[gtk+/wip/otte/vulkan: 34/41] gskrenderer: Add gsk_renderer_begin_draw_frame()

[Benjamin Otte <otte src gnome org>]

commit 18869d92e396359ae5da4021b8589c73e6939850
Author: Benjamin Otte <otte redhat com>
Date:   Sun Nov 27 16:21:02 2016 +0100

    gskrenderer: Add gsk_renderer_begin_draw_frame()
    
    This way, we can hijack the begin/end draw process and do out own
    processing before passing it on to GDK.

 docs/reference/gsk/gsk4-sections.txt |    3 +-
 gsk/gskrenderer.c                    |   69 ++++++++++++++++++++++++++++-----
 gsk/gskrenderer.h                    |    6 ++-
 gsk/gskrendererprivate.h             |    4 ++
 gtk/gtkwidget.c                      |    6 +--
 5 files changed, 71 insertions(+), 17 deletions(-)
---
diff --git a/docs/reference/gsk/gsk4-sections.txt b/docs/reference/gsk/gsk4-sections.txt
index ec761a2..8fe8a44 100644
--- a/docs/reference/gsk/gsk4-sections.txt
+++ b/docs/reference/gsk/gsk4-sections.txt
@@ -9,8 +9,9 @@ gsk_renderer_get_window
 gsk_renderer_get_display
 gsk_renderer_realize
 gsk_renderer_unrealize
+gsk_renderer_begin_draw_frame
+gsk_renderer_end_draw_frame
 gsk_renderer_create_render_node
-gsk_renderer_get_gl_context
 gsk_renderer_render
 <SUBSECTION Standard>
 GSK_IS_RENDERER
diff --git a/gsk/gskrenderer.c b/gsk/gskrenderer.c
index 947133f..8416ed9 100644
--- a/gsk/gskrenderer.c
+++ b/gsk/gskrenderer.c
@@ -115,6 +115,27 @@ gsk_renderer_real_unrealize (GskRenderer *self)
   GSK_RENDERER_WARN_NOT_IMPLEMENTED_METHOD (self, unrealize);
 }
 
+static GdkDrawingContext *
+gsk_renderer_real_begin_draw_frame (GskRenderer          *self,
+                                    const cairo_region_t *region)
+{
+  GskRendererPrivate *priv = gsk_renderer_get_instance_private (self);
+
+  return gdk_window_begin_draw_frame (priv->window,
+                                      priv->gl_context,
+                                      region);
+}
+
+static void
+gsk_renderer_real_end_draw_frame (GskRenderer       *self,
+                                  GdkDrawingContext *context)
+{
+  GskRendererPrivate *priv = gsk_renderer_get_instance_private (self);
+
+  gdk_window_end_draw_frame (priv->window,
+                             context);
+}
+
 static void
 gsk_renderer_real_render (GskRenderer *self,
                           GskRenderNode *root)
@@ -239,6 +260,8 @@ gsk_renderer_class_init (GskRendererClass *klass)
 
   klass->realize = gsk_renderer_real_realize;
   klass->unrealize = gsk_renderer_real_unrealize;
+  klass->begin_draw_frame = gsk_renderer_real_begin_draw_frame;
+  klass->end_draw_frame = gsk_renderer_real_end_draw_frame;
   klass->render = gsk_renderer_real_render;
   klass->create_cairo_surface = gsk_renderer_real_create_cairo_surface;
 
@@ -593,9 +616,7 @@ gsk_renderer_unrealize (GskRenderer *renderer)
  * gsk_renderer_render:
  * @renderer: a #GskRenderer
  * @root: a #GskRenderNode
- * @context: a #GdkDrawingContext using the context returned by
- *     gsk_renderer_get_gl_context() or %NULL if the renderer was created
- *     via gsk_renderer_create_fallback().
+ * @context: The drawing context created via gsk_renderer_begin_draw_frame()
  *
  * Renders the scene graph, described by a tree of #GskRenderNode instances,
  * using the given #GdkDrawingContext.
@@ -615,19 +636,16 @@ gsk_renderer_render (GskRenderer       *renderer,
   g_return_if_fail (GSK_IS_RENDERER (renderer));
   g_return_if_fail (priv->is_realized);
   g_return_if_fail (GSK_IS_RENDER_NODE (root));
-  g_return_if_fail (context == NULL || GDK_IS_DRAWING_CONTEXT (context));
-  g_return_if_fail (priv->drawing_context == NULL);
   g_return_if_fail (priv->root_node == NULL);
+  g_return_if_fail (context == priv->drawing_context);
 
