src/content/public/android/java/src/org/chromium/content/browser/TouchPoint.java

   1 // Copyright 2012 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 package org.chromium.content.browser;
   6
   7 import android.util.Log;
   8 import android.view.MotionEvent;
   9
  10 import org.chromium.base.CalledByNative;
  11
  12 // This class converts android MotionEvent into an array of touch points so
  13 // that they can be forwarded to the renderer process.
  14 class TouchPoint {
  15
  16     public static final int CONVERSION_ERROR = -1;
  17
  18     // Type of motion event to send to the native side. The values originate from their
  19     // webkit WebInputEvent counterparts, and are set via initializeConstants().
  20     static int TOUCH_EVENT_TYPE_START;
  21     static int TOUCH_EVENT_TYPE_MOVE;
  22     static int TOUCH_EVENT_TYPE_END;
  23     static int TOUCH_EVENT_TYPE_CANCEL;
  24
  25     // Type of motion event to send to the native side. The values originate from their
  26     // webkit WebTouchPoint counterparts, and are set via initializeConstants().
  27     private static int TOUCH_POINT_STATE_UNDEFINED;
  28     private static int TOUCH_POINT_STATE_RELEASED;
  29     private static int TOUCH_POINT_STATE_PRESSED;
  30     private static int TOUCH_POINT_STATE_MOVED;
  31     private static int TOUCH_POINT_STATE_STATIONARY;
  32     private static int TOUCH_POINT_STATE_CANCELLED;
  33
  34     private final int mState;
  35     private final int mId;
  36     private final float mX;
  37     private final float mY;
  38     private final float mPressure;
  39     private final float mTouchMajor;
  40     private final float mTouchMinor;
  41     private final float mOrientation;
  42
  43     TouchPoint(int state, int id, float x, float y, float pressure,
  44             float touchMajor, float touchMinor, float orientation) {
  45         mState = state;
  46         mId = id;
  47         mX = x;
  48         mY = y;
  49         mPressure = pressure;
  50         mTouchMajor = touchMajor;
  51         mTouchMinor = touchMinor;
  52         mOrientation = orientation;
  53     }
  54
  55     // The following methods are called by native to parse the java TouchPoint
  56     // object it has received.
  57     @SuppressWarnings("unused")
  58     @CalledByNative
  59     public int getState() { return mState; }
  60
  61     @SuppressWarnings("unused")
  62     @CalledByNative
  63     public int getId() { return mId; }
  64
  65     @SuppressWarnings("unused")
  66     @CalledByNative
  67     public int getX() { return (int) mX; }
  68
  69     @SuppressWarnings("unused")
  70     @CalledByNative
  71     public int getY() { return (int) mY; }
  72
  73     @SuppressWarnings("unused")
  74     @CalledByNative
  75     public float getPressure() { return mPressure; }
  76
  77     @SuppressWarnings("unused")
  78     @CalledByNative
  79     public float getTouchMajor() { return mTouchMajor; }
  80
  81     @SuppressWarnings("unused")
  82     @CalledByNative
  83     public float getTouchMinor() { return mTouchMinor; }
  84
  85     @SuppressWarnings("unused")
  86     @CalledByNative
  87     public float getOrientation() { return mOrientation; }
  88
  89     // Converts a MotionEvent into an array of touch points.
  90     // Returns the WebTouchEvent::Type for the MotionEvent and -1 for failure.
