cc: Compute animation scale on demand

cc/trees/property_tree.cc

Index: cc/trees/property_tree.cc
diff --git a/cc/trees/property_tree.cc b/cc/trees/property_tree.cc
index 5d70b987cf22edd75f67b71a75f8235144f3e8db..cbe027ab1ed953c9b217bf616afb7a44cf2b9722 100644
--- a/cc/trees/property_tree.cc
+++ b/cc/trees/property_tree.cc
@@ -179,11 +179,7 @@ TransformNodeData::TransformNodeData()
       affected_by_outer_viewport_bounds_delta_y(false),
       in_subtree_of_page_scale_layer(false),
       transform_changed(false),
-      post_local_scale_factor(1.0f),
-      local_maximum_animation_target_scale(0.f),
-      local_starting_animation_scale(0.f),
-      combined_maximum_animation_target_scale(0.f),
-      combined_starting_animation_scale(0.f) {}
+      post_local_scale_factor(1.0f) {}
 
 TransformNodeData::TransformNodeData(const TransformNodeData& other) = default;
 
@@ -225,14 +221,6 @@ bool TransformNodeData::operator==(const TransformNodeData& other) const {
              other.in_subtree_of_page_scale_layer &&
          transform_changed == other.transform_changed &&
          post_local_scale_factor == other.post_local_scale_factor &&
-         local_maximum_animation_target_scale ==
-             other.local_maximum_animation_target_scale &&
-         local_starting_animation_scale ==
-             other.local_starting_animation_scale &&
-         combined_maximum_animation_target_scale ==
-             other.combined_maximum_animation_target_scale &&
-         combined_starting_animation_scale ==
-             other.combined_starting_animation_scale &&
          sublayer_scale == other.sublayer_scale &&
          scroll_offset == other.scroll_offset &&
          scroll_snap == other.scroll_snap &&
@@ -306,13 +294,6 @@ void TransformNodeData::ToProtobuf(proto::TreeNode* proto) const {
   data->set_in_subtree_of_page_scale_layer(in_subtree_of_page_scale_layer);
   data->set_transform_changed(transform_changed);
   data->set_post_local_scale_factor(post_local_scale_factor);
-  data->set_local_maximum_animation_target_scale(
-      local_maximum_animation_target_scale);
-  data->set_local_starting_animation_scale(local_starting_animation_scale);
-  data->set_combined_maximum_animation_target_scale(
-      combined_maximum_animation_target_scale);
-  data->set_combined_starting_animation_scale(
-      combined_starting_animation_scale);
 
   Vector2dFToProto(sublayer_scale, data->mutable_sublayer_scale());
   ScrollOffsetToProto(scroll_offset, data->mutable_scroll_offset());
@@ -368,12 +349,6 @@ void TransformNodeData::FromProtobuf(const proto::TreeNode& proto) {
   in_subtree_of_page_scale_layer = data.in_subtree_of_page_scale_layer();
   transform_changed = data.transform_changed();
   post_local_scale_factor = data.post_local_scale_factor();
-  local_maximum_animation_target_scale =
-      data.local_maximum_animation_target_scale();
-  local_starting_animation_scale = data.local_starting_animation_scale();
-  combined_maximum_animation_target_scale =
-      data.combined_maximum_animation_target_scale();
-  combined_starting_animation_scale = data.combined_starting_animation_scale();
 
   sublayer_scale = ProtoToVector2dF(data.sublayer_scale());
   scroll_offset = ProtoToScrollOffset(data.scroll_offset());
@@ -738,6 +713,12 @@ void TransformTree::clear() {
   cached_data_.push_back(TransformCachedNodeData());
 }
 
+void TransformTree::set_needs_update(bool needs_update) {
+  if (needs_update && !PropertyTree::needs_update())
+    property_trees()->UpdateCachedNumber();

[jaydasika, 2016/06/28 23:08:40]

Should be invalidate the cache as soon as we set_needs_update(true) or when we
actually do the update ?

