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(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
);
142 /* The one success case. */
144 case svgtiny_OUT_OF_MEMORY
:
145 g_set_error_literal(error
,
148 "out of memory in svgtiny_parse()");
150 case svgtiny_LIBDOM_ERROR
:
151 g_set_error_literal(error
,
153 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
154 "invalid XML DOM in svgtiny_parse()");
156 case svgtiny_NOT_SVG
:
157 g_set_error_literal(error
,
159 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
160 "missing <svg> element in svgtiny_parse()");
162 case svgtiny_SVG_ERROR
:
165 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
166 "SVG format error in svgtiny_parse() on line %i: %s",
168 diagram
->error_message
);
172 /* All other cases above are failure */
177 * @brief Create a cairo context from a libsvgtiny diagram.
180 * A pointer to a valid libsvgtiny diagram.
182 * @return If successful, a pointer to a @c cairo_t context structure
183 * is returned; if not, @c NULL is returned. You are expected to @c
184 * cairo_destroy the result if it is valid.
186 static cairo_t
* cairo_context_from_diagram(diagram_t
* diagram
) {
188 cairo_surface_t
* surface
;
192 surface
= cairo_image_surface_create(CAIRO_FORMAT_ARGB32
,
196 crs
= cairo_surface_status(surface
);
197 if (crs
!= CAIRO_STATUS_SUCCESS
) {
199 "cairo_image_surface_create failed: %s\n",
200 cairo_status_to_string(crs
));
201 cairo_surface_destroy(surface
);
205 cr
= cairo_create(surface
);
206 crs
= cairo_status(cr
);
208 /* Immediately destroy the surface which is now accessible as
210 cairo_surface_destroy(surface
);
212 if (crs
!= CAIRO_STATUS_SUCCESS
) {
214 "cairo_create failed: %s\n",
215 cairo_status_to_string(crs
));
220 cairo_set_source_rgba(cr
, 0, 0, 0, 0);
223 /* Loop through the shapes in the diagram... */
224 for (i
= 0; i
!= diagram
->shape_count
; i
++) {
226 /* If this shape is a path, just render it. */
227 if (diagram
->shape
[i
].path
) {
228 render_path(cr
, &diagram
->shape
[i
]);
231 /* If this shape is text... */
232 if (diagram
->shape
[i
].text
) {
233 /* Figure out what color to use from the R/G/B components of the
235 cairo_set_source_rgba(cr
,
236 svgtiny_RED(diagram
->shape
[i
].stroke
) / 255.0,
237 svgtiny_GREEN(diagram
->shape
[i
].stroke
) / 255.0,
238 svgtiny_BLUE(diagram
->shape
[i
].stroke
) / 255.0,
240 /* Then move to the actual position of the text within the
243 diagram
->shape
[i
].text_x
,
244 diagram
->shape
[i
].text_y
);
247 cairo_show_text(cr
, diagram
->shape
[i
].text
);
252 /* Check the status again just for good measure? */
253 crs
= cairo_status(cr
);
254 if (crs
!= CAIRO_STATUS_SUCCESS
) {
257 cairo_status_to_string(crs
));
266 * @brief Create a GdkPixbuf from a buffer of SVG data.
269 * The buffer containing the SVG document.
272 * The number of bytes in @c buffer.
275 * The address of a @c GError pointer that we use to return errors.
277 * @return If successful, a valid pointer to a @c GdkPixbuf is
278 * returned; if not, @c NULL is returned and @c error is populated.
280 static GdkPixbuf
* gdk_pixbuf_from_svg_buffer(char* buffer
,
286 GError
* sub_error
= NULL
;
288 diagram
= svgtiny_diagram_from_buffer(buffer
,
294 g_propagate_error(error
, sub_error
);
298 cr
= cairo_context_from_diagram(diagram
);
300 svgtiny_free(diagram
);
301 g_set_error_literal(error
,
303 GDK_PIXBUF_ERROR_CORRUPT_IMAGE
,
304 "could not create Cairo surface from SVG diagram");
309 /* I've gone back and forth on this about five times: we use the
310 * diagram width and height, and not the viewport width and height.
311 * This can ultimately render an image that's larger than the
312 * viewport size, but I think GDK will resize the final pixbuf
313 * anyway. More importantly, rendering small icons at a larger
314 * (viewport) size seems to make the whole thing go ape-shit.
315 * So for now I'm back in the diagram camp.
317 pb
= gdk_pixbuf_get_from_surface(cairo_get_target(cr
),
325 g_set_error_literal(error
,
327 GDK_PIXBUF_ERROR_FAILED
,
328 "failed to obtain a GdkPixbuf from Cairo surface");
335 static gpointer
gdk_pixbuf_begin_load(GdkPixbufModuleSizeFunc size_func
,
336 GdkPixbufModulePreparedFunc prep_func
,
337 GdkPixbufModuleUpdatedFunc updated_func
,
341 SvgTinyContext
* context
= g_new(SvgTinyContext
, 1);
343 context
->size_func
= size_func
;
344 context
->prepared_func
= prep_func
;
345 context
->updated_func
= updated_func
;
346 context
->user_data
= user_data
;
348 context
->svg_data
= NULL
;
349 context
->svg_data_size
= 0;
354 static gboolean
gdk_pixbuf_load_increment(gpointer data
,
358 SvgTinyContext
* context
= (SvgTinyContext
*)data
;
360 /* YOLO, what is 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
= g_strstr_len(buffer
, buf_size
, XI_SIGNATURE
);
430 if (xi_start
== NULL
) {
434 xi
= xi_start
+ strlen(XI_SIGNATURE
);
435 xi_stop
= g_strstr_len(xi
, (buffer
+ buf_size
) - 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
447 /* All files are ASCII, right? In GTK's gdkpixbufutils.c, our base64
448 * data is encoded from a binary file stream, i.e. bytes, without
449 * any regard for what the text inside represents. Elsewhere we are
450 * pretending that gchar is a reasonable data type to use for the
451 * contents of an SVG file; here we are saying that again out loud.
