Fixed image-path not being considered as theme icon (#515)

src/functions.vala

@@ -18,15 +18,15 @@ namespace SwayNotificationCenter {
                                           Gtk.Image img,
                                           int icon_size,
                                           int radius,
-                                          bool file_exists) {
+                                          bool file_exists,
+                                          bool is_theme_icon = false) {
             const string URI_PREFIX = "file://";
-            const uint PREFIX_SIZE = 7;
-            bool is_uri = (uri.length >= PREFIX_SIZE
-                           && uri.slice (0, PREFIX_SIZE) == URI_PREFIX);
-            if (is_uri || file_exists) {
+            bool is_uri = (uri.length >= URI_PREFIX.length
+                           && uri.slice (0, URI_PREFIX.length) == URI_PREFIX);
+            if (!is_theme_icon && (is_uri || file_exists)) {
                 // Try as a URI (file:// is the only URI schema supported right now)
                 try {
-                    if (is_uri) uri = uri.slice (PREFIX_SIZE, uri.length);
+                    if (is_uri) uri = uri.slice (URI_PREFIX.length, uri.length);
 
                     var pixbuf = new Gdk.Pixbuf.from_file_at_scale (
                         uri,

src/notification/notification.vala

@@ -690,15 +690,25 @@ namespace SwayNotificationCenter {
             int app_icon_size = notification_icon_size / 3;
             img_app_icon.set_pixel_size (app_icon_size);
 
-            var img_path_exists = File.new_for_uri (
+            bool img_path_is_theme_icon = false;
+            bool img_path_exists = File.new_for_uri (
                 param.image_path ?? "").query_exists ();
             if (param.image_path != null && !img_path_exists) {
                 // Check if it's not a URI
                 img_path_exists = File.new_for_path (
                     param.image_path ?? "").query_exists ();
+
+                // Check if it's a freedesktop.org-compliant icon
+                if (!img_path_exists) {
+                    unowned Gtk.IconTheme icon_theme = Gtk.IconTheme.get_default ();
+                    Gtk.IconInfo? info = icon_theme.lookup_icon (param.image_path,
+                                                                 notification_icon_size,
+                                                                 Gtk.IconLookupFlags.USE_BUILTIN);
+                    img_path_exists = info != null;
+                    img_path_is_theme_icon = img_path_exists;
                 }
-            var app_icon_exists = File.new_for_uri (
-                app_icon_uri ?? "").query_exists ();
+            }
+            var app_icon_exists = File.new_for_uri (app_icon_uri ?? "").query_exists ();
             if (app_icon_uri != null && !img_path_exists) {
                 // Check if it's not a URI
                 app_icon_exists = File.new_for_path (
@@ -724,7 +734,8 @@ namespace SwayNotificationCenter {
                 Functions.set_image_uri (param.image_path, img,
                                          notification_icon_size,
                                          radius,
-                                          img_path_exists);
+                                         img_path_exists,
+                                         img_path_is_theme_icon);
             } else if (param.icon_data.is_initialized) {
                 Functions.set_image_data (param.icon_data, img,
                                           notification_icon_size, radius);