1 files changed, 112 insertions, 0 deletions
diff --git a/java/src/com/android/inputmethod/keyboard/KeyDetector.java b/java/src/com/android/inputmethod/keyboard/KeyDetector.java
new file mode 100644
index 000000000..777a79520
--- /dev/null
+++ b/java/src/com/android/inputmethod/keyboard/KeyDetector.java
@@ -0,0 +1,112 @@
+/*
+ * 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);
+}