[Tracking Patch] Unified gesture detection

content/browser/renderer_host/input/gestures/gesture_detector.h

+// Copyright 2013 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 CONTENT_BROWSER_RENDERER_HOST_INPUT_GESTURES_GESTURE_DETECTOR_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_GESTURES_GESTURE_DETECTOR_H_
+
+#include "base/callback.h"
+#include "base/memory/scoped_ptr.h"
+#include "content/browser/renderer_host/input/gestures/velocity_tracker_state.h"
+
+namespace content {
+
+class MotionEvent;
+
+// Port of GestureDetector.java from Android
+// * platform/frameworks/base/core/java/android/view/GestureDetector.java
+// * Change-Id: Ib470735ec929b0b358fca4597e92dc81084e675f
+// * Changes to this class should be cosmetic only, easing fork maintenance.
+class GestureDetector {
+ public:
+  struct Config {
+    Config();
+    ~Config();
+    base::TimeDelta longpress_timeout;
+    base::TimeDelta tap_timeout;
+    base::TimeDelta double_tap_timeout;
+    int scaled_touch_slop;
+    int scaled_double_tap_slop;
+    int scaled_minimum_fling_velocity;
+    int scaled_maximum_fling_velocity;
+  };
+
+  class OnGestureListener {
+   public:
+    virtual ~OnGestureListener() {}
+    virtual bool OnDown(const MotionEvent& e) = 0;
+    virtual void OnShowPress(const MotionEvent& e) = 0;
+    virtual bool OnSingleTapUp(const MotionEvent& e) = 0;
+    virtual void OnLongPress(const MotionEvent& e) = 0;
+    virtual bool OnScroll(const MotionEvent& e1, const MotionEvent& e2,
+                          float distance_x, float distance_y) = 0;
+    virtual bool OnFling(const MotionEvent& e1, const MotionEvent& e2,
+                         float velocity_x, float velocity_y) = 0;
+  };
+
+  class OnDoubleTapListener {
+   public:
+    virtual ~OnDoubleTapListener() {}
+    virtual bool OnSingleTapConfirmed(const MotionEvent& e) = 0;
+    virtual bool OnDoubleTap(const MotionEvent& e) = 0;
+    virtual bool OnDoubleTapEvent(const MotionEvent& e) = 0;
+  };
+
+  // A convenience class to extend when you only want to listen for a subset
+  // of all the gestures. This implements all methods in the
+  // |OnGestureListener| and |OnDoubleTapListener| but does
+  // nothing and returns false for all applicable methods.
+  class SimpleOnGestureListener : public OnGestureListener,
+                                  public OnDoubleTapListener {
+    // OnGestureListener
+    virtual bool OnDown(const MotionEvent& e) OVERRIDE;
+    virtual void OnShowPress(const MotionEvent& e) OVERRIDE;
+    virtual bool OnSingleTapUp(const MotionEvent& e) OVERRIDE;
+    virtual void OnLongPress(const MotionEvent& e) OVERRIDE;
+    virtual bool OnScroll(const MotionEvent& e1, const MotionEvent& e2,
+                          float distance_x, float distance_y) OVERRIDE;
+    virtual bool OnFling(const MotionEvent& e1, const MotionEvent& e2,
+                         float velocity_x, float velocity_y) OVERRIDE;
+
+    // OnDoubleTapListener
+    virtual bool OnSingleTapConfirmed(const MotionEvent& e) OVERRIDE;
+    virtual bool OnDoubleTap(const MotionEvent& e) OVERRIDE;
+    virtual bool OnDoubleTapEvent(const MotionEvent& e) OVERRIDE;
+  };
+
+  GestureDetector(Config config,
+                  OnGestureListener* listener,
+                  OnDoubleTapListener* optional_double_tap_listener);
+  ~GestureDetector();
+
+  bool OnTouchEvent(const MotionEvent& ev);
+
+  void set_on_doubletap_listener(OnDoubleTapListener* double_tap_listener) {
+    double_tap_listener_ = double_tap_listener;
+  }
+
+  void set_is_longpress_enabled(bool is_longpress_enabled) {
+    is_longpress_enabled_ = is_longpress_enabled;
+  }
+
+  bool is_longpress_enabled() const { return is_longpress_enabled_; }
+
+ private:
+  void Init(Config config);
+  void OnShowPressTimeout();
+  void OnLongPressTimeout();
+  void OnTapTimeout();
+  void Cancel();
+  void CancelTaps();
+  bool IsConsideredDoubleTap(const MotionEvent& first_down,
+                             const MotionEvent& first_up,
+                             const MotionEvent& second_down);
+
+  // Constants used by GestureHandler.
+  enum TimeoutEvent {
+    SHOW_PRESS = 0,
+    LONG_PRESS,
+    TAP,
+    TIMEOUT_EVENT_COUNT
+  };
+
+  class GestureHandler;
+  scoped_ptr<GestureHandler> handler_;
+  OnGestureListener* const listener_;
+  OnDoubleTapListener* double_tap_listener_;
+
+  int touch_slop_square_;
+  int double_tap_touch_slop_square_;
+  int double_tap_slop_square_;
+  int min_fling_velocity_;
+  int max_fling_velocity_;
+  base::TimeDelta double_tap_timeout_;
+
+  bool still_down_;
+  bool defer_confirm_single_tap_;
+  bool in_long_press_;
+  bool always_in_tap_region_;
+  bool always_in_bigger_tap_region_;
+
+  scoped_ptr<MotionEvent> current_down_event_;
+  scoped_ptr<MotionEvent> previous_up_event_;
+
+  // True when the user is still touching for the second tap (down, move, and
+  // up events). Can only be true if there is a double tap listener attached.
+  bool is_double_tapping_;
+
+  float last_focus_x_;
+  float last_focus_y_;
+  float down_focus_x_;
+  float down_focus_y_;
+
+  bool is_longpress_enabled_;
+
+  // Determines speed during touch scrolling.
+  VelocityTrackerState velocity_tracker_;
+
+  DISALLOW_COPY_AND_ASSIGN(GestureDetector);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_GESTURE_DETECTOR_H_