content/browser/android/overscroll_controller_android.h

// 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_CONTROLLER_ANDROID_H_
#define CONTENT_BROWSER_ANDROID_OVERSCROLL_CONTROLLER_ANDROID_H_

#include <memory>

#include "base/macros.h"
#include "base/time/time.h"
#include "content/common/input/input_event_ack_state.h"
#include "ui/android/overscroll_glow.h"
#include "ui/android/overscroll_refresh.h"
#include "ui/gfx/geometry/vector2d_f.h"

namespace blink {
class WebGestureEvent;
}

namespace cc {
class CompositorFrameMetadata;
class Layer;
}

namespace ui {
class WindowAndroidCompositor;
}

namespace content {

class ContentViewCoreImpl;
struct DidOverscrollParams;

// Glue class for handling all inputs into Android-specific overscroll effects,
// both the passive overscroll glow and the active overscroll pull-to-refresh.
// Note that all input coordinates (both for events and overscroll) are in DIPs.
class OverscrollControllerAndroid : public ui::OverscrollGlowClient {
 public:
  explicit OverscrollControllerAndroid(ContentViewCoreImpl* content_view_core);
  ~OverscrollControllerAndroid() override;

  // Returns true if |event| is consumed by an overscroll effect, in which
  // case it should cease propagation.
  bool WillHandleGestureEvent(const blink::WebGestureEvent& event);

  // To be called upon receipt of a gesture event ack.
  void OnGestureEventAck(const blink::WebGestureEvent& event,
                         InputEventAckState ack_result);

  // To be called upon receipt of an overscroll event.
  void OnOverscrolled(const DidOverscrollParams& overscroll_params);

  // 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, cc::Layer* parent_layer);

  // To be called whenever the content frame has been updated.
  void OnFrameMetadataUpdated(const cc::CompositorFrameMetadata& metadata);

  // Toggle activity of any overscroll effects. When disabled, events will be
  // ignored until the controller is re-enabled.
  void Enable();
  void Disable();

 private:
  // OverscrollGlowClient implementation.
  std::unique_ptr<ui::EdgeEffectBase> CreateEdgeEffect() override;

  void SetNeedsAnimate();

  ui::WindowAndroidCompositor* const compositor_;
  const float dpi_scale_;

  bool enabled_;

  // TODO(jdduke): Factor out a common API from the two overscroll effects.
  std::unique_ptr<ui::OverscrollGlow> glow_effect_;
  std::unique_ptr<ui::OverscrollRefresh> refresh_effect_;

  DISALLOW_COPY_AND_ASSIGN(OverscrollControllerAndroid);
};

}  // namespace content

#endif  // CONTENT_BROWSER_ANDROID_OVERSCROLL_CONTROLLER_ANDROID_H_