[mutter/gbsneto/content: 2/2] window-actor: Handle geometry scale

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit f6ee2dc8b9a0ff7e915cda497497b7a3ee4672b9
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Fri Jul 12 14:33:17 2019 -0300

    window-actor: Handle geometry scale
    
    Geometry scale is applied to each surface individually, using
    Clutter scales, and not only this breaks subsurfaces, it also
    pollutes the toolkit and makes the actor tree slightly too
    fragile. If GNOME Shell mistakenly tries to set the actor scale
    of any of these surfaces, for example, various artifacts might
    happen.
    
    Move geometry scale handling to MetaWindowActor. It is applied
    as an additional scale operation in the transform matrix, so
    that the Clutter-managed scale properties are left untouched.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/409

 src/compositor/meta-surface-actor.c        | 13 +++++----
 src/compositor/meta-window-actor-private.h |  5 ++++
 src/compositor/meta-window-actor.c         | 45 ++++++++++++++++++++++++++++++
 src/wayland/meta-wayland-actor-surface.c   |  4 ---
 src/wayland/meta-wayland-subsurface.c      |  6 ++--
 src/wayland/meta-window-wayland.c          | 38 +++++++++++++++++++------
 6 files changed, 89 insertions(+), 22 deletions(-)
---
diff --git a/src/compositor/meta-surface-actor.c b/src/compositor/meta-surface-actor.c
index cb1a40261..2fdf21fc1 100644
--- a/src/compositor/meta-surface-actor.c
+++ b/src/compositor/meta-surface-actor.c
@@ -22,6 +22,7 @@
 #include "clutter/clutter.h"
 #include "compositor/meta-cullable.h"
 #include "compositor/meta-shaped-texture-private.h"
+#include "compositor/meta-window-actor-private.h"
 #include "compositor/region-utils.h"
 #include "meta/meta-shaped-texture.h"
 
@@ -76,7 +77,6 @@ effective_unobscured_region (MetaSurfaceActor *surface_actor)
   return priv->unobscured_region;
 }
 
-
 static void
 set_unobscured_region (MetaSurfaceActor *surface_actor,
                        cairo_region_t   *unobscured_region)
@@ -246,18 +246,21 @@ meta_surface_actor_cull_out (MetaCullable   *cullable,
 
   if (opacity == 0xff)
     {
+      MetaWindowActor *window_actor;
       cairo_region_t *scaled_opaque_region;
       cairo_region_t *opaque_region;
-      double geometry_scale;
+      int geometry_scale = 1;
 
       opaque_region = meta_shaped_texture_get_opaque_region (priv->texture);
 
       if (!opaque_region)
         return;
 
-      clutter_actor_get_scale (CLUTTER_ACTOR (surface_actor),
-                               &geometry_scale,
-                               NULL);
+      window_actor =
+        meta_window_actor_from_actor (CLUTTER_ACTOR (surface_actor));
+      if (window_actor)
+        geometry_scale = meta_window_actor_get_geometry_scale (window_actor);
+
       scaled_opaque_region = meta_region_scale (opaque_region, geometry_scale);
 
       if (unobscured_region)
diff --git a/src/compositor/meta-window-actor-private.h b/src/compositor/meta-window-actor-private.h
index 24a4cfcb6..354edd314 100644
--- a/src/compositor/meta-window-actor-private.h
+++ b/src/compositor/meta-window-actor-private.h
@@ -88,4 +88,9 @@ void meta_window_actor_assign_surface_actor (MetaWindowActor  *self,
 MetaWindowActor *meta_window_actor_from_window (MetaWindow *window);
 MetaWindowActor *meta_window_actor_from_actor (ClutterActor *actor);
 
+void meta_window_actor_set_geometry_scale (MetaWindowActor *window_actor,
+                                           int              geometry_scale);
+
+int meta_window_actor_get_geometry_scale (MetaWindowActor *window_actor);
+
 #endif /* META_WINDOW_ACTOR_PRIVATE_H */
diff --git a/src/compositor/meta-window-actor.c b/src/compositor/meta-window-actor.c
index 4a0f74709..c35823d1d 100644
--- a/src/compositor/meta-window-actor.c
+++ b/src/compositor/meta-window-actor.c
@@ -81,6 +81,8 @@ typedef struct _MetaWindowActorPrivate
 