-  if (context != NULL)
-    priv->drawing_context = g_object_ref (context);
-  else
+  if (priv->drawing_context == NULL)
     {
       if (priv->cairo_context == NULL)
         {
           g_critical ("The given GskRenderer instance was not created using "
-                      "gsk_renderer_create_fallback(), but you forgot to pass "
-                      "a GdkDrawingContext.");
+                      "gsk_renderer_create_fallback(), but you forgot to call "
+                      "gsk_renderer_begin_draw_frame().");
           return;
         }
     }
@@ -658,7 +676,6 @@ gsk_renderer_render (GskRenderer       *renderer,
     }
 #endif
 
-  g_clear_object (&priv->drawing_context);
   g_clear_pointer (&priv->root_node, gsk_render_node_unref);
 }
 
@@ -863,6 +880,36 @@ gsk_renderer_get_gl_context (GskRenderer *renderer)
   return priv->gl_context;
 }
 
+GdkDrawingContext *
+gsk_renderer_begin_draw_frame (GskRenderer          *renderer,
+                               const cairo_region_t *region)
+{
+  GskRendererPrivate *priv = gsk_renderer_get_instance_private (renderer);
+
+  g_return_val_if_fail (GSK_IS_RENDERER (renderer), NULL);
+  g_return_val_if_fail (region != NULL, NULL);
+  g_return_val_if_fail (priv->drawing_context == NULL, NULL);
+
+  priv->drawing_context = GSK_RENDERER_GET_CLASS (renderer)->begin_draw_frame (renderer, region);
+
+  return priv->drawing_context;
+}
+
+void
+gsk_renderer_end_draw_frame (GskRenderer       *renderer,
+                             GdkDrawingContext *context)
+{
+  GskRendererPrivate *priv = gsk_renderer_get_instance_private (renderer);
+
+  g_return_if_fail (GSK_IS_RENDERER (renderer));
+  g_return_if_fail (GDK_IS_DRAWING_CONTEXT (context));
+  g_return_if_fail (priv->drawing_context == context);
+
+  priv->drawing_context = NULL;
+
+  GSK_RENDERER_GET_CLASS (renderer)->end_draw_frame (renderer, context);
+}
+
 /**
  * gsk_renderer_create_fallback:
  * @renderer: a #GskRenderer
diff --git a/gsk/gskrenderer.h b/gsk/gskrenderer.h
index 507beb3..1728fc9 100644
--- a/gsk/gskrenderer.h
+++ b/gsk/gskrenderer.h
@@ -77,11 +77,15 @@ GskRenderer *           gsk_renderer_create_fallback            (GskRenderer
                                                                  cairo_t                 *cr);
 
 GDK_AVAILABLE_IN_3_90
-GdkGLContext *          gsk_renderer_get_gl_context             (GskRenderer             *renderer);
+GdkDrawingContext *     gsk_renderer_begin_draw_frame           (GskRenderer             *renderer,
+                                                                 const cairo_region_t    *region);
 GDK_AVAILABLE_IN_3_90
 void                    gsk_renderer_render                     (GskRenderer             *renderer,
                                                                  GskRenderNode           *root,
                                                                  GdkDrawingContext       *context);
+GDK_AVAILABLE_IN_3_90
+void                    gsk_renderer_end_draw_frame             (GskRenderer             *renderer,
+                                                                 GdkDrawingContext       *context);
 
 G_END_DECLS
 
diff --git a/gsk/gskrendererprivate.h b/gsk/gskrendererprivate.h
index 8671160..2ac3c92 100644
--- a/gsk/gskrendererprivate.h
+++ b/gsk/gskrendererprivate.h
@@ -42,6 +42,10 @@ struct _GskRendererClass
                         GError **error);
   void (* unrealize) (GskRenderer *renderer);
 
+  GdkDrawingContext * (* begin_draw_frame) (GskRenderer *renderer,
+                                            const cairo_region_t *region);
+  void (* end_draw_frame) (GskRenderer *renderer,
+                           GdkDrawingContext *context);
   void (* render) (GskRenderer *renderer,
                    GskRenderNode *root);
 
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 3d3ac7b..8e0dcf5 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -15640,9 +15640,7 @@ gtk_widget_render (GtkWidget            *widget,
   if (renderer == NULL)
     return;
 
-  context = gdk_window_begin_draw_frame (window,
-                                         gsk_renderer_get_gl_context (renderer),
-                                         region);
+  context = gsk_renderer_begin_draw_frame (renderer, region);
 
   gtk_snapshot_init (&snapshot,
                      renderer,
@@ -15657,5 +15655,5 @@ gtk_widget_render (GtkWidget            *widget,
       gsk_render_node_unref (root);
     }
 
-  gdk_window_end_draw_frame (window, context);
+  gsk_renderer_end_draw_frame (renderer, context);
 }