1 #include <stdio.h> /* fprintf, printf */
2 #include <string.h> /* memcpy, memset, strstr */
6 #include <gdk-pixbuf/gdk-pixbuf.h> /* includes glib.h */
10 * The width and height of the viewport that we'll render the SVG
11 * into. The final "picture" may not actually be this size; based on
12 * the height, width, viewBox, and preserveAspectRatio attributes in
13 * the SVG itself, libsvgtiny may scale, stretch, offset, etc. the
14 * paths to make them fit nicely into the viewport.
16 #define VIEWPORT_WIDTH 512
17 #define VIEWPORT_HEIGHT 512
19 /* The start of an XInclude that was inserted by
20 * gtk-encode-symbolic-svg */
21 #define XI_SIGNATURE "<xi:include href=\"data:text/xml;base64,"
24 /* Convenient typedefs for libsvgtiny */
25 typedef struct svgtiny_diagram diagram_t
;
26 typedef struct svgtiny_shape shape_t
;
30 GdkPixbufModuleUpdatedFunc updated_func
;
31 GdkPixbufModulePreparedFunc prepared_func
;
32 GdkPixbufModuleSizeFunc size_func
;
35 /* The SVG "file" that we're building in memory. */
38 /* How far into svg_data are we? This should always point to the
39 next empty byte. If (for example) svg_data_size is 2, then
40 svg_data[0] and svg_data[1] are used, but svg_data[2] is free. */
47 * @brief Render an svgtiny path using cairo.
50 * A pointer to a valid cairo context.
53 * A pointer to an svgtiny shape that will be rendered on the
54 * cairo context's target surface.
56 static void render_path(cairo_t
* cr
, shape_t
* path
) {
60 for (j
= 0; j
!= path
->path_length
; ) {
61 switch ((int) path
->path
[j
]) {
62 case svgtiny_PATH_MOVE
:
68 case svgtiny_PATH_CLOSE
:
72 case svgtiny_PATH_LINE
:
78 case svgtiny_PATH_BEZIER
:
89 if (path
->fill
!= svgtiny_TRANSPARENT
) {
90 cairo_set_source_rgba(cr
,
91 svgtiny_RED(path
->fill
) / 255.0,
92 svgtiny_GREEN(path
->fill
) / 255.0,
93 svgtiny_BLUE(path
->fill
) / 255.0,
95 cairo_fill_preserve(cr
);
97 if (path
->stroke
!= svgtiny_TRANSPARENT
) {
98 cairo_set_source_rgba(cr
,
99 svgtiny_RED(path
->stroke
) / 255.0,
100 svgtiny_GREEN(path
->stroke
) / 255.0,
101 svgtiny_BLUE(path
->stroke
) / 255.0,
103 cairo_set_line_width(cr
, path
->stroke_width
);
104 cairo_stroke_preserve(cr
);
109 * @brief Parse a buffer of SVG data into a diagram_t structure.
112 * The buffer containing the SVG document.
115 * The number of bytes in @c buffer.
117 * @return If successful, a pointer to a @c diagram_t structure is
118 * returned; if not, @c NULL is returned. You are expected to @c
119 * svgtiny_free the result if it is valid.
121 static diagram_t
* svgtiny_diagram_from_buffer(char* buffer
,
129 diagram
= svgtiny_create();
131 g_set_error_literal(error
,
134 "out of memory in svgtiny_create()");
138 code
= svgtiny_parse(diagram
, buffer
, bytecount
, "", width
, height
);
140 if (code
!= svgtiny_OK
) {
142 case svgtiny_OUT_OF_MEMORY
:
143 g_set_error_literal(error
,
146 "out of memory in svgtiny_parse()");
148 case svgtiny_LIBDOM_ERROR
:
149 g_set_error_literal(error
,
151 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
152 "invalid XML DOM in svgtiny_parse()");
154 case svgtiny_NOT_SVG
:
155 g_set_error_literal(error
,
157 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
158 "missing <svg> element in svgtiny_parse()");
160 case svgtiny_SVG_ERROR
:
163 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
164 "SVG format error in svgtiny_parse() on line %i: %s",
166 diagram
->error_message
);
176 * @brief Create a cairo context from a libsvgtiny diagram.