  91     public static int createTouchPoints(MotionEvent event, TouchPoint[] pts) {
  92         int type;
  93         int defaultState;
  94
  95         switch (event.getActionMasked()) {
  96             case MotionEvent.ACTION_DOWN:
  97                 type = TOUCH_EVENT_TYPE_START;
  98                 defaultState = TOUCH_POINT_STATE_PRESSED;
  99                 break;
 100             case MotionEvent.ACTION_MOVE:
 101                 type = TOUCH_EVENT_TYPE_MOVE;
 102                 defaultState = TOUCH_POINT_STATE_MOVED;
 103                 break;
 104             case MotionEvent.ACTION_UP:
 105                 type = TOUCH_EVENT_TYPE_END;
 106                 defaultState = TOUCH_POINT_STATE_RELEASED;
 107                 break;
 108             case MotionEvent.ACTION_CANCEL:
 109                 type = TOUCH_EVENT_TYPE_CANCEL;
 110                 defaultState = TOUCH_POINT_STATE_CANCELLED;
 111                 break;
 112             case MotionEvent.ACTION_POINTER_DOWN:
 113                 type = TOUCH_EVENT_TYPE_START;
 114                 defaultState = TOUCH_POINT_STATE_STATIONARY;
 115                 break;
 116             case MotionEvent.ACTION_POINTER_UP:
 117                 type = TOUCH_EVENT_TYPE_END;
 118                 defaultState = TOUCH_POINT_STATE_STATIONARY;
 119                 break;
 120             default:
 121                 Log.e("Chromium", "Unknown motion event action: " + event.getActionMasked());
 122                 return CONVERSION_ERROR;
 123         }
 124
 125         for (int i = 0; i < pts.length; ++i) {
 126             int state = defaultState;
 127             if (defaultState == TOUCH_POINT_STATE_STATIONARY && event.getActionIndex() == i) {
 128                 // An additional pointer has started or ended. Map this pointer state as
 129                 // required, and all other pointers as "stationary".
 130                 state = event.getActionMasked() == MotionEvent.ACTION_POINTER_DOWN ?
 131                     TOUCH_POINT_STATE_PRESSED : TOUCH_POINT_STATE_RELEASED;
 132             }
 133             pts[i] = new TouchPoint(state, event.getPointerId(i),
 134                                     event.getX(i), event.getY(i),
 135                                     event.getPressure(i),
 136                                     event.getTouchMajor(i), event.getTouchMinor(i),
 137                                     event.getOrientation(i));
 138         }
 139
 140         return type;
 141     }
 142
 143     // This method is called by native to initialize all the constants from
 144     // their counterparts in WebInputEvent and WebTouchPoint.
 145     @SuppressWarnings("unused")
 146     @CalledByNative
 147     private static void initializeConstants(
 148             int touchTypeStart, int touchTypeMove, int touchTypeEnd, int touchTypeCancel,
 149             int touchPointUndefined, int touchPointReleased, int touchPointPressed,
 150             int touchPointMoved, int touchPointStationary, int touchPointCancelled) {
 151         TOUCH_EVENT_TYPE_START = touchTypeStart;
 152         TOUCH_EVENT_TYPE_MOVE = touchTypeMove;
 153         TOUCH_EVENT_TYPE_END = touchTypeEnd;
 154         TOUCH_EVENT_TYPE_CANCEL = touchTypeCancel;
 155         TOUCH_POINT_STATE_UNDEFINED = touchPointUndefined;
 156         TOUCH_POINT_STATE_RELEASED = touchPointReleased;
 157         TOUCH_POINT_STATE_PRESSED = touchPointPressed;
 158         TOUCH_POINT_STATE_MOVED = touchPointMoved;
 159         TOUCH_POINT_STATE_STATIONARY = touchPointStationary;
 160         TOUCH_POINT_STATE_CANCELLED = touchPointCancelled;
 161     }
 162
 163     /**
 164      * Initialize the constants to distinct values if they have not been initialized.
 165      * During pure-Java testing, initializeConstants() may not be called by native code.
 166      * Unit tests should call this method before using the values.
 167      */
 168     static void initializeConstantsForTesting() {
 169         if (TOUCH_EVENT_TYPE_START == TOUCH_EVENT_TYPE_MOVE) {
 170             initializeConstants(0, 1, 2, 3, 4, 5, 6, 7, 8, 9);
 171         }
 172     }
 173 }