blob: 81d91b871432f8500a6b9b46834e72c8a11c4d7d [file] [log] [blame]
// 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.
#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "base/time/time.h"
#include "cc/base/cc_export.h"
#include "cc/input/scrollbar.h"
#include "cc/trees/swap_promise_monitor.h"
namespace gfx {
class Point;
class PointF;
class Vector2d;
class Vector2dF;
namespace ui { struct LatencyInfo; }
namespace cc {
class LayerScrollOffsetDelegate;
class ScrollElasticityHelper;
struct CC_EXPORT InputHandlerScrollResult {
// Did any layer scroll as a result this ScrollBy call?
bool did_scroll;
// Was any of the scroll delta argument to this ScrollBy call not used?
bool did_overscroll_root;
// The total overscroll that has been accumulated by all ScrollBy calls that
// have had overscroll since the last ScrollBegin call. This resets upon a
// ScrollBy with no overscroll.
gfx::Vector2dF accumulated_root_overscroll;
// The amount of the scroll delta argument to this ScrollBy call that was not
// used for scrolling.
gfx::Vector2dF unused_scroll_delta;
class CC_EXPORT InputHandlerClient {
virtual ~InputHandlerClient() {}
virtual void WillShutdown() = 0;
virtual void Animate(base::TimeTicks time) = 0;
virtual void MainThreadHasStoppedFlinging() = 0;
virtual void ReconcileElasticOverscrollAndRootScroll() = 0;
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 {
// Note these are used in a histogram. Do not reorder or delete existing
// entries.
enum ScrollStatus {
// This must be the last entry.
// 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 SCROLL_STARTED if the layer at the coordinates
// can be scrolled, SCROLL_ON_MAIN_THREAD if the scroll event should instead
// be delegated to the main thread, or SCROLL_IGNORED if there is nothing to
// be scrolled at the given coordinates.
virtual ScrollStatus ScrollBegin(const gfx::Point& viewport_point,
ScrollInputType type) = 0;
virtual ScrollStatus ScrollAnimated(const gfx::Point& viewport_point,
const gfx::Vector2dF& scroll_delta) = 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. The return value's |did_scroll| field is
// set to false if no layer can be moved in the requested direction at all,
// and set to true if any layer is moved.
// 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
// in the return value's |accumulated_overscroll| field.
// Should only be called if ScrollBegin() returned SCROLL_STARTED.
virtual InputHandlerScrollResult ScrollBy(
const gfx::Point& viewport_point,
const gfx::Vector2dF& scroll_delta) = 0;
virtual bool ScrollVerticallyByPage(const gfx::Point& viewport_point,
ScrollDirection direction) = 0;
// Returns SCROLL_STARTED if a layer was being actively being scrolled,
virtual ScrollStatus FlingScrollBegin() = 0;
virtual void MouseMoveAt(const gfx::Point& mouse_position) = 0;
// Stop scrolling the selected layer. Should only be called if ScrollBegin()
// returned SCROLL_STARTED.
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,
const gfx::Point& anchor) = 0;
virtual void PinchGestureEnd() = 0;
// Request another callback to InputHandlerClient::Animate().
virtual void SetNeedsAnimate() = 0;
// Whether the layer under |viewport_point| is the currently scrolling layer.
virtual bool IsCurrentlyScrollingLayerAt(const gfx::Point& viewport_point,
ScrollInputType type) = 0;
virtual bool HaveWheelEventHandlersAt(const gfx::Point& viewport_point) = 0;
// Whether the page should be given the opportunity to suppress scrolling by
// consuming touch events that started at |viewport_point|.
virtual bool DoTouchEventsBlockScrollAt(const gfx::Point& viewport_point) = 0;
// Calling CreateLatencyInfoSwapPromiseMonitor() to get a scoped
// LatencyInfoSwapPromiseMonitor. During the life time of the
// LatencyInfoSwapPromiseMonitor, if SetNeedsRedraw() or SetNeedsRedrawRect()
// is called on LayerTreeHostImpl, the original latency info will be turned
// into a LatencyInfoSwapPromise.
virtual scoped_ptr<SwapPromiseMonitor> CreateLatencyInfoSwapPromiseMonitor(
ui::LatencyInfo* latency) = 0;
virtual ScrollElasticityHelper* CreateScrollElasticityHelper() = 0;
InputHandler() {}
virtual ~InputHandler() {}
} // namespace cc