[metacity] xrender: move overlay window to MetaCompositor

[Alberts Muktupāvels <muktupavels src gnome org>]

commit bd2f1660e7c0b5f9ff1a816a592ce07cfaa63861
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Wed Mar 15 17:31:15 2017 +0200

    xrender: move overlay window to MetaCompositor

 src/compositor/meta-compositor-private.h |   12 +++--
 src/compositor/meta-compositor-xrender.c |   56 +-----------------------
 src/compositor/meta-compositor.c         |   69 ++++++++++++++++++++++++++++++
 3 files changed, 78 insertions(+), 59 deletions(-)
---
diff --git a/src/compositor/meta-compositor-private.h b/src/compositor/meta-compositor-private.h
index eec2fc2..0f48511 100644
--- a/src/compositor/meta-compositor-private.h
+++ b/src/compositor/meta-compositor-private.h
@@ -74,13 +74,15 @@ struct _MetaCompositorClass
                                                 Window              xwindow);
 };
 
-gboolean     meta_compositor_check_extensions (MetaCompositor  *compositor,
-                                               GError         **error);
+gboolean     meta_compositor_check_extensions   (MetaCompositor  *compositor,
+                                                 GError         **error);
 
-gboolean     meta_compositor_set_selection    (MetaCompositor  *compositor,
-                                               GError         **error);
+gboolean     meta_compositor_set_selection      (MetaCompositor  *compositor,
+                                                 GError         **error);
 
-MetaDisplay *meta_compositor_get_display      (MetaCompositor  *compositor);
+Window       meta_compositor_get_overlay_window (MetaCompositor  *compositor);
+
+MetaDisplay *meta_compositor_get_display        (MetaCompositor  *compositor);
 
 G_END_DECLS
 
diff --git a/src/compositor/meta-compositor-xrender.c b/src/compositor/meta-compositor-xrender.c
index 4857531..474dbeb 100644
--- a/src/compositor/meta-compositor-xrender.c
+++ b/src/compositor/meta-compositor-xrender.c
@@ -2453,39 +2453,6 @@ update_shadows (MetaPreference pref,
 }
 
 static void
-show_overlay_window (MetaCompositorXRender *xrender,
-                     Display               *xdisplay)
-{
-  XserverRegion region;
-
-  region = XFixesCreateRegion (xdisplay, NULL, 0);
-
-  XFixesSetWindowShapeRegion (xdisplay, xrender->overlay_window,
-                              ShapeBounding, 0, 0, 0);
-
-  XFixesSetWindowShapeRegion (xdisplay, xrender->overlay_window,
-                              ShapeInput, 0, 0, region);
-
-  XFixesDestroyRegion (xdisplay, region);
-
-  damage_screen (xrender);
-}
-
-static void
-hide_overlay_window (MetaCompositorXRender *xrender,
-                     Display               *xdisplay)
-{
-  XserverRegion region;
-
-  region = XFixesCreateRegion (xdisplay, NULL, 0);
-
-  XFixesSetWindowShapeRegion (xdisplay, xrender->overlay_window,
-                              ShapeBounding, 0, 0, region);
-
-  XFixesDestroyRegion (xdisplay, region);
-}
-
-static void
 meta_compositor_xrender_constructed (GObject *object)
 {
   MetaCompositor *compositor;
@@ -2521,8 +2488,6 @@ meta_compositor_xrender_finalize (GObject *object)
       xrender->prefs_listener_added = FALSE;
     }
 
-  hide_overlay_window (xrender, xdisplay);
-
   /* Destroy the windows */
   for (index = xrender->windows; index; index = index->next)
     {
@@ -2547,7 +2512,6 @@ meta_compositor_xrender_finalize (GObject *object)
     }
 
   XCompositeUnredirectSubwindows (xdisplay, xroot, CompositeRedirectManual);
-  XCompositeReleaseOverlayWindow (xdisplay, xrender->overlay_window);
 
   G_OBJECT_CLASS (meta_compositor_xrender_parent_class)->finalize (object);
 }
@@ -2576,14 +2540,6 @@ meta_compositor_xrender_manage (MetaCompositor  *compositor,
       return FALSE;
     }
 
-  if (!display->have_xfixes)
-    {
-      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
-                   "Missing xfixes extension required for compositing");
-
-      return FALSE;
-    }
-
   if (!meta_compositor_set_selection (compositor, error))
     return FALSE;
 
@@ -2613,8 +2569,7 @@ meta_compositor_xrender_manage (MetaCompositor  *compositor,
       return FALSE;
     }
 
-  xrender->overlay_window = XCompositeGetOverlayWindow (xdisplay, xroot);
-  XSelectInput (xdisplay, xrender->overlay_window, ExposureMask);
+  xrender->overlay_window = meta_compositor_get_overlay_window (compositor);
 
   pa.subwindow_mode = IncludeInferiors;
   xrender->root_picture = XRenderCreatePicture (xdisplay,
@@ -2653,7 +2608,7 @@ meta_compositor_xrender_manage (MetaCompositor  *compositor,
 