453 gchar
* decoded
= (gchar
*)g_base64_decode(xi
, &decoded_size
);
456 /* We need another round of processing to strip the <xml> and <svg>
457 * elements out of "decoded", but it's simpler to just overwrite
458 * them with spaces before we proceed. We'll wind up with a document
459 * that has a conspicuous chunk of whitespace in the middle of it,
460 * but whatever. Note that we don't need to worry about the <xml>
461 * element so much, because if one exists, it has to come before the
462 * <svg>. As a result, we just need to strip everything up to the
463 * leading <svg> tag. */
464 gchar
* svg_open_start
= g_strstr_len(decoded
, decoded_size
, "<svg ");
465 if (svg_open_start
== NULL
) {
471 gchar
* svg_open_end
= g_strstr_len(svg_open_start
, decoded_size
, ">");
472 if (svg_open_end
== NULL
) {
477 memset(decoded
, ' ', (1 + (svg_open_end
- decoded
)));
480 /* We're going to keep everything up to xi_start. If the <xi:include
481 * started at, say, position three, then this would compute a size
482 * of three. Which is correct: we want to retain buffer[0],
483 * buffer[1], and buffer[2]. */
484 size_t keep_size
= xi_start
- buffer
;
485 *new_size
= keep_size
+ decoded_size
;
487 char* result
= g_malloc(*new_size
);
488 memcpy(result
, buffer
, keep_size
);
489 memcpy(result
+keep_size
, decoded
, decoded_size
);
495 static gboolean
gdk_pixbuf_stop_load(gpointer data
, GError
**error
) {
496 SvgTinyContext
* context
= (SvgTinyContext
*)data
;
497 GdkPixbuf
* pixbuf
= NULL
;
498 gboolean result
= TRUE
;
499 GError
* sub_error
= NULL
;
502 /* If we're inside of gtk-encode-symbolic-svg right now, we need to
503 process the insane librsvg-specific XInclude directive it hands
504 us before proceeding. */
506 char* newdata
= process_gtk_symbolic_svg_xinclude(context
->svg_data
,
507 context
->svg_data_size
,
509 if (newdata
!= NULL
) {
510 g_free(context
->svg_data
);
511 context
->svg_data
= newdata
;
512 context
->svg_data_size
= newsize
;
515 /* OK, we've got an SVG with no XIncludes now. */
516 pixbuf
= gdk_pixbuf_from_svg_buffer(context
->svg_data
,
517 context
->svg_data_size
,
520 if (pixbuf
!= NULL
) {
521 emit_prepared(context
, pixbuf
);
522 emit_updated(context
, pixbuf
);
523 g_object_unref(pixbuf
);
526 g_propagate_error(error
, sub_error
);
529 g_free(context
->svg_data
);
536 G_MODULE_EXPORT
void fill_vtable(GdkPixbufModule
* module);
537 void fill_vtable(GdkPixbufModule
* module) {
538 module->begin_load
= gdk_pixbuf_begin_load
;
539 module->load_increment
= gdk_pixbuf_load_increment
;
540 module->stop_load
= gdk_pixbuf_stop_load
;
543 G_MODULE_EXPORT
void fill_info(GdkPixbufFormat
*info
);
544 void fill_info(GdkPixbufFormat
* info
) {
545 /* Borrowed from librsvg-2.40.21 */
546 static const GdkPixbufModulePattern signature
[] = {
547 { " <svg", "* ", 100 },
548 { " <!DOCTYPE svg", "* ", 100 },
552 /* I'm not sure if we should support gzipped svg here? */
553 static const gchar
*mime_types
[] = {
557 "image/vnd.adobe.svg+xml",
559 "image/svg+xml-compressed",
563 static const gchar
*extensions
[] = {
571 info
->signature
= (GdkPixbufModulePattern
*)signature
;
572 info
->description
= "Scalable Vector Graphics";
573 info
->mime_types
= (gchar
**)mime_types
;
574 info
->extensions
= (gchar
**)extensions
;
575 info
->flags
= GDK_PIXBUF_FORMAT_SCALABLE
;
576 info
->license
= "AGPL3";
580 int main(int argc
, char** argv
) {
586 /* Parse arguments, and maybe print usage */
588 g_printf("Usage: %s INPUT OUTPUT\n", argv
[0]);
589 g_printf("Convert an SVG file (INPUT) to a PNG file (OUTPUT)\n");
596 pb
= gdk_pixbuf_new_from_file(svgpath
, &err
);
599 "Error %d in gdk_pixbuf_new_from_file: %s\n",
606 gdk_pixbuf_save(pb
, pngpath
, "png", NULL
, NULL
);