import WhiteRectangleDetector from '../../common/detector/WhiteRectangleDetector';
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import DetectorResult from '../../common/DetectorResult';
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import GridSamplerInstance from '../../common/GridSamplerInstance';
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import NotFoundException from '../../NotFoundException';
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import ResultPoint from '../../ResultPoint';
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/*
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* Copyright 2008 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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/**
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* <p>Encapsulates logic that can detect a Data Matrix Code in an image, even if the Data Matrix 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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this.rectangleDetector = new WhiteRectangleDetector(this.image);
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}
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/**
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* <p>Detects a Data Matrix Code in an image.</p>
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*
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* @return {@link DetectorResult} encapsulating results of detecting a Data Matrix Code
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* @throws NotFoundException if no Data Matrix Code can be found
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*/
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detect() {
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const cornerPoints = this.rectangleDetector.detect();
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let points = this.detectSolid1(cornerPoints);
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points = this.detectSolid2(points);
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points[3] = this.correctTopRight(points);
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if (!points[3]) {
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throw new NotFoundException();
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}
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points = this.shiftToModuleCenter(points);
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const topLeft = points[0];
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const bottomLeft = points[1];
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const bottomRight = points[2];
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const topRight = points[3];
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let dimensionTop = this.transitionsBetween(topLeft, topRight) + 1;
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let dimensionRight = this.transitionsBetween(bottomRight, topRight) + 1;
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if ((dimensionTop & 0x01) === 1) {
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dimensionTop += 1;
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}
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if ((dimensionRight & 0x01) === 1) {
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dimensionRight += 1;
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}
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if (4 * dimensionTop < 7 * dimensionRight && 4 * dimensionRight < 7 * dimensionTop) {
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// The matrix is square
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dimensionTop = dimensionRight = Math.max(dimensionTop, dimensionRight);
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}
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let bits = Detector.sampleGrid(this.image, topLeft, bottomLeft, bottomRight, topRight, dimensionTop, dimensionRight);
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return new DetectorResult(bits, [topLeft, bottomLeft, bottomRight, topRight]);
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}
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static shiftPoint(point, to, div) {
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let x = (to.getX() - point.getX()) / (div + 1);
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let y = (to.getY() - point.getY()) / (div + 1);
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return new ResultPoint(point.getX() + x, point.getY() + y);
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}
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static moveAway(point, fromX, fromY) {
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let x = point.getX();
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let y = point.getY();
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if (x < fromX) {
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x -= 1;
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}
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else {
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x += 1;
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}
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if (y < fromY) {
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y -= 1;
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}
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else {
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y += 1;
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}
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return new ResultPoint(x, y);
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}
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/**
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* Detect a solid side which has minimum transition.
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*/
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detectSolid1(cornerPoints) {
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// 0 2
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// 1 3
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let pointA = cornerPoints[0];
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let pointB = cornerPoints[1];
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let pointC = cornerPoints[3];
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let pointD = cornerPoints[2];
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let trAB = this.transitionsBetween(pointA, pointB);
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let trBC = this.transitionsBetween(pointB, pointC);
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let trCD = this.transitionsBetween(pointC, pointD);
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let trDA = this.transitionsBetween(pointD, pointA);
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// 0..3
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// : :
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// 1--2
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let min = trAB;
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let points = [pointD, pointA, pointB, pointC];
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if (min > trBC) {
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min = trBC;
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points[0] = pointA;
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points[1] = pointB;
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points[2] = pointC;
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points[3] = pointD;
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}
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if (min > trCD) {
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min = trCD;
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points[0] = pointB;
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points[1] = pointC;
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points[2] = pointD;
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points[3] = pointA;
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}
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if (min > trDA) {
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points[0] = pointC;
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points[1] = pointD;
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points[2] = pointA;
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points[3] = pointB;
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}
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return points;
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}
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/**
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* Detect a second solid side next to first solid side.
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*/
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detectSolid2(points) {
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// A..D
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// : :
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// B--C
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let pointA = points[0];
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let pointB = points[1];
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let pointC = points[2];
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let pointD = points[3];
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// Transition detection on the edge is not stable.
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// To safely detect, shift the points to the module center.
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let tr = this.transitionsBetween(pointA, pointD);
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let pointBs = Detector.shiftPoint(pointB, pointC, (tr + 1) * 4);
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let pointCs = Detector.shiftPoint(pointC, pointB, (tr + 1) * 4);
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let trBA = this.transitionsBetween(pointBs, pointA);
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let trCD = this.transitionsBetween(pointCs, pointD);
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// 0..3
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// | :
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// 1--2
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if (trBA < trCD) {
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// solid sides: A-B-C
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points[0] = pointA;
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points[1] = pointB;
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points[2] = pointC;
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points[3] = pointD;
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}
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else {
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// solid sides: B-C-D
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points[0] = pointB;
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points[1] = pointC;
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points[2] = pointD;
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points[3] = pointA;
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}
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return points;
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}
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/**
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* Calculates the corner position of the white top right module.
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*/
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correctTopRight(points) {
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// A..D
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// | :
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// B--C
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let pointA = points[0];
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let pointB = points[1];
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let pointC = points[2];
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let pointD = points[3];
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// shift points for safe transition detection.
