtr;
377: XGCValues gcValues;
378: GC newGC;
379: unsigned long mask;
380:
381: if (Tk_ConfigureWidget(canvasPtr->interp, canvasPtr->tkwin,
382: configSpecs, argc, argv, (char *) linePtr, flags) != TCL_OK) {
383: return TCL_ERROR;
384: }
385:
386: /*
387: * A few of the options require additional processing, such as
388: * graphics contexts.
389: */
390:
391: if (linePtr->fg == NULL) {
392: newGC = None;
393: } else {
394: gcValues.foreground = linePtr->fg->pixel;
395: gcValues.join_style = linePtr->joinStyle;
396: if (linePtr->width < 0) {
397: linePtr->width = 1;
398: }
399: gcValues.line_width = linePtr->width;
400: mask = GCForeground|GCJoinStyle|GCLineWidth;
401: if (linePtr->fillStipple != None) {
402: gcValues.stipple = linePtr->fillStipple;
403: gcValues.fill_style = FillStippled;
404: mask |= GCStipple|GCFillStyle;
405: }
406: if (linePtr->arrow == noneUid) {
407: gcValues.cap_style = linePtr->capStyle;
408: mask |= GCCapStyle;
409: }
410: newGC = Tk_GetGC(canvasPtr->tkwin, mask, &gcValues);
411: }
412: if (linePtr->gc != None) {
413: Tk_FreeGC(linePtr->gc);
414: }
415: linePtr->gc = newGC;
416:
417: /*
418: * Keep spline parameters within reasonable limits.
419: */
420:
421: if (linePtr->splineSteps < 1) {
422: linePtr->splineSteps = 1;
423: } else if (linePtr->splineSteps > 100) {
424: linePtr->splineSteps = 100;
425: }
426:
427: /*
428: * Setup arrowheads, if needed. If arrowheads are turned off,
429: * restore the line's endpoints (they were shortened when the
430: * arrowheads were added).
431: */
432:
433: if ((linePtr->firstArrowPtr != NULL) && (linePtr->arrow != firstUid)
434: && (linePtr->arrow != bothUid)) {
435: linePtr->coordPtr[0] = linePtr->firstArrowPtr[0];
436: linePtr->coordPtr[1] = linePtr->firstArrowPtr[1];
437: ckfree((char *) linePtr->firstArrowPtr);
438: linePtr->firstArrowPtr = NULL;
439: }
440: if ((linePtr->lastArrowPtr != NULL) && (linePtr->arrow != lastUid)
441: && (linePtr->arrow != bothUid)) {
442: int index;
443:
444: index = 2*(linePtr->numPoints-1);
445: linePtr->coordPtr[index] = linePtr->lastArrowPtr[0];
446: linePtr->coordPtr[index+1] = linePtr->lastArrowPtr[1];
447: ckfree((char *) linePtr->lastArrowPtr);
448: linePtr->lastArrowPtr = NULL;
449: }
450: if (linePtr->arrow != noneUid) {
451: if ((linePtr->arrow != firstUid) && (linePtr->arrow != lastUid)
452: && (linePtr->arrow != bothUid)) {
453: Tcl_AppendResult(canvasPtr->interp, "bad arrow spec \"",
454: linePtr->arrow, "\": must be none, first, last, or both",
455: (char *) NULL);
456: linePtr->arrow = noneUid;
457: return TCL_ERROR;
458: }
459: ConfigureArrows(canvasPtr, linePtr);
460: }
461:
462: /*
463: * Recompute bounding box for line.
464: */
465:
466: ComputeLineBbox(canvasPtr, linePtr);
467:
468: return TCL_OK;
469: }
470:
471: /*
472: *--------------------------------------------------------------
473: *
474: * DeleteLine --
475: *
476: * This procedure is called to clean up the data structure
477: * associated with a line item.
478: *
479: * Results:
480: * None.
481: *
482: * Side effects:
483: * Resources associated with itemPtr are released.
484: *
485: *--------------------------------------------------------------
486: */
487:
488: static void
489: DeleteLine(itemPtr)
490: Tk_Item *itemPtr; /* Item that is being deleted. */
491: {
492: register LineItem *linePtr = (LineItem *) itemPtr;
493:
494: if (linePtr->coordPtr != NULL) {
495: ckfree((char *) linePtr->coordPtr);
496: }
497: if (linePtr->fg != NULL) {
498: Tk_FreeColor(linePtr->fg);
499: }
500: if (linePtr->fillStipple != None) {
501: Tk_FreeBitmap(linePtr->fillStipple);
502: }
503: if (linePtr->gc != None) {
504: Tk_FreeGC(linePtr->gc);
505: }
506: if (linePtr->firstArrowPtr != NULL) {
507: ckfree((char *) linePtr->firstArrowPtr);
508: }
509: if (linePtr->lastArrowPtr != NULL) {
510: ckfree((char *) linePtr->lastArrowPtr);
511: }
512: }
513:
514: /*
515: *--------------------------------------------------------------
516: *
517: * ComputeLineBbox --
518: *
519: * This procedure is invoked to compute the bounding box of
520: * all the pixels that may be drawn as part of a line.
