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examples/svgtiny_display_x11.c: include the system copy of svgtiny.h
[libsvgtiny.git] / src / svgtiny_gradient.c
1 /*
2 * This file is part of Libsvgtiny
3 * Licensed under the MIT License,
4 * http://opensource.org/licenses/mit-license.php
5 * Copyright 2008 James Bursa <james@semichrome.net>
6 */
7
8 #include <assert.h>
9 #include <math.h>
10 #include <string.h>
11 #include <stdio.h>
12 #include <stdlib.h>
13
14 #include "svgtiny.h"
15 #include "svgtiny_internal.h"
16
17 #undef GRADIENT_DEBUG
18
19 static svgtiny_code svgtiny_parse_linear_gradient(dom_element *linear,
20 struct svgtiny_parse_state_gradient *grad,
21 struct svgtiny_parse_state *state);
22 static float svgtiny_parse_gradient_offset(const char *s);
23 static void svgtiny_path_bbox(float *p, unsigned int n,
24 float *x0, float *y0, float *x1, float *y1);
25 static void svgtiny_invert_matrix(float *m, float *inv);
26
27
28 /**
29 * Find a gradient by id and parse it.
30 */
31
32 void svgtiny_find_gradient(const char *id,
33 struct svgtiny_parse_state_gradient *grad,
34 struct svgtiny_parse_state *state)
35 {
36 dom_element *gradient;
37 dom_string *id_str, *name;
38 dom_exception exc;
39
40 #ifdef GRADIENT_DEBUG
41 fprintf(stderr, "svgtiny_find_gradient: id \"%s\"\n", id);
42 #endif
43
44 grad->linear_gradient_stop_count = 0;
45 if (grad->gradient_x1 != NULL)
46 dom_string_unref(grad->gradient_x1);
47 if (grad->gradient_y1 != NULL)
48 dom_string_unref(grad->gradient_y1);
49 if (grad->gradient_x2 != NULL)
50 dom_string_unref(grad->gradient_x2);
51 if (grad->gradient_y2 != NULL)
52 dom_string_unref(grad->gradient_y2);
53 grad->gradient_x1 = dom_string_ref(state->interned_zero_percent);
54 grad->gradient_y1 = dom_string_ref(state->interned_zero_percent);
55 grad->gradient_x2 = dom_string_ref(state->interned_hundred_percent);
56 grad->gradient_y2 = dom_string_ref(state->interned_zero_percent);
57 grad->gradient_user_space_on_use = false;
58 grad->gradient_transform.a = 1;
59 grad->gradient_transform.b = 0;
60 grad->gradient_transform.c = 0;
61 grad->gradient_transform.d = 1;
62 grad->gradient_transform.e = 0;
63 grad->gradient_transform.f = 0;
64
65 exc = dom_string_create_interned((const uint8_t *) id,
66 strlen(id), &id_str);
67 if (exc != DOM_NO_ERR)
68 return;
69
70 exc = dom_document_get_element_by_id(state->document, id_str,
71 &gradient);
72 dom_string_unref(id_str);
73 if (exc != DOM_NO_ERR || gradient == NULL) {
74 #ifdef GRADIENT_DEBUG
75 fprintf(stderr, "gradient \"%s\" not found\n", id);
76 #endif
77 return;
78 }
79
80 exc = dom_node_get_node_name(gradient, &name);
81 if (exc != DOM_NO_ERR) {
82 dom_node_unref(gradient);
83 return;
84 }
85
86 if (dom_string_isequal(name, state->interned_linearGradient))
87 svgtiny_parse_linear_gradient(gradient, grad, state);
88
89 dom_node_unref(gradient);
90 dom_string_unref(name);
91
92 #ifdef GRADIENT_DEBUG
93 fprintf(stderr, "linear_gradient_stop_count %i\n",
94 grad->linear_gradient_stop_count);
95 #endif
96 }
97
98
99 /**
100 * Parse a <linearGradient> element node.
