window_slider.h revision 424c4d7b64af9d0d8fd9624f381f469654d5e3d2 
1// Copyright (c) 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CONTENT_BROWSER_WEB_CONTENTS_AURA_WINDOW_SLIDER_H_
6#define CONTENT_BROWSER_WEB_CONTENTS_AURA_WINDOW_SLIDER_H_
7
8#include "base/compiler_specific.h"
9#include "base/memory/scoped_ptr.h"
10#include "base/memory/weak_ptr.h"
11#include "content/common/content_export.h"
12#include "ui/aura/window_observer.h"
13#include "ui/base/events/event_handler.h"
14
15namespace ui {
16class Layer;
17}
18
19namespace content {
20
21class ShadowLayerDelegate;
22
23// A class for sliding the layer in a Window on top of other layers.
24class CONTENT_EXPORT WindowSlider : public ui::EventHandler,
25                                    public aura::WindowObserver {
26 public:
27  class Delegate {
28   public:
29    virtual ~Delegate() {}
30
31    // Creates a layer to show in the background, as the window-layer slides
32    // with the scroll gesture.
33    // The WindowSlider takes ownership of the created layer.
34    virtual ui::Layer* CreateBackLayer() = 0;
35
36    // Creates a layer to slide on top of the window-layer with the scroll
37    // gesture.
38    // The WindowSlider takes ownership of the created layer.
39    virtual ui::Layer* CreateFrontLayer() = 0;
40
41    // Called when the slide is complete. Note that at the end of a completed
42    // slide, the window-layer may have been transformed. The callback here
43    // should reset the transform if necessary.
44    virtual void OnWindowSlideComplete() = 0;
45
46    // Called when the slide is aborted. Note that when the slide is aborted,
47    // the WindowSlider resets any transform it applied on the window-layer.
48    virtual void OnWindowSlideAborted() = 0;
49
50    // Called when the slider is destroyed.
51    virtual void OnWindowSliderDestroyed() = 0;
52  };
53
54  // The WindowSlider slides the layers in the |owner| window. It starts
55  // intercepting scroll events on |event_window|, and uses those events to
56  // control the layer-slide. The lifetime of the slider is managed by the
57  // lifetime of |owner|, i.e. if |owner| is destroyed, then the slider also
58  // destroys itself.
59  WindowSlider(Delegate* delegate,
60               aura::Window* event_window,
61               aura::Window* owner);
62
63  virtual ~WindowSlider();
64
65  // Changes the owner of the slider.
66  void ChangeOwner(aura::Window* new_owner);
67
68  bool IsSlideInProgress() const;
69
70 private:
71  // Sets up the slider layer correctly (sets the correct bounds of the layer,
72  // parents it to the right layer, and sets up the correct stacking order).
73  void SetupSliderLayer();
74
75  void UpdateForScroll(float x_offset, float y_offset);
76
77  void UpdateForFling(float x_velocity, float y_velocity);
78
79  // Resets any in-progress slide.
80  void ResetScroll();
81
82  // Cancels any scroll/animation in progress.
83  void CancelScroll();
84
85  // The following callbacks are triggered after an animation.
86  void CompleteWindowSlideAfterAnimation();
87
88  void AbortWindowSlideAfterAnimation();
89
90  // Overridden from ui::EventHandler:
91  virtual void OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
92  virtual void OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
93  virtual void OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
94  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
95
96  // Overridden from aura::WindowObserver:
97  virtual void OnWindowRemovingFromRootWindow(aura::Window* window) OVERRIDE;
98
99  Delegate* delegate_;
100
101  // The slider intercepts scroll events from this window. The slider does not
102  // own |event_window_|. If |event_window_| is destroyed, then the slider stops
103  // listening for events, but it doesn't destroy itself.
104  aura::Window* event_window_;
105
106  // The window the slider operates on. The lifetime of the slider is bound to
107  // this window (i.e. if |owner_| does, the slider destroys itself). The slider
108  // can also delete itself when a slide gesture is completed. This does not
109  // destroy |owner_|.
110  aura::Window* owner_;
111
112  // The accumulated amount of horizontal scroll.
113  float delta_x_;
114
115  // This keeps track of the layer created by the delegate.
116  scoped_ptr<ui::Layer> slider_;
117
118  // This manages the shadow for the layers.
119  scoped_ptr<ShadowLayerDelegate> shadow_;
120
121  base::WeakPtrFactory<WindowSlider> weak_factory_;
122
123  float active_start_threshold_;
124
125  const float start_threshold_touchscreen_;
126  const float start_threshold_touchpad_;
127  const float complete_threshold_;
128
129  DISALLOW_COPY_AND_ASSIGN(WindowSlider);
130};
131
132}  // namespace content
133
134#endif  // CONTENT_BROWSER_WEB_CONTENTS_AURA_WINDOW_SLIDER_H_
135