521: *
522: * Results:
523: * None.
524: *
525: * Side effects:
526: * The fields x1, y1, x2, and y2 are updated in the header
527: * for itemPtr.
528: *
529: *--------------------------------------------------------------
530: */
531:
532: static void
533: ComputeLineBbox(canvasPtr, linePtr)
534: register Tk_Canvas *canvasPtr; /* Canvas that contains item. */
535: LineItem *linePtr; /* Item whose bbos is to be
536: * recomputed. */
537: {
538: register double *coordPtr;
539: int i;
540:
541: coordPtr = linePtr->coordPtr;
542: linePtr->header.x1 = linePtr->header.x2 = *coordPtr;
543: linePtr->header.y1 = linePtr->header.y2 = coordPtr[1];
544:
545: /*
546: * Compute the bounding box of all the points in the line,
547: * then expand in all directions by the line's width to take
548: * care of butting or rounded corners and projecting or
549: * rounded caps. This expansion is an overestimate (worst-case
550: * is square root of two over two) but it's simple. Don't do
551: * anything special for curves. This causes an additional
552: * overestimate in the bounding box, but is faster.
553: */
554:
555: for (i = 1, coordPtr = linePtr->coordPtr+2; i < linePtr->numPoints;
556: i++, coordPtr += 2) {
557: TkIncludePoint(canvasPtr, (Tk_Item *) linePtr, coordPtr);
558: }
559: linePtr->header.x1 -= linePtr->width;
560: linePtr->header.x2 += linePtr->width;
561: linePtr->header.y1 -= linePtr->width;
562: linePtr->header.y2 += linePtr->width;
563:
564: /*
565: * For mitered lines, make a second pass through all the points.
566: * Compute the locations of the two miter vertex points and add
567: * those into the bounding box.
568: */
569:
570: if (linePtr->joinStyle == JoinMiter) {
571: for (i = linePtr->numPoints, coordPtr = linePtr->coordPtr; i >= 3;
572: i--, coordPtr += 2) {
573: double miter[4];
574: int j;
575:
576: if (TkGetMiterPoints(coordPtr, coordPtr+2, coordPtr+4,
577: (double) linePtr->width, miter, miter+2)) {
578: for (j = 0; j < 4; j += 2) {
579: TkIncludePoint(canvasPtr, (Tk_Item *) linePtr, miter+j);
580: }
581: }
582: }
583: }
584:
585: /*
586: * Add in the sizes of arrowheads, if any.
587: */
588:
589: if (linePtr->arrow != noneUid) {
590: if (linePtr->arrow != lastUid) {
591: for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
592: i++, coordPtr += 2) {
593: TkIncludePoint(canvasPtr, (Tk_Item *) linePtr, coordPtr);
594: }
595: }
596: if (linePtr->arrow != firstUid) {
597: for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
598: i++, coordPtr += 2) {
599: TkIncludePoint(canvasPtr, (Tk_Item *) linePtr, coordPtr);
600: }
601: }
602: }
603:
604: /*
605: * Add one more pixel of fudge factor just to be safe (e.g.
606: * X may round differently than we do).
607: */
608:
609: linePtr->header.x1 -= 1;
610: linePtr->header.x2 += 1;
611: linePtr->header.y1 -= 1;
612: linePtr->header.y2 += 1;
613: }
614:
615: /*
616: *--------------------------------------------------------------
617: *
618: * DisplayLine --
619: *
620: * This procedure is invoked to draw a line item in a given
621: * drawable.
622: *
623: * Results:
624: * None.
625: *
626: * Side effects:
627: * ItemPtr is drawn in drawable using the transformation
628: * information in canvasPtr.
629: *
630: *--------------------------------------------------------------
631: */
632:
633: static void
634: DisplayLine(canvasPtr, itemPtr, drawable)
635: register Tk_Canvas *canvasPtr; /* Canvas that contains item. */
636: Tk_Item *itemPtr; /* Item to be displayed. */
637: Drawable drawable; /* Pixmap or window in which to draw
638: * item. */
639: {
640: register LineItem *linePtr = (LineItem *) itemPtr;
641: XPoint staticPoints[MAX_STATIC_POINTS];
642: XPoint *pointPtr;
643: register XPoint *pPtr;
644: register double *coordPtr;
645: int i, numPoints;
646:
647: if (linePtr->gc == None) {
648: return;
649: }
650:
651: /*
652: * Build up an array of points in screen coordinates. Use a
653: * static array unless the line has an enormous number of points;
654: * in this case, dynamically allocate an array. For smoothed lines,
655: * generate the curve points on each redisplay.
