Add SVG load support via resvg (#2)

Co-authored-by: Kleis Auke Wolthuizen <github@kleisauke.nl>

libvips/foreign/foreign.c

@@ -3018,11 +3018,13 @@ vips_foreign_operation_init(void)
 	vips_foreign_load_pdf_source_get_type();
 #endif /*HAVE_PDFIUM*/
 
-#ifdef HAVE_RSVG
+#if (defined(HAVE_RSVG) || defined(HAVE_RESVG)) && !defined(RESVG_MODULE)
 	vips_foreign_load_svg_file_get_type();
 	vips_foreign_load_svg_buffer_get_type();
+#ifdef HAVE_RSVG
 	vips_foreign_load_svg_source_get_type();
-#endif /*HAVE_RSVG*/
+#endif
+#endif /*defined(HAVE_RSVG) || defined(HAVE_RESVG)*/
 
 #if defined(HAVE_LIBJXL) && !defined(LIBJXL_MODULE)
 	vips_foreign_load_jxl_file_get_type();

libvips/foreign/meson.build

@@ -44,7 +44,6 @@ foreign_sources = files(
     'rawsave.c',
     'spngload.c',
     'spngsave.c',
-    'svgload.c',
     'tiff2vips.c',
     'tiff.c',
     'tiffload.c',
@@ -122,6 +121,14 @@ endif
 
 libvips_sources += foreign_sources
 
+resvg_module_sources = files(
+    'svgload.c',
+)
+
+if not resvg_module
+    foreign_sources += resvg_module_sources
+endif
+
 foreign_lib = static_library('foreign',
     foreign_sources,
     foreign_headers,

libvips/foreign/svgload.c

@@ -81,25 +81,38 @@
 #include <cairo.h>
 #include <librsvg/rsvg.h>
 
-/* Render SVGs with tiles this size. They need to be pretty big to limit
- * overcomputation.
+/* A handy #define for we-will-handle-svgz.
  */
-#define TILE_SIZE (2000)
+#if LIBRSVG_CHECK_FEATURE(SVGZ)
+#define HANDLE_SVGZ
+#endif
 
-/* The <svg tag must appear within this many bytes of the start of the file.
- */
-#define SVG_HEADER_SIZE (1000)
+#elif defined(HAVE_RESVG)
 
-/* A handy #define for we-will-handle-svgz.
- */
-#if LIBRSVG_CHECK_FEATURE(SVGZ) && defined(HAVE_ZLIB)
+#include <resvg.h>
 #define HANDLE_SVGZ
+
+#endif
+
+#if defined(HAVE_RSVG) || defined(HAVE_RESVG)
+
+#ifndef HAVE_ZLIB
+#undef HANDLE_SVGZ
 #endif
 
 #ifdef HANDLE_SVGZ
 #include <zlib.h>
 #endif
 
+/* Render SVGs with tiles this size. They need to be pretty big to limit
+ * overcomputation.
+ */
+#define TILE_SIZE (2000)
+
+/* The <svg tag must appear within this many bytes of the start of the file.
+ */
+#define SVG_HEADER_SIZE (1000)
+
 typedef struct _VipsForeignLoadSvg {
 	VipsForeignLoad parent_object;
 
@@ -119,7 +132,12 @@ typedef struct _VipsForeignLoadSvg {
 	 */
 	gboolean unlimited;
 
+#ifdef HAVE_RSVG
 	RsvgHandle *page;
+#else
+	resvg_options *options;
+	resvg_render_tree *tree;
+#endif
 
 } VipsForeignLoadSvg;
 
@@ -308,7 +326,12 @@ vips_foreign_load_svg_dispose(GObject *gobject)
 {
 	VipsForeignLoadSvg *svg = (VipsForeignLoadSvg *) gobject;
 
+#ifdef HAVE_RSVG
 	VIPS_UNREF(svg->page);
+#else
+	resvg_options_destroy(svg->options);
+	VIPS_FREEF(resvg_tree_destroy, svg->tree);
+#endif
 
 	G_OBJECT_CLASS(vips_foreign_load_svg_parent_class)->dispose(gobject);
 }
@@ -327,6 +350,7 @@ vips_foreign_load_svg_get_flags(VipsForeignLoad *load)
 	return VIPS_FOREIGN_PARTIAL;
 }
 
+#ifdef HAVE_RSVG
 #if LIBRSVG_CHECK_VERSION(2, 52, 0)
 /* Derived from `CssLength::to_user` in librsvg.
  * https://gitlab.gnome.org/GNOME/librsvg/-/blob/e6607c9ae8d8409d4efff6b12993717400b3356e/src/length.rs#L368
@@ -385,6 +409,7 @@ svg_css_length_to_pixels(RsvgLength length, double dpi)
 	return value;
 }
 #endif
+#endif
 
 static int
 vips_foreign_load_svg_get_natural_size(VipsForeignLoadSvg *svg,
@@ -395,6 +420,7 @@ vips_foreign_load_svg_get_natural_size(VipsForeignLoadSvg *svg,
 	double width;
 	double height;
 
