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// Copyright 2014 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/input/scroll_elasticity_helper.h"
#include "cc/layers/layer_impl.h"
#include "cc/trees/layer_tree_host_impl.h"
#include "cc/trees/layer_tree_impl.h"
namespace cc {
ScrollElasticityHelper::ScrollElasticityHelper(LayerTreeHostImpl* layer_tree)
: layer_tree_host_impl_(layer_tree), timer_active_(false) {
}
ScrollElasticityHelper::~ScrollElasticityHelper() {
}
bool ScrollElasticityHelper::AllowsHorizontalStretching() {
// The WebKit implementation has this interface because it is written in terms
// of overscrolling on a per-layer basis, not for the whole layer tree. In
// that implementation, this always returns true for the frame view's
// scrollable area.
// TODO(ccameron): This is function is redundant and may be removed.
return true;
}
bool ScrollElasticityHelper::AllowsVerticalStretching() {
// TODO(ccameron): This is function is redundant and may be removed.
return true;
}
gfx::Vector2dF ScrollElasticityHelper::StretchAmount() {
// TODO(ccameron): Use the value of active_tree->elastic_overscroll directly
return stretch_offset_;
}
bool ScrollElasticityHelper::PinnedInDirection(
const gfx::Vector2dF& direction) {
gfx::ScrollOffset scroll_offset =
layer_tree_host_impl_->active_tree()->TotalScrollOffset();
gfx::ScrollOffset max_scroll_offset =
layer_tree_host_impl_->active_tree()->TotalMaxScrollOffset();
bool result = false;
if (direction.x() < 0)
result |= scroll_offset.x() <= 0;
if (direction.x() > 0)
result |= scroll_offset.x() >= max_scroll_offset.x();
if (direction.y() < 0)
result |= scroll_offset.y() <= 0;
if (direction.y() > 0)
result |= scroll_offset.y() >= max_scroll_offset.y();
return result;
}
bool ScrollElasticityHelper::CanScrollHorizontally() {
return layer_tree_host_impl_->active_tree()->TotalMaxScrollOffset().x() > 0;
}
bool ScrollElasticityHelper::CanScrollVertically() {
return layer_tree_host_impl_->active_tree()->TotalMaxScrollOffset().y() > 0;
}
gfx::Vector2dF ScrollElasticityHelper::AbsoluteScrollPosition() {
// TODO(ccameron): This is function is redundant and may be removed.
return StretchAmount();
}
void ScrollElasticityHelper::ImmediateScrollBy(const gfx::Vector2dF& scroll) {
// TODO(ccameron): This is function is redundant and may be removed.
}
void ScrollElasticityHelper::ImmediateScrollByWithoutContentEdgeConstraints(
const gfx::Vector2dF& scroll) {
stretch_offset_ += scroll;
// TODO(ccameron): Use the value of active_tree->elastic_overscroll directly
// Note that this assumes that this property's true value is ever changed
// by the impl thread. While this is true, it is redundant state.
layer_tree_host_impl_->active_tree()->elastic_overscroll()->SetCurrent(
-stretch_offset_);
layer_tree_host_impl_->active_tree()->set_needs_update_draw_properties();
layer_tree_host_impl_->SetNeedsCommit();
layer_tree_host_impl_->SetNeedsRedraw();
}
void ScrollElasticityHelper::StartSnapRubberbandTimer() {
if (timer_active_)
return;
timer_active_ = true;
layer_tree_host_impl_->SetNeedsAnimate();
}
void ScrollElasticityHelper::StopSnapRubberbandTimer() {
timer_active_ = false;
}
void ScrollElasticityHelper::SnapRubberbandTimerFired() {
if (timer_active_)
layer_tree_host_impl_->SetNeedsAnimate();
}
void ScrollElasticityHelper::AdjustScrollPositionToBoundsIfNecessary() {
// TODO(ccameron): This is function is redundant and may be removed.
}
} // namespace cc
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