content: /*
   * Copyright (C) 2013 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.amnesica.kryptey.inputmethod.keyboard.internal;
  
  import android.util.Log;
  import android.view.MotionEvent;
  
  import com.amnesica.kryptey.inputmethod.keyboard.Key;
  import com.amnesica.kryptey.inputmethod.keyboard.KeyDetector;
  import com.amnesica.kryptey.inputmethod.keyboard.PointerTracker;
  import com.amnesica.kryptey.inputmethod.latin.common.CoordinateUtils;
  
  public final class NonDistinctMultitouchHelper {
    private static final String TAG = NonDistinctMultitouchHelper.class.getSimpleName();
  
    private static final int MAIN_POINTER_TRACKER_ID = 0;
    private int mOldPointerCount = 1;
    private Key mOldKey;
    private final int[] mLastCoords = CoordinateUtils.newInstance();
  
    public void processMotionEvent(final MotionEvent me, final KeyDetector keyDetector) {
      final int pointerCount = me.getPointerCount();
      final int oldPointerCount = mOldPointerCount;
      mOldPointerCount = pointerCount;
      // Ignore continuous multi-touch events because we can't trust the coordinates
      // in multi-touch events.
      if (pointerCount > 1 && oldPointerCount > 1) {
        return;
      }
  
      // Use only main pointer tracker.
      final PointerTracker mainTracker = PointerTracker.getPointerTracker(
          MAIN_POINTER_TRACKER_ID);
      final int action = me.getActionMasked();
      final int index = me.getActionIndex();
      final long eventTime = me.getEventTime();
      final long downTime = me.getDownTime();
  
      // In single-touch.
      if (oldPointerCount == 1 && pointerCount == 1) {
        if (me.getPointerId(index) == mainTracker.mPointerId) {
          mainTracker.processMotionEvent(me, keyDetector);
          return;
        }
        // Inject a copied event.
        injectMotionEvent(action, me.getX(index), me.getY(index), downTime, eventTime,
            mainTracker, keyDetector);
        return;
      }
  
      // Single-touch to multi-touch transition.
      if (oldPointerCount == 1 && pointerCount == 2) {
        // Send an up event for the last pointer, be cause we can't trust the coordinates of
        // this multi-touch event.
        mainTracker.getLastCoordinates(mLastCoords);
        final int x = CoordinateUtils.x(mLastCoords);
        final int y = CoordinateUtils.y(mLastCoords);
        mOldKey = mainTracker.getKeyOn(x, y);
        // Inject an artifact up event for the old key.
        injectMotionEvent(MotionEvent.ACTION_UP, x, y, downTime, eventTime,
            mainTracker, keyDetector);
        return;
      }
  
      // Multi-touch to single-touch transition.
      if (oldPointerCount == 2 && pointerCount == 1) {
        // Send a down event for the latest pointer if the key is different from the previous
        // key.
        final int x = (int) me.getX(index);
        final int y = (int) me.getY(index);
        final Key newKey = mainTracker.getKeyOn(x, y);
        if (mOldKey != newKey) {
          // Inject an artifact down event for the new key.
          // An artifact up event for the new key will usually be injected as a single-touch.
          injectMotionEvent(MotionEvent.ACTION_DOWN, x, y, downTime, eventTime,
              mainTracker, keyDetector);
          if (action == MotionEvent.ACTION_UP) {
            // Inject an artifact up event for the new key also.
            injectMotionEvent(MotionEvent.ACTION_UP, x, y, downTime, eventTime,
                mainTracker, keyDetector);
          }
        }
        return;
      }
  
      Log.w(TAG, "Unknown touch panel behavior: pointer count is "
          + pointerCount + " (previously " + oldPointerCount + ")");
    }
  
    private static void injectMotionEvent(final int action, final float x, final float y,
                                          final long downTime, final long eventTime, final PointerTracker tracker,
                                          final KeyDetector keyDetector) {
      final MotionEvent me = MotionEvent.obtain(
          downTime, eventTime, action, x, y, 0 /* metaState */);
      try {
        tracker.processMotionEvent(me, keyDetector);
      } finally {
        me.recycle();
      }
    }
  }
  