File: | draw.c |
Location: | line 440, column 5 |
Description: | Value stored to 'dx' is never read |
1 | /* |
2 | * |
3 | Copyright (c) 1991 X Consortium |
4 | |
5 | Permission is hereby granted, free of charge, to any person obtaining a copy |
6 | of this software and associated documentation files (the "Software"), to deal |
7 | in the Software without restriction, including without limitation the rights |
8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
9 | copies of the Software, and to permit persons to whom the Software is |
10 | furnished to do so, subject to the following conditions: |
11 | |
12 | The above copyright notice and this permission notice shall be included in |
13 | all copies or substantial portions of the Software. |
14 | |
15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
18 | X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN |
19 | AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
20 | CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
21 | |
22 | Except as contained in this notice, the name of the X Consortium shall not be |
23 | used in advertising or otherwise to promote the sale, use or other dealings |
24 | in this Software without prior written authorization from the X Consortium. |
25 | * |
26 | */ |
27 | |
28 | /* |
29 | * draw.c |
30 | * |
31 | * accept dvi function calls and translate to X |
32 | */ |
33 | |
34 | /* |
35 | Support for ditroff drawing commands added: lines, circles, ellipses, |
36 | arcs and splines. Splines are approximated as short lines by iterating |
37 | a simple approximation algorithm. This seems good enough for previewing. |
38 | |
39 | David Evans <dre@cs.nott.ac.uk>, 14th March, 1990 |
40 | */ |
41 | |
42 | #include <X11/Xos.h> |
43 | #include <X11/IntrinsicP.h> |
44 | #include <X11/StringDefs.h> |
45 | #include <stdio.h> |
46 | #include <ctype.h> |
47 | #include <math.h> |
48 | #include "DviP.h" |
49 | #include <stdlib.h> |
50 | |
51 | #ifndef M_PI3.14159265358979323846264338327950288 |
52 | #define M_PI3.14159265358979323846264338327950288 3.14159265358979323846264338327950 |
53 | #endif |
54 | |
55 | /* the following are for use in the spline approximation algorithm */ |
56 | |
57 | typedef struct Point { |
58 | double x; |
59 | double y; |
60 | struct Point *next; |
61 | } Point; |
62 | |
63 | #define ITERATIONS10 10 /* iterations to approximate spline */ |
64 | |
65 | #define midx(p,q)((p->x + q->x) / 2) ((p->x + q->x) / 2) /* mid x point on pq */ |
66 | #define midy(p,q)((p->y + q->y) / 2) ((p->y + q->y) / 2) /* mid y point on pq */ |
67 | |
68 | #define length(p,q)sqrt(((q->x - p->x)*(q->x - p->x)) + ((q->y - p ->y)*(q->y - p->y))) sqrt(((q->x - p->x)*(q->x - p->x)) \ |
69 | + ((q->y - p->y)*(q->y - p->y))) /* length of pq */ |
70 | |
71 | static Point *spline = (Point *)NULL((void*)0); /* head of spline linked list */ |
72 | |
73 | static void ApproxSpline(int n); |
74 | static void DeletePoint(Point *p); |
75 | static void DrawSplineSegments(DviWidget dw); |
76 | static int GetSpline(const char *s); |
77 | static void InsertPoint(Point *p, Point *q); |
78 | static void LineApprox(Point *p1, Point *p2, Point *p3); |
79 | static Point * MakePoint(double x, double y); |