656: */
657:
658: if ((linePtr->smooth) && (linePtr->numPoints > 2)) {
659: numPoints = 1 + linePtr->numPoints*linePtr->splineSteps;
660: } else {
661: numPoints = linePtr->numPoints;
662: }
663:
664: if (numPoints <= MAX_STATIC_POINTS) {
665: pointPtr = staticPoints;
666: } else {
667: pointPtr = (XPoint *) ckalloc((unsigned) (numPoints * sizeof(XPoint)));
668: }
669:
670: if (linePtr->smooth) {
671: numPoints = TkMakeBezierCurve(canvasPtr, linePtr->coordPtr,
672: linePtr->numPoints, linePtr->splineSteps, pointPtr,
673: (double *) NULL);
674: } else {
675: for (i = 0, coordPtr = linePtr->coordPtr, pPtr = pointPtr;
676: i < linePtr->numPoints; i += 1, coordPtr += 2, pPtr++) {
677: pPtr->x = SCREEN_X(canvasPtr, *coordPtr);
678: pPtr->y = SCREEN_Y(canvasPtr, coordPtr[1]);
679: }
680: }
681:
682: /*
683: * Display line, the free up line storage if it was dynamically
684: * allocated.
685: */
686:
687: XDrawLines(Tk_Display(canvasPtr->tkwin), drawable, linePtr->gc,
688: pointPtr, numPoints, CoordModeOrigin);
689: if (pointPtr != staticPoints) {
690: ckfree((char *) pointPtr);
691: }
692:
693: /*
694: * Display arrowheads, if they are wanted.
695: */
696:
697: if (linePtr->arrow != noneUid) {
698: if (linePtr->arrow != lastUid) {
699: TkFillPolygon(canvasPtr, linePtr->firstArrowPtr, PTS_IN_ARROW,
700: drawable, linePtr->gc);
701: }
702: if (linePtr->arrow != firstUid) {
703: TkFillPolygon(canvasPtr, linePtr->lastArrowPtr, PTS_IN_ARROW,
704: drawable, linePtr->gc);
705: }
706: }
707: }
708:
709: /*
710: *--------------------------------------------------------------
711: *
712: * LineToPoint --
713: *
714: * Computes the distance from a given point to a given
715: * line, in canvas units.
716: *
717: * Results:
718: * The return value is 0 if the point whose x and y coordinates
719: * are pointPtr[0] and pointPtr[1] is inside the line. If the
720: * point isn't inside the line then the return value is the
721: * distance from the point to the line.
722: *
723: * Side effects:
724: * None.
725: *
726: *--------------------------------------------------------------
727: */
728:
729: /* ARGSUSED */
730: static double
731: LineToPoint(canvasPtr, itemPtr, pointPtr)
732: Tk_Canvas *canvasPtr; /* Canvas containing item. */
733: Tk_Item *itemPtr; /* Item to check against point. */
734: double *pointPtr; /* Pointer to x and y coordinates. */
735: {
736: register LineItem *linePtr = (LineItem *) itemPtr;
737: register double *coordPtr, *linePoints;
738: double staticSpace[2*MAX_STATIC_POINTS];
739: double poly[10];
740: double bestDist, dist;
741: int numPoints, count;
742: int changedMiterToBevel; /* Non-zero means that a mitered corner
743: * had to be treated as beveled after all
744: * because the angle was < 11 degrees. */
745:
746: bestDist = 1.0e40;
747:
748: /*
749: * Handle smoothed lines by generating an expanded set of points
750: * against which to do the check.
751: */
752:
753: if ((linePtr->smooth) && (linePtr->numPoints > 2)) {
754: numPoints = 1 + linePtr->numPoints*linePtr->splineSteps;
755: if (numPoints <= MAX_STATIC_POINTS) {
756: linePoints = staticSpace;
757: } else {
758: linePoints = (double *) ckalloc((unsigned)
759: (2*numPoints*sizeof(double)));
760: }
761: numPoints = TkMakeBezierCurve(canvasPtr, linePtr->coordPtr,
762: linePtr->numPoints, linePtr->splineSteps, (XPoint *) NULL,
763: linePoints);
764: } else {
765: numPoints = linePtr->numPoints;
766: linePoints = linePtr->coordPtr;
767: }
768:
769: /*
770: * The overall idea is to iterate through all of the edges of
771: * the line, computing a polygon for each edge and testing the
772: * point against that polygon. In addition, there are additional
773: * tests to deal with rounded joints and caps.
774: */
775:
776: changedMiterToBevel = 0;
777: for (count = numPoints, coordPtr = linePoints; count >= 2;
778: count--, coordPtr += 2) {
779:
780: /*
781: * If rounding is done around the first point then compute
782: * the distance between the point and the point.
783: */
784:
785: if (((linePtr->capStyle == CapRound) && (count == numPoints))
786: || ((linePtr->joinStyle == JoinRound)
787: && (count != numPoints))) {
788: dist = hypot(coordPtr[0] - pointPtr[0], coordPtr[1] - pointPtr[1])
789: - linePtr->width/2.0;
790: if (dist <= 0.0) {
791: bestDist = 0.0;
792: goto done;
793: } else if (dist < bestDist) {
794: bestDist = dist;
795: }
796: }
797:
798: /*
799: * Compute the polygonal shape corresponding to this edge,
800: * consisting of two points for the first point of the edge
801: * and two points for the last point of the edge.
