1 #include <string.h> /* memcpy, memset */
5 #include <gdk-pixbuf/gdk-pixbuf.h> /* includes glib.h */
6 #include <glib/gprintf.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(gchar
* buffer
,
129 diagram
= svgtiny_create();
131 g_set_error_literal(error
,
134 "out of memory in svgtiny_create()");
138 g_assert((int)width
>= 0);
139 g_assert((int)height
>= 0);
140 code
= svgtiny_parse(diagram
,
148 /* The one success case. */
150 case svgtiny_OUT_OF_MEMORY
:
151 g_set_error_literal(error
,
154 "out of memory in svgtiny_parse()");
156 case svgtiny_LIBDOM_ERROR
:
157 g_set_error_literal(error
,
159 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
160 "invalid XML DOM in svgtiny_parse()");
162 case svgtiny_NOT_SVG
:
163 g_set_error_literal(error
,
165 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
166 "missing <svg> element in svgtiny_parse()");
168 case svgtiny_SVG_ERROR
:
171 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
172 "SVG format error in svgtiny_parse() on line %i: %s",
174 diagram
->error_message
);
178 /* All other cases above are failure */
183 * @brief Create a cairo context from a libsvgtiny diagram.
186 * A pointer to a valid libsvgtiny diagram.
188 * @return If successful, a pointer to a @c cairo_t context structure
189 * is returned; if not, @c NULL is returned. You are expected to @c
190 * cairo_destroy the result if it is valid.
192 static cairo_t
* cairo_context_from_diagram(diagram_t
* diagram
) {
194 cairo_surface_t
* surface
;
198 surface
= cairo_image_surface_create(CAIRO_FORMAT_ARGB32
,
202 crs
= cairo_surface_status(surface
);
203 if (crs
!= CAIRO_STATUS_SUCCESS
) {
205 "cairo_image_surface_create failed: %s\n",
206 cairo_status_to_string(crs
));
207 cairo_surface_destroy(surface
);
211 cr
= cairo_create(surface
);
212 crs
= cairo_status(cr
);
214 /* Immediately destroy the surface which is now accessible as
216 cairo_surface_destroy(surface
);
218 if (crs
!= CAIRO_STATUS_SUCCESS
) {
220 "cairo_create failed: %s\n",
221 cairo_status_to_string(crs
));
226 cairo_set_source_rgba(cr
, 0, 0, 0, 0);
229 /* Loop through the shapes in the diagram... */
230 for (i
= 0; i
!= diagram
->shape_count
; i
++) {
232 /* If this shape is a path, just render it. */
233 if (diagram
->shape
[i
].path
) {
234 render_path(cr
, &diagram
->shape
[i
]);
237 /* If this shape is text... */
238 if (diagram
->shape
[i
].text
) {
239 /* Figure out what color to use from the R/G/B components of the
241 cairo_set_source_rgba(cr
,
242 svgtiny_RED(diagram
->shape
[i
].stroke
) / 255.0,
243 svgtiny_GREEN(diagram
->shape
[i
].stroke
) / 255.0,
244 svgtiny_BLUE(diagram
->shape
[i
].stroke
) / 255.0,
246 /* Then move to the actual position of the text within the
249 diagram
->shape
[i
].text_x
,
250 diagram
->shape
[i
].text_y
);
253 cairo_show_text(cr
, diagram
->shape
[i
].text
);
258 /* Check the status again just for good measure? */
259 crs
= cairo_status(cr
);
260 if (crs
!= CAIRO_STATUS_SUCCESS
) {
263 cairo_status_to_string(crs
));
272 * @brief Create a GdkPixbuf from a buffer of SVG data.
275 * The buffer containing the SVG document.
278 * The number of bytes in @c buffer.
281 * The address of a @c GError pointer that we use to return errors.
283 * @return If successful, a valid pointer to a @c GdkPixbuf is
284 * returned; if not, @c NULL is returned and @c error is populated.
286 static GdkPixbuf
* gdk_pixbuf_from_svg_buffer(gchar
* buffer
,
292 GError
* sub_error
= NULL
;
294 diagram
= svgtiny_diagram_from_buffer(buffer
,
300 g_propagate_error(error
, sub_error
);
304 cr
= cairo_context_from_diagram(diagram
);
306 svgtiny_free(diagram
);
307 g_set_error_literal(error
,
309 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
310 "could not create Cairo surface from SVG diagram");
315 /* I've gone back and forth on this about five times: we use the
316 * diagram width and height, and not the viewport width and height.