80 | |
81 | void |
82 | HorizontalMove(DviWidget dw, int delta) |
83 | { |
84 | dw->dvi.state->x += delta; |
85 | } |
86 | |
87 | void |
88 | HorizontalGoto(DviWidget dw, int NewPosition) |
89 | { |
90 | dw->dvi.state->x = NewPosition; |
91 | } |
92 | |
93 | void |
94 | VerticalMove(DviWidget dw, int delta) |
95 | { |
96 | dw->dvi.state->y += delta; |
97 | } |
98 | |
99 | void |
100 | VerticalGoto(DviWidget dw, int NewPosition) |
101 | { |
102 | dw->dvi.state->y = NewPosition; |
103 | } |
104 | |
105 | #ifdef USE_XFT |
106 | static void |
107 | DrawText (DviWidget dw) |
108 | { |
109 | int i; |
110 | XftFont *font; |
111 | |
112 | font = dw->dvi.cache.font; |
113 | for (i = 0; i <= dw->dvi.cache.index; i++) |
114 | { |
115 | if (dw->dvi.cache.cache[i].font) |
116 | font = dw->dvi.cache.cache[i].font; |
117 | XftDrawString8 (dw->dvi.draw, &dw->dvi.black, |
118 | font, |
119 | dw->dvi.cache.cache[i].x, |
120 | dw->dvi.cache.start_y, |
121 | (unsigned char *) dw->dvi.cache.cache[i].chars, |
122 | dw->dvi.cache.cache[i].nchars); |
123 | } |
124 | } |
125 | #endif |
126 | |
127 | void |
128 | FlushCharCache (DviWidget dw) |
129 | { |
130 | int xx, yx; |
131 | |
132 | xx = ToX(dw, dw->dvi.state->x)((int) ((dw->dvi.state->x) * (dw)->dvi.scale + 0.5)); |
133 | yx = ToX(dw, dw->dvi.state->y)((int) ((dw->dvi.state->y) * (dw)->dvi.scale + 0.5)); |
134 | if (dw->dvi.cache.char_index != 0) |
135 | { |
136 | #ifdef USE_XFT |
137 | DrawText (dw); |
138 | #else |
139 | XDrawText (XtDisplay (dw)(((dw)->core.screen)->display), XtWindow (dw)((dw)->core.window), dw->dvi.normal_GC, |
140 | dw->dvi.cache.start_x, dw->dvi.cache.start_y, |
141 | dw->dvi.cache.cache, dw->dvi.cache.index + 1); |
142 | #endif |
143 | } |
144 | dw->dvi.cache.index = 0; |
145 | dw->dvi.cache.max = DVI_TEXT_CACHE_SIZE256; |
146 | if (dw->dvi.noPolyText) |
147 | dw->dvi.cache.max = 1; |
148 | dw->dvi.cache.char_index = 0; |
149 | dw->dvi.cache.cache[0].nchars = 0; |
150 | dw->dvi.cache.start_x = dw->dvi.cache.x = xx; |
151 | dw->dvi.cache.start_y = dw->dvi.cache.y = yx; |
152 | } |
153 | |
154 | void |
155 | SetGCForDraw (DviWidget dw) |
156 | { |
157 | int lw; |
158 | if (dw->dvi.state->line_style != dw->dvi.line_style || |
159 | dw->dvi.state->line_width != dw->dvi.line_width) |
160 | { |
161 | lw = ToX(dw, dw->dvi.state->line_width)((int) ((dw->dvi.state->line_width) * (dw)->dvi.scale + 0.5)); |
162 | if (lw <= 1) |
163 | lw = 0; |
164 | XSetLineAttributes (XtDisplay (dw)(((dw)->core.screen)->display), dw->dvi.normal_GC, |
165 | lw, LineSolid0, CapButt1, JoinMiter0); |
166 | dw->dvi.line_style = dw->dvi.state->line_style; |
167 | dw->dvi.line_width = dw->dvi.state->line_width; |
168 | } |
169 | } |
170 | |
171 | void |
172 | DrawLine (DviWidget dw, int x, int y) |
173 | { |
174 | if (dw->dvi.display_enable) |
175 | XDrawLine (XtDisplay (dw)(((dw)->core.screen)->display), XtWindow (dw)((dw)->core.window), dw->dvi.normal_GC, |
176 | ToX(dw, dw->dvi.state->x)((int) ((dw->dvi.state->x) * (dw)->dvi.scale + 0.5)), ToX(dw, dw->dvi.state->y)((int) ((dw->dvi.state->y) * (dw)->dvi.scale + 0.5)), |