101 *
102 * http://www.w3.org/TR/SVG11/pservers#LinearGradients
103 */
104
105 svgtiny_code svgtiny_parse_linear_gradient(dom_element *linear,
106 struct svgtiny_parse_state_gradient *grad,
107 struct svgtiny_parse_state *state)
108 {
109 unsigned int i = 0;
110 dom_string *attr;
111 dom_exception exc;
112 dom_nodelist *stops;
113
114 exc = dom_element_get_attribute(linear, state->interned_href, &attr);
115 if (exc == DOM_NO_ERR && attr != NULL) {
116 if (dom_string_data(attr)[0] == (uint8_t) '#') {
117 char *s = strndup(dom_string_data(attr) + 1,
118 dom_string_byte_length(attr) - 1);
119 svgtiny_find_gradient(s, grad, state);
120 free(s);
121 }
122 dom_string_unref(attr);
123 }
124
125 exc = dom_element_get_attribute(linear, state->interned_x1, &attr);
126 if (exc == DOM_NO_ERR && attr != NULL) {
127 dom_string_unref(grad->gradient_x1);
128 grad->gradient_x1 = attr;
129 attr = NULL;
130 }
131
132 exc = dom_element_get_attribute(linear, state->interned_y1, &attr);
133 if (exc == DOM_NO_ERR && attr != NULL) {
134 dom_string_unref(grad->gradient_y1);
135 grad->gradient_y1 = attr;
136 attr = NULL;
137 }
138
139 exc = dom_element_get_attribute(linear, state->interned_x2, &attr);
140 if (exc == DOM_NO_ERR && attr != NULL) {
141 dom_string_unref(grad->gradient_x2);
142 grad->gradient_x2 = attr;
143 attr = NULL;
144 }
145
146 exc = dom_element_get_attribute(linear, state->interned_y2, &attr);
147 if (exc == DOM_NO_ERR && attr != NULL) {
148 dom_string_unref(grad->gradient_y2);
149 grad->gradient_y2 = attr;
150 attr = NULL;
151 }
152
153 exc = dom_element_get_attribute(linear, state->interned_gradientUnits,
154 &attr);
155 if (exc == DOM_NO_ERR && attr != NULL) {
156 grad->gradient_user_space_on_use =
157 dom_string_isequal(attr,
158 state->interned_userSpaceOnUse);
159 dom_string_unref(attr);
160 }
161
162 exc = dom_element_get_attribute(linear,
163 state->interned_gradientTransform,
164 &attr);
165 if (exc == DOM_NO_ERR && attr != NULL) {
166 float a = 1, b = 0, c = 0, d = 1, e = 0, f = 0;
167 char *s = strndup(dom_string_data(attr),
168 dom_string_byte_length(attr));
169 if (s == NULL) {
170 dom_string_unref(attr);
171 return svgtiny_OUT_OF_MEMORY;
172 }
173 svgtiny_parse_transform(s, &a, &b, &c, &d, &e, &f);
174 free(s);
175 #ifdef GRADIENT_DEBUG
176 fprintf(stderr, "transform %g %g %g %g %g %g\n",
177 a, b, c, d, e, f);
178 #endif
179 grad->gradient_transform.a = a;
180 grad->gradient_transform.b = b;
181 grad->gradient_transform.c = c;
182 grad->gradient_transform.d = d;
183 grad->gradient_transform.e = e;
184 grad->gradient_transform.f = f;
185 dom_string_unref(attr);
186 }
187
188 exc = dom_element_get_elements_by_tag_name(linear,
189 state->interned_stop,
190 &stops);
191 if (exc == DOM_NO_ERR && stops != NULL) {
192 uint32_t listlen, stopnr;
193 exc = dom_nodelist_get_length(stops, &listlen);
194 if (exc != DOM_NO_ERR) {
195 dom_nodelist_unref(stops);
196 goto no_more_stops;
197 }
198
199 for (stopnr = 0; stopnr < listlen; ++stopnr) {
200 dom_element *stop;
201 float offset = -1;
202 svgtiny_colour color = svgtiny_TRANSPARENT;
203 exc = dom_nodelist_item(stops, stopnr,
204 (dom_node **) (void *) &stop);
205 if (exc != DOM_NO_ERR)
206 continue;
207 exc = dom_element_get_attribute(stop,
