GtkIconHelper: render to cairo pattern rather than pixbuf for drawing

We render the source into a cairo_patter_t into a pixbuf so that
we can render it directly, rather than having to convert it every
time we render. We also specify the target window when creating
the cairo surface so that rendering can be faster.

gtk/gtkiconhelper.c

@@ -43,6 +43,9 @@ struct _GtkIconHelperPrivate {
 
   GdkPixbuf *rendered_pixbuf;
   GtkStateFlags last_rendered_state;
+
+  cairo_pattern_t *rendered_pattern;
+  GtkStateFlags last_pattern_state;
 };
 
 void
@@ -379,6 +382,184 @@ _gtk_icon_helper_ensure_pixbuf (GtkIconHelper *self,
   return pixbuf;
 }
 
+static gboolean
+check_invalidate_pattern (GtkIconHelper *self,
+			  GtkStyleContext *context)
+{
+  GtkStateFlags state;
+
+  state = gtk_style_context_get_state (context);
+
+  if ((self->priv->rendered_pattern != NULL) &&
+      (self->priv->last_pattern_state == state))
+    return FALSE;
+
+  self->priv->last_pattern_state = state;
+
+  if (self->priv->rendered_pattern)
+    cairo_pattern_destroy (self->priv->rendered_pattern);
+  self->priv->rendered_pattern = NULL;
+
+  return TRUE;
+}
+
+static void
+ensure_pattern_at_size (GtkIconHelper   *self,
+			GtkStyleContext *context)
+{
+  gint width, height;
+  GdkPixbuf *pixbuf;
+  cairo_surface_t *surface;
+
+  if (!check_invalidate_pattern (self, context))
+    return;
+
+  if (self->priv->rendered_pattern)
+    return;
+
+  if (self->priv->force_scale_pixbuf &&
+      (self->priv->pixel_size != -1 ||
+       self->priv->icon_size != GTK_ICON_SIZE_INVALID))
+    {
+      ensure_icon_size (self, context, &width, &height);
+
+      if (width < gdk_pixbuf_get_width (self->priv->orig_pixbuf) ||
+          height < gdk_pixbuf_get_height (self->priv->orig_pixbuf))
+	{
+	  pixbuf = gdk_pixbuf_scale_simple (self->priv->orig_pixbuf,
+					    width, height,
+					    GDK_INTERP_BILINEAR);
+	}
+      else
+	pixbuf = g_object_ref (self->priv->orig_pixbuf);
+    }
+  else
+    pixbuf = g_object_ref (self->priv->orig_pixbuf);
+
+  surface = gdk_cairo_pixbuf_to_surface (pixbuf, self->priv->window);
+  g_object_unref (pixbuf);
+  self->priv->rendered_pattern = cairo_pattern_create_for_surface (surface);
+  cairo_surface_destroy (surface);
+
+}
+
+static void
+ensure_pattern_for_icon_set (GtkIconHelper *self,
+			     GtkStyleContext *context,
+			     GtkIconSet *icon_set)
+{
+  GdkPixbuf *pixbuf;
+  cairo_surface_t *surface;
+
+  if (!check_invalidate_pattern (self, context))
+    return;
+
+  pixbuf = 
+    gtk_icon_set_render_icon_pixbuf (icon_set, context, self->priv->icon_size);
+
+  surface = gdk_cairo_pixbuf_to_surface (pixbuf, self->priv->window);
+  g_object_unref (pixbuf);
+  self->priv->rendered_pattern = cairo_pattern_create_for_surface (surface);
+  cairo_surface_destroy (surface);
+}
+
+static void
+ensure_pattern_for_icon_name_or_gicon (GtkIconHelper *self,
+				       GtkStyleContext *context)
+{
+  GtkIconTheme *icon_theme;
+  gint width, height;
+  GtkIconInfo *info;
+  GdkPixbuf *pixbuf;
+  cairo_surface_t *surface;
+  GtkIconLookupFlags flags;
+
+  if (!check_invalidate_pattern (self, context))
+    return;
+
+  icon_theme = gtk_icon_theme_get_default ();
+  flags = get_icon_lookup_flags (self);
+
+  ensure_icon_size (self, context, &width, &height);
+
+  if (self->priv->storage_type == GTK_IMAGE_ICON_NAME &&
+      self->priv->icon_name != NULL)
+    {
+      info = gtk_icon_theme_lookup_icon (icon_theme,
+                                         self->priv->icon_name,
+                                         MIN (width, height), flags);
+    }
+  else if (self->priv->storage_type == GTK_IMAGE_GICON &&
+           self->priv->gicon != NULL)
+    {
+      info = gtk_icon_theme_lookup_by_gicon (icon_theme,
+                                             self->priv->gicon,
+                                             MIN (width, height), flags);
+    }
+  else
+    {
+      g_assert_not_reached ();
+      return;
+    }
+
+  pixbuf = ensure_stated_icon_from_info (self, context, info);
+  if (pixbuf)
+    {
+      surface = gdk_cairo_pixbuf_to_surface (pixbuf, self->priv->window);
+      g_object_unref (pixbuf);
+      self->priv->rendered_pattern = cairo_pattern_create_for_surface (surface);
+      cairo_surface_destroy (surface);
+    }
+
+  if (info)
+    g_object_unref (info);
+}
+
+cairo_pattern_t *
+_gtk_icon_helper_ensure_pattern (GtkIconHelper *self,
+				 GtkStyleContext *context)
+{
+  cairo_pattern_t *pattern = NULL;
+  GtkIconSet *icon_set;
+
+  switch (self->priv->storage_type)
+    {
+    case GTK_IMAGE_PIXBUF:
+      ensure_pattern_at_size (self, context);
+      break;
+
+    case GTK_IMAGE_STOCK:
+      icon_set = gtk_style_context_lookup_icon_set (context, self->priv->stock_id);
+      if (icon_set != NULL)
+	ensure_pattern_for_icon_set (self, context, icon_set);
+      else
+	pattern = NULL;
+      break;
+
+    case GTK_IMAGE_ICON_SET:
+      icon_set = self->priv->icon_set;
+      ensure_pattern_for_icon_set (self, context, icon_set);
+      break;
+
+    case GTK_IMAGE_ICON_NAME:
+    case GTK_IMAGE_GICON:
+      ensure_pattern_for_icon_name_or_gicon (self, context);
+      break;
+
+    case GTK_IMAGE_ANIMATION:
+    case GTK_IMAGE_EMPTY:
+    default:
+      pattern = NULL;
+      break;
+    }
+
+  if (pattern == NULL &&
+      self->priv->rendered_pattern != NULL)
+    pattern = cairo_pattern_reference (self->priv->rendered_pattern);
+
+  return pattern;
+}
+
 void
 _gtk_icon_helper_get_size (GtkIconHelper *self,
                            GtkStyleContext *context,
@@ -610,14 +791,13 @@ _gtk_icon_helper_draw (GtkIconHelper *self,
                        gdouble x,
                        gdouble y)
 {
-  GdkPixbuf *pixbuf;
+  cairo_pattern_t *pattern;
 
-  pixbuf = _gtk_icon_helper_ensure_pixbuf (self, context);
-
-  if (pixbuf != NULL)
+  pattern = _gtk_icon_helper_ensure_pattern (self, context);
+  if (pattern != NULL)
     {
-      gtk_render_icon (context, cr, pixbuf, x, y);
-      g_object_unref (pixbuf);
+      gtk_render_icon_pattern (context, cr, pattern, x, y);
+      cairo_pattern_destroy (pattern);
     }
 }