317 * This can ultimately render an image that's larger than the
318 * viewport size, but I think GDK will resize the final pixbuf
319 * anyway. More importantly, rendering small icons at a larger
320 * (viewport) size seems to make the whole thing go ape-shit.
321 * So for now I'm back in the diagram camp.
323 pb
= gdk_pixbuf_get_from_surface(cairo_get_target(cr
),
331 g_set_error_literal(error
,
333 GDK_PIXBUF_ERROR_FAILED
,
334 "failed to obtain a GdkPixbuf from Cairo surface");
341 static gpointer
gdk_pixbuf_begin_load(GdkPixbufModuleSizeFunc size_func
,
342 GdkPixbufModulePreparedFunc prep_func
,
343 GdkPixbufModuleUpdatedFunc updated_func
,
347 SvgTinyContext
* context
= g_new(SvgTinyContext
, 1);
349 context
->size_func
= size_func
;
350 context
->prepared_func
= prep_func
;
351 context
->updated_func
= updated_func
;
352 context
->user_data
= user_data
;
354 context
->svg_data
= NULL
;
355 context
->svg_data_size
= 0;
360 static gboolean
gdk_pixbuf_load_increment(gpointer data
,
364 SvgTinyContext
* context
= (SvgTinyContext
*)data
;
366 /* YOLO, what is error checking? */
367 context
->svg_data
= g_realloc(context
->svg_data
,
368 context
->svg_data_size
+ buf_size
);
369 memcpy(context
->svg_data
+ context
->svg_data_size
, buf
, buf_size
);
370 context
->svg_data_size
+= buf_size
;
375 static void emit_updated(SvgTinyContext
* context
, GdkPixbuf
* pixbuf
) {
376 if (context
->updated_func
!= NULL
) {
377 (*context
->updated_func
)(pixbuf
,
380 gdk_pixbuf_get_width(pixbuf
),
381 gdk_pixbuf_get_height(pixbuf
),
386 static void emit_prepared(SvgTinyContext
* context
, GdkPixbuf
* pixbuf
) {
387 if (context
->prepared_func
!= NULL
) {
388 (*context
->prepared_func
)(pixbuf
, NULL
, context
->user_data
);
394 * @brief Process certain <xi:include> elements in an SVG buffer.
396 * GTK is very cute. Its gtk-encode-symbolic-svg tool wraps your SVG
397 * in its own boilerplate, but then rather than including your SVG
398 * data verbatim, it includes it via a sketchy XInclude that looks
401 * <xi:include href="data:text/xml;base64,PD94bWwgd..."/>
403 * Librsvg knows how to parse that, but libxml2 doesn't (the latter
404 * can handle an XInclude, just not a base64-encoded data reference).
405 * Fortunately, you can read the source to gtk-encode-symbolic-svg,
406 * and just see what the format of that line will be. Here we're going
407 * to parse out the base64 data, decode it, strip out its opening
408 * <xml> and <svg> tags, and then replace the original <xi:include>
409 * element with the result. Life is a little easier because the
410 * closing </svg> tag always immediately follows the XInclude; we can
411 * chop the whole thing off, decode the base64 stuff, and then paste
412 * the result back on the end with its own closing </svg> tag intact.
415 * A buffer containing SVG file data.
418 * The size of @c buffer (which may not be NULL-terminated).
421 * A pointer to the size of the new buffer, valid only if the
422 * return value is non-NULL.
424 * @return A pointer to a buffer where the <xi:include> has been
425 * processed. If no replacements were made, the result will be @c
426 * NULL; otherwise, you are expected to @c free it when you are done.
428 static gchar
* process_gtk_symbolic_svg_xinclude(const gchar
* buffer
,
435 xi_start
= g_strstr_len(buffer
, buf_size
, XI_SIGNATURE
);
436 if (xi_start
== NULL
) {
440 xi
= xi_start
+ strlen(XI_SIGNATURE
);
441 xi_stop
= g_strstr_len(xi
, (buffer
+ buf_size
) - xi
, "\"");
442 if(xi_stop
== NULL
) {
443 /* We found the start of an XInclude, but not the end of its
444 base64-encoded data? Play it safe and do nothing. */
448 /* g_base64_decode needs a NULL-terminated string, so let's make
453 /* All files are ASCII, right? In GTK's gdkpixbufutils.c, our base64
454 * data is encoded from a binary file stream, i.e. bytes, without
455 * any regard for what the text inside represents. Elsewhere we are
456 * pretending that gchar is a reasonable data type to use for the
457 * contents of an SVG file; here we are saying that again out loud.