802: */
803:
804: if (count == numPoints) {
805: TkGetButtPoints(coordPtr+2, coordPtr, (double) linePtr->width,
806: linePtr->capStyle == CapProjecting, poly, poly+2);
807: } else if ((linePtr->joinStyle == JoinMiter) && !changedMiterToBevel) {
808: poly[0] = poly[6];
809: poly[1] = poly[7];
810: poly[2] = poly[4];
811: poly[3] = poly[5];
812: } else {
813: TkGetButtPoints(coordPtr+2, coordPtr, (double) linePtr->width, 0,
814: poly, poly+2);
815:
816: /*
817: * If this line uses beveled joints, then check the distance
818: * to a polygon comprising the last two points of the previous
819: * polygon and the first two from this polygon; this checks
820: * the wedges that fill the mitered joint.
821: */
822:
823: if ((linePtr->joinStyle == JoinBevel) || changedMiterToBevel) {
824: poly[8] = poly[0];
825: poly[9] = poly[1];
826: dist = TkPolygonToPoint(poly, 5, pointPtr);
827: if (dist <= 0.0) {
828: bestDist = 0.0;
829: goto done;
830: } else if (dist < bestDist) {
831: bestDist = dist;
832: }
833: changedMiterToBevel = 0;
834: }
835: }
836: if (count == 2) {
837: TkGetButtPoints(coordPtr, coordPtr+2, (double) linePtr->width,
838: linePtr->capStyle == CapProjecting, poly+4, poly+6);
839: } else if (linePtr->joinStyle == JoinMiter) {
840: if (TkGetMiterPoints(coordPtr, coordPtr+2, coordPtr+4,
841: (double) linePtr->width, poly+4, poly+6) == 0) {
842: changedMiterToBevel = 1;
843: TkGetButtPoints(coordPtr, coordPtr+2, (double) linePtr->width,
844: 0, poly+4, poly+6);
845: }
846: } else {
847: TkGetButtPoints(coordPtr, coordPtr+2, (double) linePtr->width, 0,
848: poly+4, poly+6);
849: }
850: poly[8] = poly[0];
851: poly[9] = poly[1];
852: dist = TkPolygonToPoint(poly, 5, pointPtr);
853: if (dist <= 0.0) {
854: bestDist = 0.0;
855: goto done;
856: } else if (dist < bestDist) {
857: bestDist = dist;
858: }
859: }
860:
861: /*
862: * If caps are rounded, check the distance to the cap around the
863: * final end point of the line.
864: */
865:
866: if (linePtr->capStyle == CapRound) {
867: dist = hypot(coordPtr[0] - pointPtr[0], coordPtr[1] - pointPtr[1])
868: - linePtr->width/2.0;
869: if (dist <= 0.0) {
870: bestDist = 0.0;
871: goto done;
872: } else if (dist < bestDist) {
873: bestDist = dist;
874: }
875: }
876:
877: /*
878: * If there are arrowheads, check the distance to the arrowheads.
879: */
880:
881: if (linePtr->arrow != noneUid) {
882: if (linePtr->arrow != lastUid) {
883: dist = TkPolygonToPoint(linePtr->firstArrowPtr, PTS_IN_ARROW,
884: pointPtr);
885: if (dist <= 0.0) {
886: bestDist = 0.0;
887: goto done;
888: } else if (dist < bestDist) {
889: bestDist = dist;
890: }
891: }
892: if (linePtr->arrow != firstUid) {
893: dist = TkPolygonToPoint(linePtr->lastArrowPtr, PTS_IN_ARROW,
894: pointPtr);
895: if (dist <= 0.0) {
896: bestDist = 0.0;
897: goto done;
898: } else if (dist < bestDist) {
899: bestDist = dist;
900: }
901: }
902: }
903:
904: done:
905: if ((linePoints != staticSpace) && (linePoints != linePtr->coordPtr)) {
906: ckfree((char *) linePoints);
907: }
908: return bestDist;
909: }
910:
911: /*
912: *--------------------------------------------------------------
913: *
914: * LineToArea --
915: *
916: * This procedure is called to determine whether an item
917: * lies entirely inside, entirely outside, or overlapping
918: * a given rectangular area.
919: *
920: * Results:
921: * -1 is returned if the item is entirely outside the
922: * area, 0 if it overlaps, and 1 if it is entirely
923: * inside the given area.
924: *
925: * Side effects:
926: * None.
927: *
928: *--------------------------------------------------------------
929: */
930:
931: /* ARGSUSED */
932: static int
933: LineToArea(canvasPtr, itemPtr, rectPtr)
934: Tk_Canvas *canvasPtr; /* Canvas containing item. */
935: Tk_Item *itemPtr; /* Item to check against line. */
936: double *rectPtr;
937: {
938: register LineItem *linePtr = (LineItem *) itemPtr;
939: register double *coordPtr;
940: double staticSpace[2*MAX_STATIC_POINTS];
941: double *linePoints, poly[10];
942: double radius;
943: int numPoints, count;
944: int changedMiterToBevel; /* Non-zero means that a mitered corner
945: * had to be treated as beveled after all
946: * because the angle was < 11 degrees. */
947: int inside; /* Tentative guess about what to return,
948: * based on all points seen so far: one
949: * means everything seen so far was
950: * inside the area; -1 means everything
951: * was outside the area. 0 means overlap
952: * has been found. */
953:
954: radius = linePtr->width/2.0;
955: inside = -1;
956:
957: /*
958: * Handle smoothed lines by generating an expanded set of points
959: * against which to do the check.
