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// Copyright 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_INPUT_INPUT_HANDLER_H_
#define CC_INPUT_INPUT_HANDLER_H_
#include "base/basictypes.h"
#include "base/time/time.h"
#include "cc/base/cc_export.h"
#include "cc/input/scrollbar.h"
namespace gfx {
class Point;
class PointF;
class Vector2d;
class Vector2dF;
}
namespace ui { struct LatencyInfo; }
namespace cc {
class LayerScrollOffsetDelegate;
class CC_EXPORT InputHandlerClient {
public:
virtual ~InputHandlerClient() {}
virtual void WillShutdown() = 0;
virtual void Animate(base::TimeTicks time) = 0;
virtual void MainThreadHasStoppedFlinging() = 0;
// Called when scroll deltas reaching the root scrolling layer go unused.
// The accumulated overscroll is scoped by the most recent call to
// InputHandler::ScrollBegin.
virtual void DidOverscroll(gfx::Vector2dF accumulated_overscroll,
gfx::Vector2dF current_fling_velocity) = 0;
protected:
InputHandlerClient() {}
private:
DISALLOW_COPY_AND_ASSIGN(InputHandlerClient);
};
// The InputHandler is a way for the embedders to interact with the impl thread
// side of the compositor implementation. There is one InputHandler per
// LayerTreeHost. To use the input handler, implement the InputHanderClient
// interface and bind it to the handler on the compositor thread.
class CC_EXPORT InputHandler {
public:
enum ScrollStatus { ScrollOnMainThread, ScrollStarted, ScrollIgnored };
enum ScrollInputType { Gesture, Wheel, NonBubblingGesture };
// Binds a client to this handler to receive notifications. Only one client
// can be bound to an InputHandler. The client must live at least until the
// handler calls WillShutdown() on the client.
virtual void BindToClient(InputHandlerClient* client) = 0;
// Selects a layer to be scrolled at a given point in viewport (logical
// pixel) coordinates. Returns ScrollStarted if the layer at the coordinates
// can be scrolled, ScrollOnMainThread if the scroll event should instead be
// delegated to the main thread, or ScrollIgnored if there is nothing to be
// scrolled at the given coordinates.
virtual ScrollStatus ScrollBegin(gfx::Point viewport_point,
ScrollInputType type) = 0;
// Scroll the selected layer starting at the given position. If the scroll
// type given to ScrollBegin was a gesture, then the scroll point and delta
// should be in viewport (logical pixel) coordinates. Otherwise they are in
// scrolling layer's (logical pixel) space. If there is no room to move the
// layer in the requested direction, its first ancestor layer that can be
// scrolled will be moved instead. If no layer can be moved in the requested
// direction at all, then false is returned. If any layer is moved, then
// true is returned.
// If the scroll delta hits the root layer, and the layer can no longer move,
// the root overscroll accumulated within this ScrollBegin() scope is reported
// to the client.
// Should only be called if ScrollBegin() returned ScrollStarted.
virtual bool ScrollBy(gfx::Point viewport_point,
gfx::Vector2dF scroll_delta) = 0;
virtual bool ScrollVerticallyByPage(
gfx::Point viewport_point,
ScrollDirection direction) = 0;
// Returns ScrollStarted if a layer was being actively being scrolled,
// ScrollIgnored if not.
virtual ScrollStatus FlingScrollBegin() = 0;
virtual void NotifyCurrentFlingVelocity(gfx::Vector2dF velocity) = 0;
// Stop scrolling the selected layer. Should only be called if ScrollBegin()
// returned ScrollStarted.
virtual void ScrollEnd() = 0;
virtual void SetRootLayerScrollOffsetDelegate(
LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate) = 0;
// Called when the value returned by
// LayerScrollOffsetDelegate.GetTotalScrollOffset has changed for reasons
// other than a SetTotalScrollOffset call.
// NOTE: This should only called after a valid delegate was set via a call to
// SetRootLayerScrollOffsetDelegate.
virtual void OnRootLayerDelegatedScrollOffsetChanged() = 0;
virtual void PinchGestureBegin() = 0;
virtual void PinchGestureUpdate(float magnify_delta, gfx::Point anchor) = 0;
virtual void PinchGestureEnd() = 0;
virtual void StartPageScaleAnimation(gfx::Vector2d target_offset,
bool anchor_point,
float page_scale,
base::TimeTicks start_time,
base::TimeDelta duration) = 0;
// Request another callback to InputHandlerClient::Animate().
virtual void ScheduleAnimation() = 0;
virtual bool HaveTouchEventHandlersAt(gfx::Point viewport_point) = 0;
virtual void SetLatencyInfoForInputEvent(
const ui::LatencyInfo& latency_info) = 0;
protected:
InputHandler() {}
virtual ~InputHandler() {}
private:
DISALLOW_COPY_AND_ASSIGN(InputHandler);
};
} // namespace cc
#endif // CC_INPUT_INPUT_HANDLER_H_