   MetaShadowMode    shadow_mode;
 
+  int geometry_scale;
+
   guint             size_changed_id;
 
   /*
@@ -160,6 +162,21 @@ G_DEFINE_ABSTRACT_TYPE_WITH_CODE (MetaWindowActor, meta_window_actor, CLUTTER_TY
                                   G_IMPLEMENT_INTERFACE (META_TYPE_CULLABLE, cullable_iface_init)
                                   G_IMPLEMENT_INTERFACE (META_TYPE_SCREEN_CAST_WINDOW, 
screen_cast_window_iface_init));
 
+static void
+meta_window_actor_apply_transform (ClutterActor *actor,
+                                   CoglMatrix   *transform)
+{
+  MetaWindowActor *window_actor = META_WINDOW_ACTOR (actor);
+  MetaWindowActorPrivate *priv =
+    meta_window_actor_get_instance_private (window_actor);
+  ClutterActorClass *parent_class =
+    CLUTTER_ACTOR_CLASS (meta_window_actor_parent_class);
+
+  parent_class->apply_transform (actor, transform);
+
+  cogl_matrix_scale (transform, priv->geometry_scale, priv->geometry_scale, 0);
+}
+
 static void
 meta_window_actor_class_init (MetaWindowActorClass *klass)
 {
@@ -172,6 +189,7 @@ meta_window_actor_class_init (MetaWindowActorClass *klass)
   object_class->get_property = meta_window_actor_get_property;
   object_class->constructed  = meta_window_actor_constructed;
 
+  actor_class->apply_transform = meta_window_actor_apply_transform;
   actor_class->paint = meta_window_actor_paint;
   actor_class->get_paint_volume = meta_window_actor_get_paint_volume;
 
@@ -252,6 +270,10 @@ meta_window_actor_class_init (MetaWindowActorClass *klass)
 static void
 meta_window_actor_init (MetaWindowActor *self)
 {
+  MetaWindowActorPrivate *priv =
+    meta_window_actor_get_instance_private (self);
+
+  priv->geometry_scale = 1;
 }
 
 static void
@@ -1863,6 +1885,29 @@ meta_window_actor_from_window (MetaWindow *window)
   return META_WINDOW_ACTOR (meta_window_get_compositor_private (window));
 }
 
+void
+meta_window_actor_set_geometry_scale (MetaWindowActor *window_actor,
+                                      int              geometry_scale)
+{
+  MetaWindowActorPrivate *priv =
+    meta_window_actor_get_instance_private (window_actor);
+
+  if (priv->geometry_scale == geometry_scale)
+    return;
+
+  priv->geometry_scale = geometry_scale;
+  clutter_actor_queue_relayout (CLUTTER_ACTOR (window_actor));
+}
+
+int
+meta_window_actor_get_geometry_scale (MetaWindowActor *window_actor)
+{
+  MetaWindowActorPrivate *priv =
+    meta_window_actor_get_instance_private (window_actor);
+
+  return priv->geometry_scale;
+}
+
 static void
 meta_window_actor_get_frame_bounds (MetaScreenCastWindow *screen_cast_window,
                                     MetaRectangle        *bounds)
diff --git a/src/wayland/meta-wayland-actor-surface.c b/src/wayland/meta-wayland-actor-surface.c
index 17b55e333..e14279573 100644
--- a/src/wayland/meta-wayland-actor-surface.c
+++ b/src/wayland/meta-wayland-actor-surface.c
@@ -149,10 +149,6 @@ meta_wayland_actor_surface_real_sync_actor_state (MetaWaylandActorSurface *actor
 
