Port of Android platform gesture detection code to C++

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_POINTER_DOWN,
+    ACTION_POINTER_UP,
+    ACTION_DOWN,
+    ACTION_UP,
+    ACTION_CANCEL,
+    ACTION_MOVE
+  };
+
+  // The implementer promises that |GetPointerId()| will never exceed this.
+  enum { MAX_POINTER_ID = 31 };
+
+  virtual ~MotionEvent() {}
+
+  virtual Action GetAction() const = 0;
+  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 GetTouchMajor(size_t pointer_index) const = 0;
+  virtual base::TimeTicks GetEventTime() const = 0;
+
+  virtual size_t GetHistorySize() const = 0;
+  virtual base::TimeTicks GetHistoricalEventTime(
+      size_t historical_index) const = 0;
+  virtual float GetHistoricalTouchMajor(size_t pointer_index,
+                                        size_t historical_index) const = 0;
+  virtual float GetHistoricalX(size_t pointer_index,
+                               size_t historical_index) const = 0;
+  virtual float GetHistoricalY(size_t pointer_index,
+                               size_t historical_index) const = 0;
+
+  virtual scoped_ptr<MotionEvent> Clone() const = 0;
+  virtual scoped_ptr<MotionEvent> Cancel() const = 0;
+
+  // Utility accessor methods for convenience.
+  float GetX() const { return GetX(0); }
+  float GetY() const { return GetY(0); }
+  float GetRawX() const { return GetX(); }
+  float GetRawY() const { return GetY(); }
+  float GetTouchMajor() const { return GetTouchMajor(0); }
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_