[gtk+/wip/window-scales: 5/16] gdk: Add gdk_cairo_surface_create_similar

[Alexander Larsson <alexl src gnome org>]

commit 557e2e80905b5d4b2815675a4f3f926f94aaeb4b
Author: Alexander Larsson <alexl redhat com>
Date:   Mon Jun 3 17:01:36 2013 +0200

    gdk: Add gdk_cairo_surface_create_similar
    
    We track the window that each cairo surface is created for, which
    allows us to use gdk_window_create_similar_surface() when creating
    similar surfaces, even when you don't have access to the GdkWindow.
    This will be extra important when we need to create larger surfaces
    on HiDPI displays.

 gdk/gdkcairo.c     |   37 +++++++++++++++++++++++++++++++++++++
 gdk/gdkcairo.h     |    6 ++++++
 gdk/gdkinternals.h |    2 ++
 gdk/gdkwindow.c    |    7 ++++++-
 4 files changed, 51 insertions(+), 1 deletions(-)
---
diff --git a/gdk/gdkcairo.c b/gdk/gdkcairo.c
index 19bed04..1b0e83b 100644
--- a/gdk/gdkcairo.c
+++ b/gdk/gdkcairo.c
@@ -459,3 +459,40 @@ gdk_cairo_region_create_from_surface (cairo_surface_t *surface)
 
   return region;
 }
+
+static const cairo_user_data_key_t window_key;
+
+static GdkWindow  *
+_gdk_cairo_surface_get_window (cairo_surface_t *surface)
+{
+  return cairo_surface_get_user_data (surface, &window_key);
+}
+
+void
+_gdk_cairo_surface_set_window (cairo_surface_t *surface,
+                               GdkWindow  *window)
+{
+  cairo_surface_set_user_data (surface, &window_key,
+                               window, NULL);
+}
+
+cairo_surface_t *
+gdk_cairo_surface_create_similar (cairo_surface_t *surface,
+                                  cairo_content_t content,
+                                  int             width,
+                                  int             height)
+{
+  GdkWindow *window;
+
+  window = _gdk_cairo_surface_get_window (surface);
+  if (window)
+    return gdk_window_create_similar_surface (window,
+                                              content,
+                                              width,
+                                              height);
+  else
+    return cairo_surface_create_similar (surface,
+                                         content,
+                                         width,
+                                         height);
+}
diff --git a/gdk/gdkcairo.h b/gdk/gdkcairo.h
index 9cb601d..0b22c51 100644
--- a/gdk/gdkcairo.h
+++ b/gdk/gdkcairo.h
@@ -66,6 +66,12 @@ GDK_DEPRECATED_IN_3_4_FOR(gdk_cairo_set_source_rgba)
 void       gdk_cairo_set_source_color   (cairo_t              *cr,
                                          const GdkColor       *color);
 
+GDK_AVAILABLE_IN_3_10
+cairo_surface_t * gdk_cairo_surface_create_similar (cairo_surface_t *surface,
+                                                    cairo_content_t content,
+                                                    int             width,
+                                                    int             height);
+
 G_END_DECLS
 
 #endif /* __GDK_CAIRO_H__ */
diff --git a/gdk/gdkinternals.h b/gdk/gdkinternals.h
index e7eb9d5..ee5c7c4 100644
--- a/gdk/gdkinternals.h
+++ b/gdk/gdkinternals.h
@@ -318,6 +318,8 @@ void gdk_synthesize_window_state (GdkWindow     *window,
 
 gboolean _gdk_cairo_surface_extents (cairo_surface_t *surface,
                                      GdkRectangle *extents);
+void _gdk_cairo_surface_set_window (cairo_surface_t *surface,
+                                    GdkWindow  *window);
 
 /*************************************
  * Interfaces used by windowing code *
diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index 8e85427..6e4f4bc 100644
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -3094,8 +3094,9 @@ gdk_window_create_cairo_surface (GdkWindow *window,
   subsurface = cairo_surface_create_for_rectangle (surface,
                                                    window->abs_x,
                                                    window->abs_y,
-                                                   width,
+                                                   width ,
                                                    height);
+  _gdk_cairo_surface_set_window (subsurface, window);
   cairo_surface_destroy (surface);
   return subsurface;
 }
@@ -3120,6 +3121,7 @@ _gdk_window_ref_cairo_surface (GdkWindow *window)
                                                    window->abs_y,
                                                    window->width,
                                                    window->height);
+      _gdk_cairo_surface_set_window (surface, window);
     }
   else
     {
@@ -3128,6 +3130,7 @@ _gdk_window_ref_cairo_surface (GdkWindow *window)
          window->cairo_surface = gdk_window_create_cairo_surface (window,
                                                                    window->width,
                                                                    window->height);
+          _gdk_cairo_surface_set_window (window->cairo_surface, window);
 
          if (window->cairo_surface)
            {
@@ -9202,6 +9205,8 @@ gdk_window_create_similar_surface (GdkWindow *     window,
 
   cairo_surface_destroy (window_surface);
 
+  _gdk_cairo_surface_set_window (surface, window);
+
   return surface;
 }