2 * Copyright 2007 ZXing authors
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 package com.google.zxing.qrcode.detector;
19 import com.google.zxing.ResultPoint;
22 * <p>Encapsulates an alignment pattern, which are the smaller square patterns found in
23 * all but the simplest QR Codes.</p>
27 public final class AlignmentPattern extends ResultPoint {
29 private final float estimatedModuleSize;
31 AlignmentPattern(float posX, float posY, float estimatedModuleSize) {
33 this.estimatedModuleSize = estimatedModuleSize;
37 * <p>Determines if this alignment pattern "about equals" an alignment pattern at the stated
38 * position and size -- meaning, it is at nearly the same center with nearly the same size.</p>
40 boolean aboutEquals(float moduleSize, float i, float j) {
41 if (Math.abs(i - getY()) <= moduleSize && Math.abs(j - getX()) <= moduleSize) {
42 float moduleSizeDiff = Math.abs(moduleSize - estimatedModuleSize);
43 return moduleSizeDiff <= 1.0f || moduleSizeDiff <= estimatedModuleSize;
49 * Combines this object's current estimate of a finder pattern position and module size
50 * with a new estimate. It returns a new {@code FinderPattern} containing an average of the two.
52 AlignmentPattern combineEstimate(float i, float j, float newModuleSize) {
53 float combinedX = (getX() + j) / 2.0f;
54 float combinedY = (getY() + i) / 2.0f;
55 float combinedModuleSize = (estimatedModuleSize + newModuleSize) / 2.0f;
56 return new AlignmentPattern(combinedX, combinedY, combinedModuleSize);