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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_INPUT_PAGE_SCALE_ANIMATION_H_
#define CC_INPUT_PAGE_SCALE_ANIMATION_H_
#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "base/time/time.h"
#include "cc/base/cc_export.h"
#include "ui/gfx/size.h"
#include "ui/gfx/vector2d_f.h"
namespace cc {
class TimingFunction;
// 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. The supplied timing function
// is used to ease the animation.
//
// All sizes and vectors in this class's public methods are in the root scroll
// layer's coordinate space.
class CC_EXPORT PageScaleAnimation {
public:
// Construct with the state at the beginning of the animation.
static scoped_ptr<PageScaleAnimation> Create(
const gfx::Vector2dF& start_scroll_offset,
float start_page_scale_factor,
const gfx::SizeF& viewport_size,
const gfx::SizeF& root_layer_size,
scoped_ptr<TimingFunction> timing_function);
~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& target_scroll_offset,
float target_page_scale_factor,
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 target_page_scale_factor,
double duration);
// These should be called before the first frame of animation to initialize
// the start time. StartAnimation should only be called once after creation.
bool IsAnimationStarted() const;
void StartAnimation(base::TimeTicks time);
// Call these functions while the animation is in progress to output the
// current state.
gfx::Vector2dF ScrollOffsetAtTime(base::TimeTicks time) const;
float PageScaleFactorAtTime(base::TimeTicks time) const;
bool IsAnimationCompleteAtTime(base::TimeTicks time) const;
// The following methods return state which is invariant throughout the
// course of the animation.
base::TimeTicks start_time() const { return start_time_; }
base::TimeDelta duration() const { return duration_; }
base::TimeTicks end_time() const { return start_time_ + duration_; }
gfx::Vector2dF target_scroll_offset() const { return target_scroll_offset_; }
float target_page_scale_factor() const { return target_page_scale_factor_; }
protected:
PageScaleAnimation(const gfx::Vector2dF& start_scroll_offset,
float start_page_scale_factor,
const gfx::SizeF& viewport_size,
const gfx::SizeF& root_layer_size,
scoped_ptr<TimingFunction> timing_function);
private:
void ClampTargetScrollOffset();
void InferTargetScrollOffsetFromStartAnchor();
void InferTargetAnchorFromScrollOffsets();
gfx::SizeF StartViewportSize() const;
gfx::SizeF TargetViewportSize() const;
float InterpAtTime(base::TimeTicks 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 start_page_scale_factor_;
float target_page_scale_factor_;
gfx::Vector2dF start_scroll_offset_;
gfx::Vector2dF target_scroll_offset_;
gfx::Vector2dF start_anchor_;
gfx::Vector2dF target_anchor_;
gfx::SizeF viewport_size_;
gfx::SizeF root_layer_size_;
base::TimeTicks start_time_;
base::TimeDelta duration_;
scoped_ptr<TimingFunction> timing_function_;
DISALLOW_COPY_AND_ASSIGN(PageScaleAnimation);
};
} // namespace cc
#endif // CC_INPUT_PAGE_SCALE_ANIMATION_H_
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