Add support for defaulting to gdk-pixbuf

README.adoc

@@ -2,7 +2,7 @@ fastiv
 ======
 
 'fastiv' is a fast image viewer, supporting BMP, PNG, GIF, JPEG, and optionally
-RAW and SVG pictures.  Currently, it's not particularly usable.
+RAW and SVG pictures, or whatever gdk-pixbuf loads.  Currently, it's very basic.
 
 Non-goals
 ---------

fastiv-io.c

@@ -26,6 +26,10 @@
 #ifdef HAVE_LIBRSVG
 #include <librsvg/rsvg.h>
 #endif  // HAVE_LIBRSVG
+#ifdef HAVE_GDKPIXBUF
+#include <gdk/gdk.h>
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#endif  // HAVE_GDKPIXBUF
 
 #define WUFFS_IMPLEMENTATION
 #define WUFFS_CONFIG__MODULES
@@ -479,6 +483,24 @@ open_librsvg(const gchar *data, gsize len, const gchar *path, GError **error)
 }
 
 #endif  // HAVE_LIBRSVG --------------------------------------------------------
+#ifdef HAVE_GDKPIXBUF  // ------------------------------------------------------
+
+static cairo_surface_t *
+open_gdkpixbuf(const gchar *data, gsize len, GError **error)
+{
+	GInputStream *is = g_memory_input_stream_new_from_data(data, len, NULL);
+	GdkPixbuf *pixbuf = gdk_pixbuf_new_from_stream(is, NULL, error);
+	g_object_unref(is);
+	if (!pixbuf)
+		return NULL;
+
+	cairo_surface_t *surface =
+		gdk_cairo_surface_create_from_pixbuf(pixbuf, 1, NULL);
+	g_object_unref(pixbuf);
+	return surface;
+}
+
+#endif  // HAVE_GDKPIXBUF ------------------------------------------------------
 
 cairo_surface_t *
 fastiv_io_open(const gchar *path, GError **error)
@@ -550,6 +572,17 @@ fastiv_io_open_from_data(const char *data, size_t len, const gchar *path,
 			g_clear_error(error);
 		}
 #endif  // HAVE_LIBRSVG --------------------------------------------------------
+#ifdef HAVE_GDKPIXBUF  // ------------------------------------------------------
+		// This is only used as a last resort, the rest above is special-cased.
+		if ((surface = open_gdkpixbuf(data, len, error)) ||
+			(error && (*error)->code != GDK_PIXBUF_ERROR_UNKNOWN_TYPE))
+			break;
+
+		if (error) {
+			g_debug("%s", (*error)->message);
+			g_clear_error(error);
+		}
+#endif  // HAVE_GDKPIXBUF ------------------------------------------------------
 
 		// TODO(p): Integrate gdk-pixbuf as a fallback (optional dependency).
 		set_error(error, "unsupported file type");

fastiv.c

@@ -182,10 +182,12 @@ on_open(void)
 		"_Cancel", GTK_RESPONSE_CANCEL,
 		"_Open", GTK_RESPONSE_ACCEPT, NULL);
 
-	// NOTE: gdk-pixbuf has gtk_file_filter_add_pixbuf_formats().
 	GtkFileFilter *filter = gtk_file_filter_new();
 	for (const char **p = fastiv_io_supported_media_types; *p; p++)
 		gtk_file_filter_add_mime_type(filter, *p);
+#ifdef HAVE_GDKPIXBUF
+	gtk_file_filter_add_pixbuf_formats(filter);
+#endif  // HAVE_GDKPIXBUF
 	gtk_file_filter_set_name(filter, "Supported images");
 	gtk_file_chooser_add_filter(GTK_FILE_CHOOSER(dialog), filter);
 
@@ -389,6 +391,7 @@ main(int argc, char *argv[])
 		G_CALLBACK(on_key_press), NULL);
 	gtk_container_add(GTK_CONTAINER(g.window), g.stack);
 
+	// TODO(p): Also milk gdk-pixbuf, if linked in, needs to be done in runtime.
 	g.supported_globs = extract_mime_globs(fastiv_io_supported_media_types);
 	g.files = g_ptr_array_new_full(16, g_free);
 	gchar *cwd = g_get_current_dir();

meson.build

@@ -3,6 +3,7 @@ project('fastiv', 'c', default_options : ['c_std=gnu99'], version : '0.1.0')
 # TODO(p): Use libraw_r later, when we start parallelizing/preloading.
 libraw = dependency('libraw', required : get_option('libraw'))
 librsvg = dependency('librsvg-2.0', required : get_option('librsvg'))
+gdkpixbuf = dependency('gdk-pixbuf-2.0', required : get_option('gdk-pixbuf'))
 dependencies = [
 	dependency('gtk+-3.0'),
 	dependency('libturbojpeg'),
@@ -18,6 +19,7 @@ conf.set_quoted('PROJECT_NAME', meson.project_name())
 conf.set_quoted('PROJECT_VERSION', meson.project_version())
 conf.set('HAVE_LIBRAW', libraw.found())
 conf.set('HAVE_LIBRSVG', librsvg.found())
+conf.set('HAVE_GDKPIXBUF', gdkpixbuf.found())
 configure_file(
 	output : 'config.h',
 	configuration : conf,

meson_options.txt

@@ -2,3 +2,5 @@ option('libraw', type : 'feature', value : 'auto',
     description : 'Build with RAW support, requires LibRaw')
 option('librsvg', type : 'feature', value : 'auto',
 	description : 'Build with SVG support, requires librsvg')
+option('gdk-pixbuf', type : 'feature', value : 'auto',
+	description : 'Build with a fallback to the gdk-pixbuf library')