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// Copyright 2015 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/time/time.h"
#include "ui/events/event_constants.h"
namespace gfx {
class PointF;
class Vector2dF;
namespace exo {
class Pointer;
class Surface;
// Handles events on pointers in context-specific ways.
class PointerDelegate {
// Called at the top of the pointer's destructor, to give observers a
// chance to remove themselves.
virtual void OnPointerDestroying(Pointer* pointer) = 0;
// This should return true if |surface| is a valid target for this pointer.
// E.g. the surface is owned by the same client as the pointer.
virtual bool CanAcceptPointerEventsForSurface(Surface* surface) const = 0;
// Called when pointer enters a new valid target surface. |location|
// is the location of pointer relative to the origin of surface and
// |button_flags| contains all currently pressed buttons.
virtual void OnPointerEnter(Surface* surface,
const gfx::PointF& location,
int pressed_button_flags) = 0;
// Called when pointer leaves a valid target surface.
virtual void OnPointerLeave(Surface* surface) = 0;
// Called when pointer moved within the current target surface.
virtual void OnPointerMotion(base::TimeTicks time_stamp,
const gfx::PointF& location) = 0;
// Called when pointer button state changed. |changed_button_flags| contains
// all buttons that changed. |pressed| is true if buttons entered pressed
// state.
virtual void OnPointerButton(base::TimeTicks time_stamp,
int changed_button_flags,
bool pressed) = 0;
// Called when pointer is scrolling. |offset| contains the direction and
// distance of the change. |discrete| is true if the scrolling is caused
// by a discrete device such as a scroll wheel.
virtual void OnPointerScroll(base::TimeTicks time_stamp,
const gfx::Vector2dF& offset,
bool discrete) = 0;
// Called when pointer scroll has stopped and a fling is happening (e.g.
// lifting the fingers from the touchpad after scrolling quickly)
virtual void OnPointerScrollStop(base::TimeTicks time_stamp) = 0;
// Called after all pointer information of this frame has been set and the
// client should evaluate the updated state. No events are being sent before
// this method is called.
virtual void OnPointerFrame() = 0;
virtual ~PointerDelegate() {}
} // namespace exo