Only shadow ARGB windows with a frame outside the frame

An ARGB window with a frame is likely something like a transparent
terminal. It looks awful (and breaks transparency) to draw a big
opaque black shadow under the window, so clip out the region under
the terminal from the shadow we draw.

Add meta_window_get_frame_bounds() to get a cairo region for the
outer bounds of the frame of a window, and modify the frame handling
code to notice changes to the frame shape and discard a cached
region. meta_frames_apply_shapes() is refactored so we can extract
meta_frames_get_frame_bounds() from it.

https://bugzilla.gnome.org/show_bug.cgi?id=635268

NOTE: Applied only partially, compositor part is still missing...

upstream commit:
https://gitlab.gnome.org/GNOME/metacity/commit/0f2e32d1

1 files changed, 39 insertions, 6 deletions

diff --git a/src/core/window.c b/src/core/window.c
index 02e446c6..7221ae78 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -524,6 +524,7 @@ meta_window_new_with_attrs (MetaDisplay       *display,
   window->shaken_loose = FALSE;
   window->have_focus_click_grab = FALSE;
   window->disable_sync = FALSE;
+  window->frame_bounds = NULL;
 
   window->unmaps_pending = 0;
 
@@ -1221,6 +1222,9 @@ meta_window_free (MetaWindow  *window,
   if (window->mini_icon)
     g_object_unref (G_OBJECT (window->mini_icon));
 
+  if (window->frame_bounds)
+    cairo_region_destroy (window->frame_bounds);
+
   meta_icon_cache_free (&window->icon_cache);
 
   g_free (window->sm_client_id);
@@ -3481,6 +3485,7 @@ meta_window_move_resize_internal (MetaWindow          *window,
   gboolean need_resize_frame = FALSE;
   int size_dx;
   int size_dy;
+  gboolean frame_shape_changed = FALSE;
   gboolean is_configure_request;
   gboolean do_gravity_adjust;
   gboolean is_user_action;
@@ -3782,9 +3787,10 @@ meta_window_move_resize_internal (MetaWindow          *window,
     meta_window_set_gravity (window, StaticGravity);
 
   if (configure_frame_first && have_window_frame)
-    meta_frame_sync_to_window (window->frame,
-                               gravity,
-                               need_move_frame, need_resize_frame);
+    frame_shape_changed = meta_frame_sync_to_window (window->frame,
+                                                     gravity,
+                                                     need_move_frame,
+                                                     need_resize_frame);
 
   values.border_width = 0;
   values.x = client_move_x;
@@ -3839,9 +3845,10 @@ meta_window_move_resize_internal (MetaWindow          *window,
     }
 
   if (!configure_frame_first && have_window_frame)
-    meta_frame_sync_to_window (window->frame,
-                               gravity,
-                               need_move_frame, need_resize_frame);
+    frame_shape_changed = meta_frame_sync_to_window (window->frame,
+                                                     gravity,
+                                                     need_move_frame,
+                                                     need_resize_frame);
 
   /* Put gravity back to be nice to lesser window managers */
   if (use_static_gravity)
@@ -3881,6 +3888,11 @@ meta_window_move_resize_internal (MetaWindow          *window,
    *      server-side size/pos of window->xwindow and frame->xwindow
    *   b) all constraints are obeyed by window->rect and frame->rect
    */
+  if (frame_shape_changed && window->frame_bounds)
+    {
+      cairo_region_destroy (window->frame_bounds);
+      window->frame_bounds = NULL;
+    }
 
   if (meta_prefs_get_attach_modal_dialogs ())
     meta_window_foreach_transient (window, move_attached_dialog, NULL);
@@ -8760,3 +8772,24 @@ meta_window_is_client_decorated (MetaWindow *window)
    */
   return window->has_custom_frame_extents;
 }
+
+/**
+ * meta_window_get_frame_bounds:
+ *
+ * Gets a region representing the outer bounds of the window's frame.
+ *
+ * Return value: (transfer none) (allow-none): a #cairo_region_t
+ * holding the outer bounds of the window, or %NULL if the window
+ * doesn't have a frame.
+ */
+cairo_region_t *
+meta_window_get_frame_bounds (MetaWindow *window)
+{
+  if (!window->frame_bounds)
+    {
+      if (window->frame)
+        window->frame_bounds = meta_frame_get_frame_bounds (window->frame);
+    }
+
+  return window->frame_bounds;
+}