cc/input/scroll_elasticity_helper.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/input/scroll_elasticity_helper.h"
   6
   7 #include "cc/layers/layer_impl.h"
   8 #include "cc/trees/layer_tree_host_impl.h"
   9 #include "cc/trees/layer_tree_impl.h"
  10
  11 namespace cc {
  12
  13 class ScrollElasticityHelperImpl : public ScrollElasticityHelper {
  14  public:
  15   explicit ScrollElasticityHelperImpl(LayerTreeHostImpl* layer_tree_host_impl);
  16   ~ScrollElasticityHelperImpl() override;
  17
  18   gfx::Vector2dF StretchAmount() const override;
  19   void SetStretchAmount(const gfx::Vector2dF& stretch_amount) override;
  20   gfx::ScrollOffset ScrollOffset() const override;
  21   gfx::ScrollOffset MaxScrollOffset() const override;
  22   void ScrollBy(const gfx::Vector2dF& delta) override;
  23   void RequestAnimate() override;
  24
  25  private:
  26   LayerTreeHostImpl* layer_tree_host_impl_;
  27 };
  28
  29 ScrollElasticityHelperImpl::ScrollElasticityHelperImpl(
  30     LayerTreeHostImpl* layer_tree)
  31     : layer_tree_host_impl_(layer_tree) {
  32 }
  33
  34 ScrollElasticityHelperImpl::~ScrollElasticityHelperImpl() {
  35 }
  36
  37 gfx::Vector2dF ScrollElasticityHelperImpl::StretchAmount() const {
  38   return layer_tree_host_impl_->active_tree()->elastic_overscroll()->Current(
  39       true);
  40 }
  41
  42 void ScrollElasticityHelperImpl::SetStretchAmount(
  43     const gfx::Vector2dF& stretch_amount) {
  44   if (stretch_amount == StretchAmount())
  45     return;
  46
  47   layer_tree_host_impl_->active_tree()->elastic_overscroll()->SetCurrent(
  48       stretch_amount);
  49   layer_tree_host_impl_->active_tree()->set_needs_update_draw_properties();
  50   layer_tree_host_impl_->SetNeedsCommit();
  51   layer_tree_host_impl_->SetNeedsRedraw();
  52   layer_tree_host_impl_->SetFullRootLayerDamage();
  53 }
  54
  55 gfx::ScrollOffset ScrollElasticityHelperImpl::ScrollOffset() const {
  56   return layer_tree_host_impl_->active_tree()->TotalScrollOffset();
  57 }
  58
  59 gfx::ScrollOffset ScrollElasticityHelperImpl::MaxScrollOffset() const {
  60   return layer_tree_host_impl_->active_tree()->TotalMaxScrollOffset();
  61 }
  62
  63 void ScrollElasticityHelperImpl::ScrollBy(const gfx::Vector2dF& delta) {
  64   LayerImpl* root_scroll_layer =
  65       layer_tree_host_impl_->OuterViewportScrollLayer()
  66           ? layer_tree_host_impl_->OuterViewportScrollLayer()
  67           : layer_tree_host_impl_->InnerViewportScrollLayer();
  68   if (root_scroll_layer)
  69     root_scroll_layer->ScrollBy(delta);
  70 }
  71
  72 void ScrollElasticityHelperImpl::RequestAnimate() {
  73   layer_tree_host_impl_->SetNeedsAnimate();
  74 }
  75
  76 // static
  77 ScrollElasticityHelper* ScrollElasticityHelper::CreateForLayerTreeHostImpl(
  78     LayerTreeHostImpl* layer_tree_host_impl) {
  79   return new ScrollElasticityHelperImpl(layer_tree_host_impl);
  80 }
  81
  82 }  // namespace cc