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>
14 #include "svgtiny_internal.h"
18 static svgtiny_code
svgtiny_parse_linear_gradient(dom_element
*linear
,
19 struct svgtiny_parse_state
*state
);
20 static float svgtiny_parse_gradient_offset(const char *s
);
21 static void svgtiny_path_bbox(float *p
, unsigned int n
,
22 float *x0
, float *y0
, float *x1
, float *y1
);
23 static void svgtiny_invert_matrix(float *m
, float *inv
);
27 * Find a gradient by id and parse it.
30 void svgtiny_find_gradient(const char *id
, struct svgtiny_parse_state
*state
)
32 dom_element
*gradient
;
36 fprintf(stderr
, "svgtiny_find_gradient: id \"%s\"\n", id
);
38 state
->linear_gradient_stop_count
= 0;
39 state
->gradient_x1
= "0%";
40 state
->gradient_y1
= "0%";
41 state
->gradient_x2
= "100%";
42 state
->gradient_y2
= "0%";
43 state
->gradient_user_space_on_use
= false;
44 state
->gradient_transform
.a
= 1;
45 state
->gradient_transform
.b
= 0;
46 state
->gradient_transform
.c
= 0;
47 state
->gradient_transform
.d
= 1;
48 state
->gradient_transform
.e
= 0;
49 state
->gradient_transform
.f
= 0;
51 exc
= dom_string_create_interned((const uint8_t *) id
, strlen(id
),
53 if (exc
!= DOM_NO_ERR
)
56 exc
= dom_document_get_element_by_id(state
->document
, id_str
,
58 dom_string_unref(id_str
);
59 if (exc
!= DOM_NO_ERR
)
62 if (gradient
== NULL
) {
63 fprintf(stderr
, "gradient \"%s\" not found\n", id
);
67 exc
= dom_node_get_node_name(gradient
, &id_str
);
68 if (exc
!= DOM_NO_ERR
) {
69 dom_node_unref(gradient
);
73 if (dom_string_isequal(id_str
, state
->interned_linearGradient
))
74 svgtiny_parse_linear_gradient(gradient
, state
);
76 dom_string_unref(id_str
);
77 dom_node_unref(gradient
);
82 * Parse a <linearGradient> element node.
84 * http://www.w3.org/TR/SVG11/pservers#LinearGradients
87 svgtiny_code
svgtiny_parse_linear_gradient(dom_element
*linear
,
88 struct svgtiny_parse_state
*state
)
95 exc
= dom_element_get_attribute(linear
, state
->interned_href
, &attr
);
96 if (exc
== DOM_NO_ERR
&& attr
!= NULL
) {
97 if (dom_string_data(attr
)[0] == (uint8_t) '#') {
98 char *s
= strndup(dom_string_data(attr
) + 1,
99 dom_string_length(attr
) - 1);
100 svgtiny_find_gradient(s
, state
);
103 dom_string_unref(attr
);
106 for (attr
= linear
->properties
; attr
; attr
= attr
->next
) {
107 const char *name
= (const char *) attr
->name
;
108 const char *content
= (const char *) attr
->children
->content
;
109 if (strcmp(name
, "x1") == 0)
110 state
->gradient_x1
= content
;
111 else if (strcmp(name
, "y1") == 0)
112 state
->gradient_y1
= content
;
113 else if (strcmp(name
, "x2") == 0)
114 state
->gradient_x2
= content
;
115 else if (strcmp(name
, "y2") == 0)
116 state
->gradient_y2
= content
;
117 else if (strcmp(name
, "gradientUnits") == 0)
118 state
->gradient_user_space_on_use
=
119 strcmp(content
, "userSpaceOnUse") == 0;
120 else if (strcmp(name
, "gradientTransform") == 0) {
121 float a
= 1, b
= 0, c
= 0, d
= 1, e
= 0, f
= 0;
122 char *s
= strdup(content
);
124 return svgtiny_OUT_OF_MEMORY
;
125 svgtiny_parse_transform(s
, &a
, &b
, &c
, &d
, &e
, &f
);
127 fprintf(stderr
, "transform %g %g %g %g %g %g\n",
129 state
->gradient_transform
.a
= a
;
130 state
->gradient_transform
.b
= b
;
131 state
->gradient_transform
