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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_INPUT_SCROLL_ELASTICITY_HELPER_H_
#define CC_INPUT_SCROLL_ELASTICITY_HELPER_H_
#include "cc/cc_export.h"
#include "ui/gfx/geometry/point_f.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/geometry/vector2d_f.h"
namespace cc {
class LayerTreeHostImpl;
// ScrollElasticityHelper is based on
// WebKit/Source/platform/mac/ScrollElasticityController.h
/*
* Copyright (C) 2011 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
// Interface between a LayerTreeHostImpl and the ScrollElasticityController. It
// would be possible, in principle, for LayerTreeHostImpl to implement this
// interface itself. This artificial boundary is introduced to reduce the amount
// of logic and state held directly inside LayerTreeHostImpl.
class CC_EXPORT ScrollElasticityHelper {
public:
static ScrollElasticityHelper* CreateForLayerTreeHostImpl(
LayerTreeHostImpl* host_impl);
virtual ~ScrollElasticityHelper() {}
virtual bool IsUserScrollableHorizontal() const = 0;
virtual bool IsUserScrollableVertical() const = 0;
// The bounds of the root scroller.
virtual gfx::Size ScrollBounds() const = 0;
// The amount that the view is stretched past the normal allowable bounds.
virtual gfx::Vector2dF StretchAmount() const = 0;
virtual void SetStretchAmount(const gfx::Vector2dF& stretch_amount) = 0;
// Functions for the scrolling of the root scroll layer.
virtual gfx::PointF ScrollOffset() const = 0;
virtual gfx::PointF MaxScrollOffset() const = 0;
virtual void ScrollBy(const gfx::Vector2dF& delta) = 0;
// Requests that another frame happens for the controller to continue ticking
// animations.
virtual void RequestOneBeginFrame() = 0;
};
} // namespace cc
#endif // CC_INPUT_SCROLL_ELASTICITY_HELPER_H_
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