+#ifdef HAVE_RSVG
 #if LIBRSVG_CHECK_VERSION(2, 52, 0)
 
 	if (!rsvg_handle_get_intrinsic_size_in_pixels(svg->page,
@@ -482,6 +508,11 @@ vips_foreign_load_svg_get_natural_size(VipsForeignLoadSvg *svg,
 	}
 
 #endif /*LIBRSVG_CHECK_VERSION(2, 52, 0)*/
+#else  /* HAVE_RSVG */
+	resvg_size size = resvg_get_image_size(svg->tree);
+	width = size.width;
+	height = size.height;
+#endif
 
 	/* width or height below 0.5 can't be rounded to 1.
 	 */
@@ -504,9 +535,11 @@ vips_foreign_load_svg_get_scaled_size(VipsForeignLoadSvg *svg,
 	double width;
 	double height;
 
+#ifdef HAVE_RSVG
 	/* Get dimensions with the default dpi.
 	 */
 	rsvg_handle_set_dpi(svg->page, 72.0);
+#endif
 	if (vips_foreign_load_svg_get_natural_size(svg, &width, &height))
 		return -1;
 
@@ -563,24 +596,26 @@ vips_foreign_load_svg_generate(VipsRegion *out_region,
 	void *seq, void *a, void *b, gboolean *stop)
 {
 	const VipsForeignLoadSvg *svg = (VipsForeignLoadSvg *) a;
-	const VipsObjectClass *class = VIPS_OBJECT_GET_CLASS(svg);
 	const VipsRect *r = &out_region->valid;
 
-	cairo_surface_t *surface;
-	cairo_t *cr;
-	int y;
-
 #ifdef DEBUG
 	printf("vips_foreign_load_svg_generate: %p \n     "
 		   "left = %d, top = %d, width = %d, height = %d\n",
 		svg,
 		r->left, r->top, r->width, r->height);
 #endif /*DEBUG*/
 
-	/* rsvg won't always paint the background.
+	/* SVG won't always paint the background.
 	 */
 	vips_region_black(out_region);
 
+#ifdef HAVE_RSVG
+	const VipsObjectClass *class = VIPS_OBJECT_GET_CLASS(svg);
+
+	cairo_surface_t *surface;
+	cairo_t *cr;
+	int y;
+
 	surface = cairo_image_surface_create_for_data(
 		VIPS_REGION_ADDR(out_region, r->left, r->top),
 		CAIRO_FORMAT_ARGB32,
@@ -643,6 +678,41 @@ vips_foreign_load_svg_generate(VipsRegion *out_region,
 		vips__premultiplied_bgra2rgba(
 			(guint32 *) VIPS_REGION_ADDR(out_region, r->left, r->top + y),
 			r->width);
+#else
+
+	VipsPel *q = VIPS_REGION_ADDR(out_region, r->left, r->top);
+
+	resvg_render(
+		svg->tree,
+		(resvg_fit_to){ .type = RESVG_FIT_TO_TYPE_ORIGINAL },
+		(resvg_transform){
+			.a = svg->cairo_scale,
+			.d = svg->cairo_scale,
+			.e = -r->left,
+			.f = -r->top,
+		},
+		r->width,
+		r->height,
+		(char *) q);
+
+	/* Just unpremultiply.
+	 */
+	for (int i = 0; i < r->width * r->height; i++) {
+		VipsPel *restrict p = &q[i * 4];
+		VipsPel x = p[3];
+
+		/* Skip transparent and fully opaque pixels.
+		 */
+		if (x == 0 || x == 255)
+			continue;
+
+		/* Any compiler will unroll it.
+		 */
+		for (int j = 0; j < 3; j++)
+			p[j] = 255 * p[j] / x;
+	}
+
+#endif
 
 	return 0;
 }
@@ -729,8 +799,16 @@ vips_foreign_load_svg_init(VipsForeignLoadSvg *svg)
 	svg->dpi = 72.0;
 	svg->scale = 1.0;
 	svg->cairo_scale = 1.0;
+#ifdef HAVE_RESVG
+	svg->options = resvg_options_create();
+
+	/* Get dimensions with the default dpi.
+	 */
+	resvg_options_set_dpi(svg->options, 72.0);
+#endif
 }
 
+#ifdef HAVE_RSVG
 typedef struct _VipsForeignLoadSvgSource {
 	VipsForeignLoadSvg parent_object;
 