.c
= c
;
132 state
->gradient_transform
.d
= d
;
133 state
->gradient_transform
.e
= e
;
134 state
->gradient_transform
.f
= f
;
138 for (stop
= linear
->children
; stop
; stop
= stop
->next
) {
140 svgtiny_colour color
= svgtiny_TRANSPARENT
;
142 if (stop
->type
!= XML_ELEMENT_NODE
)
144 if (strcmp((const char *) stop
->name
, "stop") != 0)
147 for (attr
= stop
->properties
; attr
;
149 const char *name
= (const char *) attr
->name
;
150 const char *content
=
151 (const char *) attr
->children
->content
;
152 if (strcmp(name
, "offset") == 0)
153 offset
= svgtiny_parse_gradient_offset(content
);
154 else if (strcmp(name
, "stop-color") == 0)
155 svgtiny_parse_color(content
, &color
, state
);
156 else if (strcmp(name
, "style") == 0) {
159 if ((s
= strstr(content
, "stop-color:"))) {
163 value
= strndup(s
, strcspn(s
, "; "));
164 svgtiny_parse_color(value
, &color
,
171 if (offset
!= -1 && color
!= svgtiny_TRANSPARENT
) {
172 fprintf(stderr
, "stop %g %x\n", offset
, color
);
173 state
->gradient_stop
[i
].offset
= offset
;
174 state
->gradient_stop
[i
].color
= color
;
178 if (i
== svgtiny_MAX_STOPS
)
183 state
->linear_gradient_stop_count
= i
;
189 float svgtiny_parse_gradient_offset(const char *s
)
191 int num_length
= strspn(s
, "0123456789+-.");
192 const char *unit
= s
+ num_length
;
193 float n
= atof((const char *) s
);
197 else if (unit
[0] == '%')
211 * Add a path with a linear gradient fill to the svgtiny_diagram.
214 svgtiny_code
svgtiny_add_path_linear_gradient(float *p
, unsigned int n
,
215 struct svgtiny_parse_state
*state
)
220 float object_x0
, object_y0
, object_x1
, object_y1
;
221 float gradient_x0
, gradient_y0
, gradient_x1
, gradient_y1
,
222 gradient_dx
, gradient_dy
;
224 unsigned int steps
= 10;
225 float x0
= 0, y0
= 0, x0_trans
, y0_trans
, r0
; /* segment start point */
226 float x1
, y1
, x1_trans
, y1_trans
, r1
; /* segment end point */
227 /* segment control points (beziers only) */
228 float c0x
= 0, c0y
= 0, c1x
= 0, c1y
= 0;
229 float gradient_norm_squared
;
230 struct svgtiny_list
*pts
;
232 unsigned int min_pt
= 0;
234 unsigned int stop_count
;
235 unsigned int current_stop
;
237 float current_stop_r
;
238 int red0
, green0
, blue0
, red1
, green1
, blue1
;
239 unsigned int t
, a
, b
;
241 /* determine object bounding box */
242 svgtiny_path_bbox(p
, n
, &object_x0
, &object_y0
, &object_x1
, &object_y1
);
243 #ifdef GRADIENT_DEBUG
244 fprintf(stderr
, "object bbox: (%g %g) (%g %g)\n",
245 object_x0
, object_y0
, object_x1
, object_y1
);
248 /* compute gradient vector */
249 fprintf(stderr
, "x1 %s, y1 %s, x2 %s, y2 %s\n",
250 state
->gradient_x1
, state
->gradient_y1
,
251 state
->gradient_x2
, state
->gradient_y2
);
252 if (!state
->gradient_user_space_on_use
) {
253 gradient_x0
= object_x0
+
254 svgtiny_parse_length(state
->gradient_x1
,
255 object_x1
- object_x0
, *state
);
256 gradient_y0
= object_y0
+
257 svgtiny_parse_length(state
->gradient_y1
,
258 object_y1
- object_y0
, *state
);
259 gradient_x1
= object_x0
+
260 svgtiny_parse_length(state
->gradient_x2
,
261 object_x1
- object_x0
, *state
);
262 gradient_y1
= object_y0
+
263 svgtiny_parse_length(state
->gradient_y2
,
264 object_y1
- object_y0
, *state
);
266 gradient_x0
= svgtiny_parse_length(state
