Introduce Gala.Icon

Author: leolost2605

lib/Icon.vala

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2025 elementary, Inc. (https://elementary.io)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Authored by: Leonhard Kargl <[email protected]>
+ */
+
+public class Gala.Icon : Clutter.Actor {
+    private class ResourceIconSource : Object, IconSource {
+        public string path { get; construct; }
+
+        public ResourceIconSource (string path) {
+            Object (path: path);
+        }
+
+        public string? get_cache_key (int size, float scale) {
+            return "%s-%d".printf (path, get_texture_size (size, scale));
+        }
+
+        public Gdk.Pixbuf create_pixbuf (int size, float scale) throws Error {
+            return new Gdk.Pixbuf.from_resource_at_scale (path, -1, get_texture_size (size, scale), true);
+        }
+    }
+
+    private interface IconSource : Object {
+        public abstract string? get_cache_key (int size, float scale);
+        /**
+         * Should look up the icon for the given size (e.g. if there are more detailed icons
+         * for larger sizes) and return a texture of size * scale.
+         */
+        public abstract Gdk.Pixbuf create_pixbuf (int size, float scale) throws Error;
+
+        protected static int get_texture_size (int size, float scale) {
+            return (int) Math.ceilf (size * scale);
+        }
+    }
+
+    private static HashTable<string, Gdk.Pixbuf> icon_pixbufs = new HashTable<string, Gdk.Pixbuf> (str_hash, str_equal);
+
+    public int icon_size { get; construct set; }
+    public float monitor_scale { get; construct set; }
+
+    public string resource_path { set { source = new ResourceIconSource (value); } }
+
+    private IconSource _source;
+    private IconSource source {
+        get { return _source; }
+        set {
+            _source = value;
+            load_pixbuf ();
+        }
+    }
+
+    public Icon.from_resource (int icon_size, float monitor_scale, string resource_path) {
+        Object (icon_size: icon_size, monitor_scale: monitor_scale, resource_path: resource_path);
+    }
+
+    construct {
+        notify["icon-size"].connect (load_pixbuf);
+        notify["monitor-scale"].connect (load_pixbuf);
+        resource_scale_changed.connect (load_pixbuf);
+    }
+
+    private void load_pixbuf () {
+        var actor_size = Utils.scale_to_int (icon_size, monitor_scale);
+        set_size (actor_size, actor_size);
+
+        var scale = monitor_scale * get_resource_scale ();
+
+        try {
+            var pixbuf = get_pixbuf (icon_size, scale);
+            content = new Gala.Image.from_pixbuf_with_size (actor_size, actor_size, pixbuf);
+
+            set_background_color (null);
+        } catch (Error e) {
+            critical ("Could not load icon pixbuf: %s", e.message);
+            background_color = { 255, 0, 0, 255 };
+        }
+    }
+
+    private Gdk.Pixbuf get_pixbuf (int size, float scale) throws Error {
+        var cache_key = source.get_cache_key (size, scale);
+
+        if (cache_key == null) {
+            return source.create_pixbuf (size, scale);
+        }
+
+        if (!(cache_key in icon_pixbufs)) {
+            icon_pixbufs[cache_key] = source.create_pixbuf (size, scale);
+        }
+
+        return icon_pixbufs[cache_key];
+    }
+}

lib/meson.build

@@ -17,6 +17,7 @@ gala_lib_sources = files(
     'Drawing/Color.vala',
     'Drawing/StyleManager.vala',
     'Drawing/Utilities.vala',
+    'Icon.vala',
     'Image.vala',
     'Plugin.vala',
     'RoundedCornersEffect.vala',