459 gchar
* decoded
= (gchar
*)g_base64_decode(xi
, &decoded_size
);
462 /* We need another round of processing to strip the <xml> and <svg>
463 * elements out of "decoded", but it's simpler to just overwrite
464 * them with spaces before we proceed. We'll wind up with a document
465 * that has a conspicuous chunk of whitespace in the middle of it,
466 * but whatever. Note that we don't need to worry about the <xml>
467 * element so much, because if one exists, it has to come before the
468 * <svg>. As a result, we just need to strip everything up to the
469 * leading <svg> tag. */
470 gchar
* svg_open_start
= g_strstr_len(decoded
, decoded_size
, "<svg ");
471 if (svg_open_start
== NULL
) {
477 gchar
* svg_open_end
= g_strstr_len(svg_open_start
, decoded_size
, ">");
478 if (svg_open_end
== NULL
) {
483 memset(decoded
, ' ', (1 + (svg_open_end
- decoded
)));
486 /* We're going to keep everything up to xi_start. If the <xi:include
487 * started at, say, position three, then this would compute a size
488 * of three. Which is correct: we want to retain buffer[0],
489 * buffer[1], and buffer[2]. */
490 gsize keep_size
= xi_start
- buffer
;
491 *new_size
= keep_size
+ decoded_size
;
493 gchar
* result
= g_malloc(*new_size
);
494 memcpy(result
, buffer
, keep_size
);
495 memcpy(result
+keep_size
, decoded
, decoded_size
);
501 static gboolean
gdk_pixbuf_stop_load(gpointer data
, GError
**error
) {
502 SvgTinyContext
* context
= (SvgTinyContext
*)data
;
503 GdkPixbuf
* pixbuf
= NULL
;
504 gboolean result
= TRUE
;
505 GError
* sub_error
= NULL
;
508 /* If we're inside of gtk-encode-symbolic-svg right now, we need to
509 process the insane librsvg-specific XInclude directive it hands
510 us before proceeding. */
512 gchar
* newdata
= process_gtk_symbolic_svg_xinclude(context
->svg_data
,
513 context
->svg_data_size
,
515 if (newdata
!= NULL
) {
516 g_free(context
->svg_data
);
517 context
->svg_data
= newdata
;
518 context
->svg_data_size
= newsize
;
521 /* OK, we've got an SVG with no XIncludes now. */
522 pixbuf
= gdk_pixbuf_from_svg_buffer(context
->svg_data
,
523 context
->svg_data_size
,
526 if (pixbuf
!= NULL
) {
527 emit_prepared(context
, pixbuf
);
528 emit_updated(context
, pixbuf
);
529 g_object_unref(pixbuf
);
532 g_propagate_error(error
, sub_error
);
535 g_free(context
->svg_data
);
542 G_MODULE_EXPORT
void fill_vtable(GdkPixbufModule
* module);
543 void fill_vtable(GdkPixbufModule
* module) {
544 module->begin_load
= gdk_pixbuf_begin_load
;
545 module->load_increment
= gdk_pixbuf_load_increment
;
546 module->stop_load
= gdk_pixbuf_stop_load
;
549 G_MODULE_EXPORT
void fill_info(GdkPixbufFormat
*info
);
550 void fill_info(GdkPixbufFormat
* info
) {
551 /* Borrowed from librsvg-2.40.21 */
552 static const GdkPixbufModulePattern signature
[] = {
553 { " <svg", "* ", 100 },
554 { " <!DOCTYPE svg", "* ", 100 },
558 /* I'm not sure if we should support gzipped svg here? */
559 static const gchar
*mime_types
[] = {
563 "image/vnd.adobe.svg+xml",
565 "image/svg+xml-compressed",
569 static const gchar
*extensions
[] = {
577 info
->signature
= (GdkPixbufModulePattern
*)signature
;
578 info
->description
= "Scalable Vector Graphics";
579 info
->mime_types
= (gchar
**)mime_types
;
580 info
->extensions
= (gchar
**)extensions
;
581 info
->flags
= GDK_PIXBUF_FORMAT_SCALABLE
;
582 info
->license
= "AGPL3";
586 int main(int argc
, char** argv
) {
592 /* Parse arguments, and maybe print usage */
594 g_printf("Usage: %s INPUT OUTPUT\n", argv
[0]);
595 g_printf("Convert an SVG file (INPUT) to a PNG file (OUTPUT)\n");
602 pb
= gdk_pixbuf_new_from_file(svgpath
, &err
);
605 "Error %d in gdk_pixbuf_new_from_file: %s\n",
612 gdk_pixbuf_save(pb
, pngpath
, "png", NULL
, NULL
);