->gradient_x1
,
267 state
->viewport_width
, *state
);
268 gradient_y0
= svgtiny_parse_length(state
->gradient_y1
,
269 state
->viewport_height
, *state
);
270 gradient_x1
= svgtiny_parse_length(state
->gradient_x2
,
271 state
->viewport_width
, *state
);
272 gradient_y1
= svgtiny_parse_length(state
->gradient_y2
,
273 state
->viewport_height
, *state
);
275 gradient_dx
= gradient_x1
- gradient_x0
;
276 gradient_dy
= gradient_y1
- gradient_y0
;
277 #ifdef GRADIENT_DEBUG
278 fprintf(stderr
, "gradient vector: (%g %g) => (%g %g)\n",
279 gradient_x0
, gradient_y0
, gradient_x1
, gradient_y1
);
282 /* show theoretical gradient strips for debugging */
283 /*unsigned int strips = 10;
284 for (unsigned int z = 0; z != strips; z++) {
285 float f0, fd, strip_x0, strip_y0, strip_dx, strip_dy;
286 f0 = (float) z / (float) strips;
287 fd = (float) 1 / (float) strips;
288 strip_x0 = gradient_x0 + f0 * gradient_dx;
289 strip_y0 = gradient_y0 + f0 * gradient_dy;
290 strip_dx = fd * gradient_dx;
291 strip_dy = fd * gradient_dy;
292 fprintf(stderr, "strip %i vector: (%g %g) + (%g %g)\n",
293 z, strip_x0, strip_y0, strip_dx, strip_dy);
295 float *p = malloc(13 * sizeof p[0]);
297 return svgtiny_OUT_OF_MEMORY;
298 p[0] = svgtiny_PATH_MOVE;
299 p[1] = strip_x0 + (strip_dy * 3);
300 p[2] = strip_y0 - (strip_dx * 3);
301 p[3] = svgtiny_PATH_LINE;
302 p[4] = p[1] + strip_dx;
303 p[5] = p[2] + strip_dy;
304 p[6] = svgtiny_PATH_LINE;
305 p[7] = p[4] - (strip_dy * 6);
306 p[8] = p[5] + (strip_dx * 6);
307 p[9] = svgtiny_PATH_LINE;
308 p[10] = p[7] - strip_dx;
309 p[11] = p[8] - strip_dy;
310 p[12] = svgtiny_PATH_CLOSE;
311 svgtiny_transform_path(p, 13, state);
312 struct svgtiny_shape *shape = svgtiny_add_shape(state);
315 return svgtiny_OUT_OF_MEMORY;
318 shape->path_length = 13;
319 shape->fill = svgtiny_TRANSPARENT;
320 shape->stroke = svgtiny_RGB(0, 0xff, 0);
321 state->diagram->shape_count++;
324 /* invert gradient transform for applying to vertices */
325 svgtiny_invert_matrix(&state
->gradient_transform
.a
, trans
);
326 fprintf(stderr
, "inverse transform %g %g %g %g %g %g\n",
327 trans
[0], trans
[1], trans
[2], trans
[3],
330 /* compute points on the path for triangle vertices */
331 /* r, r0, r1 are distance along gradient vector */
332 gradient_norm_squared
= gradient_dx
* gradient_dx
+
333 gradient_dy
* gradient_dy
;
334 pts
= svgtiny_list_create(
335 sizeof (struct grad_point
));
337 return svgtiny_OUT_OF_MEMORY
;
338 for (j
= 0; j
!= n
; ) {
339 int segment_type
= (int) p
[j
];
340 struct grad_point
*point
;
343 if (segment_type
== svgtiny_PATH_MOVE
) {
350 assert(segment_type
== svgtiny_PATH_CLOSE
||
351 segment_type
== svgtiny_PATH_LINE
||
352 segment_type
== svgtiny_PATH_BEZIER
);
354 /* start point (x0, y0) */
355 x0_trans
= trans
[0]*x0
+ trans
[2]*y0
+ trans
[4];
356 y0_trans
= trans
[1]*x0
+ trans
[3]*y0
+ trans
[5];
357 r0
= ((x0_trans
- gradient_x0
) * gradient_dx
+
358 (y0_trans
- gradient_y0
) * gradient_dy
) /
359 gradient_norm_squared
;
360 point
= svgtiny_list_push(pts
);
362 svgtiny_list_free(pts
);
363 return svgtiny_OUT_OF_MEMORY
;
370 min_pt
= svgtiny_list_size(pts
) - 1;
373 /* end point (x1, y1) */
374 if (segment_type
== svgtiny_PATH_LINE
) {
378 } else if (segment_type