   /* Wayland surface coordinate space -> stage coordinate space */
   geometry_scale = meta_wayland_actor_surface_get_geometry_scale (actor_surface);
-  clutter_actor_set_scale (CLUTTER_ACTOR (surface_actor),
-                           geometry_scale,
-                           geometry_scale);
-
   surface_rect = (cairo_rectangle_int_t) {
     .width = meta_wayland_surface_get_width (surface) * geometry_scale,
     .height = meta_wayland_surface_get_height (surface) * geometry_scale,
diff --git a/src/wayland/meta-wayland-subsurface.c b/src/wayland/meta-wayland-subsurface.c
index bde7bef6e..3b813a191 100644
--- a/src/wayland/meta-wayland-subsurface.c
+++ b/src/wayland/meta-wayland-subsurface.c
@@ -56,7 +56,6 @@ sync_actor_subsurface_state (MetaWaylandSurface *surface)
 {
   ClutterActor *actor = CLUTTER_ACTOR (meta_wayland_surface_get_actor (surface));
   MetaWindow *toplevel_window;
-  int geometry_scale;
   int x, y;
 
   toplevel_window = meta_wayland_surface_get_toplevel_window (surface);
@@ -66,9 +65,8 @@ sync_actor_subsurface_state (MetaWaylandSurface *surface)
   if (toplevel_window->client_type == META_WINDOW_CLIENT_TYPE_X11)
     return;
 
-  geometry_scale = meta_window_wayland_get_geometry_scale (toplevel_window);
-  x = (surface->offset_x + surface->sub.x) * geometry_scale;
-  y = (surface->offset_y + surface->sub.y) * geometry_scale;
+  x = surface->offset_x + surface->sub.x;
+  y = surface->offset_y + surface->sub.y;
 
   clutter_actor_set_position (actor, x, y);
 
diff --git a/src/wayland/meta-window-wayland.c b/src/wayland/meta-window-wayland.c
index d72b3bbc1..41232caef 100644
--- a/src/wayland/meta-window-wayland.c
+++ b/src/wayland/meta-window-wayland.c
@@ -33,6 +33,7 @@
 #include "backends/meta-backend-private.h"
 #include "backends/meta-logical-monitor.h"
 #include "compositor/meta-surface-actor-wayland.h"
+#include "compositor/meta-window-actor-private.h"
 #include "core/boxes-private.h"
 #include "core/stack-tracker.h"
 #include "core/window-private.h"
@@ -69,6 +70,19 @@ struct _MetaWindowWaylandClass
 
 G_DEFINE_TYPE (MetaWindowWayland, meta_window_wayland, META_TYPE_WINDOW)
 
+static void
+set_geometry_scale_for_window (MetaWindowWayland *wayland_window,
+                               int                geometry_scale)
+{
+  MetaWindowActor *window_actor;
+
+  wayland_window->geometry_scale = geometry_scale;
+
+  window_actor = meta_window_actor_from_window (META_WINDOW (wayland_window));
+  if (window_actor)
+    meta_window_actor_set_geometry_scale (window_actor, geometry_scale);
+}
+
 static int
 get_window_geometry_scale_for_logical_monitor (MetaLogicalMonitor *logical_monitor)
 {
@@ -526,8 +540,7 @@ meta_window_wayland_main_monitor_changed (MetaWindow               *window,
       meta_wayland_actor_surface_sync_actor_state (actor_surface);
     }
 
-  wl_window->geometry_scale = geometry_scale;
-
+  set_geometry_scale_for_window (wl_window, geometry_scale);
   meta_window_emit_size_changed (window);
 }
 
@@ -663,6 +676,8 @@ meta_window_wayland_new (MetaDisplay        *display,
                          MetaWaylandSurface *surface)
 {
   XWindowAttributes attrs = { 0 };
+  MetaWindowWayland *wl_window;
+  MetaWindow *window;
 
   /*
    * Set attributes used by _meta_window_shared_new, don't bother trying to fake
@@ -677,13 +692,18 @@ meta_window_wayland_new (MetaDisplay        *display,
   attrs.map_state = IsUnmapped;
   attrs.override_redirect = False;
 
-  return _meta_window_shared_new (display,
-                                  META_WINDOW_CLIENT_TYPE_WAYLAND,
-                                  surface,
-                                  None,
-                                  WithdrawnState,
-                                  META_COMP_EFFECT_CREATE,
-                                  &attrs);
+  window = _meta_window_shared_new (display,
+                                    META_WINDOW_CLIENT_TYPE_WAYLAND,
+                                    surface,
+                                    None,
+                                    WithdrawnState,
+                                    META_COMP_EFFECT_CREATE,
+                                    &attrs);
+
+  wl_window = META_WINDOW_WAYLAND (window);
+  set_geometry_scale_for_window (wl_window, wl_window->geometry_scale);
+
+  return window;
 }
 
 static gboolean