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.
5 #ifndef CC_INPUT_INPUT_HANDLER_H_
6 #define CC_INPUT_INPUT_HANDLER_H_
8 #include "base/basictypes.h"
9 #include "base/memory/scoped_ptr.h"
10 #include "base/time/time.h"
11 #include "cc/base/cc_export.h"
12 #include "cc/input/scrollbar.h"
13 #include "cc/trees/swap_promise_monitor.h"
22 namespace ui
{ struct LatencyInfo
; }
26 class LayerScrollOffsetDelegate
;
27 class ScrollElasticityHelper
;
29 struct CC_EXPORT InputHandlerScrollResult
{
30 InputHandlerScrollResult();
31 // Did any layer scroll as a result this ScrollBy call?
33 // Was any of the scroll delta argument to this ScrollBy call not used?
34 bool did_overscroll_root
;
35 // The total overscroll that has been accumulated by all ScrollBy calls that
36 // have had overscroll since the last ScrollBegin call. This resets upon a
37 // ScrollBy with no overscroll.
38 gfx::Vector2dF accumulated_root_overscroll
;
39 // The amount of the scroll delta argument to this ScrollBy call that was not
40 // used for scrolling.
41 gfx::Vector2dF unused_scroll_delta
;
44 class CC_EXPORT InputHandlerClient
{
46 virtual ~InputHandlerClient() {}
48 virtual void WillShutdown() = 0;
49 virtual void Animate(base::TimeTicks time
) = 0;
50 virtual void MainThreadHasStoppedFlinging() = 0;
51 virtual void ReconcileElasticOverscrollAndRootScroll() = 0;
54 InputHandlerClient() {}
57 DISALLOW_COPY_AND_ASSIGN(InputHandlerClient
);
60 // The InputHandler is a way for the embedders to interact with the impl thread
61 // side of the compositor implementation. There is one InputHandler per
62 // LayerTreeHost. To use the input handler, implement the InputHanderClient
63 // interface and bind it to the handler on the compositor thread.
64 class CC_EXPORT InputHandler
{
66 // Note these are used in a histogram. Do not reorder or delete existing
69 SCROLL_ON_MAIN_THREAD
= 0,
73 // This must be the last entry.
76 enum ScrollInputType
{ GESTURE
, WHEEL
, NON_BUBBLING_GESTURE
};
78 // Binds a client to this handler to receive notifications. Only one client
79 // can be bound to an InputHandler. The client must live at least until the
80 // handler calls WillShutdown() on the client.
81 virtual void BindToClient(InputHandlerClient
* client
) = 0;
83 // Selects a layer to be scrolled at a given point in viewport (logical
84 // pixel) coordinates. Returns SCROLL_STARTED if the layer at the coordinates
85 // can be scrolled, SCROLL_ON_MAIN_THREAD if the scroll event should instead
86 // be delegated to the main thread, or SCROLL_IGNORED if there is nothing to
87 // be scrolled at the given coordinates.
88 virtual ScrollStatus
ScrollBegin(const gfx::Point
& viewport_point
,
89 ScrollInputType type
) = 0;
91 virtual ScrollStatus
ScrollAnimated(const gfx::Point
& viewport_point
,
92 const gfx::Vector2dF
& scroll_delta
) = 0;
94 // Scroll the selected layer starting at the given position. If the scroll
95 // type given to ScrollBegin was a gesture, then the scroll point and delta
96 // should be in viewport (logical pixel) coordinates. Otherwise they are in
97 // scrolling layer's (logical pixel) space. If there is no room to move the
98 // layer in the requested direction, its first ancestor layer that can be
99 // scrolled will be moved instead. The return value's |did_scroll| field is
100 // set to false if no layer can be moved in the requested direction at all,
101 // and set to true if any layer is moved.
102 // If the scroll delta hits the root layer, and the layer can no longer move,
103 // the root overscroll accumulated within this ScrollBegin() scope is reported
104 // in the return value's |accumulated_overscroll| field.
105 // Should only be called if ScrollBegin() returned SCROLL_STARTED.
106 virtual InputHandlerScrollResult
ScrollBy(
107 const gfx::Point
& viewport_point
,
108 const gfx::Vector2dF
& scroll_delta
) = 0;
110 virtual bool ScrollVerticallyByPage(const gfx::Point
& viewport_point
,
111 ScrollDirection direction
) = 0;
113 // Returns SCROLL_STARTED if a layer was being actively being scrolled,
114 // SCROLL_IGNORED if not.
115 virtual ScrollStatus
FlingScrollBegin() = 0;
117 virtual void MouseMoveAt(const gfx::Point
& mouse_position
) = 0;
119 // Stop scrolling the selected layer. Should only be called if ScrollBegin()
120 // returned SCROLL_STARTED.
121 virtual void ScrollEnd() = 0;
123 virtual void SetRootLayerScrollOffsetDelegate(
124 LayerScrollOffsetDelegate
* root_layer_scroll_offset_delegate
) = 0;
126 // Called when the value returned by
127 // LayerScrollOffsetDelegate.GetTotalScrollOffset has changed for reasons
128 // other than a SetTotalScrollOffset call.
129 // NOTE: This should only called after a valid delegate was set via a call to
130 // SetRootLayerScrollOffsetDelegate.
131 virtual void OnRootLayerDelegatedScrollOffsetChanged() = 0;
133 virtual void PinchGestureBegin() = 0;
134 virtual void PinchGestureUpdate(float magnify_delta
,
135 const gfx::Point
& anchor
) = 0;
136 virtual void PinchGestureEnd() = 0;
138 // Request another callback to InputHandlerClient::Animate().
139 virtual void SetNeedsAnimate() = 0;
141 // Whether the layer under |viewport_point| is the currently scrolling layer.
142 virtual bool IsCurrentlyScrollingLayerAt(const gfx::Point
& viewport_point
,
143 ScrollInputType type
) = 0;
145 virtual bool HaveWheelEventHandlersAt(const gfx::Point
& viewport_point
) = 0;
147 // Whether the page should be given the opportunity to suppress scrolling by
148 // consuming touch events that started at |viewport_point|.
149 virtual bool DoTouchEventsBlockScrollAt(const gfx::Point
& viewport_point
) = 0;
151 // Calling CreateLatencyInfoSwapPromiseMonitor() to get a scoped
152 // LatencyInfoSwapPromiseMonitor. During the life time of the
153 // LatencyInfoSwapPromiseMonitor, if SetNeedsRedraw() or SetNeedsRedrawRect()
154 // is called on LayerTreeHostImpl, the original latency info will be turned
155 // into a LatencyInfoSwapPromise.
156 virtual scoped_ptr
<SwapPromiseMonitor
> CreateLatencyInfoSwapPromiseMonitor(
157 ui::LatencyInfo
* latency
) = 0;
159 virtual ScrollElasticityHelper
* CreateScrollElasticityHelper() = 0;
163 virtual ~InputHandler() {}
166 DISALLOW_COPY_AND_ASSIGN(InputHandler
);
171 #endif // CC_INPUT_INPUT_HANDLER_H_