179 * A pointer to a valid libsvgtiny diagram.
181 * @return If successful, a pointer to a @c cairo_t context structure
182 * is returned; if not, @c NULL is returned. You are expected to @c
183 * cairo_destroy the result if it is valid.
185 static cairo_t
* cairo_context_from_diagram(diagram_t
* diagram
) {
187 cairo_surface_t
* surface
;
191 surface
= cairo_image_surface_create(CAIRO_FORMAT_ARGB32
,
195 crs
= cairo_surface_status(surface
);
196 if (crs
!= CAIRO_STATUS_SUCCESS
) {
198 "cairo_image_surface_create failed: %s\n",
199 cairo_status_to_string(crs
));
200 cairo_surface_destroy(surface
);
204 cr
= cairo_create(surface
);
205 crs
= cairo_status(cr
);
207 /* Immediately destroy the surface which is now accessible as
209 cairo_surface_destroy(surface
);
211 if (crs
!= CAIRO_STATUS_SUCCESS
) {
213 "cairo_create failed: %s\n",
214 cairo_status_to_string(crs
));
219 cairo_set_source_rgba(cr
, 0, 0, 0, 0);
222 /* Loop through the shapes in the diagram... */
223 for (i
= 0; i
!= diagram
->shape_count
; i
++) {
225 /* If this shape is a path, just render it. */
226 if (diagram
->shape
[i
].path
) {
227 render_path(cr
, &diagram
->shape
[i
]);
230 /* If this shape is text... */
231 if (diagram
->shape
[i
].text
) {
232 /* Figure out what color to use from the R/G/B components of the
234 cairo_set_source_rgba(cr
,
235 svgtiny_RED(diagram
->shape
[i
].stroke
) / 255.0,
236 svgtiny_GREEN(diagram
->shape
[i
].stroke
) / 255.0,
237 svgtiny_BLUE(diagram
->shape
[i
].stroke
) / 255.0,
239 /* Then move to the actual position of the text within the
242 diagram
->shape
[i
].text_x
,
243 diagram
->shape
[i
].text_y
);
246 cairo_show_text(cr
, diagram
->shape
[i
].text
);
251 /* Check the status again just for good measure? */
252 crs
= cairo_status(cr
);
253 if (crs
!= CAIRO_STATUS_SUCCESS
) {
256 cairo_status_to_string(crs
));
265 * @brief Create a GdkPixbuf from a buffer of SVG data.
268 * The buffer containing the SVG document.
271 * The number of bytes in @c buffer.
274 * The address of a @c GError pointer that we use to return errors.
276 * @return If successful, a valid pointer to a @c GdkPixbuf is
277 * returned; if not, @c NULL is returned and @c error is populated.
279 static GdkPixbuf
* gdk_pixbuf_from_svg_buffer(char* buffer
,
285 GError
* sub_error
= NULL
;
287 diagram
= svgtiny_diagram_from_buffer(buffer
,
293 g_propagate_error(error
, sub_error
);
297 cr
= cairo_context_from_diagram(diagram
);
299 svgtiny_free(diagram
);
300 g_set_error_literal(error
,
302 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
303 "could not create Cairo surface from SVG diagram");
308 /* I've gone back and forth on this about five times: we use the
309 * diagram width and height, and not the viewport width and height.
310 * This can ultimately render an image that's larger than the
311 * viewport size, but I think GDK will resize the final pixbuf
312 * anyway. More importantly, rendering small icons at a larger
313 * (viewport) size seems to make the whole thing go ape-shit.
314 * So for now I'm back in the diagram camp.