960: */
961:
962: if ((linePtr->smooth) && (linePtr->numPoints > 2)) {
963: numPoints = 1 + linePtr->numPoints*linePtr->splineSteps;
964: if (numPoints <= MAX_STATIC_POINTS) {
965: linePoints = staticSpace;
966: } else {
967: linePoints = (double *) ckalloc((unsigned)
968: (2*numPoints*sizeof(double)));
969: }
970: numPoints = TkMakeBezierCurve(canvasPtr, linePtr->coordPtr,
971: linePtr->numPoints, linePtr->splineSteps, (XPoint *) NULL,
972: linePoints);
973: } else {
974: numPoints = linePtr->numPoints;
975: linePoints = linePtr->coordPtr;
976: }
977:
978: coordPtr = linePoints;
979: if ((coordPtr[0] >= rectPtr[0]) && (coordPtr[0] <= rectPtr[2])
980: && (coordPtr[1] >= rectPtr[1]) && (coordPtr[1] <= rectPtr[3])) {
981: inside = 1;
982: }
983:
984: /*
985: * Iterate through all of the edges of the line, computing a polygon
986: * for each edge and testing the area against that polygon. In
987: * addition, there are additional tests to deal with rounded joints
988: * and caps.
989: */
990:
991: changedMiterToBevel = 0;
992: for (count = numPoints; count >= 2; count--, coordPtr += 2) {
993:
994: /*
995: * If rounding is done around the first point of the edge
996: * then test a circular region around the point with the
997: * area.
998: */
999:
1000: if (((linePtr->capStyle == CapRound) && (count == numPoints))
1001: || ((linePtr->joinStyle == JoinRound)
1002: && (count != numPoints))) {
1003: poly[0] = coordPtr[0] - radius;
1004: poly[1] = coordPtr[1] - radius;
1005: poly[2] = coordPtr[0] + radius;
1006: poly[3] = coordPtr[1] + radius;
1007: if (TkOvalToArea(poly, rectPtr) != inside) {
1008: inside = 0;
1009: goto done;
1010: }
1011: }
1012:
1013: /*
1014: * Compute the polygonal shape corresponding to this edge,
1015: * consisting of two points for the first point of the edge
1016: * and two points for the last point of the edge.
1017: */
1018:
1019: if (count == numPoints) {
1020: TkGetButtPoints(coordPtr+2, coordPtr, (double) linePtr->width,
1021: linePtr->capStyle == CapProjecting, poly, poly+2);
1022: } else if ((linePtr->joinStyle == JoinMiter) && !changedMiterToBevel) {
1023: poly[0] = poly[6];
1024: poly[1] = poly[7];
1025: poly[2] = poly[4];
1026: poly[3] = poly[5];
1027: } else {
1028: TkGetButtPoints(coordPtr+2, coordPtr, (double) linePtr->width, 0,
1029: poly, poly+2);
1030:
1031: /*
1032: * If the last joint was beveled, then also check a
1033: * polygon comprising the last two points of the previous
1034: * polygon and the first two from this polygon; this checks
1035: * the wedges that fill the beveled joint.
1036: */
1037:
1038: if ((linePtr->joinStyle == JoinBevel) || changedMiterToBevel) {
1039: poly[8] = poly[0];
1040: poly[9] = poly[1];
1041: if (TkPolygonToArea(poly, 5, rectPtr) != inside) {
1042: inside = 0;
1043: goto done;
1044: }
1045: changedMiterToBevel = 0;
1046: }
1047: }
1048: if (count == 2) {
1049: TkGetButtPoints(coordPtr, coordPtr+2, (double) linePtr->width,
1050: linePtr->capStyle == CapProjecting, poly+4, poly+6);
1051: } else if (linePtr->joinStyle == JoinMiter) {
1052: if (TkGetMiterPoints(coordPtr, coordPtr+2, coordPtr+4,
1053: (double) linePtr->width, poly+4, poly+6) == 0) {
1054: changedMiterToBevel = 1;
1055: TkGetButtPoints(coordPtr, coordPtr+2, (double) linePtr->width,
1056: 0, poly+4, poly+6);
1057: }
1058: } else {
1059: TkGetButtPoints(coordPtr, coordPtr+2, (double) linePtr->width, 0,
1060: poly+4, poly+6);
1061: }
1062: poly[8] = poly[0];
1063: poly[9] = poly[1];
1064: if (TkPolygonToArea(poly, 5, rectPtr) != inside) {
1065: inside = 0;
1066: goto done;
1067: }
1068: }
1069:
1070: /*
1071: * If caps are rounded, check the cap around the final point
1072: * of the line.
