[mutter] clutter/stage: Add private API to get max view scale for rect

[Jonas Ådahl <jadahl src gnome org>]

commit c69547147547471e50df28aee20c5320570f6099
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Sat Dec 23 04:17:03 2017 +0100

    clutter/stage: Add private API to get max view scale for rect
    
    Move the same code from ClutterActor as this is something we can
    reuse elsewhere.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=765011
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/3

 clutter/clutter/clutter-actor.c         | 20 +++-----------------
 clutter/clutter/clutter-stage-private.h |  3 +++
 clutter/clutter/clutter-stage.c         | 29 +++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 17 deletions(-)
---
diff --git a/clutter/clutter/clutter-actor.c b/clutter/clutter/clutter-actor.c
index d0f7434ef..fd38338c7 100644
--- a/clutter/clutter/clutter-actor.c
+++ b/clutter/clutter/clutter-actor.c
@@ -17785,29 +17785,15 @@ _clutter_actor_get_resource_scale_for_rect (ClutterActor *self,
                                             float        *resource_scale)
 {
   ClutterActor *stage;
-  GList *views;
-  GList *l;
   float max_scale = 0;
 
   stage = _clutter_actor_get_stage_internal (self);
   if (!stage)
     return FALSE;
 
-  views = _clutter_stage_peek_stage_views (CLUTTER_STAGE (stage));
-  for (l = views; l; l = l->next)
-    {
-      ClutterStageView *view = l->data;
-      cairo_rectangle_int_t view_layout;
-      ClutterRect view_rect;
-
-      clutter_stage_view_get_layout (view, &view_layout);
-      _clutter_util_rect_from_rectangle (&view_layout, &view_rect);
-
-      if (clutter_rect_intersection (&view_rect, bounding_rect, NULL))
-        max_scale = MAX (clutter_stage_view_get_scale (view), max_scale);
-    }
-
-  if (max_scale == 0)
+  if (!_clutter_stage_get_max_view_scale_factor_for_rect (CLUTTER_STAGE (stage),
+                                                          bounding_rect,
+                                                          &max_scale))
     return FALSE;
 
   *resource_scale = max_scale;
diff --git a/clutter/clutter/clutter-stage-private.h b/clutter/clutter/clutter-stage-private.h
index 688768bac..4799c29e1 100644
--- a/clutter/clutter/clutter-stage-private.h
+++ b/clutter/clutter/clutter-stage-private.h
@@ -124,6 +124,9 @@ gboolean                _clutter_stage_update_state     (ClutterStage      *stag
 
 void                    _clutter_stage_set_scale_factor (ClutterStage      *stage,
                                                          int                factor);
+gboolean                _clutter_stage_get_max_view_scale_factor_for_rect (ClutterStage *stage,
+                                                                           ClutterRect  *rect,
+                                                                           float        *view_scale);
 
 void            _clutter_stage_presented                (ClutterStage      *stage,
                                                          CoglFrameEvent     frame_event,
diff --git a/clutter/clutter/clutter-stage.c b/clutter/clutter/clutter-stage.c
index d284692c0..7ed83184a 100644
--- a/clutter/clutter/clutter-stage.c
+++ b/clutter/clutter/clutter-stage.c
@@ -5018,3 +5018,32 @@ clutter_stage_update_resource_scales (ClutterStage *stage)
 {
   _clutter_actor_queue_update_resource_scale_recursive (CLUTTER_ACTOR (stage));
 }
+
+gboolean
+_clutter_stage_get_max_view_scale_factor_for_rect (ClutterStage *stage,
+                                                   ClutterRect  *rect,
+                                                   float        *view_scale)
+{
+  ClutterStagePrivate *priv = stage->priv;
+  float scale = 0.0f;
+  GList *l;
+
+  for (l = _clutter_stage_window_get_views (priv->impl); l; l = l->next)
+    {
+      ClutterStageView *view = l->data;
+      cairo_rectangle_int_t view_layout;
+      ClutterRect view_rect;
+
+      clutter_stage_view_get_layout (view, &view_layout);
+      _clutter_util_rect_from_rectangle (&view_layout, &view_rect);
+
+      if (clutter_rect_intersection (&view_rect, rect, NULL))
+        scale = MAX (clutter_stage_view_get_scale (view), scale);
+    }
+
+  if (scale == 0.0)
+    return FALSE;
+
+  *view_scale = scale;
+  return TRUE;
+}