content: /*
   * Copyright (C) 2010 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;
  
  /**
   * This class handles key detection.
   */
  public class KeyDetector {
    private final int mKeyHysteresisDistanceSquared;
    private final int mKeyHysteresisDistanceForSlidingModifierSquared;
  
    private Keyboard mKeyboard;
    private int mCorrectionX;
    private int mCorrectionY;
  
    public KeyDetector() {
      this(0.0f /* keyHysteresisDistance */, 0.0f /* keyHysteresisDistanceForSlidingModifier */);
    }
  
    /**
     * Key detection object constructor with key hysteresis distances.
     *
     * @param keyHysteresisDistance                   if the pointer movement distance is smaller than this, the
     *                                                movement will not be handled as meaningful movement. The unit is pixel.
     * @param keyHysteresisDistanceForSlidingModifier the same parameter for sliding input that
     *                                                starts from a modifier key such as shift and symbols key.
     */
    public KeyDetector(final float keyHysteresisDistance,
                       final float keyHysteresisDistanceForSlidingModifier) {
      mKeyHysteresisDistanceSquared = (int) (keyHysteresisDistance * keyHysteresisDistance);
      mKeyHysteresisDistanceForSlidingModifierSquared = (int) (
          keyHysteresisDistanceForSlidingModifier * keyHysteresisDistanceForSlidingModifier);
    }
  
    public void setKeyboard(final Keyboard keyboard, final float correctionX,
                            final float correctionY) {
      if (keyboard == null) {
        throw new NullPointerException();
      }
      mCorrectionX = (int) correctionX;
      mCorrectionY = (int) correctionY;
      mKeyboard = keyboard;
    }
  
    public int getKeyHysteresisDistanceSquared(final boolean isSlidingFromModifier) {
      return isSlidingFromModifier
          ? mKeyHysteresisDistanceForSlidingModifierSquared : mKeyHysteresisDistanceSquared;
    }
  
    public int getTouchX(final int x) {
      return x + mCorrectionX;
    }
  
    // TODO: Remove vertical correction.
    public int getTouchY(final int y) {
      return y + mCorrectionY;
    }
  
    public Keyboard getKeyboard() {
      return mKeyboard;
    }
  
    public boolean alwaysAllowsKeySelectionByDraggingFinger() {
      return false;
    }
  
    /**
     * Detect the key whose hitbox the touch point is in.
     *
     * @param x The x-coordinate of a touch point
     * @param y The y-coordinate of a touch point
     * @return the key that the touch point hits.
     */
    public Key detectHitKey(final int x, final int y) {
      if (mKeyboard == null) {
        return null;
      }
      final int touchX = getTouchX(x);
      final int touchY = getTouchY(y);
  
      for (final Key key : mKeyboard.getNearestKeys(touchX, touchY)) {
        if (key.isOnKey(touchX, touchY)) {
          return key;
        }
      }
      return null;
    }
  }
  