[sunxd, 2016/06/30 15:29:43]

Hmm, that depends on whether we get animation scale after setting needs_update
and before updating transforms. I prefer doing this if we don't. As updating
cached number is equivalent to setting the flag.

+  PropertyTree::set_needs_update(needs_update);
+}
+
 bool TransformTree::ComputeTransform(int source_id,
                                      int dest_id,
                                      gfx::Transform* transform) const {
@@ -1060,89 +1041,16 @@ void TransformTree::UpdateAnimationProperties(TransformNode* node,
                                               TransformNode* parent_node) {
   bool ancestor_is_animating = false;
   bool ancestor_is_animating_scale = false;
-  float ancestor_maximum_target_scale = 0.f;
-  float ancestor_starting_animation_scale = 0.f;
   if (parent_node) {
     ancestor_is_animating = parent_node->data.to_screen_is_potentially_animated;
     ancestor_is_animating_scale =
         parent_node->data.to_screen_has_scale_animation;
-    ancestor_maximum_target_scale =
-        parent_node->data.combined_maximum_animation_target_scale;
-    ancestor_starting_animation_scale =
-        parent_node->data.combined_starting_animation_scale;
   }
   node->data.to_screen_is_potentially_animated =
       node->data.has_potential_animation || ancestor_is_animating;
   node->data.to_screen_has_scale_animation =
       !node->data.has_only_translation_animations ||
       ancestor_is_animating_scale;
-
-  // Once we've failed to compute a maximum animated scale at an ancestor, we
-  // continue to fail.
-  bool failed_at_ancestor =

[jaydasika, 2016/06/28 23:08:40]

Can we move comments to GetAnimationScales ?

[sunxd, 2016/06/30 15:29:44]

Done.

-      ancestor_is_animating_scale && ancestor_maximum_target_scale == 0.f;
-
-  // Computing maximum animated scale in the presence of non-scale/translation
-  // transforms isn't supported.
-  bool failed_for_non_scale_or_translation =
-      !ToTarget(node->id).IsScaleOrTranslation();
-
-  // We don't attempt to accumulate animation scale from multiple nodes with
-  // scale animations, because of the risk of significant overestimation. For
-  // example, one node might be increasing scale from 1 to 10 at the same time
-  // as another node is decreasing scale from 10 to 1. Naively combining these
-  // scales would produce a scale of 100.
-  bool failed_for_multiple_scale_animations =
-      ancestor_is_animating_scale &&
-      !node->data.has_only_translation_animations;
-
-  if (failed_at_ancestor || failed_for_non_scale_or_translation ||
-      failed_for_multiple_scale_animations) {
-    node->data.combined_maximum_animation_target_scale = 0.f;
-    node->data.combined_starting_animation_scale = 0.f;
-
-    // This ensures that descendants know we've failed to compute a maximum
-    // animated scale.
-    node->data.to_screen_has_scale_animation = true;
-    return;
-  }
-
-  if (!node->data.to_screen_has_scale_animation) {
-    node->data.combined_maximum_animation_target_scale = 0.f;
-    node->data.combined_starting_animation_scale = 0.f;
-    return;
-  }
-
-  // At this point, we know exactly one of this node or an ancestor is animating
-  // scale.
-  if (node->data.has_only_translation_animations) {
-    // An ancestor is animating scale.
-    gfx::Vector2dF local_scales =
-        MathUtil::ComputeTransform2dScaleComponents(node->data.local, 0.f);
-    float max_local_scale = std::max(local_scales.x(), local_scales.y());
-    node->data.combined_maximum_animation_target_scale =
-        max_local_scale * ancestor_maximum_target_scale;
-    node->data.combined_starting_animation_scale =
-        max_local_scale * ancestor_starting_animation_scale;
-    return;
-  }
-
-  if (node->data.local_starting_animation_scale == 0.f ||
-      node->data.local_maximum_animation_target_scale == 0.f) {
-    node->data.combined_maximum_animation_target_scale = 0.f;
-    node->data.combined_starting_animation_scale = 0.f;
-    return;
-  }
-
-  gfx::Vector2dF ancestor_scales =
-      parent_node ? MathUtil::ComputeTransform2dScaleComponents(
-                        ToTarget(parent_node->id), 0.f)
-                  : gfx::Vector2dF(1.f, 1.f);
-  float max_ancestor_scale = std::max(ancestor_scales.x(), ancestor_scales.y());
-  node->data.combined_maximum_animation_target_scale =
-      max_ancestor_scale * node->data.local_maximum_animation_target_scale;
-  node->data.combined_starting_animation_scale =
-      max_ancestor_scale * node->data.local_starting_animation_scale;
 }
 
