/*
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* Copyright 2007 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import MathUtils from '../../common/detector/MathUtils';
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import DetectorResult from '../../common/DetectorResult';
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// import GridSampler from '../../common/GridSampler';
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import GridSamplerInstance from '../../common/GridSamplerInstance';
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import PerspectiveTransform from '../../common/PerspectiveTransform';
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import DecodeHintType from '../../DecodeHintType';
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import NotFoundException from '../../NotFoundException';
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import ResultPoint from '../../ResultPoint';
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import Version from '../decoder/Version';
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import AlignmentPatternFinder from './AlignmentPatternFinder';
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import FinderPatternFinder from './FinderPatternFinder';
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/*import java.util.Map;*/
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/**
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* <p>Encapsulates logic that can detect a QR Code in an image, even if the QR Code
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* is rotated or skewed, or partially obscured.</p>
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*
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* @author Sean Owen
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*/
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export default class Detector {
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constructor(image) {
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this.image = image;
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}
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getImage() {
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return this.image;
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}
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getResultPointCallback() {
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return this.resultPointCallback;
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}
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/**
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* <p>Detects a QR Code in an image.</p>
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*
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* @return {@link DetectorResult} encapsulating results of detecting a QR Code
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* @throws NotFoundException if QR Code cannot be found
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* @throws FormatException if a QR Code cannot be decoded
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*/
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// public detect(): DetectorResult /*throws NotFoundException, FormatException*/ {
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// return detect(null)
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// }
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/**
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* <p>Detects a QR Code in an image.</p>
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*
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* @param hints optional hints to detector
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* @return {@link DetectorResult} encapsulating results of detecting a QR Code
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* @throws NotFoundException if QR Code cannot be found
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* @throws FormatException if a QR Code cannot be decoded
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*/
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detect(hints) {
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this.resultPointCallback = (hints === null || hints === undefined) ? null :
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/*(ResultPointCallback) */ hints.get(DecodeHintType.NEED_RESULT_POINT_CALLBACK);
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const finder = new FinderPatternFinder(this.image, this.resultPointCallback);
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const info = finder.find(hints);
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return this.processFinderPatternInfo(info);
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}
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processFinderPatternInfo(info) {
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const topLeft = info.getTopLeft();
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const topRight = info.getTopRight();
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const bottomLeft = info.getBottomLeft();
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const moduleSize = this.calculateModuleSize(topLeft, topRight, bottomLeft);
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if (moduleSize < 1.0) {
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throw new NotFoundException('No pattern found in proccess finder.');
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}
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const dimension = Detector.computeDimension(topLeft, topRight, bottomLeft, moduleSize);
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const provisionalVersion = Version.getProvisionalVersionForDimension(dimension);
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const modulesBetweenFPCenters = provisionalVersion.getDimensionForVersion() - 7;
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let alignmentPattern = null;
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// Anything above version 1 has an alignment pattern
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if (provisionalVersion.getAlignmentPatternCenters().length > 0) {
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// Guess where a "bottom right" finder pattern would have been
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const bottomRightX = topRight.getX() - topLeft.getX() + bottomLeft.getX();
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const bottomRightY = topRight.getY() - topLeft.getY() + bottomLeft.getY();
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// Estimate that alignment pattern is closer by 3 modules
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// from "bottom right" to known top left location
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const correctionToTopLeft = 1.0 - 3.0 / modulesBetweenFPCenters;
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const estAlignmentX = /*(int) */ Math.floor(topLeft.getX() + correctionToTopLeft * (bottomRightX - topLeft.getX()));
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const estAlignmentY = /*(int) */ Math.floor(topLeft.getY() + correctionToTopLeft * (bottomRightY - topLeft.getY()));
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// Kind of arbitrary -- expand search radius before giving up
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for (let i = 4; i <= 16; i <<= 1) {
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try {
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alignmentPattern = this.findAlignmentInRegion(moduleSize, estAlignmentX, estAlignmentY, i);
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break;
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}
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catch (re /*NotFoundException*/) {
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if (!(re instanceof NotFoundException)) {
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throw re;
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}
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// try next round
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}
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}
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// If we didn't find alignment pattern... well try anyway without it
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}
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const transform = Detector.createTransform(topLeft, topRight, bottomLeft, alignmentPattern, dimension);
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const bits = Detector.sampleGrid(this.image, transform, dimension);
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let points;
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if (alignmentPattern === null) {