316 pb
= gdk_pixbuf_get_from_surface(cairo_get_target(cr
),
324 g_set_error_literal(error
,
326 GDK_PIXBUF_ERROR_FAILED
,
327 "failed to obtain a GdkPixbuf from Cairo surface");
334 static gpointer
gdk_pixbuf_begin_load(GdkPixbufModuleSizeFunc size_func
,
335 GdkPixbufModulePreparedFunc prep_func
,
336 GdkPixbufModuleUpdatedFunc updated_func
,
340 SvgTinyContext
* context
= g_new(SvgTinyContext
, 1);
342 context
->size_func
= size_func
;
343 context
->prepared_func
= prep_func
;
344 context
->updated_func
= updated_func
;
345 context
->user_data
= user_data
;
347 context
->svg_data
= NULL
;
348 context
->svg_data_size
= 0;
353 static gboolean
gdk_pixbuf_load_increment(gpointer data
,
357 size_t increment
= 0;
358 SvgTinyContext
* context
= (SvgTinyContext
*)data
;
360 /* YOLO, no error checking */
361 context
->svg_data
= g_realloc(context
->svg_data
,
362 context
->svg_data_size
+ buf_size
);
363 memcpy(context
->svg_data
+ context
->svg_data_size
, buf
, buf_size
);
364 context
->svg_data_size
+= buf_size
;
369 static void emit_updated(SvgTinyContext
* context
, GdkPixbuf
* pixbuf
) {
370 if (context
->updated_func
!= NULL
) {
371 (*context
->updated_func
)(pixbuf
,
374 gdk_pixbuf_get_width(pixbuf
),
375 gdk_pixbuf_get_height(pixbuf
),
380 static void emit_prepared(SvgTinyContext
* context
, GdkPixbuf
* pixbuf
) {
381 if (context
->prepared_func
!= NULL
) {
382 (*context
->prepared_func
)(pixbuf
, NULL
, context
->user_data
);
388 * @brief Process certain <xi:include> elements in an SVG buffer.
390 * GTK is very cute. Its gtk-encode-symbolic-svg tool wraps your SVG
391 * in its own boilerplate, but then rather than including your SVG
392 * data verbatim, it includes it via a sketchy XInclude that looks
395 * <xi:include href="data:text/xml;base64,PD94bWwgd..."/>
397 * Librsvg knows how to parse that, but libxml2 doesn't (the latter
398 * can handle an XInclude, just not a base64-encoded data reference).
399 * Fortunately, you can read the source to gtk-encode-symbolic-svg,
400 * and just see what the format of that line will be. Here we're going
401 * to parse out the base64 data, decode it, strip out its opening
402 * <xml> and <svg> tags, and then replace the original <xi:include>
403 * element with the result. Life is a little easier because the
404 * closing </svg> tag always immediately follows the XInclude; we can
405 * chop the whole thing off, decode the base64 stuff, and then paste
406 * the result back on the end with its own closing </svg> tag intact.
409 * A buffer containing SVG file data.
412 * The size of @c buffer (which may not be NULL-terminated).
415 * A pointer to the size of the new buffer, valid only if the
416 * return value is non-NULL.
418 * @return A pointer to a buffer where the <xi:include> has been
419 * processed. If no replacements were made, the result will be @c
420 * NULL; otherwise, you are expected to @c free it when you are done.