177 | ToX(dw, dw->dvi.state->x + x)((int) ((dw->dvi.state->x + x) * (dw)->dvi.scale + 0.5 )), ToX(dw,dw->dvi.state->y + y)((int) ((dw->dvi.state->y + y) * (dw)->dvi.scale + 0.5 ))); |
178 | dw->dvi.state->x += x; |
179 | dw->dvi.state->y += y; |
180 | } |
181 | |
182 | void |
183 | DrawCircle (DviWidget dw, int diameter) |
184 | { |
185 | if (dw->dvi.display_enable) |
186 | XDrawArc (XtDisplay (dw)(((dw)->core.screen)->display), XtWindow (dw)((dw)->core.window), dw->dvi.normal_GC, |
187 | ToX(dw, dw->dvi.state->x)((int) ((dw->dvi.state->x) * (dw)->dvi.scale + 0.5)), |
188 | ToX(dw, dw->dvi.state->y - (diameter / 2))((int) ((dw->dvi.state->y - (diameter / 2)) * (dw)-> dvi.scale + 0.5)), |
189 | ToX(dw, diameter)((int) ((diameter) * (dw)->dvi.scale + 0.5)), ToX(dw, diameter)((int) ((diameter) * (dw)->dvi.scale + 0.5)), 0, 360 * 64); |
190 | dw->dvi.state->x += diameter; |
191 | } |
192 | |
193 | void |
194 | DrawEllipse (DviWidget dw, int a, int b) |
195 | { |
196 | if (dw->dvi.display_enable) |
197 | XDrawArc (XtDisplay (dw)(((dw)->core.screen)->display), XtWindow (dw)((dw)->core.window), dw->dvi.normal_GC, |
198 | ToX(dw, dw->dvi.state->x)((int) ((dw->dvi.state->x) * (dw)->dvi.scale + 0.5)), ToX(dw, dw->dvi.state->y - (b / 2))((int) ((dw->dvi.state->y - (b / 2)) * (dw)->dvi.scale + 0.5)), |
199 | ToX(dw,a)((int) ((a) * (dw)->dvi.scale + 0.5)), ToX(dw,b)((int) ((b) * (dw)->dvi.scale + 0.5)), 0, 360 * 64); |
200 | dw->dvi.state->x += a; |
201 | } |
202 | |
203 | |
204 | /* Convert angle in degrees to 64ths of a degree */ |
205 | |
206 | static int |
207 | ConvertAngle(int theta) |
208 | { |
209 | return(theta * 64); |
210 | } |
211 | |
212 | void |
213 | DrawArc (DviWidget dw, int x0, int y0, int x1, int y1) |
214 | { |
215 | int xc, yc, x2, y2, r; |
216 | int angle1, angle2; |
217 | |
218 | /* centre */ |
219 | xc = dw->dvi.state->x + x0; |
220 | yc = dw->dvi.state->y + y0; |
221 | |
222 | /* to */ |
223 | x2 = xc + x1; |
224 | y2 = yc + y1; |
225 | |
226 | dw->dvi.state->x = x2; |
227 | dw->dvi.state->y = y2; |
228 | |
229 | if (dw->dvi.display_enable) { |
230 | |
231 | /* radius */ |
232 | r = (int)sqrt((float) x1 * x1 + (float) y1 * y1); |
233 | |
234 | /* start and finish angles */ |
235 | if (x0 == 0) { |
236 | if (y0 >= 0) |
237 | angle1 = 90; |
238 | else |
239 | angle1 = 270; |
240 | } |
241 | else { |
242 | angle1 = (int) (atan((double)(y0) / (double)(x0)) * 180 / M_PI3.14159265358979323846264338327950288); |
243 | if (x0 > 0) |
244 | angle1 = 180 - angle1; |
245 | else |
246 | angle1 = -angle1; |
247 | } |
248 | |
249 | if (x1 == 0) { |
250 | if (y1 <= 0) |
251 | angle2 = 90; |
252 | else |
253 | angle2 = 270; |
254 | } |
255 | else { |
256 | angle2 = (int) (atan((double)(y1) / (double)(x1)) * 180 / M_PI3.14159265358979323846264338327950288); |
257 | if (x1 < 0) |
258 | angle2 = 180 - angle2; |
259 | else |
260 | angle2 = -angle2; |
261 | } |
262 | |
263 | if (angle1 < 0) |
264 | angle1 += 360; |
265 | if (angle2 < 0) |
266 | angle2 += 360; |
267 | |
268 | if (angle2 < angle1) |
269 | angle1 -= 360; |
270 | angle2 = angle2 - angle1; |
271 | |
272 | angle1 = ConvertAngle(angle1); |
273 | angle2 = ConvertAngle(angle2); |
274 | |
275 | XDrawArc (XtDisplay (dw)(((dw)->core.screen)->display), XtWindow (dw)((dw)->core.window), dw->dvi.normal_GC, |
