icon theme: Add a texture cache

Return cached textures for icons. This lets us avoid duplicate
texture uploads for icons whose surfaces we already cache.

docs/reference/gtk/gtk4-sections.txt

@@ -5446,6 +5446,7 @@ gtk_icon_theme_lookup_by_gicon_for_scale
 gtk_icon_theme_load_icon
 gtk_icon_theme_load_icon_for_scale
 gtk_icon_theme_load_surface
+gtk_icon_theme_load_texture
 gtk_icon_theme_list_contexts
 gtk_icon_theme_list_icons
 gtk_icon_theme_get_icon_sizes

gtk/gtkicontheme.c

@@ -225,6 +225,7 @@ struct _GtkIconInfo
    */
   GdkPixbuf *pixbuf;
   GdkPixbuf *proxy_pixbuf;
+  GskTexture *texture;
   GError *load_error;
   gdouble unscaled_scale;
   gdouble scale;
@@ -4004,6 +4005,40 @@ gtk_icon_info_load_icon (GtkIconInfo *icon_info,
   return icon_info->proxy_pixbuf;
 }
 
+/**
+ * gtk_icon_info_load_texture:
+ * @icon_info: a #GtkIconInfo
+ *
+ * Returns a texture object that can be used to render the icon
+ * with GSK.
+ *
+ * Returns: (transfer full): the icon texture; this may be a newly
+ *     created texture or a new reference to an exiting texture, so you must
+ *     not modify the icon. Use g_object_unref() to release your
+ *     reference.
+ *
+ * Since: 3.94
+ */
+GskTexture *
+gtk_icon_info_load_texture (GtkIconInfo *icon_info)
+{
+  if (!icon_info->texture)
+    {
+      GdkPixbuf *pixbuf;
+
+      pixbuf = gtk_icon_info_load_icon (icon_info, NULL);
+      icon_info->texture = gsk_texture_new_for_pixbuf (pixbuf);
+      g_object_unref (pixbuf);
+
+      g_object_add_weak_pointer (icon_info->texture, &icon_info->texture);
+    }
+
+  if (icon_info->in_cache != NULL)
+    ensure_in_lru_cache (icon_info->in_cache, icon_info);
+
+  return g_object_ref (icon_info->texture);
+}
+
 /**
  * gtk_icon_info_load_surface:
  * @icon_info: a #GtkIconInfo from gtk_icon_theme_lookup_icon()

gtk/gtkicontheme.h

@@ -25,6 +25,7 @@
 #include <gdk-pixbuf/gdk-pixbuf.h>
 #include <gdk/gdk.h>
 #include <gtk/gtkstylecontext.h>
+#include <gsk/gsk.h>
 
 G_BEGIN_DECLS
 
@@ -293,6 +294,9 @@ GDK_AVAILABLE_IN_3_10
 cairo_surface_t *     gtk_icon_info_load_surface       (GtkIconInfo   *icon_info,
 							GdkWindow     *for_window,
 							GError       **error);
+GDK_AVAILABLE_IN_3_94
+GskTexture *          gtk_icon_info_load_texture       (GtkIconInfo   *icon_info);
+
 GDK_AVAILABLE_IN_3_8
 void                  gtk_icon_info_load_icon_async   (GtkIconInfo          *icon_info,
 						       GCancellable         *cancellable,