406 lines
16 KiB
PHP
406 lines
16 KiB
PHP
<?php
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/*
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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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namespace Zxing\Qrcode\Detector;
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use Zxing\DecodeHintType;
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use Zxing\FormatException;
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use Zxing\NotFoundException;
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use Zxing\ResultPoint;
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use Zxing\ResultPointCallback;
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use Zxing\Common\BitMatrix;
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use Zxing\Common\DetectorResult;
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use Zxing\Common\GridSampler;
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use Zxing\Common\PerspectiveTransform;
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use Zxing\Common\Detector\MathUtils;
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use Zxing\Qrcode\Decoder\Version;
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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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?>
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<?php
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class Detector {
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private $image;
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private $resultPointCallback;
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public function __construct($image) {
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$this->image = $image;
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}
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protected final function getImage() {
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return $this->image;
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}
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protected final function getResultPointCallback() {
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return $this->resultPointCallback;
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}
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/**
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* <p>Detects a QR Code in an image.</p>
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*
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* @return {@link DetectorResult} encapsulating results of detecting a QR Code
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* @throws NotFoundException if QR Code cannot be found
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* @throws FormatException if a QR Code cannot be decoded
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*/
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/**
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* <p>Detects a QR Code in an image.</p>
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*
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* @param hints optional hints to detector
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* @return {@link DetectorResult} encapsulating results of detecting a QR Code
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* @throws NotFoundException if QR Code cannot be found
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* @throws FormatException if a QR Code cannot be decoded
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*/
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public final function detect($hints=null){/*Map<DecodeHintType,?>*/
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$resultPointCallback = $hints == null ? null :
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$hints->get('NEED_RESULT_POINT_CALLBACK');
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/* resultPointCallback = hints == null ? null :
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(ResultPointCallback) hints.get(DecodeHintType.NEED_RESULT_POINT_CALLBACK);*/
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$finder = new FinderPatternFinder($this->image, $resultPointCallback);
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$info = $finder->find($hints);
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return $this->processFinderPatternInfo($info);
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}
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protected final function processFinderPatternInfo($info){
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$topLeft = $info->getTopLeft();
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$topRight = $info->getTopRight();
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$bottomLeft = $info->getBottomLeft();
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$moduleSize = (float) $this->calculateModuleSize($topLeft, $topRight, $bottomLeft);
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if ($moduleSize < 1.0) {
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throw NotFoundException::getNotFoundInstance();
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}
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$dimension =(int) $this->computeDimension($topLeft, $topRight, $bottomLeft, $moduleSize);
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$provisionalVersion = Version::getProvisionalVersionForDimension($dimension);
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$modulesBetweenFPCenters = $provisionalVersion->getDimensionForVersion() - 7;
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$alignmentPattern = null;
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// Anything above version 1 has an alignment pattern
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if (count($provisionalVersion->getAlignmentPatternCenters())> 0) {
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// Guess where a "bottom right" finder pattern would have been
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$bottomRightX = $topRight->getX() - $topLeft->getX() + $bottomLeft->getX();
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$bottomRightY = $topRight->getY() - $topLeft->getY() + $bottomLeft->getY();
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// Estimate that alignment pattern is closer by 3 modules
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// from "bottom right" to known top left location
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$correctionToTopLeft = 1.0 - 3.0 / (float) $modulesBetweenFPCenters;
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$estAlignmentX = (int) ($topLeft->getX() + $correctionToTopLeft * ($bottomRightX - $topLeft->getX()));
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$estAlignmentY = (int) ($topLeft->getY() + $correctionToTopLeft * ($bottomRightY - $topLeft->getY()));
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// Kind of arbitrary -- expand search radius before giving up
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for ($i = 4; $i <= 16; $i <<= 1) {//??????????