   XClearArea (xdisplay, xrender->overlay_window, 0, 0, 0, 0, TRUE);
 
-  show_overlay_window (xrender, xdisplay);
+  damage_screen (xrender);
 
   meta_prefs_add_listener (update_shadows, xrender);
   xrender->prefs_listener_added = TRUE;
@@ -3111,13 +3066,6 @@ static gboolean
 meta_compositor_xrender_is_our_xwindow (MetaCompositor *compositor,
                                         Window          xwindow)
 {
-  MetaCompositorXRender *xrender;
-
-  xrender = META_COMPOSITOR_XRENDER (compositor);
-
-  if (xrender->overlay_window == xwindow)
-    return TRUE;
-
   return FALSE;
 }
 
diff --git a/src/compositor/meta-compositor.c b/src/compositor/meta-compositor.c
index d64bf8e..4b8af1e 100644
--- a/src/compositor/meta-compositor.c
+++ b/src/compositor/meta-compositor.c
@@ -18,6 +18,10 @@
 
 #include "config.h"
 
+#include <X11/extensions/shape.h>
+#include <X11/extensions/Xcomposite.h>
+#include <X11/extensions/Xfixes.h>
+
 #include "display-private.h"
 #include "meta-compositor-none.h"
 #include "meta-compositor-xrender.h"
@@ -32,6 +36,9 @@ typedef struct
   Atom         cm_atom;
   Window       cm_window;
   guint32      cm_timestamp;
+
+  /* XCompositeGetOverlayWindow */
+  Window       overlay_window;
 } MetaCompositorPrivate;
 
 enum
@@ -83,6 +90,21 @@ meta_compositor_finalize (GObject *object)
   priv = meta_compositor_get_instance_private (compositor);
   xdisplay = priv->display->xdisplay;
 
+  if (priv->overlay_window != None)
+    {
+      Window overlay;
+      XserverRegion region;
+
+      overlay = priv->overlay_window;
+
+      region = XFixesCreateRegion (xdisplay, NULL, 0);
+      XFixesSetWindowShapeRegion (xdisplay, overlay, ShapeBounding, 0, 0, region);
+      XFixesDestroyRegion (xdisplay, region);
+
+      XCompositeReleaseOverlayWindow (xdisplay, overlay);
+      priv->overlay_window = None;
+    }
+
   if (priv->cm_window != None)
     {
       XSetSelectionOwner (xdisplay, priv->cm_atom, None, priv->cm_timestamp);
@@ -364,6 +386,9 @@ meta_compositor_is_our_xwindow (MetaCompositor *compositor,
   if (priv->cm_window == xwindow)
     return TRUE;
 
+  if (priv->overlay_window == xwindow)
+    return TRUE;
+
   return compositor_class->is_our_xwindow (compositor, xwindow);
 }
 
@@ -397,6 +422,14 @@ meta_compositor_check_extensions (MetaCompositor  *compositor,
       return FALSE;
     }
 
+  if (!priv->display->have_xfixes)
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                   "Missing xfixes extension required for compositing");
+
+      return FALSE;
+    }
+
   return TRUE;
 }
 
@@ -434,6 +467,42 @@ meta_compositor_set_selection (MetaCompositor  *compositor,
   return TRUE;
 }
 
+Window
+meta_compositor_get_overlay_window (MetaCompositor *compositor)
+{
+  MetaCompositorPrivate *priv;
+  Display *xdisplay;
+  Window xroot;
+  Window overlay;
+  XserverRegion region;
+
+  priv = meta_compositor_get_instance_private (compositor);
+
+  if (priv->overlay_window != None)
+    return priv->overlay_window;
+
+  xdisplay = priv->display->xdisplay;
+  xroot = DefaultRootWindow (xdisplay);
+
+  overlay = XCompositeGetOverlayWindow (xdisplay, xroot);
+
+  /* Get Expose events about window regions that have lost contents. */
+  XSelectInput (xdisplay, overlay, ExposureMask);
+
+  /* Make sure there isn't any left-over output shape on the overlay
+   * window by setting the whole screen to be an output region.
+   */
+  XFixesSetWindowShapeRegion (xdisplay, overlay, ShapeBounding, 0, 0, 0);
+
+  /* Allow events to pass through the overlay */
+  region = XFixesCreateRegion (xdisplay, NULL, 0);
+  XFixesSetWindowShapeRegion (xdisplay, overlay, ShapeInput, 0, 0, region);
+  XFixesDestroyRegion (xdisplay, region);
+
+  priv->overlay_window = overlay;
+  return overlay;
+}
+
 MetaDisplay *
 meta_compositor_get_display (MetaCompositor *compositor)
 {