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// Copyright 2011 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.
#ifndef CC_PAGE_SCALE_ANIMATION_H_
#define CC_PAGE_SCALE_ANIMATION_H_
#include "base/memory/scoped_ptr.h"
#include "ui/gfx/size.h"
#include "ui/gfx/vector2d_f.h"
namespace cc {
// A small helper class that does the math for zoom animations, primarily for
// double-tap zoom. Initialize it with starting and ending scroll/page scale
// positions and an animation length time, then call ...AtTime() at every frame
// to obtain the current interpolated position.
//
// All sizes and vectors in this class's public methods are in the root scroll
// layer's coordinate space.
class PageScaleAnimation {
public:
// Construct with the state at the beginning of the animation.
static scoped_ptr<PageScaleAnimation> create(const gfx::Vector2dF& startScrollOffset, float startPageScaleFactor, const gfx::SizeF& viewportSize, const gfx::SizeF& rootLayerSize, double startTime);
~PageScaleAnimation();
// The following methods initialize the animation. Call one of them
// immediately after construction to set the final scroll and page scale.
// Zoom while explicitly specifying the top-left scroll position.
void zoomTo(const gfx::Vector2dF& targetScrollOffset, float targetPageScaleFactor, double duration);
// Zoom based on a specified anchor. The animator will attempt to keep it
// at the same position on the physical display throughout the animation,
// unless the edges of the root layer are hit. The anchor is specified
// as an offset from the content layer.
void zoomWithAnchor(const gfx::Vector2dF& anchor, float targetPageScaleFactor, double duration);
// Call these functions while the animation is in progress to output the
// current state.
gfx::Vector2dF scrollOffsetAtTime(double time) const;
float pageScaleFactorAtTime(double time) const;
bool isAnimationCompleteAtTime(double time) const;
// The following methods return state which is invariant throughout the
// course of the animation.
double startTime() const { return m_startTime; }
double duration() const { return m_duration; }
double endTime() const { return m_startTime + m_duration; }
const gfx::Vector2dF& targetScrollOffset() const { return m_targetScrollOffset; }
float targetPageScaleFactor() const { return m_targetPageScaleFactor; }
protected:
PageScaleAnimation(const gfx::Vector2dF& startScrollOffset, float startPageScaleFactor, const gfx::SizeF& viewportSize, const gfx::SizeF& rootLayerSize, double startTime);
private:
void clampTargetScrollOffset();
void inferTargetScrollOffsetFromStartAnchor();
void inferTargetAnchorFromScrollOffsets();
gfx::SizeF startViewportSize() const;
gfx::SizeF targetViewportSize() const;
float interpAtTime(double time) const;
gfx::SizeF viewportSizeAt(float interp) const;
gfx::Vector2dF scrollOffsetAt(float interp) const;
gfx::Vector2dF anchorAt(float interp) const;
gfx::Vector2dF viewportRelativeAnchorAt(float interp) const;
float pageScaleFactorAt(float interp) const;
float m_startPageScaleFactor;
float m_targetPageScaleFactor;
gfx::Vector2dF m_startScrollOffset;
gfx::Vector2dF m_targetScrollOffset;
gfx::Vector2dF m_startAnchor;
gfx::Vector2dF m_targetAnchor;
gfx::SizeF m_viewportSize;
gfx::SizeF m_rootLayerSize;
double m_startTime;
double m_duration;
};
} // namespace cc
#endif // CC_PAGE_SCALE_ANIMATION_H_
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