From 161d2540e659fa8ed5efc74f350a741b2430417d Mon Sep 17 00:00:00 2001
From: Carlos Garnacho <carlosg@gnome.org>
Date: Sat, 29 Apr 2017 13:43:33 +0200
Subject: [PATCH] ClutterActor: Preserve valid paint volumes till the next
 relayout/repaint

Cuts down approximately all paint volume calculations when there's
windows that redraw frequently, but don't move.

https://bugzilla.gnome.org/show_bug.cgi?id=782344
---
 clutter/clutter/clutter-actor.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/clutter/clutter/clutter-actor.c b/clutter/clutter/clutter-actor.c
index 3e00a11db..2ba61ba9e 100644
--- a/clutter/clutter/clutter-actor.c
+++ b/clutter/clutter/clutter-actor.c
@@ -840,6 +840,7 @@ struct _ClutterActorPrivate
   guint needs_compute_expand        : 1;
   guint needs_x_expand              : 1;
   guint needs_y_expand              : 1;
+  guint needs_paint_volume_update   : 1;
 };
 
 enum
@@ -1504,6 +1505,8 @@ clutter_actor_real_map (ClutterActor *self)
 
   CLUTTER_ACTOR_SET_FLAGS (self, CLUTTER_ACTOR_MAPPED);
 
+  self->priv->needs_paint_volume_update = TRUE;
+
   stage = _clutter_actor_get_stage_internal (self);
   priv->pick_id = _clutter_stage_acquire_pick_id (CLUTTER_STAGE (stage), self);
 
@@ -2737,6 +2740,7 @@ clutter_actor_real_queue_relayout (ClutterActor *self)
   priv->needs_width_request  = TRUE;
   priv->needs_height_request = TRUE;
   priv->needs_allocation     = TRUE;
+  priv->needs_paint_volume_update = TRUE;
 
   /* reset the cached size requests */
   memset (priv->width_requests, 0,
@@ -8518,6 +8522,7 @@ clutter_actor_init (ClutterActor *self)
   priv->needs_width_request = TRUE;
   priv->needs_height_request = TRUE;
   priv->needs_allocation = TRUE;
+  priv->needs_paint_volume_update = TRUE;
 
   priv->cached_width_age = 1;
   priv->cached_height_age = 1;
@@ -10084,6 +10089,9 @@ clutter_actor_allocate (ClutterActor           *self,
       return;
     }
 
+  if (CLUTTER_ACTOR_IS_MAPPED (self))
+    self->priv->needs_paint_volume_update = TRUE;
+
   if (!stage_allocation_changed)
     {
       /* If the actor didn't move but needs_allocation is set, we just
@@ -12972,6 +12980,9 @@ clutter_actor_add_child_internal (ClutterActor              *self,
       child->priv->needs_height_request = TRUE;
       child->priv->needs_allocation = TRUE;
 
+      if (CLUTTER_ACTOR_IS_MAPPED (child))
+        child->priv->needs_paint_volume_update = TRUE;
+
       /* we only queue a relayout here, because any possible
        * redraw has already been queued either by show() or
        * by our call to queue_redraw() above
@@ -17514,11 +17525,16 @@ _clutter_actor_get_paint_volume_mutable (ClutterActor *self)
   priv = self->priv;
 
   if (priv->paint_volume_valid)
-    clutter_paint_volume_free (&priv->paint_volume);
+    {
+      if (!priv->needs_paint_volume_update)
+        return &priv->paint_volume;
+      clutter_paint_volume_free (&priv->paint_volume);
+    }
 
   if (_clutter_actor_get_paint_volume_real (self, &priv->paint_volume))
     {
       priv->paint_volume_valid = TRUE;
+      priv->needs_paint_volume_update = FALSE;
       return &priv->paint_volume;
     }
   else