Unified Gesture Recognizer

ui/events/gestures/motion_event_aura.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_UI_MOTION_EVENT_H_
+#define UI_EVENTS_GESTURE_DETECTION_UI_MOTION_EVENT_H_
+
+#include "ui/events/gesture_detection/motion_event.h"
+
+#include <map>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/time/time.h"
+#include "ui/events/event.h"
+#include "ui/events/events_export.h"
+#include "ui/events/gestures/gesture_sequence.h"
+
+namespace ui {
+
+// Implementation of MotionEvent which takes a stream of ui::TouchEvents.
+class EVENTS_EXPORT MotionEventAura : public MotionEvent {
+ public:
+  MotionEventAura();
+  virtual ~MotionEventAura();
+
+  void OnTouch(const TouchEvent& touch);
+
+  // MotionEventAura implementation.

[jdduke (slow), 2014/05/05 16:57:09]

Hmm, think this get the rename treatment, "MotionEvent implementation."

[tdresser, 2014/05/05 17:45:14]

Done.

+  virtual int GetId() const OVERRIDE;
+  virtual Action GetAction() const OVERRIDE;
+  virtual int GetActionIndex() const OVERRIDE;
+  virtual size_t GetPointerCount() const OVERRIDE;
+  virtual int GetPointerId(size_t pointer_index) const OVERRIDE;
+  virtual float GetX(size_t pointer_index) const OVERRIDE;
+  virtual float GetY(size_t pointer_index) const OVERRIDE;
+  virtual float GetTouchMajor(size_t pointer_index) const OVERRIDE;
+  virtual float GetPressure(size_t pointer_index) const OVERRIDE;
+  virtual base::TimeTicks GetEventTime() const OVERRIDE;
+
+  virtual size_t GetHistorySize() const OVERRIDE;
+  virtual base::TimeTicks GetHistoricalEventTime(size_t historical_index) const
+      OVERRIDE;
+  virtual float GetHistoricalTouchMajor(size_t pointer_index,
+                                        size_t historical_index) const OVERRIDE;
+  virtual float GetHistoricalX(size_t pointer_index,
+                               size_t historical_index) const OVERRIDE;
+  virtual float GetHistoricalY(size_t pointer_index,
+                               size_t historical_index) const OVERRIDE;
+
+  virtual scoped_ptr<MotionEvent> Clone() const OVERRIDE;
+  virtual scoped_ptr<MotionEvent> Cancel() const OVERRIDE;
+
+  int GetSourceDeviceId(size_t pointer_index) const;
+
+  // We can't cleanup removed touch points immediately upon receipt of a
+  // TouchCancel or TouchRelease, as the MotionEvent needs to be able to report
+  // information about those touch events. Once the MotionEvent has been
+  // processed, we call CleanupRemovedTouchPoints to do the required
+  // book-keeping.
+  void CleanupRemovedTouchPoints(const TouchEvent& event);
+
+ private:
+  struct PointData {
+    PointData() {

[jdduke (slow), 2014/05/05 16:57:09]

Nit: Constructor implementation in the .cc file, and might as well use
initializer list.

[tdresser, 2014/05/05 17:45:14]

Done.

+      x = 0;
+      y = 0;
+      touch_id = 0;
+      pressure = 0;
+      source_device_id = 0;
+      major_radius = 0;
+    }
+    float x;
+    float y;
+    int touch_id;
+    float pressure;
+    int source_device_id;
+    float major_radius;
+  };
+
+  MotionEventAura(
+      size_t pointer_count,
+      const base::TimeDelta& last_touch_time,
+      Action cached_action,
+      int cached_action_index,
+      const PointData (&active_touches)[GestureSequence::kMaxGesturePoints]);
+
+  static PointData GetPointDataFromTouchEvent(const TouchEvent& touch);
+  void AddTouch(const TouchEvent& touch);
+  void UpdateTouch(const TouchEvent& touch);
+  void UpdateCachedAction(const TouchEvent& touch);
+  size_t GetIndexFromId(int id);

[jdduke (slow), 2014/05/05 16:57:09]

Nit: const method.

[tdresser, 2014/05/05 17:45:14]

Done.

+
+  size_t pointer_count_;
+  base::TimeTicks last_touch_time_;
+  Action cached_action_;
+  // The index of the touch responsible for last ACTION_POINTER_DOWN or
+  // ACTION_POINTER_UP. -1 if no such action has occurred.
+  int cached_action_index_;
+
+  // We want constant time indexing by pointer_index, and fast indexing by id.
+  // TODO(tdresser): figure out which constant to use here.
+  PointData active_touches_[GestureSequence::kMaxGesturePoints];
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_GESTURE_DETECTION_UI_MOTION_EVENT_H_