208 state->interned_offset,
209 &attr);
210 if (exc == DOM_NO_ERR && attr != NULL) {
211 char *s = strndup(dom_string_data(attr),
212 dom_string_byte_length(attr));
213 offset = svgtiny_parse_gradient_offset(s);
214 free(s);
215 dom_string_unref(attr);
216 }
217 exc = dom_element_get_attribute(stop,
218 state->interned_stop_color,
219 &attr);
220 if (exc == DOM_NO_ERR && attr != NULL) {
221 svgtiny_parse_color(attr, &color, NULL, state);
222 dom_string_unref(attr);
223 }
224 exc = dom_element_get_attribute(stop,
225 state->interned_style,
226 &attr);
227 if (exc == DOM_NO_ERR && attr != NULL) {
228 char *content = strndup(dom_string_data(attr),
229 dom_string_byte_length(attr));
230 const char *s;
231 dom_string *value;
232 if ((s = strstr(content, "stop-color:"))) {
233 s += 11;
234 while (*s == ' ')
235 s++;
236 exc = dom_string_create_interned(
237 (const uint8_t *) s,
238 strcspn(s, "; "),
239 &value);
240 if (exc == DOM_NO_ERR &&
241 value != NULL) {
242 svgtiny_parse_color(value,
243 &color,
244 NULL,
245 state);
246 dom_string_unref(value);
247 }
248 }
249 free(content);
250 dom_string_unref(attr);
251 }
252 if (offset != -1 && color != svgtiny_TRANSPARENT) {
253 #ifdef GRADIENT_DEBUG
254 fprintf(stderr, "stop %g %x\n", offset, color);
255 #endif
256 grad->gradient_stop[i].offset = offset;
257 grad->gradient_stop[i].color = color;
258 i++;
259 }
260 dom_node_unref(stop);
261 if (i == svgtiny_MAX_STOPS)
262 break;
263 }
264
265 dom_nodelist_unref(stops);
266 }
267 no_more_stops:
268 if (i > 0)
269 grad->linear_gradient_stop_count = i;
270
271 return svgtiny_OK;
272 }
273
274
275 float svgtiny_parse_gradient_offset(const char *s)
276 {
277 int num_length = strspn(s, "0123456789+-.");
278 const char *unit = s + num_length;
279 float n = atof((const char *) s);
280
281 if (unit[0] == 0)
282 ;
283 else if (unit[0] == '%')
284 n /= 100.0;
285 else
286 return -1;
287
288 if (n < 0)
289 n = 0;
290 if (1 < n)
291 n = 1;
292 return n;
293 }
294
295
296 /**
297 * Add a path with a linear gradient fill to the svgtiny_diagram.
298 */
299
300 svgtiny_code svgtiny_add_path_linear_gradient(float *p, unsigned int n,
301 struct svgtiny_parse_state *state)
302 {
303 struct grad_point {
304 float x, y, r;
305 };
306 float object_x0, object_y0, object_x1, object_y1;
307 float gradient_x0, gradient_y0, gradient_x1, gradient_y1,
308 gradient_dx, gradient_dy;
309 float trans[6];
310 unsigned int steps = 10;
311 float x0 = 0, y0 = 0, x0_trans, y0_trans, r0; /* segment start point */
312 float x1, y1, x1_trans, y1_trans, r1; /* segment end point */
313 /* segment control points (beziers only) */
314 float c0x = 0, c0y = 0, c1x = 0, c1y = 0;
315 float gradient_norm_squared;
316 struct svgtiny_list *pts;
317 float min_r = 1000;
318 unsigned int min_pt = 0;
319 unsigned int j;
320 unsigned int stop_count;
321 unsigned int current_stop;
322 float last_stop_r;
323 float current_stop_r;
324 int red0, green0, blue0, red1, green1, blue1;
325 unsigned int t, a, b;
326 struct svgtiny_parse_state_gradient *grad;
327
328 assert(state->fill == svgtiny_LINEAR_GRADIENT);
329 grad = &state->fill_grad;
330
331 /* determine object bounding box */
332 svgtiny_path_bbox(p, n, &object_x0, &object_y0, &object_x1, &object_y1);