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try {
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$alignmentPattern = $this->findAlignmentInRegion($moduleSize,
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$estAlignmentX,
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$estAlignmentY,
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(float) $i);
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break;
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} catch (NotFoundException $re) {
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// try next round
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}
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}
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// If we didn't find alignment pattern... well try anyway without it
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}
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$transform =
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$this->createTransform($topLeft, $topRight, $bottomLeft, $alignmentPattern, $dimension);
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$bits = $this->sampleGrid($this->image, $transform, $dimension);
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$points = array();
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if ($alignmentPattern == null) {
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$points = array($bottomLeft, $topLeft, $topRight);
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} else {
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// die('$points = new ResultPoint[]{bottomLeft, topLeft, topRight, alignmentPattern};');
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$points = array($bottomLeft, $topLeft, $topRight, $alignmentPattern);
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}
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return new DetectorResult($bits, $points);
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}
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private static function createTransform($topLeft,
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$topRight,
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$bottomLeft,
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$alignmentPattern,
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$dimension) {
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$dimMinusThree = (float) $dimension - 3.5;
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$bottomRightX = 0.0;
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$bottomRightY = 0.0;
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$sourceBottomRightX = 0.0;
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$sourceBottomRightY = 0.0;
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if ($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 = $sourceBottomRightX;
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} else {
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// Don't have an alignment pattern, just make up the bottom-right point
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$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 = $dimMinusThree;
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}
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return PerspectiveTransform::quadrilateralToQuadrilateral(
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3.5,
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3.5,
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$dimMinusThree,
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3.5,
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$sourceBottomRightX,
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$sourceBottomRightY,
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3.5,
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$dimMinusThree,
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$topLeft->getX(),
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$topLeft->getY(),
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$topRight->getX(),
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$topRight->getY(),
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$bottomRightX,
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$bottomRightY,
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$bottomLeft->getX(),
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$bottomLeft->getY());
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}
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private static function sampleGrid($image, $transform,
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$dimension) {
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$sampler = GridSampler::getInstance();
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return $sampler->sampleGrid_($image, $dimension, $dimension, $transform);
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}
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/**
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* <p>Computes the dimension (number of modules on a size) of the QR Code based on the position
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* of the finder patterns and estimated module size.</p>
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*/
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private static function computeDimension($topLeft,
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$topRight,
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$bottomLeft,
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$moduleSize) {
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$tltrCentersDimension = MathUtils::round(ResultPoint::distance($topLeft, $topRight) / $moduleSize);
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$tlblCentersDimension = MathUtils::round(ResultPoint::distance($topLeft, $bottomLeft) / $moduleSize);
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$dimension = (($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 NotFoundException::getNotFoundInstance();
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}
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return $dimension;
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}
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/**
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* <p>Computes an average estimated module size based on estimated derived from the positions
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* of the three finder patterns.</p>
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*
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* @param topLeft detected top-left finder pattern center
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* @param topRight detected top-right finder pattern center
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* @param bottomLeft detected bottom-left finder pattern center
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* @return estimated module size
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*/
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protected final function calculateModuleSize($topLeft,
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$topRight,
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$bottomLeft) {
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// Take the average
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return ($this->calculateModuleSizeOneWay($topLeft, $topRight) +
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$this->calculateModuleSizeOneWay($topLeft, $bottomLeft)) / 2.0;
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}
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/**
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* <p>Estimates module size based on two finder patterns -- it uses
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* {@link #sizeOfBlackWhiteBlackRunBothWays(int, int, int, int)} to figure the
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* width of each, measuring along the axis between their centers.</p>
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*/
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private function calculateModuleSizeOneWay($pattern, $otherPattern) {
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$moduleSizeEst1 = $this->sizeOfBlackWhiteBlackRunBothWays($pattern->getX(),
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(int) $pattern->getY(),
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(int) $otherPattern->getX(),
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(int) $otherPattern->getY());
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$moduleSizeEst2 = $this->sizeOfBlackWhiteBlackRunBothWays((int) $otherPattern->getX(),
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(int) $otherPattern->getY(),
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(int) $pattern->getX(),
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(int) $pattern->getY());
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if (is_nan($moduleSizeEst1)) {
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return $moduleSizeEst2 / 7.0;
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}