1073: */
1074:
1075: if (linePtr->capStyle == CapRound) {
1076: poly[0] = coordPtr[0] - radius;
1077: poly[1] = coordPtr[1] - radius;
1078: poly[2] = coordPtr[0] + radius;
1079: poly[3] = coordPtr[1] + radius;
1080: if (TkOvalToArea(poly, rectPtr) != inside) {
1081: inside = 0;
1082: goto done;
1083: }
1084: }
1085:
1086: /*
1087: * Check arrowheads, if any.
1088: */
1089:
1090: if (linePtr->arrow != noneUid) {
1091: if (linePtr->arrow != lastUid) {
1092: if (TkPolygonToArea(linePtr->firstArrowPtr, PTS_IN_ARROW,
1093: rectPtr) != inside) {
1094: inside = 0;
1095: goto done;
1096: }
1097: }
1098: if (linePtr->arrow != firstUid) {
1099: if (TkPolygonToArea(linePtr->lastArrowPtr, PTS_IN_ARROW,
1100: rectPtr) != inside) {
1101: inside = 0;
1102: goto done;
1103: }
1104: }
1105: }
1106:
1107: done:
1108: if ((linePoints != staticSpace) && (linePoints != linePtr->coordPtr)) {
1109: ckfree((char *) linePoints);
1110: }
1111: return inside;
1112: }
1113:
1114: /*
1115: *--------------------------------------------------------------
1116: *
1117: * ScaleLine --
1118: *
1119: * This procedure is invoked to rescale a line item.
1120: *
1121: * Results:
1122: * None.
1123: *
1124: * Side effects:
1125: * The line referred to by itemPtr is rescaled so that the
1126: * following transformation is applied to all point
1127: * coordinates:
1128: * x' = originX + scaleX*(x-originX)
1129: * y' = originY + scaleY*(y-originY)
1130: *
1131: *--------------------------------------------------------------
1132: */
1133:
1134: static void
1135: ScaleLine(canvasPtr, itemPtr, originX, originY, scaleX, scaleY)
1136: Tk_Canvas *canvasPtr; /* Canvas containing line. */
1137: Tk_Item *itemPtr; /* Line to be scaled. */
1138: double originX, originY; /* Origin about which to scale rect. */
1139: double scaleX; /* Amount to scale in X direction. */
1140: double scaleY; /* Amount to scale in Y direction. */
1141: {
1142: LineItem *linePtr = (LineItem *) itemPtr;
1143: register double *coordPtr;
1144: int i;
1145:
1146: for (i = 0, coordPtr = linePtr->coordPtr; i < linePtr->numPoints;
1147: i++, coordPtr += 2) {
1148: coordPtr[0] = originX + scaleX*(*coordPtr - originX);
1149: coordPtr[1] = originY + scaleY*(coordPtr[1] - originY);
1150: }
1151: if (linePtr->firstArrowPtr != NULL) {
1152: for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
1153: i++, coordPtr += 2) {
1154: coordPtr[0] = originX + scaleX*(coordPtr[0] - originX);
1155: coordPtr[1] = originY + scaleY*(coordPtr[1] - originY);
1156: }
1157: }
1158: if (linePtr->lastArrowPtr != NULL) {
1159: for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
1160: i++, coordPtr += 2) {
1161: coordPtr[0] = originX + scaleX*(coordPtr[0] - originX);
1162: coordPtr[1] = originY + scaleY*(coordPtr[1] - originY);
1163: }
1164: }
1165: ComputeLineBbox(canvasPtr, linePtr);
1166: }
1167:
1168: /*
1169: *--------------------------------------------------------------
1170: *
1171: * TranslateLine --
1172: *
1173: * This procedure is called to move a line by a given amount.
1174: *
1175: * Results:
1176: * None.
1177: *
1178: * Side effects:
1179: * The position of the line is offset by (xDelta, yDelta), and
1180: * the bounding box is updated in the generic part of the item
1181: * structure.
1182: *
1183: *--------------------------------------------------------------
1184: */
1185:
1186: static void
1187: TranslateLine(canvasPtr, itemPtr, deltaX, deltaY)
1188: Tk_Canvas *canvasPtr; /* Canvas containing item. */
1189: Tk_Item *itemPtr; /* Item that is being moved. */
1190: double deltaX, deltaY; /* Amount by which item is to be
1191: * moved. */
1192: {
1193: LineItem *linePtr = (LineItem *) itemPtr;
1194: register double *coordPtr;
1195: int i;
1196:
1197: for (i = 0, coordPtr = linePtr->coordPtr; i < linePtr->numPoints;
1198: i++, coordPtr += 2) {
1199: coordPtr[0] += deltaX;
1200: coordPtr[1] += deltaY;
1201: }
1202: if (linePtr->firstArrowPtr != NULL) {
1203: for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
1204: i++, coordPtr += 2) {
1205: coordPtr[0] += deltaX;
1206: coordPtr[1] += deltaY;
1207: }
1208: }
1209: if (linePtr->lastArrowPtr != NULL) {
1210: for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
1211: i++, coordPtr += 2) {
1212: coordPtr[0] += deltaX;
1213: coordPtr[1] += deltaY;
1214: }
1215: }
1216: ComputeLineBbox(canvasPtr, linePtr);
1217: }
1218:
1219: /*
1220: *--------------------------------------------------------------
1221: *
1222: * ParseArrowShape --
1223: *
1224: * This procedure is called back during option parsing to
1225: * parse arrow shape information.