333 #ifdef GRADIENT_DEBUG
334 fprintf(stderr, "object bbox: (%g %g) (%g %g)\n",
335 object_x0, object_y0, object_x1, object_y1);
336 #endif
337
338 if (!grad->gradient_user_space_on_use) {
339 gradient_x0 = object_x0 +
340 svgtiny_parse_length(grad->gradient_x1,
341 object_x1 - object_x0, *state);
342 gradient_y0 = object_y0 +
343 svgtiny_parse_length(grad->gradient_y1,
344 object_y1 - object_y0, *state);
345 gradient_x1 = object_x0 +
346 svgtiny_parse_length(grad->gradient_x2,
347 object_x1 - object_x0, *state);
348 gradient_y1 = object_y0 +
349 svgtiny_parse_length(grad->gradient_y2,
350 object_y1 - object_y0, *state);
351 } else {
352 gradient_x0 = svgtiny_parse_length(grad->gradient_x1,
353 state->viewport_width, *state);
354 gradient_y0 = svgtiny_parse_length(grad->gradient_y1,
355 state->viewport_height, *state);
356 gradient_x1 = svgtiny_parse_length(grad->gradient_x2,
357 state->viewport_width, *state);
358 gradient_y1 = svgtiny_parse_length(grad->gradient_y2,
359 state->viewport_height, *state);
360 }
361 gradient_dx = gradient_x1 - gradient_x0;
362 gradient_dy = gradient_y1 - gradient_y0;
363 #ifdef GRADIENT_DEBUG
364 fprintf(stderr, "gradient vector: (%g %g) => (%g %g)\n",
365 gradient_x0, gradient_y0, gradient_x1, gradient_y1);
366 #endif
367
368 /* show theoretical gradient strips for debugging */
369 /*unsigned int strips = 10;
370 for (unsigned int z = 0; z != strips; z++) {
371 float f0, fd, strip_x0, strip_y0, strip_dx, strip_dy;
372 f0 = (float) z / (float) strips;
373 fd = (float) 1 / (float) strips;
374 strip_x0 = gradient_x0 + f0 * gradient_dx;
375 strip_y0 = gradient_y0 + f0 * gradient_dy;
376 strip_dx = fd * gradient_dx;
377 strip_dy = fd * gradient_dy;
378 fprintf(stderr, "strip %i vector: (%g %g) + (%g %g)\n",
379 z, strip_x0, strip_y0, strip_dx, strip_dy);
380
381 float *p = malloc(13 * sizeof p[0]);
382 if (!p)
383 return svgtiny_OUT_OF_MEMORY;
384 p[0] = svgtiny_PATH_MOVE;
385 p[1] = strip_x0 + (strip_dy * 3);
386 p[2] = strip_y0 - (strip_dx * 3);
387 p[3] = svgtiny_PATH_LINE;
388 p[4] = p[1] + strip_dx;
389 p[5] = p[2] + strip_dy;
390 p[6] = svgtiny_PATH_LINE;
391 p[7] = p[4] - (strip_dy * 6);
392 p[8] = p[5] + (strip_dx * 6);
393 p[9] = svgtiny_PATH_LINE;
394 p[10] = p[7] - strip_dx;
395 p[11] = p[8] - strip_dy;
396 p[12] = svgtiny_PATH_CLOSE;
397 svgtiny_transform_path(p, 13, state);
398 struct svgtiny_shape *shape = svgtiny_add_shape(state);
399 if (!shape) {
400 free(p);
401 return svgtiny_OUT_OF_MEMORY;
402 }
403 shape->path = p;
404 shape->path_length = 13;
405 shape->fill = svgtiny_TRANSPARENT;
406 shape->stroke = svgtiny_RGB(0, 0xff, 0);
407 state->diagram->shape_count++;
408 }*/
409
410 /* invert gradient transform for applying to vertices */
411 svgtiny_invert_matrix(&grad->gradient_transform.a, trans);
412 #ifdef GRADIENT_DEBUG
413 fprintf(stderr, "inverse transform %g %g %g %g %g %g\n",
414 trans[0], trans[1], trans[2], trans[3],
415 trans[4], trans[5]);
416 #endif
417
418 /* compute points on the path for triangle vertices */
419 /* r, r0, r1 are distance along gradient vector */
420 gradient_norm_squared = gradient_dx * gradient_dx +
421 gradient_dy * gradient_dy;
422 pts = svgtiny_list_create(sizeof (struct grad_point));