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if (is_nan($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 + $moduleSizeEst2) / 14.0;
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}
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/**
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* See {@link #sizeOfBlackWhiteBlackRun(int, int, int, int)}; computes the total width of
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* a finder pattern by looking for a black-white-black run from the center in the direction
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* of another po$(another finder pattern center), and in the opposite direction too.</p>
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*/
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private function sizeOfBlackWhiteBlackRunBothWays($fromX, $fromY, $toX, $toY) {
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$result = $this->sizeOfBlackWhiteBlackRun($fromX, $fromY, $toX, $toY);
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// Now count other way -- don't run off image though of course
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$scale = 1.0;
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$otherToX = $fromX - ($toX - $fromX);
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if ($otherToX < 0) {
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$scale = (float) $fromX / (float) ($fromX - $otherToX);
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$otherToX = 0;
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} else if ($otherToX >= $this->image->getWidth()) {
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$scale = (float) ($this->image->getWidth() - 1 - $fromX) / (float) ($otherToX - $fromX);
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$otherToX = $this->image->getWidth() - 1;
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}
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$otherToY = (int) ($fromY - ($toY - $fromY) * $scale);
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$scale = 1.0;
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if ($otherToY < 0) {
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$scale = (float) $fromY / (float) ($fromY - $otherToY);
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$otherToY = 0;
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} else if ($otherToY >= $this->image->getHeight()) {
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$scale = (float) ($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) ($fromX + ($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 $result - 1.0;
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}
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/**
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* <p>This method traces a line from a po$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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private function sizeOfBlackWhiteBlackRun($fromX, $fromY, $toX, $toY) {
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// Mild variant of Bresenham's algorithm;
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// see http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
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$steep = abs($toY - $fromY) > abs($toX - $fromX);
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if ($steep) {
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$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 = $temp;
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}
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$dx = abs($toX - $fromX);
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$dy = abs($toY - $fromY);
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$error = -$dx / 2;
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$xstep = $fromX < $toX ? 1 : -1;
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$ystep = $fromY < $toY ? 1 : -1;
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// In black pixels, looking for white, first or second time.
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$state = 0;
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// Loop up until x == toX, but not beyond
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$xLimit = $toX + $xstep;
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for ($x = $fromX, $y = $fromY; $x != $xLimit; $x += $xstep) {
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$realX = $steep ? $y : $x;
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$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 -= $dx;
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}
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}
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// Found black-white-black; give the benefit of the doubt that the next pixel outside the image
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// is "white" so this last po$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, $fromY);
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}
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// else we didn't find even black-white-black; no estimate is really possible
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return NAN;
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}
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/**
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* <p>Attempts to locate an alignment pattern in a limited region of the image, which is
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* guessed to contain it. This method uses {@link AlignmentPattern}.</p>
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*
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* @param overallEstModuleSize estimated module size so far
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* @param estAlignmentX x coordinate of center of area probably containing alignment pattern
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* @param estAlignmentY y coordinate of above
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* @param allowanceFactor number of pixels in all directions to search from the center
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* @return {@link AlignmentPattern} if found, or null otherwise
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* @throws NotFoundException if an unexpected error occurs during detection
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*/
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protected final function findAlignmentInRegion($overallEstModuleSize,
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$estAlignmentX,
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$estAlignmentY,
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$allowanceFactor)
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{
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// Look for an alignment pattern (3 modules in size) around where it
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// should be
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$allowance = (int) ($allowanceFactor * $overallEstModuleSize);
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$alignmentAreaLeftX = max(0, $estAlignmentX - $allowance);
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$alignmentAreaRightX = min($this->image->getWidth() - 1, $estAlignmentX + $allowance);
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if ($alignmentAreaRightX - $alignmentAreaLeftX < $overallEstModuleSize * 3) {
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throw NotFoundException::getNotFoundInstance();
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}
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$alignmentAreaTopY = max(0, $estAlignmentY - $allowance);
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$alignmentAreaBottomY = min($this->image->getHeight() - 1, $estAlignmentY + $allowance);
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if ($alignmentAreaBottomY - $alignmentAreaTopY < $overallEstModuleSize * 3) {
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throw NotFoundException::getNotFoundInstance();
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}
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$alignmentFinder =
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new AlignmentPatternFinder(
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$this->image,
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$alignmentAreaLeftX,
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$alignmentAreaTopY,
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$alignmentAreaRightX - $alignmentAreaLeftX,
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$alignmentAreaBottomY - $alignmentAreaTopY,
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$overallEstModuleSize,
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$this->resultPointCallback);
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return $alignmentFinder->find();
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}
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}
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