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points = [bottomLeft, topLeft, topRight];
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}
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else {
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points = [bottomLeft, topLeft, topRight, alignmentPattern];
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}
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return new DetectorResult(bits, points);
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}
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static createTransform(topLeft, topRight, bottomLeft, alignmentPattern, dimension /*int*/) {
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const dimMinusThree = dimension - 3.5;
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let bottomRightX; /*float*/
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let bottomRightY; /*float*/
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let sourceBottomRightX; /*float*/
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let sourceBottomRightY; /*float*/
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if (alignmentPattern !== null) {
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bottomRightX = alignmentPattern.getX();
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bottomRightY = alignmentPattern.getY();
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sourceBottomRightX = dimMinusThree - 3.0;
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sourceBottomRightY = sourceBottomRightX;
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}
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else {
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// Don't have an alignment pattern, just make up the bottom-right point
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bottomRightX = (topRight.getX() - topLeft.getX()) + bottomLeft.getX();
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bottomRightY = (topRight.getY() - topLeft.getY()) + bottomLeft.getY();
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sourceBottomRightX = dimMinusThree;
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sourceBottomRightY = dimMinusThree;
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}
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return PerspectiveTransform.quadrilateralToQuadrilateral(3.5, 3.5, dimMinusThree, 3.5, sourceBottomRightX, sourceBottomRightY, 3.5, dimMinusThree, topLeft.getX(), topLeft.getY(), topRight.getX(), topRight.getY(), bottomRightX, bottomRightY, bottomLeft.getX(), bottomLeft.getY());
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}
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static sampleGrid(image, transform, dimension /*int*/) {
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const sampler = GridSamplerInstance.getInstance();
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return sampler.sampleGridWithTransform(image, dimension, dimension, transform);
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}
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/**
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* <p>Computes the dimension (number of modules on a size) of the QR Code based on the position
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* of the finder patterns and estimated module size.</p>
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*/
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static computeDimension(topLeft, topRight, bottomLeft, moduleSize /*float*/) {
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const tltrCentersDimension = MathUtils.round(ResultPoint.distance(topLeft, topRight) / moduleSize);
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const tlblCentersDimension = MathUtils.round(ResultPoint.distance(topLeft, bottomLeft) / moduleSize);
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let dimension = Math.floor((tltrCentersDimension + tlblCentersDimension) / 2) + 7;
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switch (dimension & 0x03) { // mod 4
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case 0:
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dimension++;
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break;
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// 1? do nothing
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case 2:
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dimension--;
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break;
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case 3:
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throw new NotFoundException('Dimensions could be not found.');
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}
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return dimension;
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}
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/**
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* <p>Computes an average estimated module size based on estimated derived from the positions
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* of the three finder patterns.</p>
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*
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* @param topLeft detected top-left finder pattern center
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* @param topRight detected top-right finder pattern center
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* @param bottomLeft detected bottom-left finder pattern center
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* @return estimated module size
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*/
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calculateModuleSize(topLeft, topRight, bottomLeft) {
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// Take the average
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return (this.calculateModuleSizeOneWay(topLeft, topRight) +
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this.calculateModuleSizeOneWay(topLeft, bottomLeft)) / 2.0;
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}
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/**
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* <p>Estimates module size based on two finder patterns -- it uses
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* {@link #sizeOfBlackWhiteBlackRunBothWays(int, int, int, int)} to figure the
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* width of each, measuring along the axis between their centers.</p>
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*/
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calculateModuleSizeOneWay(pattern, otherPattern) {
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const moduleSizeEst1 = this.sizeOfBlackWhiteBlackRunBothWays(/*(int) */ Math.floor(pattern.getX()),
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/*(int) */ Math.floor(pattern.getY()),
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/*(int) */ Math.floor(otherPattern.getX()),
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/*(int) */ Math.floor(otherPattern.getY()));
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const moduleSizeEst2 = this.sizeOfBlackWhiteBlackRunBothWays(/*(int) */ Math.floor(otherPattern.getX()),
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/*(int) */ Math.floor(otherPattern.getY()),
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/*(int) */ Math.floor(pattern.getX()),
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/*(int) */ Math.floor(pattern.getY()));
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if (isNaN(moduleSizeEst1)) {
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return moduleSizeEst2 / 7.0;
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}
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if (isNaN(moduleSizeEst2)) {
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return moduleSizeEst1 / 7.0;
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}
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// Average them, and divide by 7 since we've counted the width of 3 black modules,
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// and 1 white and 1 black module on either side. Ergo, divide sum by 14.
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return (moduleSizeEst1 + moduleSizeEst2) / 14.0;
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}
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/**
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* See {@link #sizeOfBlackWhiteBlackRun(int, int, int, int)}; computes the total width of
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* a finder pattern by looking for a black-white-black run from the center in the direction
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* of another point (another finder pattern center), and in the opposite direction too.
