1// Copyright 2011 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 CC_INPUT_INPUT_HANDLER_H_
6#define CC_INPUT_INPUT_HANDLER_H_
7
8#include "base/basictypes.h"
9#include "base/time/time.h"
10#include "cc/base/cc_export.h"
11#include "cc/base/swap_promise_monitor.h"
12#include "cc/input/scrollbar.h"
13
14namespace gfx {
15class Point;
16class PointF;
17class Vector2d;
18class Vector2dF;
19}
20
21namespace ui { struct LatencyInfo; }
22
23namespace cc {
24
25class LayerScrollOffsetDelegate;
26
27struct DidOverscrollParams {
28  gfx::Vector2dF accumulated_overscroll;
29  gfx::Vector2dF latest_overscroll_delta;
30  gfx::Vector2dF current_fling_velocity;
31};
32
33class CC_EXPORT InputHandlerClient {
34 public:
35  virtual ~InputHandlerClient() {}
36
37  virtual void WillShutdown() = 0;
38  virtual void Animate(base::TimeTicks time) = 0;
39  virtual void MainThreadHasStoppedFlinging() = 0;
40
41  // Called when scroll deltas reaching the root scrolling layer go unused.
42  // The accumulated overscroll is scoped by the most recent call to
43  // InputHandler::ScrollBegin.
44  virtual void DidOverscroll(const DidOverscrollParams& params) = 0;
45
46 protected:
47  InputHandlerClient() {}
48
49 private:
50  DISALLOW_COPY_AND_ASSIGN(InputHandlerClient);
51};
52
53// The InputHandler is a way for the embedders to interact with the impl thread
54// side of the compositor implementation. There is one InputHandler per
55// LayerTreeHost. To use the input handler, implement the InputHanderClient
56// interface and bind it to the handler on the compositor thread.
57class CC_EXPORT InputHandler {
58 public:
59  enum ScrollStatus { ScrollOnMainThread, ScrollStarted, ScrollIgnored };
60  enum ScrollInputType { Gesture, Wheel, NonBubblingGesture };
61
62  // Binds a client to this handler to receive notifications. Only one client
63  // can be bound to an InputHandler. The client must live at least until the
64  // handler calls WillShutdown() on the client.
65  virtual void BindToClient(InputHandlerClient* client) = 0;
66
67  // Selects a layer to be scrolled at a given point in viewport (logical
68  // pixel) coordinates. Returns ScrollStarted if the layer at the coordinates
69  // can be scrolled, ScrollOnMainThread if the scroll event should instead be
70  // delegated to the main thread, or ScrollIgnored if there is nothing to be
71  // scrolled at the given coordinates.
72  virtual ScrollStatus ScrollBegin(gfx::Point viewport_point,
73                                   ScrollInputType type) = 0;
74
75  // Scroll the selected layer starting at the given position. If the scroll
76  // type given to ScrollBegin was a gesture, then the scroll point and delta
77  // should be in viewport (logical pixel) coordinates. Otherwise they are in
78  // scrolling layer's (logical pixel) space. If there is no room to move the
79  // layer in the requested direction, its first ancestor layer that can be
80  // scrolled will be moved instead. If no layer can be moved in the requested
81  // direction at all, then false is returned. If any layer is moved, then
82  // true is returned.
83  // If the scroll delta hits the root layer, and the layer can no longer move,
84  // the root overscroll accumulated within this ScrollBegin() scope is reported
85  // to the client.
86  // Should only be called if ScrollBegin() returned ScrollStarted.
87  virtual bool ScrollBy(gfx::Point viewport_point,
88                        gfx::Vector2dF scroll_delta) = 0;
89
90  virtual bool ScrollVerticallyByPage(
91      gfx::Point viewport_point,
92      ScrollDirection direction) = 0;
93
94  // Returns ScrollStarted if a layer was being actively being scrolled,
95  // ScrollIgnored if not.
96  virtual ScrollStatus FlingScrollBegin() = 0;
97
98  virtual void NotifyCurrentFlingVelocity(gfx::Vector2dF velocity) = 0;
99
100  virtual void MouseMoveAt(gfx::Point mouse_position) = 0;
101
102  // Stop scrolling the selected layer. Should only be called if ScrollBegin()
103  // returned ScrollStarted.
104  virtual void ScrollEnd() = 0;
105
106  virtual void SetRootLayerScrollOffsetDelegate(
107      LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate) = 0;
108
109  // Called when the value returned by
110  // LayerScrollOffsetDelegate.GetTotalScrollOffset has changed for reasons
111  // other than a SetTotalScrollOffset call.
112  // NOTE: This should only called after a valid delegate was set via a call to
113  // SetRootLayerScrollOffsetDelegate.
114  virtual void OnRootLayerDelegatedScrollOffsetChanged() = 0;
115
116  virtual void PinchGestureBegin() = 0;
117  virtual void PinchGestureUpdate(float magnify_delta, gfx::Point anchor) = 0;
118  virtual void PinchGestureEnd() = 0;
119
120  virtual void StartPageScaleAnimation(gfx::Vector2d target_offset,
121                                       bool anchor_point,
122                                       float page_scale,
123                                       base::TimeDelta duration) = 0;
124
125  // Request another callback to InputHandlerClient::Animate().
126  virtual void ScheduleAnimation() = 0;
127
128  virtual bool HaveTouchEventHandlersAt(gfx::Point viewport_point) = 0;
129
130  // Calling CreateLatencyInfoSwapPromiseMonitor() to get a scoped
131  // LatencyInfoSwapPromiseMonitor. During the life time of the
132  // LatencyInfoSwapPromiseMonitor, if SetNeedsRedraw() or SetNeedsRedrawRect()
133  // is called on LayerTreeHostImpl, the original latency info will be turned
134  // into a LatencyInfoSwapPromise.
135  virtual scoped_ptr<SwapPromiseMonitor> CreateLatencyInfoSwapPromiseMonitor(
136      ui::LatencyInfo* latency) = 0;
137
138 protected:
139  InputHandler() {}
140  virtual ~InputHandler() {}
141
142 private:
143  DISALLOW_COPY_AND_ASSIGN(InputHandler);
144};
145
146}  // namespace cc
147
148#endif  // CC_INPUT_INPUT_HANDLER_H_
149