ui/events/gesture_detection/motion_event.h

// Copyright 2014 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_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_
#define UI_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_

#include "base/memory/scoped_ptr.h"
#include "base/time/time.h"
#include "ui/events/gesture_detection/gesture_detection_export.h"

namespace ui {

// Abstract class for a generic motion-related event, patterned after that
// subset of Android's MotionEvent API used in gesture detection.
class GESTURE_DETECTION_EXPORT MotionEvent {
 public:
  enum Action {
    ACTION_NONE,
    ACTION_DOWN,
    ACTION_UP,
    ACTION_MOVE,
    ACTION_CANCEL,
    ACTION_POINTER_DOWN,
    ACTION_POINTER_UP,
  };

  enum ToolType {
    TOOL_TYPE_UNKNOWN,
    TOOL_TYPE_FINGER,
    TOOL_TYPE_STYLUS,
    TOOL_TYPE_MOUSE,
    TOOL_TYPE_ERASER
  };

  enum ButtonType {
    BUTTON_PRIMARY = 1 << 0,
    BUTTON_SECONDARY = 1 << 1,
    BUTTON_TERTIARY = 1 << 2,
    BUTTON_BACK = 1 << 3,
    BUTTON_FORWARD = 1 << 4,
    BUTTON_STYLUS_PRIMARY = 1 << 5,
    BUTTON_STYLUS_SECONDARY = 1 << 6,
  };

  // The implementer promises that |GetPointerId()| will never exceed
  // MAX_POINTER_ID.
  enum { MAX_POINTER_ID = 31, MAX_TOUCH_POINT_COUNT = 16 };

  virtual ~MotionEvent() {}

  // An unique identifier this motion event.
  virtual uint32 GetUniqueEventId() const = 0;
  virtual Action GetAction() const = 0;
  // Only valid if |GetAction()| returns ACTION_POINTER_UP or
  // ACTION_POINTER_DOWN.
  virtual int GetActionIndex() const = 0;
  virtual size_t GetPointerCount() const = 0;
  virtual int GetPointerId(size_t pointer_index) const = 0;
  virtual float GetX(size_t pointer_index) const = 0;
  virtual float GetY(size_t pointer_index) const = 0;
  virtual float GetRawX(size_t pointer_index) const = 0;
  virtual float GetRawY(size_t pointer_index) const = 0;
  virtual float GetTouchMajor(size_t pointer_index) const = 0;
  virtual float GetTouchMinor(size_t pointer_index) const = 0;
  virtual float GetOrientation(size_t pointer_index) const = 0;
  virtual float GetPressure(size_t pointer_index) const = 0;
  virtual ToolType GetToolType(size_t pointer_index) const = 0;
  virtual int GetButtonState() const = 0;
  virtual int GetFlags() const = 0;
  virtual base::TimeTicks GetEventTime() const = 0;

  // Optional historical data, default implementation provides an empty history.
  virtual size_t GetHistorySize() const;
  virtual base::TimeTicks GetHistoricalEventTime(size_t historical_index) const;
  virtual float GetHistoricalTouchMajor(size_t pointer_index,
                                        size_t historical_index) const;
  virtual float GetHistoricalX(size_t pointer_index,
                               size_t historical_index) const;
  virtual float GetHistoricalY(size_t pointer_index,
                               size_t historical_index) const;

  // Get the id of the device which created the event. Currently Aura only.
  virtual int GetSourceDeviceId(size_t pointer_index) const;

  // Utility accessor methods for convenience.
  int GetPointerId() const { return GetPointerId(0); }
  float GetX() const { return GetX(0); }
  float GetY() const { return GetY(0); }
  float GetRawX() const { return GetRawX(0); }
  float GetRawY() const { return GetRawY(0); }
  float GetRawOffsetX() const { return GetRawX() - GetX(); }
  float GetRawOffsetY() const { return GetRawY() - GetY(); }

  float GetTouchMajor() const { return GetTouchMajor(0); }
  float GetTouchMinor() const { return GetTouchMinor(0); }

  // Returns the orientation in radians. The meaning is overloaded:
  // * For a touch screen or pad, it's the orientation of the major axis
  //   clockwise from vertical. The return value lies in [-PI/2, PI/2].
  // * For a stylus, it indicates the direction in which the stylus is pointing.
  //   The return value lies in [-PI, PI].
  float GetOrientation() const { return GetOrientation(0); }

  float GetPressure() const { return GetPressure(0); }
  ToolType GetToolType() const { return GetToolType(0); }

  // O(N) search of pointers (use sparingly!). Returns -1 if |id| nonexistent.
  int FindPointerIndexOfId(int id) const;

  // Note that these methods perform shallow copies of the originating events.
  // They guarantee only that the returned type will reflect the same
  // data exposed by the MotionEvent interface; no guarantees are made that the
  // underlying implementation is identical to the source implementation.
  scoped_ptr<MotionEvent> Clone() const;
  scoped_ptr<MotionEvent> Cancel() const;
};

}  // namespace ui

#endif  // UI_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_