Render SVG files at output resolution

This adds an optional dependency on librsvg to directly render the SVG images, instead of using gdk-pixbuf to draw them to an intermediate image.
swaywm · Oct 26, 2024 · 1e585f8 · 1e585f8
1 parent d7ec784
commit 1e585f8
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Showing 5 changed files with 149 additions and 10 deletions.
diff --git a/background-image.c b/background-image.c
@@ -123,3 +123,95 @@ void render_background_image(cairo_t *cairo, cairo_surface_t *image,
 	cairo_paint(cairo);
 	cairo_restore(cairo);
 }
+
+#if HAVE_RSVG
+void render_background_image_svg(cairo_t *cairo, RsvgHandle *svg,
+		enum background_mode mode, int buffer_width, int buffer_height) {
+	gdouble nat_width, nat_height;
+	if (!rsvg_handle_get_intrinsic_size_in_pixels(svg, &nat_width, &nat_height)) {
+		nat_width = buffer_width;
+		nat_height = buffer_height;
+	}
+	RsvgRectangle viewport;
+	GError *error = NULL;;
+	switch (mode) {
+	case BACKGROUND_MODE_STRETCH:
+		viewport.x = 0;
+		viewport.y = 0;
+		viewport.width = nat_width;
+		viewport.height = nat_height;
+		cairo_scale(cairo, buffer_width / nat_width, buffer_height / nat_height);
+		rsvg_handle_render_document(svg, cairo, &viewport, &error);
+		break;
+	case BACKGROUND_MODE_FILL: {
+		double window_ratio = (double)buffer_width / buffer_height;
+		double bg_ratio = nat_width / nat_height;
+
+		if (window_ratio > bg_ratio) {
+			double scale = (double)buffer_width / nat_width;
+
+			viewport.x = 0;
+			viewport.y = (double)buffer_height / 2 - scale * nat_height / 2;
+			viewport.width = buffer_width;
+			viewport.height = scale * nat_height;
+		} else {
+			double scale = (double)buffer_height / nat_height;
+
+			viewport.x = (double)buffer_width / 2 - scale *nat_width / 2;
+			viewport.y = 0;
+			viewport.width = scale * nat_width;
+			viewport.height = buffer_height;
+		}
+
+		rsvg_handle_render_document(svg, cairo, &viewport, &error);
+		break;
+	}
+	case BACKGROUND_MODE_FIT: {
+		double window_ratio = (double)buffer_width / buffer_height;
+		double bg_ratio =  nat_width / nat_height;
+
+		if (window_ratio < bg_ratio) {
+			double scale = (double)buffer_width / nat_width;
+
+			viewport.x = 0;
+			viewport.y = (double)buffer_height / 2 - scale * nat_height / 2;
+			viewport.width = buffer_width;
+			viewport.height = scale * nat_height;
+		} else {
+			double scale = (double)buffer_height / nat_height;
+
+			viewport.x = (double)buffer_width / 2 - scale * nat_width / 2;
+			viewport.y = 0;
+			viewport.width = scale * nat_width;
+			viewport.height = buffer_height;
+		}
+		rsvg_handle_render_document(svg, cairo, &viewport, &error);
+		break;
+	}
+	case BACKGROUND_MODE_CENTER: {
+		viewport.x = (double)buffer_width / 2 - nat_width / 2;
+		viewport.y = (double)buffer_height / 2 - nat_height / 2;
+		viewport.width = nat_width;
+		viewport.height = nat_height;
+		rsvg_handle_render_document(svg, cairo, &viewport, &error);
+		break;
+	}
+	case BACKGROUND_MODE_TILE: {
+		for (int x = 0; x * nat_width < buffer_width; x++) {
+			for (int y = 0; y * nat_height < buffer_height; y++) {
+				viewport.x = nat_width * x;
+				viewport.y = nat_height * y;
+				viewport.width = nat_width;
+				viewport.height = nat_height;
+				rsvg_handle_render_document(svg, cairo, &viewport, &error);
+			}
+		}
+		break;
+	}
+	case BACKGROUND_MODE_SOLID_COLOR:
+	case BACKGROUND_MODE_INVALID:
+		assert(0);
+		break;
+	}
+}
+#endif
diff --git a/include/background-image.h b/include/background-image.h
@@ -1,6 +1,11 @@
 #ifndef _SWAY_BACKGROUND_IMAGE_H
 #define _SWAY_BACKGROUND_IMAGE_H
 #include "cairo_util.h"
+#if HAVE_RSVG
+#include "librsvg/rsvg.h"
+#else
+typedef struct _RsvgHandle RsvgHandle;
+#endif
 
 enum background_mode {
 	BACKGROUND_MODE_STRETCH,
@@ -16,5 +21,9 @@ enum background_mode parse_background_mode(const char *mode);
 cairo_surface_t *load_background_image(const char *path);
 void render_background_image(cairo_t *cairo, cairo_surface_t *image,
 		enum background_mode mode, int buffer_width, int buffer_height);
+#if HAVE_RSVG
+void render_background_image_svg(cairo_t *cairo, RsvgHandle *svg,
+				 enum background_mode mode, int buffer_width, int buffer_height);
+#endif
 
 #endif
diff --git a/main.c b/main.c
@@ -7,6 +7,9 @@
 #include <string.h>
 #include <strings.h>
 #include <wayland-client.h>
+#if HAVE_RSVG
+#include <librsvg/rsvg.h>
+#endif
 #include "background-image.h"
 #include "cairo_util.h"
 #include "log.h"
@@ -98,7 +101,8 @@ struct swaybg_output {
 
