Pinch/Zoom Infrastructure & Plumbing CL

cc/layers/layer.cc

 // Copyright 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/layer.h"
 
 #include <algorithm>
 
 #include "base/debug/trace_event.h"
 #include "base/location.h"
 #include "base/metrics/histogram.h"
 #include "base/single_thread_task_runner.h"
 #include "cc/animation/animation.h"
 #include "cc/animation/animation_events.h"
 #include "cc/animation/keyframed_animation_curve.h"
 #include "cc/animation/layer_animation_controller.h"
 #include "cc/layers/layer_client.h"
 #include "cc/layers/layer_impl.h"
+#include "cc/layers/scrollbar_layer_interface.h"
 #include "cc/output/copy_output_request.h"
 #include "cc/output/copy_output_result.h"
 #include "cc/trees/layer_tree_host.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "third_party/skia/include/core/SkImageFilter.h"
+#include "ui/gfx/geometry/vector2d_conversions.h"
 #include "ui/gfx/rect_conversions.h"
 
 namespace cc {
 
 static int s_next_layer_id = 1;
 
 scoped_refptr<Layer> Layer::Create() {
   return make_scoped_refptr(new Layer());
 }
 
 Layer::Layer()
     : needs_push_properties_(false),
       num_dependents_need_push_properties_(false),
       stacking_order_changed_(false),
       layer_id_(s_next_layer_id++),
       ignore_set_needs_commit_(false),
       parent_(NULL),
       layer_tree_host_(NULL),
-      scrollable_(false),
+      scroll_clip_layer_id_(INVALID_ID),
       should_scroll_on_main_thread_(false),
       have_wheel_event_handlers_(false),
       user_scrollable_horizontal_(true),
       user_scrollable_vertical_(true),
       is_root_for_isolated_group_(false),
       is_container_for_fixed_position_layers_(false),
       is_drawable_(false),
       hide_layer_and_subtree_(false),
       masks_to_bounds_(false),
       contents_opaque_(false),
@@ skipping 619 matching lines @@
 
 void Layer::RemoveClipChild(Layer* child) {
   clip_children_->erase(child);
   if (clip_children_->empty())
     clip_children_.reset();
   SetNeedsCommit();
 }
 
 void Layer::SetScrollOffset(gfx::Vector2d scroll_offset) {
   DCHECK(IsPropertyChangeAllowed());
+
+  if (layer_tree_host()) {
+    scroll_offset = layer_tree_host()->DistributeScrollOffsetToViewports(
+        scroll_offset, this);
+  }
+
   if (scroll_offset_ == scroll_offset)
     return;
   scroll_offset_ = scroll_offset;
   SetNeedsCommit();
 }
 
 void Layer::SetScrollOffsetFromImplSide(gfx::Vector2d scroll_offset) {
   DCHECK(IsPropertyChangeAllowed());
   // This function only gets called during a BeginMainFrame, so there
   // is no need to call SetNeedsUpdate here.
   DCHECK(layer_tree_host_ && layer_tree_host_->CommitRequested());
   if (scroll_offset_ == scroll_offset)
     return;
   scroll_offset_ = scroll_offset;
   SetNeedsPushProperties();
   if (!did_scroll_callback_.is_null())
     did_scroll_callback_.Run();
   // The callback could potentially change the layer structure:
   // "this" may have been destroyed during the process.
 }
 
-void Layer::SetMaxScrollOffset(gfx::Vector2d max_scroll_offset) {
+// TODO(wjmaclean) We should template this and put it into LayerTreeHostCommon
+// so that both Layer and LayerImpl are using the same code. In order
+// to template it we should avoid calling layer_tree_host() by giving
+// Layer/LayerImpl local accessors for page_scale_layer() and
+// page_scale_factor().
+gfx::Vector2d Layer::MaxScrollOffset() const {
+  const Layer* scroll_clip_layer =
+      layer_tree_host()->LayerById(scroll_clip_layer_id_);

[enne (OOO), 2014/01/29 21:25:30]

Inside of MaxScrollOffset seems like an unfortunate place to add a recursive
tree walk.

Can you do any better?  How often does this function get called?

