[mutter] surface-actor: Implement meta_cullable_is_untransformed interface

[Carlos Garnacho <carlosg src gnome org>]

commit 264f68858ace1279072841aebb9499968a09cd3f
Author: Robert Mader <robert mader posteo de>
Date:   Mon Feb 3 21:25:39 2020 +0100

    surface-actor: Implement meta_cullable_is_untransformed interface
    
    Its `cull_out()` method was already implemented with geometry scale
    in mind. Add a corresponding `is_untransformed()` method so culling
    succeeds with geometry scale > 1.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/1036

 src/compositor/meta-surface-actor.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
---
diff --git a/src/compositor/meta-surface-actor.c b/src/compositor/meta-surface-actor.c
index b7fda124f..3a8cdf869 100644
--- a/src/compositor/meta-surface-actor.c
+++ b/src/compositor/meta-surface-actor.c
@@ -20,6 +20,7 @@
 #include "compositor/meta-surface-actor.h"
 
 #include "clutter/clutter.h"
+#include "compositor/clutter-utils.h"
 #include "compositor/meta-cullable.h"
 #include "compositor/meta-shaped-texture-private.h"
 #include "compositor/meta-window-actor-private.h"
@@ -292,6 +293,27 @@ meta_surface_actor_cull_out (MetaCullable   *cullable,
     }
 }
 
+static gboolean
+meta_surface_actor_is_untransformed (MetaCullable *cullable)
+{
+  ClutterActor *actor = CLUTTER_ACTOR (cullable);
+  MetaWindowActor *window_actor;
+  float width, height;
+  graphene_point3d_t verts[4];
+  int geometry_scale;
+
+  clutter_actor_get_size (actor, &width, &height);
+  clutter_actor_get_abs_allocation_vertices (actor, verts);
+
+  window_actor = meta_window_actor_from_actor (actor);
+  geometry_scale = meta_window_actor_get_geometry_scale (window_actor);
+
+  return meta_actor_vertices_are_untransformed (verts,
+                                                width * geometry_scale,
+                                                height * geometry_scale,
+                                                NULL, NULL);
+}
+
 static void
 meta_surface_actor_reset_culling (MetaCullable *cullable)
 {
@@ -304,6 +326,7 @@ static void
 cullable_iface_init (MetaCullableInterface *iface)
 {
   iface->cull_out = meta_surface_actor_cull_out;
+  iface->is_untransformed = meta_surface_actor_is_untransformed;
   iface->reset_culling = meta_surface_actor_reset_culling;
 }