Add GtkIconProvider

This is a minimal interface to provide icon lookup by name.
It is implemented by GtkIconTheme, but platform libraries or
applications can provide their own implementation and pass it
to GTK.

gtk/gtk.h

@@ -163,6 +163,7 @@
 #include <gtk/gtkgridview.h>
 #include <gtk/gtkheaderbar.h>
 #include <gtk/gtkicontheme.h>
+#include <gtk/gtkiconprovider.h>
 #include <gtk/deprecated/gtkiconview.h>
 #include <gtk/gtkimage.h>
 #include <gtk/gtkimcontext.h>

gtk/gtkiconhelper.c

@@ -34,6 +34,7 @@
 #include "gtkwidgetprivate.h"
 #include "gdk/gdkprofilerprivate.h"
 #include "gtksymbolicpaintable.h"
+#include "gtkiconprovider.h"
 
 struct _GtkIconHelper
 {
@@ -111,13 +112,25 @@ ensure_paintable_for_gicon (GtkIconHelper    *self,
   return GDK_PAINTABLE (icon);
 }
 
+static GdkPaintable *
+ensure_paintable_for_icon_name (GtkIconHelper *self,
+                                const char    *name)
+{
+  int size;
+  float scale;
+
+  size = gtk_icon_helper_get_size (self);
+  scale = gtk_widget_get_scale_factor (self->owner);
+
+  return gtk_lookup_icon (gtk_widget_get_display (self->owner), name, size, scale);
+}
+
 static GdkPaintable *
 gtk_icon_helper_load_paintable (GtkIconHelper   *self,
                                 gboolean         preload,
                                 gboolean        *out_symbolic)
 {
   GdkPaintable *paintable;
-  GIcon *gicon;
   gboolean symbolic;
 
   switch (gtk_image_definition_get_storage_type (self->def))
@@ -128,18 +141,12 @@ gtk_icon_helper_load_paintable (GtkIconHelper   *self,
       break;
 
     case GTK_IMAGE_ICON_NAME:
-      if (self->use_fallback)
-        gicon = g_themed_icon_new_with_default_fallbacks (gtk_image_definition_get_icon_name (self->def));
+      paintable = ensure_paintable_for_icon_name (self,
+                                                  gtk_image_definition_get_icon_name (self->def));
+      if (GTK_IS_ICON_PAINTABLE (paintable))
+        symbolic = gtk_icon_paintable_is_symbolic (GTK_ICON_PAINTABLE (paintable));
       else
-        gicon = g_themed_icon_new (gtk_image_definition_get_icon_name (self->def));
-      paintable = ensure_paintable_for_gicon (self,
-                                              gtk_css_node_get_style (self->node),
-                                              gtk_widget_get_scale_factor (self->owner),
-                                              gtk_widget_get_direction (self->owner),
-                                              preload,
-                                              gicon,
-                                              &symbolic);
-      g_object_unref (gicon);
+        symbolic = GTK_IS_SYMBOLIC_PAINTABLE (paintable);
       break;
 
     case GTK_IMAGE_GICON:

