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// Copyright (c) 2012 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 CONTENT_BROWSER_ANDROID_OVERSCROLL_GLOW_H_
#define CONTENT_BROWSER_ANDROID_OVERSCROLL_GLOW_H_
#include "base/callback.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/time/time.h"
#include "ui/gfx/size_f.h"
#include "ui/gfx/vector2d_f.h"
namespace cc {
class Layer;
}
namespace content {
class EdgeEffectBase;
/* |OverscrollGlow| mirrors its Android counterpart, OverscrollGlow.java.
* Conscious tradeoffs were made to align this as closely as possible with the
* original Android Java version.
*/
class OverscrollGlow {
public:
enum Edge { EDGE_TOP = 0, EDGE_LEFT, EDGE_BOTTOM, EDGE_RIGHT, EDGE_COUNT };
// Allows lazy creation of the edge effects.
typedef base::Callback<scoped_ptr<EdgeEffectBase>(void)> EdgeEffectProvider;
// |edge_effect_provider| must be valid for the duration of the effect's
// lifetime. The effect is enabled by default, but will remain dormant until
// the first overscroll event.
explicit OverscrollGlow(const EdgeEffectProvider& edge_effect_provider);
~OverscrollGlow();
// Enable the effect. If the effect was previously disabled, it will remain
// dormant until subsequent calls to |OnOverscrolled()|.
void Enable();
// Deactivate and detach the effect. Subsequent calls to |OnOverscrolled()| or
// |Animate()| will have no effect.
void Disable();
// Effect layers will be attached to |overscrolling_layer| if necessary.
// |accumulated_overscroll| and |overscroll_delta| are in device pixels, while
// |velocity| is in device pixels / second.
// Returns true if the effect still needs animation ticks.
bool OnOverscrolled(cc::Layer* overscrolling_layer,
base::TimeTicks current_time,
gfx::Vector2dF accumulated_overscroll,
gfx::Vector2dF overscroll_delta,
gfx::Vector2dF velocity,
gfx::Vector2dF overscroll_location);
// Returns true if the effect still needs animation ticks.
// Note: The effect will detach itself when no further animation is required.
bool Animate(base::TimeTicks current_time);
// Update the effect according to the most recent display parameters,
// Note: All dimensions are in device pixels.
struct DisplayParameters {
DisplayParameters();
gfx::SizeF size;
float edge_offsets[EDGE_COUNT];
};
void UpdateDisplayParameters(const DisplayParameters& params);
private:
enum Axis { AXIS_X, AXIS_Y };
// Returns whether the effect is initialized.
bool InitializeIfNecessary();
bool NeedsAnimate() const;
void UpdateLayerAttachment(cc::Layer* parent);
void Detach();
void Pull(base::TimeTicks current_time,
const gfx::Vector2dF& overscroll_delta,
const gfx::Vector2dF& overscroll_location);
void Absorb(base::TimeTicks current_time,
const gfx::Vector2dF& velocity,
bool x_overscroll_started,
bool y_overscroll_started);
void Release(base::TimeTicks current_time);
EdgeEffectBase* GetOppositeEdge(int edge_index);
EdgeEffectProvider edge_effect_provider_;
scoped_ptr<EdgeEffectBase> edge_effects_[EDGE_COUNT];
DisplayParameters display_params_;
bool enabled_;
bool initialized_;
scoped_refptr<cc::Layer> root_layer_;
DISALLOW_COPY_AND_ASSIGN(OverscrollGlow);
};
} // namespace content
#endif // CONTENT_BROWSER_ANDROID_SCROLL_GLOW_H_
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