423 if (!pts) {
424 free(p);
425 return svgtiny_OUT_OF_MEMORY;
426 }
427 for (j = 0; j != n; ) {
428 int segment_type = (int) p[j];
429 struct grad_point *point;
430 unsigned int z;
431
432 if (segment_type == svgtiny_PATH_MOVE) {
433 x0 = p[j + 1];
434 y0 = p[j + 2];
435 j += 3;
436 continue;
437 }
438
439 assert(segment_type == svgtiny_PATH_CLOSE ||
440 segment_type == svgtiny_PATH_LINE ||
441 segment_type == svgtiny_PATH_BEZIER);
442
443 /* start point (x0, y0) */
444 x0_trans = trans[0]*x0 + trans[2]*y0 + trans[4];
445 y0_trans = trans[1]*x0 + trans[3]*y0 + trans[5];
446 r0 = ((x0_trans - gradient_x0) * gradient_dx +
447 (y0_trans - gradient_y0) * gradient_dy) /
448 gradient_norm_squared;
449 point = svgtiny_list_push(pts);
450 if (!point) {
451 free(p);
452 svgtiny_list_free(pts);
453 return svgtiny_OUT_OF_MEMORY;
454 }
455 point->x = x0;
456 point->y = y0;
457 point->r = r0;
458 if (r0 < min_r) {
459 min_r = r0;
460 min_pt = svgtiny_list_size(pts) - 1;
461 }
462
463 /* end point (x1, y1) */
464 if (segment_type == svgtiny_PATH_LINE) {
465 x1 = p[j + 1];
466 y1 = p[j + 2];
467 j += 3;
468 } else if (segment_type == svgtiny_PATH_CLOSE) {
469 x1 = p[1];
470 y1 = p[2];
471 j++;
472 } else /* svgtiny_PATH_BEZIER */ {
473 c0x = p[j + 1];
474 c0y = p[j + 2];
475 c1x = p[j + 3];
476 c1y = p[j + 4];
477 x1 = p[j + 5];
478 y1 = p[j + 6];
479 j += 7;
480 }
481 x1_trans = trans[0]*x1 + trans[2]*y1 + trans[4];
482 y1_trans = trans[1]*x1 + trans[3]*y1 + trans[5];
483 r1 = ((x1_trans - gradient_x0) * gradient_dx +
484 (y1_trans - gradient_y0) * gradient_dy) /
485 gradient_norm_squared;
486
487 /* determine steps from change in r */
488
489 if(isnan(r0) || isnan(r1)) {
490 steps = 1;
491 } else {
492 steps = ceilf(fabsf(r1 - r0) / 0.05);
493 }
494
495 if (steps == 0)
496 steps = 1;
497 #ifdef GRADIENT_DEBUG
498 fprintf(stderr, "r0 %g, r1 %g, steps %i\n",
499 r0, r1, steps);
500 #endif
501
502 /* loop through intermediate points */
503 for (z = 1; z != steps; z++) {
504 float t, x, y, x_trans, y_trans, r;
505 struct grad_point *point;
506 t = (float) z / (float) steps;
507 if (segment_type == svgtiny_PATH_BEZIER) {
508 x = (1-t) * (1-t) * (1-t) * x0 +
509 3 * t * (1-t) * (1-t) * c0x +
510 3 * t * t * (1-t) * c1x +
511 t * t * t * x1;
512 y = (1-t) * (1-t) * (1-t) * y0 +
513 3 * t * (1-t) * (1-t) * c0y +
514 3 * t * t * (1-t) * c1y +
515 t * t * t * y1;
516 } else {
517 x = (1-t) * x0 + t * x1;
518 y = (1-t) * y0 + t * y1;
519 }
520 x_trans = trans[0]*x + trans[2]*y + trans[4];
521 y_trans = trans[1]*x + trans[3]*y + trans[5];
522 r = ((x_trans - gradient_x0) * gradient_dx +
523 (y_trans - gradient_y0) * gradient_dy) /
524 gradient_norm_squared;
525 #ifdef GRADIENT_DEBUG
526 fprintf(stderr, "(%g %g [%g]) ", x, y, r);
527 #endif
528 point = svgtiny_list_push(pts);
529 if (!point) {
530 free(p);
531 svgtiny_list_free(pts);
532 return svgtiny_OUT_OF_MEMORY;
533 }
534 point->x = x;
535 point->y = y;
536 point->r = r;
537 if (r < min_r) {
538 min_r = r;
539 min_pt = svgtiny_list_size(pts) - 1;
540 }
541 }
542 #ifdef GRADIENT_DEBUG
543 fprintf(stderr, "\n");
544 #endif
545
546 /* next segment start point is this segment end point */
547 x0 = x1;
548 y0 = y1;
549 }