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*/
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sizeOfBlackWhiteBlackRunBothWays(fromX /*int*/, fromY /*int*/, toX /*int*/, toY /*int*/) {
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let result = this.sizeOfBlackWhiteBlackRun(fromX, fromY, toX, toY);
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// Now count other way -- don't run off image though of course
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let scale = 1.0;
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let otherToX = fromX - (toX - fromX);
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if (otherToX < 0) {
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scale = fromX / /*(float) */ (fromX - otherToX);
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otherToX = 0;
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}
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else if (otherToX >= this.image.getWidth()) {
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scale = (this.image.getWidth() - 1 - fromX) / /*(float) */ (otherToX - fromX);
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otherToX = this.image.getWidth() - 1;
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}
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let otherToY = /*(int) */ Math.floor(fromY - (toY - fromY) * scale);
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scale = 1.0;
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if (otherToY < 0) {
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scale = fromY / /*(float) */ (fromY - otherToY);
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otherToY = 0;
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}
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else if (otherToY >= this.image.getHeight()) {
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scale = (this.image.getHeight() - 1 - fromY) / /*(float) */ (otherToY - fromY);
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otherToY = this.image.getHeight() - 1;
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}
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otherToX = /*(int) */ Math.floor(fromX + (otherToX - fromX) * scale);
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result += this.sizeOfBlackWhiteBlackRun(fromX, fromY, otherToX, otherToY);
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// Middle pixel is double-counted this way; subtract 1
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return result - 1.0;
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}
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/**
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* <p>This method traces a line from a point in the image, in the direction towards another point.
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* It begins in a black region, and keeps going until it finds white, then black, then white again.
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* It reports the distance from the start to this point.</p>
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*
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* <p>This is used when figuring out how wide a finder pattern is, when the finder pattern
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* may be skewed or rotated.</p>
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*/
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sizeOfBlackWhiteBlackRun(fromX /*int*/, fromY /*int*/, toX /*int*/, toY /*int*/) {
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// Mild variant of Bresenham's algorithm
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// see http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
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const steep = Math.abs(toY - fromY) > Math.abs(toX - fromX);
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if (steep) {
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let temp = fromX;
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fromX = fromY;
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fromY = temp;
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temp = toX;
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toX = toY;
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toY = temp;
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}
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const dx = Math.abs(toX - fromX);
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const dy = Math.abs(toY - fromY);
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let error = -dx / 2;
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const xstep = fromX < toX ? 1 : -1;
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const ystep = fromY < toY ? 1 : -1;
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// In black pixels, looking for white, first or second time.
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let state = 0;
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// Loop up until x == toX, but not beyond
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const xLimit = toX + xstep;
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for (let x = fromX, y = fromY; x !== xLimit; x += xstep) {
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const realX = steep ? y : x;
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const realY = steep ? x : y;
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// Does current pixel mean we have moved white to black or vice versa?
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// Scanning black in state 0,2 and white in state 1, so if we find the wrong
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// color, advance to next state or end if we are in state 2 already
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if ((state === 1) === this.image.get(realX, realY)) {
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if (state === 2) {
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return MathUtils.distance(x, y, fromX, fromY);
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}
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state++;
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}
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error += dy;
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if (error > 0) {
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if (y === toY) {
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break;
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}
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y += ystep;
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error -= dx;
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}
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}
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// Found black-white-black; give the benefit of the doubt that the next pixel outside the image
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// is "white" so this last point at (toX+xStep,toY) is the right ending. This is really a
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// small approximation; (toX+xStep,toY+yStep) might be really correct. Ignore this.
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if (state === 2) {
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return MathUtils.distance(toX + xstep, toY, fromX, fromY);
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}
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// else we didn't find even black-white-black; no estimate is really possible
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return NaN;
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}
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/**
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* <p>Attempts to locate an alignment pattern in a limited region of the image, which is
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* guessed to contain it. This method uses {@link AlignmentPattern}.</p>
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*
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* @param overallEstModuleSize estimated module size so far
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* @param estAlignmentX x coordinate of center of area probably containing alignment pattern
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* @param estAlignmentY y coordinate of above
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* @param allowanceFactor number of pixels in all directions to search from the center
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* @return {@link AlignmentPattern} if found, or null otherwise
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* @throws NotFoundException if an unexpected error occurs during detection
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*/
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findAlignmentInRegion(overallEstModuleSize /*float*/, estAlignmentX /*int*/, estAlignmentY /*int*/, allowanceFactor /*float*/) {
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// Look for an alignment pattern (3 modules in size) around where it
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// should be
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const allowance = /*(int) */ Math.floor(allowanceFactor * overallEstModuleSize);
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const alignmentAreaLeftX = Math.max(0, estAlignmentX - allowance);
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const alignmentAreaRightX = Math.min(this.image.getWidth() - 1, estAlignmentX + allowance);
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if (alignmentAreaRightX - alignmentAreaLeftX < overallEstModuleSize * 3) {
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throw new NotFoundException('Alignment top exceeds estimated module size.');
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}
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const alignmentAreaTopY = Math.max(0, estAlignmentY - allowance);
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const alignmentAreaBottomY = Math.min(this.image.getHeight() - 1, estAlignmentY + allowance);
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if (alignmentAreaBottomY - alignmentAreaTopY < overallEstModuleSize * 3) {
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throw new NotFoundException('Alignment bottom exceeds estimated module size.');
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}
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const alignmentFinder = new AlignmentPatternFinder(this.image, alignmentAreaLeftX, alignmentAreaTopY, alignmentAreaRightX - alignmentAreaLeftX, alignmentAreaBottomY - alignmentAreaTopY, overallEstModuleSize, this.resultPointCallback);
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return alignmentFinder.find();
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}
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}
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