 void TransformTree::UndoSnapping(TransformNode* node) {
@@ -2149,6 +2057,13 @@ gfx::ScrollOffset ScrollTree::ClampScrollOffsetToLimits(
   return offset;
 }
 
+PropertyTreesCachedData::PropertyTreesCachedData()
+    : property_tree_update_number(0) {
+  animation_scales.clear();
+}
+
+PropertyTreesCachedData::~PropertyTreesCachedData() {}
+
 PropertyTrees::PropertyTrees()
     : needs_rebuild(true),
       non_root_surfaces_enabled(true),
@@ -2211,6 +2126,7 @@ PropertyTrees& PropertyTrees::operator=(const PropertyTrees& from) {
   effect_tree.SetPropertyTrees(this);
   clip_tree.SetPropertyTrees(this);
   scroll_tree.SetPropertyTrees(this);
+  ResetCachedData();
   return *this;
 }
 
@@ -2393,4 +2309,127 @@ std::unique_ptr<base::trace_event::TracedValue> PropertyTrees::AsTracedValue()
   return value;
 }
 
+CombinedAnimationScale PropertyTrees::GetAnimationScales(
+    int transform_node_id,
+    LayerTreeImpl* layer_tree_impl) {
+  if (cached_data_.animation_scales[transform_node_id].update_number !=
+      cached_data_.property_tree_update_number) {
+    TransformNode* node = transform_tree.Node(transform_node_id);
+    TransformNode* parent_node = transform_tree.parent(node);
+    bool ancestor_is_animating_scale = false;
+    float ancestor_maximum_target_scale = 0.f;
+    float ancestor_starting_animation_scale = 0.f;
+    if (parent_node) {
+      ancestor_is_animating_scale =
+          parent_node->data.to_screen_has_scale_animation;
+      CombinedAnimationScale combined_animation_scale = GetAnimationScales(
+          transform_tree.Node(transform_node_id)->parent_id, layer_tree_impl);
+      ancestor_maximum_target_scale =
+          combined_animation_scale.maximum_animation_scale;
+      ancestor_starting_animation_scale =
+          combined_animation_scale.starting_animation_scale;
+    }
+
+    bool failed_at_ancestor =
+        ancestor_is_animating_scale && ancestor_maximum_target_scale == 0.f;
+    bool failed_for_non_scale_or_translation =
+        !transform_tree.ToTarget(transform_node_id).IsScaleOrTranslation();
+    bool failed_for_multiple_scale_animations =
+        ancestor_is_animating_scale &&
+        !node->data.has_only_translation_animations;
+
+    if (failed_at_ancestor || failed_for_non_scale_or_translation ||
+        failed_for_multiple_scale_animations) {
+      node->data.to_screen_has_scale_animation = true;
+      cached_data_.animation_scales[transform_node_id]
+          .combined_maximum_animation_target_scale = 0.f;
+      cached_data_.animation_scales[transform_node_id]
+          .combined_starting_animation_scale = 0.f;
+    } else if (!node->data.to_screen_has_scale_animation) {
+      cached_data_.animation_scales[transform_node_id]
+          .combined_maximum_animation_target_scale = 0.f;
+      cached_data_.animation_scales[transform_node_id]
+          .combined_starting_animation_scale = 0.f;
+    } else if (node->data.has_only_translation_animations) {
+      gfx::Vector2dF local_scales =
+          MathUtil::ComputeTransform2dScaleComponents(node->data.local, 0.f);
+      float max_local_scale = std::max(local_scales.x(), local_scales.y());
+      cached_data_.animation_scales[transform_node_id]
+          .combined_maximum_animation_target_scale =
+          max_local_scale * ancestor_maximum_target_scale;
+      cached_data_.animation_scales[transform_node_id]
+          .combined_starting_animation_scale =
+          max_local_scale * ancestor_starting_animation_scale;
+    } else {
+      LayerImpl* layer_impl = layer_tree_impl->LayerById(node->owner_id);
+      layer_tree_impl->MaximumTargetScale(
+          layer_impl, &cached_data_.animation_scales[transform_node_id]