276 | ToX(dw, xc - r)((int) ((xc - r) * (dw)->dvi.scale + 0.5)), ToX(dw, yc - r)((int) ((yc - r) * (dw)->dvi.scale + 0.5)), |
277 | ToX(dw, 2 * r)((int) ((2 * r) * (dw)->dvi.scale + 0.5)), ToX(dw, 2 * r)((int) ((2 * r) * (dw)->dvi.scale + 0.5)), |
278 | angle1, angle2); |
279 | } |
280 | } |
281 | |
282 | /* copy next non-blank string from p to temp, update p */ |
283 | |
284 | static const char * |
285 | getstr(const char *p, char *temp) |
286 | { |
287 | while (*p == ' ' || *p == '\t' || *p == '\n') |
288 | p++; |
289 | if (*p == '\0') { |
290 | temp[0] = 0; |
291 | return((char *)NULL((void*)0)); |
292 | } |
293 | while (*p != ' ' && *p != '\t' && *p != '\n' && *p != '\0') |
294 | *temp++ = *p++; |
295 | *temp = '\0'; |
296 | return(p); |
297 | } |
298 | |
299 | |
300 | /* Draw a spline by approximating with short lines. */ |
301 | |
302 | /*ARGSUSED*/ |
303 | void |
304 | DrawSpline (DviWidget dw, const char *s, int len) |
305 | { |
306 | int n; |
307 | |
308 | /* get coordinate pairs into spline linked list */ |
309 | if ((n = GetSpline(s)) <= 0) |
310 | return; |
311 | |
312 | ApproxSpline(n); |
313 | |
314 | DrawSplineSegments(dw); |
315 | } |
316 | |
317 | |
318 | /* Parse string s to create a linked list of Point's with spline */ |
319 | /* as its head. Return the number of coordinate pairs found. */ |
320 | |
321 | static int |
322 | GetSpline(const char *s) |
323 | { |
324 | double x, y, x1, y1; |
325 | int n = 0; |
326 | Point *pt; |
327 | const char *p = s; |
328 | char d[10]; |
329 | |
330 | if (!*p) |
331 | return(n); |
332 | |
333 | pt = spline = MakePoint(0.0, 0.0); |
334 | n = 1; |
335 | x = y = 0.0; |
336 | p = s; |
337 | while (p && *p) { |
338 | if ((p = getstr(p, d)) == (const char *)NULL((void*)0)) |
339 | break; |
340 | x1 = x + atof(d); |
341 | if ((p = getstr(p, d)) == (const char *)NULL((void*)0)) |
342 | break; |
343 | y1 = y + atof(d); |
344 | pt->next = MakePoint(x1, y1); |
345 | pt = pt->next; |
346 | x = pt->x; |
347 | y = pt->y; |
348 | n++; |
349 | } |
350 | |
351 | /* number of pairs of points */ |
352 | |
353 | return(n); |
354 | } |
355 | |
356 | /* Approximate a spline by lines generated by iterations of the */ |
357 | /* approximation algorithm from the original n points in the spline. */ |
358 | |
359 | static void |
360 | ApproxSpline(int n) |
361 | { |
362 | int mid, j; |
363 | Point *p1, *p2, *p3, *p; |
364 | |
365 | if (n < 3) |
366 | return; |
367 | |
368 | /* number of mid-points to calculate */ |
369 | mid = n - 3; |
370 | |
371 | /* remember original points are stored as an array of n points */ |
372 | /* so I can index it directly to calculate mid-points only. */ |
373 | if (mid > 0) { |
374 | p = spline->next; |
375 | j = 1; |
376 | while (j < n-2) { |
377 | p1 = p; |
378 | p = p->next; |
379 | p2 = p; |
380 | InsertPoint(p1, MakePoint(midx(p1, p2)((p1->x + p2->x) / 2), midy(p1, p2)((p1->y + p2->y) / 2))); |
381 | j++; |
382 | } |
383 | } |
384 | |
385 | /* Now approximate curve by line segments. */ |
386 | /* There *should* be the correct number of points now! */ |
387 | |
388 | p = spline; |
389 | while (p != (Point *)NULL((void*)0)) { |
390 | p1 = p; |
