ui: always set the frame background to None

This way the xserver never paints the frame background, even if
the client window is destroyed. This allows us to have clean
destroy window animation.

There is no problem with interactive resizing because applications
are using the XSync protocol, so we're not painting unless the
client has redrawn.

https://bugzilla.gnome.org/show_bug.cgi?id=734054

origin commit:
https://gitlab.gnome.org/GNOME/metacity/commit/78c283c

1 files changed, 12 insertions, 17 deletions

diff --git a/src/ui/ui.c b/src/ui/ui.c
index b3f40062..00c1176a 100644
--- a/src/ui/ui.c
+++ b/src/ui/ui.c
@@ -305,6 +305,17 @@ meta_ui_get_frame_geometry (MetaUI *ui,
                             left_width, right_width);
 }
 
+static void
+set_background_none (Display *xdisplay,
+                     Window   xwindow)
+{
+  XSetWindowAttributes attrs;
+
+  attrs.background_pixmap = None;
+  XChangeWindowAttributes (xdisplay, xwindow,
+                           CWBackPixmap, &attrs);
+}
+
 Window
 meta_ui_create_frame_window (MetaUI *ui,
                              Display *xdisplay,
@@ -363,6 +374,7 @@ meta_ui_create_frame_window (MetaUI *ui,
 		    &attrs, attributes_mask);
 
   gdk_window_resize (window, width, height);
+  set_background_none (xdisplay, GDK_WINDOW_XID (window));
 
   meta_frames_manage_window (ui->frames, GDK_WINDOW_XID (window), window);
 
@@ -418,16 +430,6 @@ meta_ui_unmap_frame (MetaUI *ui,
 }
 
 void
-meta_ui_unflicker_frame_bg (MetaUI *ui,
-                            Window  xwindow,
-                            int     target_width,
-                            int     target_height)
-{
-  meta_frames_unflicker_bg (ui->frames, xwindow,
-                            target_width, target_height);
-}
-
-void
 meta_ui_repaint_frame (MetaUI *ui,
                        Window xwindow)
 {
@@ -435,13 +437,6 @@ meta_ui_repaint_frame (MetaUI *ui,
 }
 
 void
-meta_ui_reset_frame_bg (MetaUI *ui,
-                        Window xwindow)
-{
-  meta_frames_reset_bg (ui->frames, xwindow);
-}
-
-void
 meta_ui_apply_frame_shape  (MetaUI  *ui,
                             Window   xwindow,
                             int      new_window_width,