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let trTop = this.transitionsBetween(pointA, pointD);
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let trRight = this.transitionsBetween(pointB, pointD);
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let pointAs = Detector.shiftPoint(pointA, pointB, (trRight + 1) * 4);
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let pointCs = Detector.shiftPoint(pointC, pointB, (trTop + 1) * 4);
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trTop = this.transitionsBetween(pointAs, pointD);
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trRight = this.transitionsBetween(pointCs, pointD);
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let candidate1 = new ResultPoint(pointD.getX() + (pointC.getX() - pointB.getX()) / (trTop + 1), pointD.getY() + (pointC.getY() - pointB.getY()) / (trTop + 1));
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let candidate2 = new ResultPoint(pointD.getX() + (pointA.getX() - pointB.getX()) / (trRight + 1), pointD.getY() + (pointA.getY() - pointB.getY()) / (trRight + 1));
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if (!this.isValid(candidate1)) {
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if (this.isValid(candidate2)) {
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return candidate2;
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}
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return null;
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}
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if (!this.isValid(candidate2)) {
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return candidate1;
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}
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let sumc1 = this.transitionsBetween(pointAs, candidate1) + this.transitionsBetween(pointCs, candidate1);
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let sumc2 = this.transitionsBetween(pointAs, candidate2) + this.transitionsBetween(pointCs, candidate2);
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if (sumc1 > sumc2) {
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return candidate1;
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}
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else {
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return candidate2;
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}
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}
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/**
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* Shift the edge points to the module center.
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*/
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shiftToModuleCenter(points) {
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// A..D
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// | :
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// B--C
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let pointA = points[0];
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let pointB = points[1];
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let pointC = points[2];
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let pointD = points[3];
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// calculate pseudo dimensions
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let dimH = this.transitionsBetween(pointA, pointD) + 1;
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let dimV = this.transitionsBetween(pointC, pointD) + 1;
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// shift points for safe dimension detection
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let pointAs = Detector.shiftPoint(pointA, pointB, dimV * 4);
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let pointCs = Detector.shiftPoint(pointC, pointB, dimH * 4);
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// calculate more precise dimensions
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dimH = this.transitionsBetween(pointAs, pointD) + 1;
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dimV = this.transitionsBetween(pointCs, pointD) + 1;
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if ((dimH & 0x01) === 1) {
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dimH += 1;
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}
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if ((dimV & 0x01) === 1) {
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dimV += 1;
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}
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// WhiteRectangleDetector returns points inside of the rectangle.
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// I want points on the edges.
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let centerX = (pointA.getX() + pointB.getX() + pointC.getX() + pointD.getX()) / 4;
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let centerY = (pointA.getY() + pointB.getY() + pointC.getY() + pointD.getY()) / 4;
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pointA = Detector.moveAway(pointA, centerX, centerY);
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pointB = Detector.moveAway(pointB, centerX, centerY);
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pointC = Detector.moveAway(pointC, centerX, centerY);
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pointD = Detector.moveAway(pointD, centerX, centerY);
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let pointBs;
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let pointDs;
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// shift points to the center of each modules
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pointAs = Detector.shiftPoint(pointA, pointB, dimV * 4);
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pointAs = Detector.shiftPoint(pointAs, pointD, dimH * 4);
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pointBs = Detector.shiftPoint(pointB, pointA, dimV * 4);
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pointBs = Detector.shiftPoint(pointBs, pointC, dimH * 4);
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pointCs = Detector.shiftPoint(pointC, pointD, dimV * 4);
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pointCs = Detector.shiftPoint(pointCs, pointB, dimH * 4);
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pointDs = Detector.shiftPoint(pointD, pointC, dimV * 4);
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pointDs = Detector.shiftPoint(pointDs, pointA, dimH * 4);
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return [pointAs, pointBs, pointCs, pointDs];
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}
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isValid(p) {
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return p.getX() >= 0 && p.getX() < this.image.getWidth() && p.getY() > 0 && p.getY() < this.image.getHeight();
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}
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static sampleGrid(image, topLeft, bottomLeft, bottomRight, topRight, dimensionX, dimensionY) {
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const sampler = GridSamplerInstance.getInstance();
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return sampler.sampleGrid(image, dimensionX, dimensionY, 0.5, 0.5, dimensionX - 0.5, 0.5, dimensionX - 0.5, dimensionY - 0.5, 0.5, dimensionY - 0.5, topLeft.getX(), topLeft.getY(), topRight.getX(), topRight.getY(), bottomRight.getX(), bottomRight.getY(), bottomLeft.getX(), bottomLeft.getY());
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}
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/**
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* Counts the number of black/white transitions between two points, using something like Bresenham's algorithm.
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*/
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transitionsBetween(from, to) {
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// See QR Code Detector, sizeOfBlackWhiteBlackRun()
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let fromX = Math.trunc(from.getX());
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let fromY = Math.trunc(from.getY());
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let toX = Math.trunc(to.getX());
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let toY = Math.trunc(to.getY());
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let 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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let dx = Math.abs(toX - fromX);
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let dy = Math.abs(toY - fromY);
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let error = -dx / 2;
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let ystep = fromY < toY ? 1 : -1;
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let xstep = fromX < toX ? 1 : -1;
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let transitions = 0;
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let inBlack = this.image.get(steep ? fromY : fromX, steep ? fromX : fromY);
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for (let x = fromX, y = fromY; x !== toX; x += xstep) {
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let isBlack = this.image.get(steep ? y : x, steep ? x : y);
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if (isBlack !== inBlack) {
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transitions++;
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inBlack = isBlack;
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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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return transitions;
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}
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}
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