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      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 
     14 namespace gfx {
     15 class Point;
     16 class PointF;
     17 class Vector2d;
     18 class Vector2dF;
     19 }
     20 
     21 namespace ui { struct LatencyInfo; }
     22 
     23 namespace cc {
     24 
     25 class LayerScrollOffsetDelegate;
     26 
     27 struct DidOverscrollParams {
     28   gfx::Vector2dF accumulated_overscroll;
     29   gfx::Vector2dF latest_overscroll_delta;
     30   gfx::Vector2dF current_fling_velocity;
     31 };
     32 
     33 class 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.
     57 class 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