Fixes related to actor allocations and new optimization

Fix some issues with allocations and add an optimization to bail out of allocation cycles
if only the absolute origin changed (we can do this because now we no longer need to notify
all actors about the absolute origin change using the allocation flag).

Author: Sunderland93

clutter/clutter/clutter-actor.c

@@ -2583,6 +2583,22 @@ clutter_actor_notify_if_geometry_changed (ClutterActor          *self,
   g_object_thaw_notify (obj);
 }
 
+static void
+absolute_allocation_changed (ClutterActor *actor)
+{
+  actor->priv->needs_compute_resource_scale = TRUE;
+}
+
+static ClutterActorTraverseVisitFlags
+absolute_allocation_changed_cb (ClutterActor *actor,
+                                int           depth,
+                                gpointer      user_data)
+{
+  absolute_allocation_changed (actor);
+
+  return CLUTTER_ACTOR_TRAVERSE_VISIT_CONTINUE;
+}
+
 /*< private >
  * clutter_actor_set_allocation_internal:
  * @self: a #ClutterActor
@@ -2626,6 +2642,11 @@ clutter_actor_set_allocation_internal (ClutterActor           *self,
   priv->needs_height_request = FALSE;
   priv->needs_allocation = FALSE;
 
+  priv->absolute_origin_changed |= x1_changed || y1_changed;
+
+  if (priv->absolute_origin_changed || x2_changed || y2_changed)
+    absolute_allocation_changed (self);
+
   if (x1_changed ||
       y1_changed ||
       x2_changed ||
@@ -10246,7 +10267,6 @@ clutter_actor_allocate (ClutterActor          *self,
 {
   ClutterActorBox old_allocation, real_allocation;
   gboolean origin_changed, size_changed;
-  gboolean stage_allocation_changed;
   ClutterActorPrivate *priv;
 
   g_return_if_fail (CLUTTER_IS_ACTOR (self));
@@ -10258,11 +10278,25 @@ clutter_actor_allocate (ClutterActor          *self,
       return;
     }
 
-  if (!clutter_actor_is_visible (self))
-    return;
-
   priv = self->priv;
 
+  priv->absolute_origin_changed = priv->parent
+                                ? priv->parent->priv->absolute_origin_changed
+                                : FALSE;
+
+  if (!CLUTTER_ACTOR_IS_VISIBLE (self))
+    {
+      if (priv->absolute_origin_changed)
+        {
+          _clutter_actor_traverse (self,
+                                   CLUTTER_ACTOR_TRAVERSE_DEPTH_FIRST,
+                                   absolute_allocation_changed_cb,
+                                   NULL,
+                                   NULL);
+        }
+      goto out;
+    }
+
   old_allocation = priv->allocation;
   real_allocation = *box;
 
@@ -10299,49 +10333,45 @@ clutter_actor_allocate (ClutterActor          *self,
   size_changed = (real_allocation.x2 != old_allocation.x2 ||
                   real_allocation.y2 != old_allocation.y2);
 
-  priv->absolute_origin_changed = priv->parent
-                                ? priv->parent->priv->absolute_origin_changed
-                                : FALSE;
-
-  priv->absolute_origin_changed |= origin_changed;
-
-  stage_allocation_changed = priv->absolute_origin_changed || size_changed;
-
-  /* If we get an allocation "out of the blue"
-   * (we did not queue relayout), then we want to
-   * ignore it. But if we have needs_allocation set,
-   * we want to guarantee that allocate() virtual
-   * method is always called, i.e. that queue_relayout()
-   * always results in an allocate() invocation on
-   * an actor.
+  /* When needs_allocation is set but we didn't move nor resize, we still
+   * want to call the allocate() vfunc because a child probably called
+   * queue_relayout() and needs a new allocation.
    *
-   * The optimization here is to avoid re-allocating
-   * actors that did not queue relayout and were
-   * not moved.
+   * In case needs_allocation isn't set and we didn't move nor resize, we
+   * can safely stop allocating, but we need to notify the sub-tree in case
+   * our absolute origin changed.
    */
-  if (!priv->needs_allocation && !stage_allocation_changed)
+  if (!priv->needs_allocation && !origin_changed && !size_changed)
     {
+      if (priv->absolute_origin_changed)
+        {
+          _clutter_actor_traverse (self,
+                                   CLUTTER_ACTOR_TRAVERSE_DEPTH_FIRST,
+                                   absolute_allocation_changed_cb,
+                                   NULL,
+                                   NULL);
+        }
+
       CLUTTER_NOTE (LAYOUT, "No allocation needed");
-      return;
+      goto out;
     }
 
   if (CLUTTER_ACTOR_IS_MAPPED (self))
     self->priv->needs_paint_volume_update = TRUE;
 
-  if (stage_allocation_changed)
-    priv->needs_compute_resource_scale = TRUE;
-
-  if (!stage_allocation_changed)
+  if (!origin_changed && !size_changed)
     {
       /* If the actor didn't move but needs_allocation is set, we just
-       * need to allocate the children */
+       * need to allocate the children (see comment above) */
       clutter_actor_allocate_internal (self, &real_allocation);
-      return;
+      goto out;
     }
 
