cc/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 CCInputHandler_h
   6 #define CCInputHandler_h
   7
   8 #include "base/basictypes.h"
   9 #include <wtf/PassOwnPtr.h>
  10
  11 namespace cc {
  12
  13 class IntPoint;
  14 class IntSize;
  15
  16 // The CCInputHandler is a way for the embedders to interact with
  17 // the impl thread side of the compositor implementation.
  18 //
  19 // There is one CCInputHandler for every CCLayerTreeHost. It is
  20 // created on the main thread and used only on the impl thread.
  21 //
  22 // The CCInputHandler is constructed with a CCInputHandlerClient, which is the
  23 // interface by which the handler can manipulate the LayerTree.
  24 class CCInputHandlerClient {
  25 public:
  26     enum ScrollStatus { ScrollOnMainThread, ScrollStarted, ScrollIgnored };
  27     enum ScrollInputType { Gesture, Wheel };
  28
  29     // Selects a layer to be scrolled at a given point in window coordinates.
  30     // Returns ScrollStarted if the layer at the coordinates can be scrolled,
  31     // ScrollOnMainThread if the scroll event should instead be delegated to the
  32     // main thread, or ScrollIgnored if there is nothing to be scrolled at the
  33     // given coordinates.
  34     virtual ScrollStatus scrollBegin(const IntPoint&, ScrollInputType) = 0;
  35
  36     // Scroll the selected layer starting at the given window coordinate. If
  37     // there is no room to move the layer in the requested direction, its first
  38     // ancestor layer that can be scrolled will be moved instead. Should only be
  39     // called if scrollBegin() returned ScrollStarted.
  40     virtual void scrollBy(const IntPoint&, const IntSize&) = 0;
  41
  42     // Stop scrolling the selected layer. Should only be called if scrollBegin()
  43     // returned ScrollStarted.
  44     virtual void scrollEnd() = 0;
  45
  46     virtual void pinchGestureBegin() = 0;
  47     virtual void pinchGestureUpdate(float magnifyDelta, const IntPoint& anchor) = 0;
  48     virtual void pinchGestureEnd() = 0;
  49
  50     virtual void startPageScaleAnimation(const IntSize& targetPosition,
  51                                          bool anchorPoint,
  52                                          float pageScale,
  53                                          double startTime,
  54                                          double duration) = 0;
  55
  56     // Request another callback to CCInputHandler::animate().
  57     virtual void scheduleAnimation() = 0;
  58
  59 protected:
  60     CCInputHandlerClient() { }
  61     virtual ~CCInputHandlerClient() { }
  62
  63 private:
  64     DISALLOW_COPY_AND_ASSIGN(CCInputHandlerClient);
  65 };
  66
  67 class CCInputHandler {
  68 public:
  69     virtual ~CCInputHandler() { }
  70
  71     virtual void bindToClient(CCInputHandlerClient*) = 0;
  72     virtual void animate(double monotonicTime) = 0;
  73
  74 protected:
  75     CCInputHandler() { }
  76
  77 private:
  78     DISALLOW_COPY_AND_ASSIGN(CCInputHandler);
  79 };
  80
  81 }
  82
  83 #endif