LatinIME/java/src/com/android/inputmethod/keyboard/KeyDetector.java

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/*
* Copyright (C) 2010 Google Inc.
*
* 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.android.inputmethod.keyboard;
import java.util.Arrays;
import java.util.List;
public abstract class KeyDetector {
public static final int NOT_A_KEY = -1;
protected Keyboard mKeyboard;
private Key[] mKeys;
protected int mCorrectionX;
protected int mCorrectionY;
protected boolean mProximityCorrectOn;
protected int mProximityThresholdSquare;
public Key[] setKeyboard(Keyboard keyboard, float correctionX, float correctionY) {
if (keyboard == null)
throw new NullPointerException();
mCorrectionX = (int)correctionX;
mCorrectionY = (int)correctionY;
mKeyboard = keyboard;
List<Key> keys = mKeyboard.getKeys();
Key[] array = keys.toArray(new Key[keys.size()]);
mKeys = array;
return array;
}
protected int getTouchX(int x) {
return x + mCorrectionX;
}
protected int getTouchY(int y) {
return y + mCorrectionY;
}
protected Key[] getKeys() {
if (mKeys == null)
throw new IllegalStateException("keyboard isn't set");
// mKeyboard is guaranteed not to be null at setKeybaord() method if mKeys is not null
return mKeys;
}
public void setProximityCorrectionEnabled(boolean enabled) {
mProximityCorrectOn = enabled;
}
public boolean isProximityCorrectionEnabled() {
return mProximityCorrectOn;
}
public void setProximityThreshold(int threshold) {
mProximityThresholdSquare = threshold * threshold;
}
/**
* Allocates array that can hold all key indices returned by {@link #getKeyIndexAndNearbyCodes}
* method. The maximum size of the array should be computed by {@link #getMaxNearbyKeys}.
*
* @return Allocates and returns an array that can hold all key indices returned by
* {@link #getKeyIndexAndNearbyCodes} method. All elements in the returned array are
* initialized by {@link com.android.inputmethod.latin.LatinKeyboardView.NOT_A_KEY}
* value.
*/
public int[] newCodeArray() {
int[] codes = new int[getMaxNearbyKeys()];
Arrays.fill(codes, NOT_A_KEY);
return codes;
}
/**
* Computes maximum size of the array that can contain all nearby key indices returned by
* {@link #getKeyIndexAndNearbyCodes}.
*
* @return Returns maximum size of the array that can contain all nearby key indices returned
* by {@link #getKeyIndexAndNearbyCodes}.
*/
abstract protected int getMaxNearbyKeys();
/**
* Finds all possible nearby key indices around a touch event point and returns the nearest key
* index. The algorithm to determine the nearby keys depends on the threshold set by
* {@link #setProximityThreshold(int)} and the mode set by
* {@link #setProximityCorrectionEnabled(boolean)}.
*
* @param x The x-coordinate of a touch point
* @param y The y-coordinate of a touch point
* @param allKeys All nearby key indices are returned in this array
* @return The nearest key index
*/
abstract public int getKeyIndexAndNearbyCodes(int x, int y, int[] allKeys);
}