== svgtiny_PATH_CLOSE
) {
382 } else /* svgtiny_PATH_BEZIER */ {
391 x1_trans
= trans
[0]*x1
+ trans
[2]*y1
+ trans
[4];
392 y1_trans
= trans
[1]*x1
+ trans
[3]*y1
+ trans
[5];
393 r1
= ((x1_trans
- gradient_x0
) * gradient_dx
+
394 (y1_trans
- gradient_y0
) * gradient_dy
) /
395 gradient_norm_squared
;
397 /* determine steps from change in r */
398 steps
= ceilf(fabsf(r1
- r0
) / 0.05);
401 fprintf(stderr
, "r0 %g, r1 %g, steps %i\n",
404 /* loop through intermediate points */
405 for (z
= 1; z
!= steps
; z
++) {
406 float t
, x
, y
, x_trans
, y_trans
, r
;
407 struct grad_point
*point
;
408 t
= (float) z
/ (float) steps
;
409 if (segment_type
== svgtiny_PATH_BEZIER
) {
410 x
= (1-t
) * (1-t
) * (1-t
) * x0
+
411 3 * t
* (1-t
) * (1-t
) * c0x
+
412 3 * t
* t
* (1-t
) * c1x
+
414 y
= (1-t
) * (1-t
) * (1-t
) * y0
+
415 3 * t
* (1-t
) * (1-t
) * c0y
+
416 3 * t
* t
* (1-t
) * c1y
+
419 x
= (1-t
) * x0
+ t
* x1
;
420 y
= (1-t
) * y0
+ t
* y1
;
422 x_trans
= trans
[0]*x
+ trans
[2]*y
+ trans
[4];
423 y_trans
= trans
[1]*x
+ trans
[3]*y
+ trans
[5];
424 r
= ((x_trans
- gradient_x0
) * gradient_dx
+
425 (y_trans
- gradient_y0
) * gradient_dy
) /
426 gradient_norm_squared
;
427 fprintf(stderr
, "(%g %g [%g]) ", x
, y
, r
);
428 point
= svgtiny_list_push(pts
);
430 svgtiny_list_free(pts
);
431 return svgtiny_OUT_OF_MEMORY
;
438 min_pt
= svgtiny_list_size(pts
) - 1;
441 fprintf(stderr
, "\n");
443 /* next segment start point is this segment end point */
447 fprintf(stderr
, "pts size %i, min_pt %i, min_r %.3f\n",
448 svgtiny_list_size(pts
), min_pt
, min_r
);
450 /* render triangles */
451 stop_count
= state
->linear_gradient_stop_count
;
452 assert(2 <= stop_count
);
455 current_stop_r
= state
->gradient_stop
[0].offset
;
456 red0
= red1
= svgtiny_RED(state
->gradient_stop
[0].color
);
457 green0
= green1
= svgtiny_GREEN(state
->gradient_stop
[0].color
);
458 blue0
= blue1
= svgtiny_BLUE(state
->gradient_stop
[0].color
);
460 a
= (min_pt
+ 1) % svgtiny_list_size(pts
);
461 b
= min_pt
== 0 ? svgtiny_list_size(pts
) - 1 : min_pt
- 1;
463 struct grad_point
*point_t
= svgtiny_list_get(pts
, t
);
464 struct grad_point
*point_a
= svgtiny_list_get(pts
, a
);
465 struct grad_point
*point_b
= svgtiny_list_get(pts
, b
);
466 float mean_r
= (point_t
->r
+ point_a
->r
+ point_b
->r
) / 3;
468 struct svgtiny_shape
*shape
;
469 /*fprintf(stderr, "triangle: t %i %.3f a %i %.3f b %i %.3f "
471 t, pts[t].r, a, pts[a].r, b, pts[b].r,
473 while (current_stop
!= stop_count
&& current_stop_r
< mean_r
) {
475 if (current_stop
== stop_count
)
480 red1
= svgtiny_RED(state
->
481 gradient_stop
[current_stop
].color
);
482 green1
= svgtiny_GREEN(state
->
483 gradient_stop
[current_stop
].color
);
484 blue1
= svgtiny_BLUE(state
->
485 gradient_stop
[current_stop
].color
);
486 last_stop_r
= current_stop_r
;
487 current_stop_r
= state
->
488 gradient_stop
[current_stop
].offset
;
490 p
= malloc(10 * sizeof p
[0]);
492 return svgtiny_OUT_OF_MEMORY
;
493 p
[0] = svgtiny_PATH_MOVE
;
496 p
[3] = svgtiny_PATH_LINE
;
499 p
[6] = svgtiny_PATH_LINE
;
502 p
[9] = svgtiny_PATH_CLOSE
;
503 svgtiny_transform_path(p
, 10, state
);
504 shape
= svgtiny_add_shape(state
);
507 return svgtiny_OUT_OF_MEMORY
;
510 shape
->path_length
= 10;
