cc/input/input_handler.h

   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                         const 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(const 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(const 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_