@@ -781,7 +859,6 @@ vips_foreign_load_svg_source_header(VipsForeignLoad *load)
 		return -1;
 	}
 	g_object_unref(gstream);
-
 	return vips_foreign_load_svg_header(load);
 }
 
@@ -830,6 +907,7 @@ static void
 vips_foreign_load_svg_source_init(VipsForeignLoadSvgSource *source)
 {
 }
+#endif
 
 typedef struct _VipsForeignLoadSvgFile {
 	VipsForeignLoadSvg parent_object;
@@ -856,11 +934,35 @@ vips_foreign_load_svg_file_is_a(const char *filename)
 		vips_foreign_load_svg_is_a(buf, bytes);
 }
 
+#ifdef HAVE_RESVG
+static const char *
+resvg_error_msg(resvg_error e)
+{
+	switch (e) {
+	case RESVG_ERROR_NOT_AN_UTF8_STR:
+		return "only UTF-8 content is supported";
+	case RESVG_ERROR_FILE_OPEN_FAILED:
+		return "failed to open the provided file";
+	case RESVG_ERROR_MALFORMED_GZIP:
+		return "compressed SVG must use the GZip algorithm";
+	case RESVG_ERROR_ELEMENTS_LIMIT_REACHED:
+		return "we do not allow SVG with more than 1_000_000 elements for security reasons";
+	case RESVG_ERROR_INVALID_SIZE:
+		return "SVG doesn't have a valid size";
+	case RESVG_ERROR_PARSING_FAILED:
+		return "failed to parse SVG data";
+	default:
+		return "unknown error";
+	}
+}
+#endif
+
 static int
 vips_foreign_load_svg_file_header(VipsForeignLoad *load)
 {
 	VipsForeignLoadSvg *svg = (VipsForeignLoadSvg *) load;
 	VipsForeignLoadSvgFile *file = (VipsForeignLoadSvgFile *) load;
+#ifdef HAVE_RSVG
 	RsvgHandleFlags flags = svg->unlimited ? RSVG_HANDLE_FLAG_UNLIMITED : 0;
 
 	GError *error = NULL;
@@ -875,7 +977,15 @@ vips_foreign_load_svg_file_header(VipsForeignLoad *load)
 		return -1;
 	}
 	g_object_unref(gfile);
-
+#else
+	resvg_error error = resvg_parse_tree_from_file(
+		file->filename, svg->options, &svg->tree);
+	if (error != RESVG_OK) {
+		vips_error(VIPS_OBJECT_GET_CLASS(svg)->nickname,
+			"%s", resvg_error_msg(error));
+		return -1;
+	}
+#endif
 	VIPS_SETSTR(load->out->filename, file->filename);
 
 	return vips_foreign_load_svg_header(load);
@@ -885,7 +995,7 @@ static const char *vips_foreign_svg_suffs[] = {
 	".svg",
 /* librsvg supports svgz directly, no need to check for zlib here.
  */
-#if LIBRSVG_CHECK_FEATURE(SVGZ)
+#ifdef HANDLE_SVGZ
 	".svgz",
 	".svg.gz",
 #endif
@@ -944,6 +1054,7 @@ vips_foreign_load_svg_buffer_header(VipsForeignLoad *load)
 	VipsForeignLoadSvg *svg = (VipsForeignLoadSvg *) load;
 	VipsForeignLoadSvgBuffer *buffer =
 		(VipsForeignLoadSvgBuffer *) load;
+#ifdef HAVE_RSVG
 	RsvgHandleFlags flags = svg->unlimited ? RSVG_HANDLE_FLAG_UNLIMITED : 0;
 
 	GError *error = NULL;
@@ -959,7 +1070,15 @@ vips_foreign_load_svg_buffer_header(VipsForeignLoad *load)
 		return -1;
 	}
 	g_object_unref(gstream);
-
+#else
+	resvg_error error = resvg_parse_tree_from_data(
+		buffer->buf->data, buffer->buf->length, svg->options, &svg->tree);
+	if (error != RESVG_OK) {
+		vips_error(VIPS_OBJECT_GET_CLASS(svg)->nickname,
+			"%s", resvg_error_msg(error));
+		return -1;
+	}
+#endif
 	return vips_foreign_load_svg_header(load);
 }
 

libvips/meson.build

@@ -127,3 +127,14 @@ if openslide_module
         install_dir: module_dir
     )
 endif
+
+if resvg_module
+    shared_module('vips-resvg',
+        'module/resvg.c',
+        resvg_module_sources,
+        name_prefix: '',
+        dependencies: [libvips_dep, resvg_dep],
+        install: true,
+        install_dir: module_dir
+    )
+endif