511 /*shape->fill = svgtiny_TRANSPARENT;*/
512 if (current_stop
== 0)
513 shape
->fill
= state
->gradient_stop
[0].color
;
514 else if (current_stop
== stop_count
)
515 shape
->fill
= state
->
516 gradient_stop
[stop_count
- 1].color
;
518 float stop_r
= (mean_r
- last_stop_r
) /
519 (current_stop_r
- last_stop_r
);
520 shape
->fill
= svgtiny_RGB(
521 (int) ((1 - stop_r
) * red0
+ stop_r
* red1
),
522 (int) ((1 - stop_r
) * green0
+ stop_r
* green1
),
523 (int) ((1 - stop_r
) * blue0
+ stop_r
* blue1
));
525 shape
->stroke
= svgtiny_TRANSPARENT
;
526 #ifdef GRADIENT_DEBUG
527 shape
->stroke
= svgtiny_RGB(0, 0, 0xff);
529 state
->diagram
->shape_count
++;
530 if (point_a
->r
< point_b
->r
) {
532 a
= (a
+ 1) % svgtiny_list_size(pts
);
535 b
= b
== 0 ? svgtiny_list_size(pts
) - 1 : b
- 1;
539 /* render gradient vector for debugging */
540 #ifdef GRADIENT_DEBUG
542 float *p
= malloc(7 * sizeof p
[0]);
544 return svgtiny_OUT_OF_MEMORY
;
545 p
[0] = svgtiny_PATH_MOVE
;
548 p
[3] = svgtiny_PATH_LINE
;
551 p
[6] = svgtiny_PATH_CLOSE
;
552 svgtiny_transform_path(p
, 7, state
);
553 struct svgtiny_shape
*shape
= svgtiny_add_shape(state
);
556 return svgtiny_OUT_OF_MEMORY
;
559 shape
->path_length
= 7;
560 shape
->fill
= svgtiny_TRANSPARENT
;
561 shape
->stroke
= svgtiny_RGB(0xff, 0, 0);
562 state
->diagram
->shape_count
++;
566 /* render triangle vertices with r values for debugging */
567 #ifdef GRADIENT_DEBUG
568 for (unsigned int i
= 0; i
!= pts
->size
; i
++) {
569 struct grad_point
*point
= svgtiny_list_get(pts
, i
);
570 struct svgtiny_shape
*shape
= svgtiny_add_shape(state
);
572 return svgtiny_OUT_OF_MEMORY
;
573 char *text
= malloc(20);
575 return svgtiny_OUT_OF_MEMORY
;
576 sprintf(text
, "%i=%.3f", i
, point
->r
);
578 shape
->text_x
= state
->ctm
.a
* point
->x
+
579 state
->ctm
.c
* point
->y
+ state
->ctm
.e
;
580 shape
->text_y
= state
->ctm
.b
* point
->x
+
581 state
->ctm
.d
* point
->y
+ state
->ctm
.f
;
582 shape
->fill
= svgtiny_RGB(0, 0, 0);
583 shape
->stroke
= svgtiny_TRANSPARENT
;
584 state
->diagram
->shape_count
++;
588 /* plot actual path outline */
589 if (state
->stroke
!= svgtiny_TRANSPARENT
) {
590 struct svgtiny_shape
*shape
;
591 svgtiny_transform_path(p
, n
, state
);
593 shape
= svgtiny_add_shape(state
);
596 return svgtiny_OUT_OF_MEMORY
;
599 shape
->path_length
= n
;
600 shape
->fill
= svgtiny_TRANSPARENT
;
601 state
->diagram
->shape_count
++;
606 svgtiny_list_free(pts
);
613 * Get the bounding box of path.
616 void svgtiny_path_bbox(float *p
, unsigned int n
,
617 float *x0
, float *y0
, float *x1
, float *y1
)
624 for (j
= 0; j
!= n
; ) {
625 unsigned int points
= 0;
627 switch ((int) p
[j
]) {
628 case svgtiny_PATH_MOVE
:
629 case svgtiny_PATH_LINE
:
632 case svgtiny_PATH_CLOSE
:
635 case svgtiny_PATH_BEZIER
:
642 for (k
= 0; k
!= points
; k
++) {
643 float x
= p
[j
], y
= p
[j
+ 1];
659 * Invert a transformation matrix.
661 void svgtiny_invert_matrix(float *m
, float *inv
)
663 float determinant
= m
[0]*m
[3] - m
[1]*m
[2];
664 inv
[0] = m
[3] / determinant
;
665 inv
[1] = -m
[1] / determinant
;
666 inv
[2] = -m
[2] / determinant
;
667 inv
[3] = m
[0] / determinant
;
668 inv
[4] = (m
[2]*m
[5] - m
[3]*m
[4]) / determinant
;
669 inv
[5] = (m
[1]*m
[4] - m
[0]*m
[5]) / determinant
;