391 | if ((p = p->next) == (Point *)NULL((void*)0)) |
392 | break; |
393 | p2 = p; |
394 | if ((p = p->next) == (Point *)NULL((void*)0)) |
395 | break; |
396 | p3 = p; /* This point becomes first point of next curve */ |
397 | |
398 | LineApprox(p1, p2, p3); |
399 | } |
400 | } |
401 | |
402 | |
403 | /* p1, p2, and p3 are initially 3 *consecutive* points on the curve. */ |
404 | /* For each adjacent pair of points find the mid-point, insert this */ |
405 | /* in the linked list, delete the first of the two used (unless it */ |
406 | /* is the first for this curve). Repeat this ITERATIONS times. */ |
407 | |
408 | /*ARGSUSED*/ |
409 | static void |
410 | LineApprox(Point *p1, Point *p2, Point *p3) |
411 | { |
412 | Point *p4, *p; |
413 | int reps = ITERATIONS10; |
414 | |
415 | while (reps) { |
416 | for (p = p1; p != (Point *)NULL((void*)0) && p != p3; ) { |
417 | InsertPoint(p, p4 = MakePoint( midx(p,p->next)((p->x + p->next->x) / 2), midy(p,p->next)((p->y + p->next->y) / 2) )); |
418 | if (p != p1) |
419 | DeletePoint(p); |
420 | p = p4->next; /* skip inserted point! */ |
421 | } |
422 | reps--; |
423 | } |
424 | } |
425 | |
426 | |
427 | /* Traverse the linked list, calling DrawLine to approximate the */ |
428 | /* spline curve. Rounding errors are taken into account so that */ |
429 | /* the "curve" is continuous, and ends up where expected. */ |
430 | |
431 | static void |
432 | DrawSplineSegments(DviWidget dw) |
433 | { |
434 | Point *p, *q; |
435 | double x1, y1; |
436 | int dx, dy; |
437 | double xpos, ypos; |
438 | |
439 | p = spline; |
440 | dx = dy = 0; |
Value stored to 'dx' is never read | |
441 | |
442 | /* save the start position */ |
443 | |
444 | xpos = dw->dvi.state->x; |
445 | ypos = dw->dvi.state->y; |
446 | |
447 | x1 = y1 = 0.0; |
448 | |
449 | while (p != (Point *)NULL((void*)0)) { |
450 | dx = p->x - x1 + 0.5; |
451 | dy = p->y - y1 + 0.5; |
452 | DrawLine (dw, dx, dy); |
453 | |
454 | x1 = p->x; |
455 | y1 = p->y; |
456 | dw->dvi.state->x = xpos + x1; |
457 | dw->dvi.state->y = ypos + y1; |
458 | |
459 | q = p; |
460 | p = p->next; |
461 | XtFree((char *)q); |
462 | } |
463 | spline = (Point *)NULL((void*)0); |
464 | } |
465 | |
466 | |
467 | /* Malloc memory for a Point, and initialise the elements to x, y, NULL */ |
468 | /* Return a pointer to the new Point. */ |
469 | |
470 | static Point * |
471 | MakePoint(double x, double y) |
472 | { |
473 | Point *p; |
474 | |
475 | p = (Point *) XtMalloc (sizeof (Point)); |
476 | p->x = x; |
477 | p->y = y; |
478 | p->next = (Point *)NULL((void*)0); |
479 | |
480 | return(p); |
481 | } |
482 | |
483 | |
484 | /* Insert point q in linked list after point p. */ |
485 | |
486 | static void |
487 | InsertPoint(Point *p, Point *q) |
488 | { |
489 | /* point q to the next point */ |
490 | q->next = p->next; |
491 | |
492 | /* point p to new inserted one */ |
493 | p->next = q; |
494 | } |
495 | |
496 | /* Delete point p from the linked list. */ |
497 | |
498 | static void |
499 | DeletePoint(Point *p) |
500 | { |
501 | Point *tmp; |
502 | |
503 | tmp = p->next; |
504 | p->x = p->next->x; |
505 | p->y = p->next->y; |
506 | p->next = p->next->next; |
507 | XtFree((char *)tmp); |
508 | } |