Refactor getKeyIndexAndNearbyCodes into independent class

Bug: 2910379
Change-Id: Ib26a898ea108ee4292f9f91b6d7d10c1fc380fd1

1 files changed, 113 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/latin/ProximityKeyDetector.java b/java/src/com/android/inputmethod/latin/ProximityKeyDetector.java
new file mode 100644
index 000000000..eae2d7f08
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/ProximityKeyDetector.java
@@ -0,0 +1,113 @@
+/*
+ * 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.latin;
+
+import android.inputmethodservice.Keyboard;
+import android.inputmethodservice.Keyboard.Key;
+
+import java.util.Arrays;
+
+class ProximityKeyDetector {
+    private static final int MAX_NEARBY_KEYS = 12;
+
+    private Keyboard mKeyboard;
+    private Key[] mKeys;
+
+    private boolean mProximityCorrectOn;
+    private int mProximityThresholdSquare;
+
+    // working area
+    private int[] mDistances = new int[MAX_NEARBY_KEYS];
+
+    public void setKeyboard(Keyboard keyboard, Key[] keys) {
+        if (keyboard == null || keys == null)
+            throw new NullPointerException();
+        mKeyboard = keyboard;
+        mKeys = keys;
+    }
+
+    public void setProximityCorrectionEnabled(boolean enabled) {
+        mProximityCorrectOn = enabled;
+    }
+
+    public boolean isProximityCorrectionEnabled() {
+        return mProximityCorrectOn;
+    }
+
+    public void setProximityThreshold(int threshold) {
+        mProximityThresholdSquare = threshold * threshold;
+    }
+
+    public int[] newCodeArray() {
+        int[] codes = new int[MAX_NEARBY_KEYS];
+        Arrays.fill(codes, LatinKeyboardBaseView.NOT_A_KEY);
+        return codes;
+    }
+
+    public int getKeyIndexAndNearbyCodes(int x, int y, int[] allKeys) {
+        final Key[] keys = mKeys;
+        if (keys == null)
+            throw new IllegalStateException("keyboard isn't set");
+        // mKeyboard is guaranteed not null at setKeybaord() method
+        int primaryIndex = LatinKeyboardBaseView.NOT_A_KEY;
+        int closestKey = LatinKeyboardBaseView.NOT_A_KEY;
+        int closestKeyDist = mProximityThresholdSquare + 1;
+        int[] distances = mDistances;
+        Arrays.fill(distances, Integer.MAX_VALUE);
+        int [] nearestKeyIndices = mKeyboard.getNearestKeys(x, y);
+        final int keyCount = nearestKeyIndices.length;
+        for (int i = 0; i < keyCount; i++) {
+            final Key key = keys[nearestKeyIndices[i]];
+            int dist = 0;
+            boolean isInside = key.isInside(x,y);
+            if (isInside) {
+                primaryIndex = nearestKeyIndices[i];
+            }
+
+            if (((mProximityCorrectOn
+                    && (dist = key.squaredDistanceFrom(x, y)) < mProximityThresholdSquare)
+                    || isInside)
+                    && key.codes[0] > 32) {
+                // Find insertion point
+                final int nCodes = key.codes.length;
+                if (dist < closestKeyDist) {
+                    closestKeyDist = dist;
+                    closestKey = nearestKeyIndices[i];
+                }
+
+                if (allKeys == null) continue;
+
+                for (int j = 0; j < distances.length; j++) {
+                    if (distances[j] > dist) {
+                        // Make space for nCodes codes
+                        System.arraycopy(distances, j, distances, j + nCodes,
+                                distances.length - j - nCodes);
+                        System.arraycopy(allKeys, j, allKeys, j + nCodes,
+                                allKeys.length - j - nCodes);
+                        System.arraycopy(key.codes, 0, allKeys, j, nCodes);
+                        Arrays.fill(distances, j, j + nCodes, dist);
+                        break;
+                    }
+                }
+            }
+        }
+        if (primaryIndex == LatinKeyboardBaseView.NOT_A_KEY) {
+            primaryIndex = closestKey;
+        }
+        return primaryIndex;
+    }
+}
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