550 #ifdef GRADIENT_DEBUG
551 fprintf(stderr, "pts size %i, min_pt %i, min_r %.3f\n",
552 svgtiny_list_size(pts), min_pt, min_r);
553 #endif
554
555 /* There must be at least a single point for the gradient */
556 if (svgtiny_list_size(pts) == 0) {
557 svgtiny_list_free(pts);
558 free(p);
559
560 return svgtiny_OK;
561 }
562
563 /* render triangles */
564 stop_count = grad->linear_gradient_stop_count;
565 assert(2 <= stop_count);
566 current_stop = 0;
567 last_stop_r = 0;
568 current_stop_r = grad->gradient_stop[0].offset;
569 red0 = red1 = svgtiny_RED(grad->gradient_stop[0].color);
570 green0 = green1 = svgtiny_GREEN(grad->gradient_stop[0].color);
571 blue0 = blue1 = svgtiny_BLUE(grad->gradient_stop[0].color);
572 t = min_pt;
573 a = (min_pt + 1) % svgtiny_list_size(pts);
574 b = min_pt == 0 ? svgtiny_list_size(pts) - 1 : min_pt - 1;
575 while (a != b) {
576 struct grad_point *point_t = svgtiny_list_get(pts, t);
577 struct grad_point *point_a = svgtiny_list_get(pts, a);
578 struct grad_point *point_b = svgtiny_list_get(pts, b);
579 float mean_r = (point_t->r + point_a->r + point_b->r) / 3;
580 float *p;
581 struct svgtiny_shape *shape;
582 /*fprintf(stderr, "triangle: t %i %.3f a %i %.3f b %i %.3f "
583 "mean_r %.3f\n",
584 t, pts[t].r, a, pts[a].r, b, pts[b].r,
585 mean_r);*/
586 while (current_stop != stop_count && current_stop_r < mean_r) {
587 current_stop++;
588 if (current_stop == stop_count)
589 break;
590 red0 = red1;
591 green0 = green1;
592 blue0 = blue1;
593 red1 = svgtiny_RED(grad->
594 gradient_stop[current_stop].color);
595 green1 = svgtiny_GREEN(grad->
596 gradient_stop[current_stop].color);
597 blue1 = svgtiny_BLUE(grad->
598 gradient_stop[current_stop].color);
599 last_stop_r = current_stop_r;
600 current_stop_r = grad->
601 gradient_stop[current_stop].offset;
602 }
603 p = malloc(10 * sizeof p[0]);
604 if (!p)
605 return svgtiny_OUT_OF_MEMORY;
606 p[0] = svgtiny_PATH_MOVE;
607 p[1] = point_t->x;
608 p[2] = point_t->y;
609 p[3] = svgtiny_PATH_LINE;
610 p[4] = point_a->x;
611 p[5] = point_a->y;
612 p[6] = svgtiny_PATH_LINE;
613 p[7] = point_b->x;
614 p[8] = point_b->y;
615 p[9] = svgtiny_PATH_CLOSE;
616 svgtiny_transform_path(p, 10, state);
617 shape = svgtiny_add_shape(state);
618 if (!shape) {
619 free(p);
620 return svgtiny_OUT_OF_MEMORY;
621 }
622 shape->path = p;
623 shape->path_length = 10;
624 /*shape->fill = svgtiny_TRANSPARENT;*/
625 if (current_stop == 0)
626 shape->fill = grad->gradient_stop[0].color;
627 else if (current_stop == stop_count)
628 shape->fill = grad->gradient_stop[stop_count - 1].color;
629 else {
630 float stop_r = (mean_r - last_stop_r) /
631 (current_stop_r - last_stop_r);
632 shape->fill = svgtiny_RGB(
633 (int) ((1 - stop_r) * red0 + stop_r * red1),
634 (int) ((1 - stop_r) * green0 + stop_r * green1),
635 (int) ((1 - stop_r) * blue0 + stop_r * blue1));
636 }
637 shape->stroke = svgtiny_TRANSPARENT;
638 #ifdef GRADIENT_DEBUG
639 shape->stroke = svgtiny_RGB(0, 0, 0xff);
640 #endif
641 state->diagram->shape_count++;
642 if (point_a->r < point_b->r) {
643 t = a;
644 a = (a + 1) % svgtiny_list_size(pts);
645 } else {
646 t = b;
647 b = b == 0 ? svgtiny_list_size(pts) - 1 : b - 1;
648 }
649 }
650
651 /* render gradient vector for debugging */