422 static char* process_gtk_symbolic_svg_xinclude(const char* buffer
,
429 xi_start
= strstr(buffer
, XI_SIGNATURE
);
430 if (xi_start
== NULL
) {
434 xi
= xi_start
+ strlen(XI_SIGNATURE
);
435 xi_stop
= strstr(xi
, "\"");
436 if(xi_stop
== NULL
) {
437 /* We found the start of an XInclude, but not the end of its
438 base64-encoded data? Play it safe and do nothing. */
442 /* g_base64_decode needs a NULL-terminated string, so let's make
446 guchar
* decoded
= g_base64_decode(xi
, &decoded_size
);
448 /* We need another round of processing to strip the <xml> and <svg>
449 * elements out of "decoded", but it's simpler to just overwrite
450 * them with spaces before we proceed. We'll wind up with a document
451 * that has a conspicuous chunk of whitespace in the middle of it,
452 * but whatever. Note that we don't need to worry about the <xml>
453 * element so much, because if one exists, it has to come before the
454 * <svg>. As a result, we just need to strip everything up to the
455 * leading <svg> tag. */
456 guchar
* svg_open_start
= strstr(decoded
, "<svg ");
457 guchar
* svg_open_end
= strstr(svg_open_start
, ">");
458 memset(decoded
, ' ', (1 + (svg_open_end
- decoded
)));
460 /* We're going to keep everything up to xi_start. If the <xi:include
461 * started at, say, position three, then this would compute a size
462 * of three. Which is correct: we want to retain buffer[0],
463 * buffer[1], and buffer[2]. */
464 size_t keep_size
= xi_start
- buffer
;
465 *new_size
= keep_size
+ decoded_size
;
467 char* result
= g_malloc(*new_size
);
468 memcpy(result
, buffer
, keep_size
);
469 memcpy(result
+keep_size
, decoded
, decoded_size
);
475 static gboolean
gdk_pixbuf_stop_load(gpointer data
, GError
**error
) {
476 SvgTinyContext
* context
= (SvgTinyContext
*)data
;
477 GdkPixbuf
* pixbuf
= NULL
;
478 gboolean result
= TRUE
;
479 GError
* sub_error
= NULL
;
482 /* If we're inside of gtk-encode-symbolic-svg right now, we need to
483 process the insane librsvg-specific XInclude directive it hands
484 us before proceeding. */
486 char* newdata
= process_gtk_symbolic_svg_xinclude(context
->svg_data
,
487 context
->svg_data_size
,
489 if (newdata
!= NULL
) {
490 g_free(context
->svg_data
);
491 context
->svg_data
= newdata
;
492 context
->svg_data_size
= newsize
;
495 /* OK, we've got an SVG with no XIncludes now. */
496 pixbuf
= gdk_pixbuf_from_svg_buffer(context
->svg_data
,
497 context
->svg_data_size
,
500 if (pixbuf
!= NULL
) {
501 emit_prepared(context
, pixbuf
);
502 emit_updated(context
, pixbuf
);
503 g_object_unref(pixbuf
);
506 g_propagate_error(error
, sub_error
);
509 g_free(context
->svg_data
);
516 G_MODULE_EXPORT
void fill_vtable(GdkPixbufModule
* module);
517 void fill_vtable(GdkPixbufModule
* module) {
518 module->begin_load
= gdk_pixbuf_begin_load
;
519 module->load_increment
= gdk_pixbuf_load_increment
;
520 module->stop_load
= gdk_pixbuf_stop_load
;
523 G_MODULE_EXPORT
void fill_info(GdkPixbufFormat
*info
);
524 void fill_info(GdkPixbufFormat
* info
) {
525 /* Borrowed from librsvg-2.40.21 */
526 static const GdkPixbufModulePattern signature
[] = {
527 { " <svg", "* ", 100 },
528 { " <!DOCTYPE svg", "* ", 100 },
532 /* I'm not sure if we should support gzipped svg here? */
533 static const gchar
*mime_types
[] = {
537 "image/vnd.adobe.svg+xml",
539 "image/svg+xml-compressed",
543 static const gchar
*extensions
[] = {
551 info
->signature
= (GdkPixbufModulePattern
*)signature
;
552 info
->description
= "Scalable Vector Graphics";
553 info
->mime_types
= (gchar
**)mime_types
;
554 info
->extensions
= (gchar
**)extensions
;
555 info
->flags
= GDK_PIXBUF_FORMAT_SCALABLE
;
556 info
->license
= "AGPL3";
560 int main(int argc
, char** argv
) {
567 /* Parse arguments, and maybe print usage */
569 printf("Usage: %s INPUT OUTPUT\n", argv
[0]);
570 printf("Convert an SVG file (INPUT) to a PNG file (OUTPUT)\n");
577 pb
= gdk_pixbuf_new_from_file(svgpath
, &err
);
580 "Error %d in gdk_pixbuf_new_from_file: %s\n",
587 gdk_pixbuf_save(pb
, pngpath
, "png", NULL
, NULL
);