content/browser/renderer_host/input/motion_event_android.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_MOTION_EVENT_ANDROID_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_MOTION_EVENT_ANDROID_H_
   7
   8 #include <jni.h>
   9
  10 #include "base/android/scoped_java_ref.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/time/time.h"
  13 #include "ui/events/gesture_detection/motion_event.h"
  14 #include "ui/gfx/geometry/point_f.h"
  15
  16 namespace content {
  17
  18 // Implementation of ui::MotionEvent wrapping a native Android MotionEvent.
  19 // All *input* coordinates are in device pixels (as with Android MotionEvent),
  20 // while all *output* coordinates are in DIPs (as with WebTouchEvent).
  21 class MotionEventAndroid : public ui::MotionEvent {
  22  public:
  23   // Forcing the caller to provide all cached values upon construction
  24   // eliminates the need to perform a JNI call to retrieve values individually.
  25   MotionEventAndroid(float pix_to_dip,
  26                      JNIEnv* env,
  27                      jobject event,
  28                      jlong time_ms,
  29                      jint android_action,
  30                      jint pointer_count,
  31                      jint history_size,
  32                      jint action_index,
  33                      jfloat pos_x_0_pixels,
  34                      jfloat pos_y_0_pixels,
  35                      jfloat pos_x_1_pixels,
  36                      jfloat pos_y_1_pixels,
  37                      jint pointer_id_0,
  38                      jint pointer_id_1,
  39                      jfloat touch_major_0_pixels,
  40                      jfloat touch_major_1_pixels);
  41   virtual ~MotionEventAndroid();
  42
  43   // ui::MotionEvent methods.
  44   virtual int GetId() const OVERRIDE;
  45   virtual Action GetAction() const OVERRIDE;
  46   virtual int GetActionIndex() const OVERRIDE;
  47   virtual size_t GetPointerCount() const OVERRIDE;
  48   virtual int GetPointerId(size_t pointer_index) const OVERRIDE;
  49   virtual float GetX(size_t pointer_index) const OVERRIDE;
  50   virtual float GetY(size_t pointer_index) const OVERRIDE;
  51   virtual float GetTouchMajor(size_t pointer_index) const OVERRIDE;
  52   virtual float GetPressure(size_t pointer_index) const OVERRIDE;
  53   virtual base::TimeTicks GetEventTime() const OVERRIDE;
  54   virtual size_t GetHistorySize() const OVERRIDE;
  55   virtual base::TimeTicks GetHistoricalEventTime(
  56       size_t historical_index) const OVERRIDE;
  57   virtual float GetHistoricalTouchMajor(
  58       size_t pointer_index,
  59       size_t historical_index) const OVERRIDE;
  60   virtual float GetHistoricalX(
  61       size_t pointer_index,
  62       size_t historical_index) const OVERRIDE;
  63   virtual float GetHistoricalY(
  64       size_t pointer_index,
  65       size_t historical_index) const OVERRIDE;
  66   virtual scoped_ptr<MotionEvent> Clone() const OVERRIDE;
  67   virtual scoped_ptr<MotionEvent> Cancel() const OVERRIDE;
  68
  69   // Additional Android MotionEvent methods.
  70   float GetTouchMinor() const { return GetTouchMinor(0); }
  71   float GetTouchMinor(size_t pointer_index) const;
  72   float GetOrientation() const;
  73   base::TimeTicks GetDownTime() const;
  74
  75   static bool RegisterMotionEventAndroid(JNIEnv* env);
  76
  77   static base::android::ScopedJavaLocalRef<jobject> Obtain(
  78       const MotionEventAndroid& event);
  79   static base::android::ScopedJavaLocalRef<jobject> Obtain(
  80       base::TimeTicks down_time,
  81       base::TimeTicks event_time,
  82       Action action,
  83       float x_pixels,
  84       float y_pixels);
  85
  86  private:
  87   MotionEventAndroid();
  88   MotionEventAndroid(float pix_to_dip, JNIEnv* env, jobject event);
  89   MotionEventAndroid(const MotionEventAndroid&);
  90   MotionEventAndroid& operator=(const MotionEventAndroid&);
  91
  92   float ToDips(float pixels) const;
  93   gfx::PointF ToDips(const gfx::PointF& pixels) const;
  94
  95   // Cache pointer coords, id's and major lengths for the most common
  96   // touch-related scenarios, i.e., scrolling and pinching.  This prevents
  97   // redundant JNI fetches for the same bits.
  98   enum { MAX_POINTERS_TO_CACHE = 2 };
  99
 100   // The Java reference to the underlying MotionEvent.
 101   base::android::ScopedJavaGlobalRef<jobject> event_;
 102
 103   base::TimeTicks cached_time_;
 104   Action cached_action_;
 105   size_t cached_pointer_count_;
 106   size_t cached_history_size_;
 107   int cached_action_index_;
 108   gfx::PointF cached_positions_[MAX_POINTERS_TO_CACHE];
 109   int cached_pointer_ids_[MAX_POINTERS_TO_CACHE];
 110   float cached_touch_majors_[MAX_POINTERS_TO_CACHE];
 111
 112   // Used to convert pixel coordinates from the Java-backed MotionEvent to
 113   // DIP coordinates cached/returned by the MotionEventAndroid.
 114   const float pix_to_dip_;
 115
 116   // Whether |event_| should be recycled on destruction. This will only be true
 117   // for those events generated via |Obtain(...)|.
 118   bool should_recycle_;
 119 };
 120
 121 }  // namespace content
 122
 123 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_MOTION_EVENT_ANDROID_H_