gtk/gtkiconprovider.c

@@ -0,0 +1,164 @@
+/*
+ * Copyright © 2024 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Matthias Clasen <mclasen@redhat.com>
+ */
+
+#include "config.h"
+
+#include "gtkiconprovider.h"
+#include "gtkicontheme.h"
+#include "gtkenums.h"
+#include "gtkwidgetprivate.h"
+#include "gtkprivate.h"
+
+
+G_DEFINE_INTERFACE (GtkIconProvider, gtk_icon_provider, G_TYPE_OBJECT)
+
+static void
+gtk_icon_provider_default_init (GtkIconProviderInterface *iface)
+{
+}
+
+void
+gtk_icon_provider_set_for_display (GdkDisplay      *display,
+                                   GtkIconProvider *provider)
+{
+  g_object_set_data_full (G_OBJECT (display), "--gtk-icon-provider",
+                          g_object_ref (provider), g_object_unref);
+
+  gtk_system_setting_changed (display, GTK_SYSTEM_SETTING_ICON_THEME);
+}
+
+GtkIconProvider *
+gtk_icon_provider_get_for_display (GdkDisplay *display)
+{
+  GtkIconProvider *provider;
+
+  provider = g_object_get_data (G_OBJECT (display), "--gtk-icon-provider");
+
+  if (provider)
+    return provider;
+
+  return GTK_ICON_PROVIDER (gtk_icon_theme_get_for_display (display));
+}
+
+static GdkPaintable *gtk_lookup_builtin_icon (GdkDisplay *display,
+                                              const char *name,
+                                              int         size,
+                                              float       scale);
+
+GdkPaintable *
+gtk_lookup_icon (GdkDisplay *display,
+                 const char *name,
+                 int         size,
+                 float       scale)
+{
+  GtkIconProvider *provider;
+  GdkPaintable *icon;
+
+  provider = gtk_icon_provider_get_for_display (display);
+
+  icon = GTK_ICON_PROVIDER_GET_IFACE (provider)->lookup_icon (provider, name, size, scale);
+
+  if (!icon)
+    {
+      GTK_DISPLAY_DEBUG (display, ICONTHEME,
+                         "%s: Looking up icon %s size %d@%f: not found",
+                         G_OBJECT_TYPE_NAME (provider), name, size, scale);
+
+      icon = gtk_lookup_builtin_icon (display, name, size, scale);
+    }
+
+  return icon;
+}
+
+static GdkPaintable *
+gtk_lookup_builtin_icon (GdkDisplay *display,
+                         const char *name,
+                         int         size,
+                         float       scale)
+{
+  int sizes[] = { 16, 32, 64 };
+  char pixel_size[24] = { 0, };
+  const char *contexts[] = {
+    "actions",
+    "categories",
+    "devices",
+    "emblems",
+    "emotes",
+    "mimetypes",
+    "places",
+    "status",
+  };
+  const char *extension;
+  GdkPaintable *icon = NULL;
+
+  for (int i = 0; i < G_N_ELEMENTS (sizes); i++)
+    {
+      if (sizes[i] >= size * scale)
+        {
+          size = sizes[i];
+          g_snprintf (pixel_size, sizeof (pixel_size), "%dx%d", size, size);
+          break;
+        }
+    }
+  if (pixel_size[0] == '\0')
+    {
+      g_snprintf (pixel_size, sizeof (pixel_size), "64x64");
+      size = 64;
+    }
+
+  if (g_str_has_suffix (name, "-symbolic"))
+    extension = ".symbolic.png";
+  else
+    extension = ".png";
+
+  for (int i = 0; i < G_N_ELEMENTS (contexts); i++)
+    {
+      char *uri;
+      GFile *file;
+
+      uri = g_strconcat ("resource:///org/gtk/libgtk/icons/", pixel_size, "/", contexts[i], "/", name, extension, NULL);
+      file = g_file_new_for_uri (uri);
+
+      if (g_file_query_exists (file, NULL))
+        {
+          GTK_DISPLAY_DEBUG (display, ICONTHEME,
+                             "Looking up builtin icon %s size %d@%f: %s",
+                             name, size, scale, uri);
+
+          icon = GDK_PAINTABLE (gtk_icon_paintable_new_for_file (file, size, 1));
+        }
+
+      g_object_unref (file);
+      g_free (uri);
+
+      if (icon)
+        break;
+    }
+
+  if (!icon)
+    {
+      GTK_DISPLAY_DEBUG (display, ICONTHEME,
+                         "Looking up builtin icon %s size %d@%f: not found",
+                         name, size, scale);
+
+      icon = GDK_PAINTABLE (gdk_texture_new_from_resource ("/org/gtk/libgtk/icons/16x16/status/image-missing.png"));
+    }
+
+  return icon;
+}

