[gtk+/client-side-windows: 79/284] Add _gdk_drawable_get_subwindow_scratch_gc as a way to get cached gcs with GDK_INCLUDE_INFERIORS

[Alexander Larsson <alexl src gnome org>]

commit 1ad01acbf2a86af4decb34496f4ef1f05184ee5e
Author: Alexander Larsson <alexl redhat com>
Date:   Wed Jan 14 22:14:57 2009 +0100

    Add  _gdk_drawable_get_subwindow_scratch_gc as a way to get cached gcs with GDK_INCLUDE_INFERIORS
---
 gdk/gdkdraw.c      |   46 ++++++++++++++++++++++++++++++++++++++++++++++
 gdk/gdkinternals.h |    1 +
 gdk/gdkscreen.h    |    1 +
 3 files changed, 48 insertions(+), 0 deletions(-)

diff --git a/gdk/gdkdraw.c b/gdk/gdkdraw.c
index 73f262a..9c9385f 100644
--- a/gdk/gdkdraw.c
+++ b/gdk/gdkdraw.c
@@ -1785,6 +1785,52 @@ _gdk_drawable_get_scratch_gc (GdkDrawable *drawable,
 }
 
 /**
+ * _gdk_drawable_get_subwindow_scratch_gc:
+ * @drawable: A #GdkDrawable
+ * 
+ * Returns a #GdkGC suitable for drawing on @drawable. The #GdkGC has
+ * the standard values for @drawable, except for the graphics_exposures
+ * field which is %TRUE and the subwindow mode which is %GDK_INCLUDE_INFERIORS.
+ *
+ * The foreground color of the returned #GdkGC is undefined. The #GdkGC
+ * must not be altered in any way, except to change its foreground color.
+ * 
+ * Return value: A #GdkGC suitable for drawing on @drawable
+ * 
+ * Since: 2.18
+ **/
+GdkGC *
+_gdk_drawable_get_subwindow_scratch_gc (GdkDrawable *drawable)
+{
+  GdkScreen *screen;
+  gint depth;
+
+  g_return_val_if_fail (GDK_IS_DRAWABLE (drawable), NULL);
+
+  screen = gdk_drawable_get_screen (drawable);
+
+  g_return_val_if_fail (!screen->closed, NULL);
+
+  depth = gdk_drawable_get_depth (drawable) - 1;
+
+  if (!screen->subwindow_gcs[depth])
+    {
+      GdkGCValues values;
+      GdkGCValuesMask mask;
+      
+      values.graphics_exposures = TRUE;
+      values.subwindow_mode = GDK_INCLUDE_INFERIORS;
+      mask = GDK_GC_EXPOSURES | GDK_GC_SUBWINDOW;  
+      
+      screen->subwindow_gcs[depth] =
+	gdk_gc_new_with_values (drawable, &values, mask);
+    }
+  
+  return screen->subwindow_gcs[depth];
+}
+
+
+/**
  * _gdk_drawable_get_source_drawable:
  * @drawable: a #GdkDrawable
  *
diff --git a/gdk/gdkinternals.h b/gdk/gdkinternals.h
index 62d9f13..3841885 100644
--- a/gdk/gdkinternals.h
+++ b/gdk/gdkinternals.h
@@ -241,6 +241,7 @@ cairo_surface_t * _gdk_drawable_create_cairo_surface (GdkDrawable *drawable,
 /* GC caching */
 GdkGC *_gdk_drawable_get_scratch_gc (GdkDrawable *drawable,
 				     gboolean     graphics_exposures);
+GdkGC *_gdk_drawable_get_subwindow_scratch_gc (GdkDrawable *drawable);
 
 void _gdk_gc_update_context (GdkGC          *gc,
 			     cairo_t        *cr,
diff --git a/gdk/gdkscreen.h b/gdk/gdkscreen.h
index b1f3b8e..96ff8d4 100644
--- a/gdk/gdkscreen.h
+++ b/gdk/gdkscreen.h
@@ -51,6 +51,7 @@ struct _GdkScreen
 
   GdkGC *normal_gcs[32];
   GdkGC *exposure_gcs[32];
+  GdkGC *subwindow_gcs[32];
 
   cairo_font_options_t *font_options;
   double resolution;		/* pixels/points scale factor for fonts */