+                           .local_maximum_animation_target_scale);
+      layer_tree_impl->AnimationStartScale(
+          layer_impl, &cached_data_.animation_scales[transform_node_id]
+                           .local_starting_animation_scale);
+      gfx::Vector2dF local_scales =
+          MathUtil::ComputeTransform2dScaleComponents(node->data.local, 0.f);
+      float max_local_scale = std::max(local_scales.x(), local_scales.y());
+
+      if (cached_data_.animation_scales[transform_node_id]
+                  .local_starting_animation_scale == 0.f ||
+          cached_data_.animation_scales[transform_node_id]
+                  .local_maximum_animation_target_scale == 0.f) {
+        cached_data_.animation_scales[transform_node_id]
+            .combined_maximum_animation_target_scale =
+            max_local_scale * ancestor_maximum_target_scale;
+        cached_data_.animation_scales[transform_node_id]
+            .combined_starting_animation_scale =
+            max_local_scale * ancestor_starting_animation_scale;
+      } else {
+        gfx::Vector2dF ancestor_scales =
+            parent_node ? MathUtil::ComputeTransform2dScaleComponents(
+                              transform_tree.ToTarget(parent_node->id), 0.f)
+                        : gfx::Vector2dF(1.f, 1.f);
+        float max_ancestor_scale =
+            std::max(ancestor_scales.x(), ancestor_scales.y());
+        cached_data_.animation_scales[transform_node_id]
+            .combined_maximum_animation_target_scale =
+            max_ancestor_scale *
+            cached_data_.animation_scales[transform_node_id]
+                .local_maximum_animation_target_scale;
+        cached_data_.animation_scales[transform_node_id]
+            .combined_starting_animation_scale =
+            max_ancestor_scale *
+            cached_data_.animation_scales[transform_node_id]
+                .local_starting_animation_scale;
+      }
+    }
+    cached_data_.animation_scales[transform_node_id].update_number =
+        cached_data_.property_tree_update_number;
+  }
+  return CombinedAnimationScale(cached_data_.animation_scales[transform_node_id]
+                                    .combined_maximum_animation_target_scale,
+                                cached_data_.animation_scales[transform_node_id]
+                                    .combined_starting_animation_scale);
+}
+
+void PropertyTrees::SetAnimationScalesForTesting(
+    int transform_id,
+    float maximum_animation_scale,
+    float starting_animation_scale) {
+  cached_data_.animation_scales[transform_id]
+      .combined_maximum_animation_target_scale = maximum_animation_scale;
+  cached_data_.animation_scales[transform_id]
+      .combined_starting_animation_scale = starting_animation_scale;
+  cached_data_.animation_scales[transform_id].update_number =
+      cached_data_.property_tree_update_number;
+}
+
+void PropertyTrees::ResetCachedData() {
+  cached_data_.property_tree_update_number = 0;
+  cached_data_.animation_scales = std::vector<AnimationScaleData>(
+      transform_tree.nodes().size(), AnimationScaleData());
+}
+
+void PropertyTrees::UpdateCachedNumber() {
+  cached_data_.property_tree_update_number++;
+}
+

[jaydasika, 2016/06/28 23:08:40]

Add cached_data_ to PropertyTrees::operator==

[sunxd, 2016/06/30 15:29:43]

I think cached_data_ should be considered separately. It stores transient data
so that the way of accessing the cached data can affect the actual data stored.

Also for test, I think we can have specific test that compares the cached_data_
instead of compare them along with other member variables of property trees.

 }  // namespace cc