[gtk+/gtk-2-24] win32: always recreate the cairo surface if requested to do so

[Matthias Clasen <matthiasc src gnome org>]

commit 4ecbef0791d420c014ecca911cd2a1cc18122e9a
Author: Aleksander Morgado <aleksander lanedo com>
Date:   Fri Mar 15 10:56:27 2013 +0100

    win32: always recreate the cairo surface if requested to do so
    
    When _gdk_windowing_create_cairo_surface() gets called, we should always create
    a fully new cairo surface, instead of just referencing the available one, which
    may already be finished (i.e. in CAIRO_STATUS_SURFACE_FINISHED state).
    
    A new user_data key is added to the surface to explicitly release the acquired
    DC when the surface is destroyed, independent to the user_data key added to
    clear the impl->user_data pointer.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=695636

 gdk/win32/gdkdrawable-win32.c |   44 ++++++++++++++++++++++++++++++----------
 1 files changed, 33 insertions(+), 11 deletions(-)
---
diff --git a/gdk/win32/gdkdrawable-win32.c b/gdk/win32/gdkdrawable-win32.c
index 14d9f45..3fce570 100644
--- a/gdk/win32/gdkdrawable-win32.c
+++ b/gdk/win32/gdkdrawable-win32.c
@@ -144,6 +144,7 @@ static GdkVisual*   gdk_win32_get_visual     (GdkDrawable    *drawable);
 static void gdk_drawable_impl_win32_finalize   (GObject *object);
 
 static const cairo_user_data_key_t gdk_win32_cairo_key;
+static const cairo_user_data_key_t gdk_win32_cairo_hdc_key;
 
 G_DEFINE_TYPE (GdkDrawableImplWin32,  _gdk_drawable_impl_win32, GDK_TYPE_DRAWABLE)
 
@@ -1926,13 +1927,33 @@ _gdk_win32_drawable_release_dc (GdkDrawable *drawable)
     }
 }
 
+static void
+gdk_win32_cairo_surface_release_hdc (void *data)
+{
+  _gdk_win32_drawable_release_dc (GDK_DRAWABLE (data));
+}
+
 cairo_surface_t *
 _gdk_windowing_create_cairo_surface (GdkDrawable *drawable,
                                     gint width,
                                     gint height)
 {
-  /* width and height are determined from the DC */
-  return gdk_win32_ref_cairo_surface (drawable);
+  cairo_surface_t *surface;
+  HDC hdc;
+
+  hdc = _gdk_win32_drawable_acquire_dc (drawable);
+  if (!hdc)
+    return NULL;
+
+  surface = cairo_win32_surface_create (hdc);
+
+  /* Whenever the cairo surface is destroyed, we need to release the
+   * HDC that was acquired */
+  cairo_surface_set_user_data (surface, &gdk_win32_cairo_hdc_key,
+                              drawable,
+                              gdk_win32_cairo_surface_release_hdc);
+
+  return surface;
 }
 
 static void
@@ -1940,7 +1961,6 @@ gdk_win32_cairo_surface_destroy (void *data)
 {
   GdkDrawableImplWin32 *impl = data;
 
-  _gdk_win32_drawable_release_dc (GDK_DRAWABLE (impl));
   impl->cairo_surface = NULL;
 }
 
@@ -1955,14 +1975,14 @@ gdk_win32_ref_cairo_surface (GdkDrawable *drawable)
 
   if (!impl->cairo_surface)
     {
-      HDC hdc = _gdk_win32_drawable_acquire_dc (drawable);
-      if (!hdc)
-       return NULL;
-
-      impl->cairo_surface = cairo_win32_surface_create (hdc);
+      /* width and height are determined from the DC */
+      impl->cairo_surface = _gdk_windowing_create_cairo_surface (drawable, 0, 0);
 
+      /* Whenever the cairo surface is destroyed, we need to clear the
+       * pointer that we had stored here */
       cairo_surface_set_user_data (impl->cairo_surface, &gdk_win32_cairo_key,
-                                  drawable, gdk_win32_cairo_surface_destroy);
+                                  drawable,
+                                  gdk_win32_cairo_surface_destroy);
     }
   else
     cairo_surface_reference (impl->cairo_surface);
@@ -2041,9 +2061,11 @@ _gdk_win32_drawable_finish (GdkDrawable *drawable)
   if (impl->cairo_surface)
     {
       cairo_surface_finish (impl->cairo_surface);
+      cairo_surface_set_user_data (impl->cairo_surface, &gdk_win32_cairo_hdc_key, NULL, NULL);
       cairo_surface_set_user_data (impl->cairo_surface, &gdk_win32_cairo_key, NULL, NULL);
     }
 
-  g_assert (impl->hdc_count == 0);
+  /* impl->hdc_count doesn't have to be 0 here; as there may still be surfaces
+   * created with gdk_windowing_create_cairo_surface() out there, which are not
+   * managed internally by the drawable */
 }
-