gtk/gtkiconprovider.h

@@ -0,0 +1,62 @@
+
+/*
+ * Copyright © 2024 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Matthias Clasen <mclasen@redhat.com>
+ */
+
+#pragma once
+
+#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gtk/gtk.h> can be included directly."
+#endif
+
+#include <gtk/gtktypes.h>
+#include <gdk/gdkpaintable.h>
+#include <gdk/gdkdisplay.h>
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_ICON_PROVIDER (gtk_icon_provider_get_type ())
+
+GDK_AVAILABLE_IN_4_16
+G_DECLARE_INTERFACE (GtkIconProvider, gtk_icon_provider, GTK, ICON_PROVIDER, GObject)
+
+struct _GtkIconProviderInterface
+{
+  GTypeInterface g_iface;
+
+  GdkPaintable * (* lookup_icon) (GtkIconProvider  *provider,
+                                  const char       *icon_name,
+                                  int               size,
+                                  float             scale);
+};
+
+GDK_AVAILABLE_IN_4_16
+void              gtk_icon_provider_set_for_display (GdkDisplay      *display,
+                                                     GtkIconProvider *provider);
+
+GDK_AVAILABLE_IN_4_16
+GtkIconProvider * gtk_icon_provider_get_for_display (GdkDisplay      *display);
+
+GDK_AVAILABLE_IN_4_16
+GdkPaintable *    gtk_lookup_icon                   (GdkDisplay      *display,
+                                                     const char      *icon_name,
+                                                     int              size,
+                                                     float            scale);
+
+G_END_DECLS
+

gtk/gtkicontheme.c

@@ -54,6 +54,7 @@
 #include "gdktextureutilsprivate.h"
 #include "gdk/gdktextureprivate.h"
 #include "gdk/gdkprofilerprivate.h"
+#include "gtkiconprovider.h"
 
 #define GDK_ARRAY_ELEMENT_TYPE char *
 #define GDK_ARRAY_NULL_TERMINATED 1
@@ -812,7 +813,25 @@ icon_cache_clear (GtkIconTheme *theme)
 
 /****************** End of icon cache ***********************/
 
-G_DEFINE_TYPE (GtkIconTheme, gtk_icon_theme, G_TYPE_OBJECT)
+static GdkPaintable *
+gtk_icon_theme_lookup_icon_as_provider (GtkIconProvider *provider,
+                                        const char      *name,
+                                        int              size,
+                                        float            scale)
+{
+  GtkIconTheme *self = GTK_ICON_THEME (provider);
+
+  return GDK_PAINTABLE (gtk_icon_theme_lookup_icon (self, name, NULL, size, (int) ceilf (scale), GTK_TEXT_DIR_LTR, 0));
+}
+
+static void
+gtk_icon_provider_init (GtkIconProviderInterface *iface)
+{
+  iface->lookup_icon = gtk_icon_theme_lookup_icon_as_provider;
+}
+
+G_DEFINE_TYPE_WITH_CODE (GtkIconTheme, gtk_icon_theme, G_TYPE_OBJECT,
+                         G_IMPLEMENT_INTERFACE (GTK_TYPE_ICON_PROVIDER, gtk_icon_provider_init))
 
 /**
  * gtk_icon_theme_new:

gtk/meson.build

@@ -258,6 +258,7 @@ gtk_public_sources = files([
   'gtkgridview.c',
   'gtkheaderbar.c',
   'gtkicontheme.c',
+  'gtkiconprovider.c',
   'gtkimage.c',
   'gtkimagedefinition.c',
   'gtkimcontext.c',
@@ -511,6 +512,7 @@ gtk_public_headers = files([
   'gtkgridview.h',
   'gtkheaderbar.h',
   'gtkicontheme.h',
+  'gtkiconprovider.h',
   'gtkimage.h',
   'gtkimcontext.h',
   'gtkimcontextsimple.h',