   _clutter_actor_create_transition (self, obj_props[PROP_ALLOCATION],
                                     &priv->allocation,
                                     &real_allocation);
+out:
+  priv->absolute_origin_changed = FALSE;
 }
 
 /**

clutter/clutter/clutter-stage-private.h

@@ -53,11 +53,7 @@ ClutterStageWindow *_clutter_stage_get_window            (ClutterStage
 void                _clutter_stage_get_projection_matrix (ClutterStage          *stage,
                                                           CoglMatrix            *projection);
 void                _clutter_stage_dirty_projection      (ClutterStage          *stage);
-void                _clutter_stage_set_viewport          (ClutterStage          *stage,
-                                                          float                  x,
-                                                          float                  y,
-                                                          float                  width,
-                                                          float                  height);
+
 void                _clutter_stage_get_viewport          (ClutterStage          *stage,
                                                           float                 *x,
                                                           float                 *y,

clutter/clutter/clutter-stage.c

@@ -215,6 +215,9 @@ static void capture_view_into (ClutterStage          *stage,
                                uint8_t               *data,
                                int                    stride);
 static void clutter_stage_update_view_perspective (ClutterStage *stage);
+static void clutter_stage_set_viewport (ClutterStage *stage,
+                                        float         width,
+                                        float         height);
 
 static void clutter_container_iface_init (ClutterContainerIface *iface);
 
@@ -645,7 +648,6 @@ clutter_stage_allocate (ClutterActor           *self,
 {
   ClutterStagePrivate *priv = CLUTTER_STAGE (self)->priv;
   ClutterActorBox alloc = CLUTTER_ACTOR_BOX_INIT_ZERO;
-  float old_width, old_height;
   float new_width, new_height;
   float width, height;
   cairo_rectangle_int_t window_size;
@@ -654,10 +656,6 @@ clutter_stage_allocate (ClutterActor           *self,
   if (priv->impl == NULL)
     return;
 
-  /* our old allocation */
-  clutter_actor_get_allocation_box (self, &alloc);
-  clutter_actor_box_get_size (&alloc, &old_width, &old_height);
-
   /* the current allocation */
   clutter_actor_box_get_size (box, &width, &height);
 
@@ -745,27 +743,11 @@ clutter_stage_allocate (ClutterActor           *self,
                                        &override);
     }
 
-  /* reset the viewport if the allocation effectively changed */
+  /* set the viewport to the new allocation */
   clutter_actor_get_allocation_box (self, &alloc);
   clutter_actor_box_get_size (&alloc, &new_width, &new_height);
 
-  if (CLUTTER_NEARBYINT (old_width) != CLUTTER_NEARBYINT (new_width) ||
-      CLUTTER_NEARBYINT (old_height) != CLUTTER_NEARBYINT (new_height))
-    {
-      int real_width = CLUTTER_NEARBYINT (new_width);
-      int real_height = CLUTTER_NEARBYINT (new_height);
-
-      _clutter_stage_set_viewport (CLUTTER_STAGE (self),
-                                   0, 0,
-                                   real_width,
-                                   real_height);
-
-      /* Note: we don't assume that set_viewport will queue a full redraw
-       * since it may bail-out early if something preemptively set the
-       * viewport before the stage was really allocated its new size.
-       */
-      queue_full_redraw (CLUTTER_STAGE (self));
-    }
+  clutter_stage_set_viewport (CLUTTER_STAGE (self), new_width, new_height);
 }
 
 typedef struct _Vector4
@@ -2433,10 +2415,7 @@ clutter_stage_init (ClutterStage *self)
   g_signal_connect (self, "notify::min-height",
                     G_CALLBACK (clutter_stage_notify_min_size), NULL);
 
-  _clutter_stage_set_viewport (self,
-                               0, 0,
-                               geom.width,
-                               geom.height);
+  clutter_stage_set_viewport (self, geom.width, geom.height);
 
   priv->paint_volume_stack =
     g_array_new (FALSE, FALSE, sizeof (ClutterPaintVolume));
@@ -2653,8 +2632,6 @@ _clutter_stage_dirty_projection (ClutterStage *stage)
 /*
  * clutter_stage_set_viewport:
  * @stage: A #ClutterStage
- * @x: The X postition to render the stage at, in window coordinates
- * @y: The Y position to render the stage at, in window coordinates
  * @width: The width to render the stage at, in window coordinates
  * @height: The height to render the stage at, in window coordinates
  *
@@ -2687,19 +2664,22 @@ _clutter_stage_dirty_projection (ClutterStage *stage)
  *
  * Since: 1.6
  */
-void
-_clutter_stage_set_viewport (ClutterStage *stage,
-                             float         x,
-                             float         y,
-                             float         width,
-                             float         height)
+static void
+clutter_stage_set_viewport (ClutterStage *stage,
+                            float         width,
+                            float         height)
 {
   ClutterStagePrivate *priv;
+  float x, y;
 
   g_return_if_fail (CLUTTER_IS_STAGE (stage));
 
   priv = stage->priv;
 
+  x = 0.f;
+  y = 0.f;
+  width = roundf (width);
+  height = roundf (height);
 
   if (x == priv->viewport[0] &&
       y == priv->viewport[1] &&