1226: *
1227: * Results:
1228: * The return value is a standard Tcl result: TCL_OK means
1229: * that the arrow shape information was parsed ok, and
1230: * TCL_ERROR means it couldn't be parsed.
1231: *
1232: * Side effects:
1233: * Arrow information in recordPtr is updated.
1234: *
1235: *--------------------------------------------------------------
1236: */
1237:
1238: /* ARGSUSED */
1239: static int
1240: ParseArrowShape(clientData, interp, tkwin, value, recordPtr, offset)
1241: ClientData clientData; /* Not used. */
1242: Tcl_Interp *interp; /* Used for error reporting. */
1243: Tk_Window tkwin; /* Not used. */
1244: char *value; /* Textual specification of arrow shape. */
1245: char *recordPtr; /* Pointer to item record in which to
1246: * store arrow information. */
1247: int offset; /* Offset of shape information in widget
1248: * record. */
1249: {
1250: LineItem *linePtr = (LineItem *) recordPtr;
1251: double a, b, c;
1252: int argc;
1253: char **argv = NULL;
1254:
1255: if (offset != Tk_Offset(LineItem, arrowShapeA)) {
1256: panic("ParseArrowShape received bogus offset");
1257: }
1258:
1259: if (Tcl_SplitList(interp, value, &argc, &argv) != TCL_OK) {
1260: syntaxError:
1261: Tcl_ResetResult(interp);
1262: Tcl_AppendResult(interp, "bad arrow shape \"", value,
1263: "\": must be list with three numbers", (char *) NULL);
1264: if (argv != NULL) {
1265: ckfree((char *) argv);
1266: }
1267: return TCL_ERROR;
1268: }
1269: if (argc != 3) {
1270: goto syntaxError;
1271: }
1272: if ((TkGetCanvasCoord(linePtr->canvasPtr, argv[0], &a) != TCL_OK)
1273: || (TkGetCanvasCoord(linePtr->canvasPtr, argv[1], &b) != TCL_OK)
1274: || (TkGetCanvasCoord(linePtr->canvasPtr, argv[2], &c) != TCL_OK)) {
1275: goto syntaxError;
1276: }
1277: linePtr->arrowShapeA = a;
1278: linePtr->arrowShapeB = b;
1279: linePtr->arrowShapeC = c;
1280: ckfree((char *) argv);
1281: return TCL_OK;
1282: }
1283:
1284: /*
1285: *--------------------------------------------------------------
1286: *
1287: * PrintArrowShape --
1288: *
1289: * This procedure is a callback invoked by the configuration
1290: * code to return a printable value describing an arrow shape.
1291: *
1292: * Results:
1293: * None.
1294: *
1295: * Side effects:
1296: * None.
1297: *
1298: *--------------------------------------------------------------
1299: */
1300:
1301: /* ARGSUSED */
1302: static char *
1303: PrintArrowShape(clientData, tkwin, recordPtr, offset, freeProcPtr)
1304: ClientData clientData; /* Not used. */
1305: Tk_Window tkwin; /* Window associated with linePtr's widget. */
1306: char *recordPtr; /* Pointer to item record containing current
1307: * shape information. */
1308: int offset; /* Offset of arrow information in record. */
1309: Tcl_FreeProc **freeProcPtr; /* Store address of procedure to call to
1310: * free string here. */
1311: {
1312: LineItem *linePtr = (LineItem *) recordPtr;
1313: char *buffer;
1314:
1315: buffer = ckalloc(120);
1316: sprintf(buffer, "%.5g %.5g %.5g", linePtr->arrowShapeA,
1317: linePtr->arrowShapeB, linePtr->arrowShapeC);
1318: *freeProcPtr = (Tcl_FreeProc *) free;
1319: return buffer;
1320: }
1321:
1322: /*
1323: *--------------------------------------------------------------
1324: *
1325: * ConfigureArrows --
1326: *
1327: * If arrowheads have been requested for a line, this
1328: * procedure makes arrangements for the arrowheads.
1329: *
1330: * Results:
1331: * A standard Tcl return value. If an error occurs, then
1332: * an error message is left in canvasPtr->interp->result.
1333: *
1334: * Side effects:
1335: * Information in linePtr is set up for one or two arrowheads.
1336: * the firstArrowPtr and lastArrowPtr polygons are allocated
1337: * and initialized, if need be, and the end points of the line
1338: * are adjusted so that a thick line doesn't stick out past
1339: * the arrowheads.
