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// Copyright (c) 2012 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 UI_BASE_GESTURES_GESTURE_POINT_H_
#define UI_BASE_GESTURES_GESTURE_POINT_H_
#include "base/basictypes.h"
#include "ui/base/gestures/velocity_calculator.h"
#include "ui/gfx/point.h"
#include "ui/gfx/rect.h"
namespace ui {
class TouchEvent;
// A GesturePoint represents a single touch-point/finger during a gesture
// recognition process.
class GesturePoint {
public:
GesturePoint();
~GesturePoint();
// Resets various states.
void Reset();
void ResetVelocity();
// Updates some states when a Tap gesture has been recognized for this point.
void UpdateForTap();
// Updates some states when a Scroll gesture has been recognized for this
// point.
void UpdateForScroll();
// Updates states depending on the event and the gesture-state.
void UpdateValues(const TouchEvent& event);
// Responds according to the state of the gesture point (i.e. the point can
// represent a click or scroll etc.)
bool IsInClickWindow(const TouchEvent& event) const;
bool IsInDoubleClickWindow(const TouchEvent& event) const;
bool IsInScrollWindow(const TouchEvent& event) const;
bool IsInFlickWindow(const TouchEvent& event);
bool IsInHorizontalRailWindow() const;
bool IsInVerticalRailWindow() const;
bool IsInsideManhattanSquare(const TouchEvent& event) const;
bool HasEnoughDataToEstablishRail() const;
bool BreaksHorizontalRail();
bool BreaksVerticalRail();
bool DidScroll(const TouchEvent& event, int distance) const;
const gfx::Point& first_touch_position() const {
return first_touch_position_;
}
double last_touch_time() const { return last_touch_time_; }
const gfx::Point& last_touch_position() const { return last_touch_position_; }
int x() const { return last_touch_position_.x(); }
int y() const { return last_touch_position_.y(); }
// point_id_ is used to drive GestureSequence::ProcessTouchEventForGesture.
// point_ids are maintained such that the set of point_ids is always
// contiguous, from 0 to the number of current touches.
// A lower point_id indicates that a touch occurred first.
// A negative point_id indicates that the GesturePoint is not currently
// associated with a touch.
void set_point_id(int point_id) { point_id_ = point_id; }
int point_id() const { return point_id_; }
void set_touch_id(int touch_id) { touch_id_ = touch_id; }
int touch_id() const { return touch_id_; }
bool in_use() const { return point_id_ >= 0; }
double x_delta() const {
return last_touch_position_.x() - first_touch_position_.x();
}
double y_delta() const {
return last_touch_position_.y() - first_touch_position_.y();
}
float XVelocity() { return velocity_calculator_.XVelocity(); }
float YVelocity() { return velocity_calculator_.YVelocity(); }
const gfx::Rect& enclosing_rectangle() const { return enclosing_rect_; }
private:
// Various statistical functions to manipulate gestures.
bool IsInClickTimeWindow() const;
bool IsInSecondClickTimeWindow() const;
bool IsSecondClickInsideManhattanSquare(const TouchEvent& event) const;
bool IsOverMinFlickSpeed();
// The enclosing rectangle represents a rectangular touch region generated
// by a sequence of ET_TOUCH_PRESSED, ET_TOUCH_MOVED, and ET_TOUCH_RELEASED
// events forming a GESTURE_TAP event. The enclosing rectangle is updated
// to be the union of the touch data from each of these events. It is
// cleared on a ET_TOUCH_PRESSED event (i.e., at the beginning of a possible
// GESTURE_TAP event) or when Reset is called.
void UpdateEnclosingRectangle(const TouchEvent& event);
void clear_enclosing_rectangle() { enclosing_rect_ = gfx::Rect(); }
gfx::Point first_touch_position_;
double first_touch_time_;
gfx::Point last_touch_position_;
double last_touch_time_;
double last_tap_time_;
gfx::Point last_tap_position_;
VelocityCalculator velocity_calculator_;
int point_id_;
int touch_id_;
// Represents the rectangle that encloses the circles/ellipses
// generated by a sequence of touch events
gfx::Rect enclosing_rect_;
DISALLOW_COPY_AND_ASSIGN(GesturePoint);
};
} // namespace ui
#endif // UI_BASE_GESTURES_GESTURE_POINT_H_
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