652 #ifdef GRADIENT_DEBUG
653 {
654 float *p = malloc(7 * sizeof p[0]);
655 if (!p)
656 return svgtiny_OUT_OF_MEMORY;
657 p[0] = svgtiny_PATH_MOVE;
658 p[1] = gradient_x0;
659 p[2] = gradient_y0;
660 p[3] = svgtiny_PATH_LINE;
661 p[4] = gradient_x1;
662 p[5] = gradient_y1;
663 p[6] = svgtiny_PATH_CLOSE;
664 svgtiny_transform_path(p, 7, state);
665 struct svgtiny_shape *shape = svgtiny_add_shape(state);
666 if (!shape) {
667 free(p);
668 return svgtiny_OUT_OF_MEMORY;
669 }
670 shape->path = p;
671 shape->path_length = 7;
672 shape->fill = svgtiny_TRANSPARENT;
673 shape->stroke = svgtiny_RGB(0xff, 0, 0);
674 state->diagram->shape_count++;
675 }
676 #endif
677
678 /* render triangle vertices with r values for debugging */
679 #ifdef GRADIENT_DEBUG
680 for (unsigned int i = 0; i != svgtiny_list_size(pts); i++) {
681 struct grad_point *point = svgtiny_list_get(pts, i);
682 struct svgtiny_shape *shape = svgtiny_add_shape(state);
683 if (!shape)
684 return svgtiny_OUT_OF_MEMORY;
685 char *text = malloc(20);
686 if (!text)
687 return svgtiny_OUT_OF_MEMORY;
688 sprintf(text, "%i=%.3f", i, point->r);
689 shape->text = text;
690 shape->text_x = state->ctm.a * point->x +
691 state->ctm.c * point->y + state->ctm.e;
692 shape->text_y = state->ctm.b * point->x +
693 state->ctm.d * point->y + state->ctm.f;
694 shape->fill = svgtiny_RGB(0, 0, 0);
695 shape->stroke = svgtiny_TRANSPARENT;
696 state->diagram->shape_count++;
697 }
698 #endif
699
700 /* plot actual path outline */
701 if (state->stroke != svgtiny_TRANSPARENT) {
702 struct svgtiny_shape *shape;
703 svgtiny_transform_path(p, n, state);
704
705 shape = svgtiny_add_shape(state);
706 if (!shape) {
707 free(p);
708 return svgtiny_OUT_OF_MEMORY;
709 }
710 shape->path = p;
711 shape->path_length = n;
712 shape->fill = svgtiny_TRANSPARENT;
713 state->diagram->shape_count++;
714 } else {
715 free(p);
716 }
717
718 svgtiny_list_free(pts);
719
720 return svgtiny_OK;
721 }
722
723
724 /**
725 * Get the bounding box of path.
726 */
727
728 void svgtiny_path_bbox(float *p, unsigned int n,
729 float *x0, float *y0, float *x1, float *y1)
730 {
731 unsigned int j;
732
733 *x0 = *x1 = p[1];
734 *y0 = *y1 = p[2];
735
736 for (j = 0; j != n; ) {
737 unsigned int points = 0;
738 unsigned int k;
739 switch ((int) p[j]) {
740 case svgtiny_PATH_MOVE:
741 case svgtiny_PATH_LINE:
742 points = 1;
743 break;
744 case svgtiny_PATH_CLOSE:
745 points = 0;
746 break;
747 case svgtiny_PATH_BEZIER:
748 points = 3;
749 break;
750 default:
751 assert(0);
752 }
753 j++;
754 for (k = 0; k != points; k++) {
755 float x = p[j], y = p[j + 1];
756 if (x < *x0)
757 *x0 = x;
758 else if (*x1 < x)
759 *x1 = x;
760 if (y < *y0)
761 *y0 = y;
762 else if (*y1 < y)
763 *y1 = y;
764 j += 2;
765 }
766 }
767 }
768
769
770 /**
771 * Invert a transformation matrix.
772 */
773 void svgtiny_invert_matrix(float *m, float *inv)
774 {
775 float determinant = m[0]*m[3] - m[1]*m[2];
776 inv[0] = m[3] / determinant;
777 inv[1] = -m[1] / determinant;
778 inv[2] = -m[2] / determinant;
779 inv[3] = m[0] / determinant;
780 inv[4] = (m[2]*m[5] - m[3]*m[4]) / determinant;
781 inv[5] = (m[1]*m[4] - m[0]*m[5]) / determinant;
782 }
783
Development fork of https://git.netsurf-browser.org/libsvgtiny.git