1340: *
1341: *--------------------------------------------------------------
1342: */
1343:
1344: /* ARGSUSED */
1345: static int
1346: ConfigureArrows(canvasPtr, linePtr)
1347: Tk_Canvas *canvasPtr; /* Canvas in which arrows will be
1348: * displayed (interp and tkwin
1349: * fields are needed). */
1350: register LineItem *linePtr; /* Item to configure for arrows. */
1351: {
1352: double *poly, *coordPtr;
1353: double dx, dy, length, sinTheta, cosTheta, temp, shapeC;
1354: double fracHeight; /* Line width as fraction of
1355: * arrowhead width. */
1356: double backup; /* Distance to backup end points
1357: * so the line ends in the middle
1358: * of the arrowhead. */
1359: double vertX, vertY; /* Position of arrowhead vertex. */
1360:
1361: /*
1362: * If there's an arrowhead on the first point of the line, compute
1363: * its polygon and adjust the first point of the line so that the
1364: * line doesn't stick out past the leading edge of the arrowhead.
1365: */
1366:
1367: shapeC = linePtr->arrowShapeC + linePtr->width/2.0;
1368: fracHeight = (linePtr->width/2.0)/shapeC;
1369: backup = fracHeight*linePtr->arrowShapeB
1370: + linePtr->arrowShapeA*(1.0 - fracHeight)/2.0;
1371: if (linePtr->arrow != lastUid) {
1372: poly = linePtr->firstArrowPtr;
1373: if (poly == NULL) {
1374: poly = (double *) ckalloc((unsigned)
1375: (2*PTS_IN_ARROW*sizeof(double)));
1376: poly[0] = poly[10] = linePtr->coordPtr[0];
1377: poly[1] = poly[11] = linePtr->coordPtr[1];
1378: linePtr->firstArrowPtr = poly;
1379: }
1380: dx = poly[0] - linePtr->coordPtr[2];
1381: dy = poly[1] - linePtr->coordPtr[3];
1382: length = hypot(dx, dy);
1383: if (length == 0) {
1384: sinTheta = cosTheta = 0.0;
1385: } else {
1386: sinTheta = dy/length;
1387: cosTheta = dx/length;
1388: }
1389: vertX = poly[0] - linePtr->arrowShapeA*cosTheta;
1390: vertY = poly[1] - linePtr->arrowShapeA*sinTheta;
1391: temp = shapeC*sinTheta;
1392: poly[2] = poly[0] - linePtr->arrowShapeB*cosTheta + temp;
1393: poly[8] = poly[2] - 2*temp;
1394: temp = shapeC*cosTheta;
1395: poly[3] = poly[1] - linePtr->arrowShapeB*sinTheta - temp;
1396: poly[9] = poly[3] + 2*temp;
1397: poly[4] = poly[2]*fracHeight + vertX*(1.0-fracHeight);
1398: poly[5] = poly[3]*fracHeight + vertY*(1.0-fracHeight);
1399: poly[6] = poly[8]*fracHeight + vertX*(1.0-fracHeight);
1400: poly[7] = poly[9]*fracHeight + vertY*(1.0-fracHeight);
1401:
1402: /*
1403: * Polygon done. Now move the first point towards the second so
1404: * that the corners at the end of the line are inside the
1405: * arrowhead.
1406: */
1407:
1408: linePtr->coordPtr[0] = poly[0] - backup*cosTheta;
1409: linePtr->coordPtr[1] = poly[1] - backup*sinTheta;
1410: }
1411:
1412: /*
1413: * Similar arrowhead calculation for the last point of the line.
1414: */
1415:
1416: if (linePtr->arrow != firstUid) {
1417: coordPtr = linePtr->coordPtr + 2*(linePtr->numPoints-2);
1418: poly = linePtr->lastArrowPtr;
1419: if (poly == NULL) {
1420: poly = (double *) ckalloc((unsigned)
1421: (2*PTS_IN_ARROW*sizeof(double)));
1422: poly[0] = poly[10] = coordPtr[2];
1423: poly[1] = poly[11] = coordPtr[3];
1424: linePtr->lastArrowPtr = poly;
1425: }
1426: dx = poly[0] - coordPtr[0];
1427: dy = poly[1] - coordPtr[1];
1428: length = hypot(dx, dy);
1429: if (length == 0) {
1430: sinTheta = cosTheta = 0.0;
1431: } else {
1432: sinTheta = dy/length;
1433: cosTheta = dx/length;
1434: }
1435: vertX = poly[0] - linePtr->arrowShapeA*cosTheta;
1436: vertY = poly[1] - linePtr->arrowShapeA*sinTheta;
1437: temp = shapeC*sinTheta;
1438: poly[2] = poly[0] - linePtr->arrowShapeB*cosTheta + temp;
1439: poly[8] = poly[2] - 2*temp;
1440: temp = shapeC*cosTheta;
1441: poly[3] = poly[1] - linePtr->arrowShapeB*sinTheta - temp;
1442: poly[9] = poly[3] + 2*temp;
1443: poly[4] = poly[2]*fracHeight + vertX*(1.0-fracHeight);
1444: poly[5] = poly[3]*fracHeight + vertY*(1.0-fracHeight);
1445: poly[6] = poly[8]*fracHeight + vertX*(1.0-fracHeight);
1446: poly[7] = poly[9]*fracHeight + vertY*(1.0-fracHeight);
1447: coordPtr[2] = poly[0] - backup*cosTheta;
1448: coordPtr[3] = poly[1] - backup*sinTheta;
1449: }
1450:
1451: return TCL_OK;
1452: }
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