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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.
#ifndef CONTENT_BROWSER_ANDROID_OVERSCROLL_REFRESH_H_
#define CONTENT_BROWSER_ANDROID_OVERSCROLL_REFRESH_H_
#include "base/memory/scoped_ptr.h"
#include "base/time/time.h"
#include "content/common/content_export.h"
#include "ui/gfx/geometry/size_f.h"
#include "ui/gfx/geometry/vector2d_f.h"
namespace cc {
class Layer;
}
namespace ui {
class ResourceManager;
}
namespace content {
// Allows both page reload activation and page reloading state queries.
class CONTENT_EXPORT OverscrollRefreshClient {
public:
virtual ~OverscrollRefreshClient() {}
// Called when the effect is released beyond the activation threshold. This
// should cause a refresh of some kind, e.g., page reload.
virtual void TriggerRefresh() = 0;
// Whether the triggered refresh has yet to complete. The effect will continue
// animating until the refresh completes (or it reaches a reasonable timeout).
virtual bool IsStillRefreshing() const = 0;
};
// Simple pull-to-refresh styled effect. Listens to scroll events, conditionally
// activating when:
// 1) The scroll begins when the page's root layer 1) has no vertical scroll
// offset and 2) lacks the overflow-y:hidden property.
// 2) The page doesn't consume the initial scroll events.
// 3) The initial scroll direction is upward.
// The actual page reload action is triggered only when the effect is active
// and beyond a particular threshold when released.
class CONTENT_EXPORT OverscrollRefresh {
public:
// Minmum number of overscrolling pull events required to activate the effect.
// Useful for avoiding accidental triggering when a scroll janks (is delayed),
// capping the impulse per event.
enum { kMinPullsToActivate = 3 };
// Both |resource_manager| and |client| must not be null.
// |target_drag_offset_pixels| is the threshold beyond which the effect
// will trigger a refresh action when released. When |mirror| is true,
// the effect and its rotation will be mirrored about the y axis.
OverscrollRefresh(ui::ResourceManager* resource_manager,
OverscrollRefreshClient* client,
float target_drag_offset_pixels,
bool mirror);
~OverscrollRefresh();
// Scroll event stream listening methods.
void OnScrollBegin();
void OnScrollEnd(const gfx::Vector2dF& velocity);
// Scroll ack listener. The effect will only be activated if the initial
// updates go unconsumed.
void OnScrollUpdateAck(bool was_consumed);
// Returns true if the effect has consumed the |scroll_delta|.
bool WillHandleScrollUpdate(const gfx::Vector2dF& scroll_delta);
// Release the effect (if active), preventing any associated refresh action.
void ReleaseWithoutActivation();
// Returns true if the effect still needs animation ticks, with effect layers
// attached to |parent| if necessary.
// Note: The effect will detach itself when no further animation is required.
bool Animate(base::TimeTicks current_time, cc::Layer* parent_layer);
// Update the effect according to the most recent display parameters,
// Note: All dimensions are in device pixels.
void UpdateDisplay(const gfx::SizeF& viewport_size,
const gfx::Vector2dF& content_scroll_offset,
bool root_overflow_y_hidden);
// Reset the effect to its inactive state, immediately detaching and
// disabling any active effects.
void Reset();
// Returns true if the refresh effect is either being manipulated or animated.
bool IsActive() const;
// Returns true if the effect is waiting for an unconsumed scroll to start.
bool IsAwaitingScrollUpdateAck() const;
private:
void Release(bool allow_activation);
OverscrollRefreshClient* const client_;
gfx::SizeF viewport_size_;
bool scrolled_to_top_;
bool overflow_y_hidden_;
enum ScrollConsumptionState {
DISABLED,
AWAITING_SCROLL_UPDATE_ACK,
ENABLED,
} scroll_consumption_state_;
class Effect;
scoped_ptr<Effect> effect_;
DISALLOW_COPY_AND_ASSIGN(OverscrollRefresh);
};
} // namespace content
#endif // CONTENT_BROWSER_ANDROID_OVERSCROLL_REFRESH_H_
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