gtk: Add a GskRenderer to GtkWindow

Each top-level should have its own GskRenderer, to be used when drawing
the render node tree.

gtk/gtkwindow.c

@@ -30,6 +30,7 @@
 #include <stdlib.h>
 #include <errno.h>
 #include <limits.h>
+#include <graphene.h>
 
 #include "gtkprivate.h"
 #include "gtkwindowprivate.h"
@@ -270,6 +271,8 @@ struct _GtkWindowPrivate
   GdkWindow *hardcoded_window;
 
   GtkCssNode *decoration_node;
+
+  GskRenderer *renderer;
 };
 
 static const GtkTargetEntry dnd_dest_targets [] = {
@@ -6839,6 +6842,16 @@ gtk_window_realize (GtkWidget *widget)
 
   _gtk_widget_get_allocation (widget, &allocation);
 
+  if (priv->renderer == NULL)
+    {
+      graphene_rect_t viewport;
+
+      priv->renderer = gsk_renderer_get_for_display (gtk_widget_get_display (widget));
+
+      graphene_rect_init (&viewport, 0, 0, allocation.width, allocation.height);
+      gsk_renderer_set_viewport (priv->renderer, &viewport);
+    }
+
   if (gtk_widget_get_parent_window (widget))
     {
       gdk_window = gdk_window_new_child (gtk_widget_get_parent_window (widget),
@@ -6857,6 +6870,9 @@ gtk_window_realize (GtkWidget *widget)
           popover_realize (popover->widget, popover, window);
         }
 
+      gsk_renderer_set_window (priv->renderer, gdk_window);
+      gsk_renderer_realize (priv->renderer);
+
       return;
     }
 
@@ -7051,6 +7067,11 @@ gtk_window_realize (GtkWidget *widget)
     }
 
   check_scale_changed (window);
+
+  /* Renderer */
+  gsk_renderer_set_window (priv->renderer, gdk_window);
+  gsk_renderer_set_use_alpha (priv->renderer, TRUE);
+  gsk_renderer_realize (priv->renderer);
 }
 
 static void
@@ -7078,6 +7099,9 @@ gtk_window_unrealize (GtkWidget *widget)
   GList *link;
   gint i;
 
+  if (priv->renderer != NULL)
+    gsk_renderer_unrealize (priv->renderer);
+
   /* On unrealize, we reset the size of the window such
    * that we will re-apply the default sizing stuff
    * next time we show the window.
@@ -7224,6 +7248,21 @@ _gtk_window_set_allocation (GtkWindow           *window,
   child_allocation.width = allocation->width;
   child_allocation.height = allocation->height;
 
+  if (priv->renderer != NULL)
+    {
+      graphene_rect_t viewport;
+      graphene_matrix_t projection;
+
+      graphene_rect_init (&viewport, 0, 0, allocation->width, allocation->height);
+      gsk_renderer_set_viewport (priv->renderer, &viewport);
+
+      graphene_matrix_init_ortho (&projection,
+                                  0, allocation->width,
+                                  0, allocation->height,
+                                  -1, 1);
+      gsk_renderer_set_projection (priv->renderer, &projection);
+    }
+
   get_shadow_width (window, &window_border);
 
   if (_gtk_widget_get_realized (widget))
@@ -11735,3 +11774,11 @@ gtk_window_unexport_handle (GtkWindow *window)
     }
 #endif
 }
+
+GskRenderer *
+gtk_window_get_renderer (GtkWindow *window)
+{
+  GtkWindowPrivate *priv = window->priv;
+
+  return priv->renderer;
+}

gtk/gtkwindowprivate.h

@@ -142,6 +142,8 @@ gboolean      gtk_window_export_handle   (GtkWindow               *window,
                                           gpointer                 user_data);
 void          gtk_window_unexport_handle (GtkWindow               *window);
 
+GskRenderer *gtk_window_get_renderer (GtkWindow *window);
+
 G_END_DECLS
 
 #endif /* __GTK_WINDOW_PRIVATE_H__ */