 // Create a wl_buffer with the specified dimensions and content
 static struct wl_buffer *draw_buffer(const struct swaybg_output *output,
-		cairo_surface_t *surface, uint32_t buffer_width, uint32_t buffer_height) {
+		cairo_surface_t *surface, RsvgHandle *svg,
+		uint32_t buffer_width, uint32_t buffer_height) {
 	uint32_t bg_color = output->config->color ? output->config->color : 0x000000ff;
 
 	if (buffer_width == 1 && buffer_height == 1 &&
@@ -132,6 +136,12 @@ static struct wl_buffer *draw_buffer(const struct swaybg_output *output,
 		render_background_image(cairo, surface,
 			output->config->mode, buffer_width, buffer_height);
 	}
+#if HAVE_RSVG
+	if (svg) {
+		render_background_image_svg(cairo, svg, output->config->mode,
+			buffer_width, buffer_height);
+	}
+#endif
 
 	// return wl_buffer for caller to use and destroy
 	struct wl_buffer *wl_buf = buffer.buffer;
@@ -161,15 +171,16 @@ static void get_buffer_size(const struct swaybg_output *output,
 	}
 }
 
-static void render_frame(struct swaybg_output *output, cairo_surface_t *surface) {
+static void render_frame(struct swaybg_output *output, cairo_surface_t *surface,
+		RsvgHandle *svg) {
 	uint32_t buffer_width, buffer_height;
 	get_buffer_size(output, &buffer_width, &buffer_height);
 
 	// Attach a new buffer if the desired size has changed
 	struct wl_buffer *buf = NULL;
 	if (buffer_width != output->buffer_width ||
 			buffer_height != output->buffer_height) {
-		buf = draw_buffer(output, surface,
+		buf = draw_buffer(output, surface, svg,
 			buffer_width, buffer_height);
 		if (!buf) {
 			return;
@@ -660,28 +671,51 @@ int main(int argc, char **argv) {
 				continue;
 			}
 
-			cairo_surface_t *surface = load_background_image(image->path);
-			if (!surface) {
-				swaybg_log(LOG_ERROR, "Failed to load image: %s", image->path);
-				continue;
+			cairo_surface_t *surface = NULL;
+			RsvgHandle *svg = NULL;
+#if HAVE_RSVG
+			const char *suffix = strrchr(image->path, '.');
+			if (suffix && (!strcmp(suffix, ".svg") || !strcmp(suffix, ".SVG"))) {
+				GError *error = NULL;
+				svg = rsvg_handle_new_from_file(image->path, &error);
+				if (!svg) {
+					swaybg_log(LOG_ERROR, "Failed to load image: %s, %s", image->path, error->message);
+					continue;
+				}
+				rsvg_handle_set_dpi(svg, 96.0);
+#else
+			if (false) {
+#endif
+			} else {
+				svg = NULL;
+				surface = load_background_image(image->path);
+				if (!surface) {
+					swaybg_log(LOG_ERROR, "Failed to load image: %s", image->path);
+					continue;
+				}
 			}
 
 			wl_list_for_each(output, &state.outputs, link) {
 				if (output->dirty && output->config->image == image) {
 					output->dirty = false;
-					render_frame(output, surface);
+					render_frame(output, surface, svg);
 				}
 			}
 
 			image->load_required = false;
-			cairo_surface_destroy(surface);
+			if (surface) {
+				cairo_surface_destroy(surface);
+			}
+			if (svg) {
+				g_object_unref(svg);
+			}
 		}
 
 		// Redraw outputs without associated image
 		wl_list_for_each(output, &state.outputs, link) {
 			if (output->dirty) {
 				output->dirty = false;
-				render_frame(output, NULL);
+				render_frame(output, NULL, NULL);
 			}
 		}
 	}

diff --git a/meson.build b/meson.build
@@ -34,6 +34,7 @@ wayland_protos = dependency('wayland-protocols', version: '>=1.31')
 wayland_scanner = dependency('wayland-scanner', version: '>=1.14.91', native: true)
 cairo = dependency('cairo')
 gdk_pixbuf = dependency('gdk-pixbuf-2.0', required: get_option('gdk-pixbuf'))
+rsvg = dependency('librsvg-2.0', required: get_option('rsvg'))
 
 git = find_program('git', required: false, native: true)
 scdoc = find_program('scdoc', required: get_option('man-pages'), native: true)
@@ -54,6 +55,7 @@ endif
 add_project_arguments([
 	'-DSWAYBG_VERSION=@0@'.format(version),
 	'-DHAVE_GDK_PIXBUF=@0@'.format(gdk_pixbuf.found().to_int()),
+	'-DHAVE_RSVG=@0@'.format(rsvg.found().to_int()),
 ], language: 'c')
 
 wl_protocol_dir = wayland_protos.get_variable('pkgdatadir')
@@ -103,6 +105,7 @@ executable(
 		rt,
 		gdk_pixbuf,
 		wayland_client,
+		rsvg,
 	],
 	install: true
 )

diff --git a/meson_options.txt b/meson_options.txt
@@ -1,2 +1,3 @@
 option('gdk-pixbuf', type: 'feature', value: 'auto', description: 'Enable support for more image formats')
+option('rsvg', type: 'feature', value: 'auto', description: 'Enable support for directly rendering SVG images')
 option('man-pages', type: 'feature', value: 'auto', description: 'Generate and install man pages')