+  if (!scroll_clip_layer)
+    return gfx::Vector2d();
+
+  gfx::Size scaled_scroll_bounds(bounds());
+  Layer const* current_layer = this;
+  Layer const* page_scale_layer = layer_tree_host()->page_scale_layer();
+  float scale_factor = 1.f;
+  do {
+    if (current_layer == page_scale_layer) {
+      scale_factor = layer_tree_host()->page_scale_factor();
+      scaled_scroll_bounds.SetSize(
+          scale_factor * scaled_scroll_bounds.width(),
+          scale_factor * scaled_scroll_bounds.height());
+    }
+    current_layer = current_layer->parent();
+  } while (current_layer && current_layer != scroll_clip_layer);
+  DCHECK(current_layer == scroll_clip_layer);
+
+  gfx::Vector2dF max_offset(
+      scaled_scroll_bounds.width() - scroll_clip_layer->bounds().width(),
+      scaled_scroll_bounds.height() - scroll_clip_layer->bounds().height());
+  // We need the final scroll offset to be in CSS coords.
+  max_offset.Scale(1.f / scale_factor);
+  max_offset.SetToMax(gfx::Vector2dF());
+  return gfx::ToFlooredVector2d(max_offset);
+}
+
+void Layer::SetScrollClipLayerId(int clip_layer_id) {
   DCHECK(IsPropertyChangeAllowed());
-  if (max_scroll_offset_ == max_scroll_offset)
+  if (scroll_clip_layer_id_ == clip_layer_id)
     return;
-  max_scroll_offset_ = max_scroll_offset;
+  scroll_clip_layer_id_ = clip_layer_id;
   SetNeedsCommit();
 }
 
-void Layer::SetScrollable(bool scrollable) {
-  DCHECK(IsPropertyChangeAllowed());
-  if (scrollable_ == scrollable)
-    return;
-  scrollable_ = scrollable;
-  SetNeedsCommit();
-}
-
 void Layer::SetUserScrollable(bool horizontal, bool vertical) {
   DCHECK(IsPropertyChangeAllowed());
   if (user_scrollable_horizontal_ == horizontal &&
       user_scrollable_vertical_ == vertical)
     return;
   user_scrollable_horizontal_ = horizontal;
   user_scrollable_vertical_ = vertical;
   SetNeedsCommit();
 }
 
@@ skipping 175 matching lines @@
       IsContainerForFixedPositionLayers());
   layer->SetFixedContainerSizeDelta(gfx::Vector2dF());
   layer->SetPositionConstraint(position_constraint_);
   layer->SetPreserves3d(preserves_3d());
   layer->SetUseParentBackfaceVisibility(use_parent_backface_visibility_);
   layer->SetSublayerTransform(sublayer_transform_);
   if (!layer->TransformIsAnimatingOnImplOnly() && !TransformIsAnimating())
     layer->SetTransform(transform_);
   DCHECK(!(TransformIsAnimating() && layer->TransformIsAnimatingOnImplOnly()));
 
-  layer->SetScrollable(scrollable_);
+  layer->SetScrollClipLayer(scroll_clip_layer_id_);
   layer->set_user_scrollable_horizontal(user_scrollable_horizontal_);
   layer->set_user_scrollable_vertical(user_scrollable_vertical_);
-  layer->SetMaxScrollOffset(max_scroll_offset_);
 
   LayerImpl* scroll_parent = NULL;
   if (scroll_parent_)
     scroll_parent = layer->layer_tree_impl()->LayerById(scroll_parent_->id());
 
   layer->SetScrollParent(scroll_parent);
   if (scroll_children_) {
     std::set<LayerImpl*>* scroll_children = new std::set<LayerImpl*>;
     for (std::set<Layer*>::iterator it = scroll_children_->begin();
         it != scroll_children_->end(); ++it)
@@ skipping 238 matching lines @@
     clip_parent_->RemoveClipChild(this);
 
   clip_parent_ = NULL;
 }
 
 void Layer::RunMicroBenchmark(MicroBenchmark* benchmark) {
   benchmark->RunOnLayer(this);
 }
 
 }  // namespace cc