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<?php |
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/** |
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* Class FinderPatternFinder |
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* |
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* @created 17.01.2021 |
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* @author ZXing Authors |
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* @author Smiley <[email protected]> |
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* @copyright 2021 Smiley |
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* @license Apache-2.0 |
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* |
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* @phan-file-suppress PhanTypePossiblyInvalidDimOffset |
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*/ |
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namespace chillerlan\QRCode\Detector; |
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use RuntimeException; |
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use chillerlan\QRCode\Decoder\BitMatrix; |
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use function abs, count, usort; |
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use const PHP_FLOAT_MAX; |
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/** |
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* <p>This class attempts to find finder patterns in a QR Code. Finder patterns are the square |
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* markers at three corners of a QR Code.</p> |
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* |
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* <p>This class is thread-safe but not reentrant. Each thread must allocate its own object. |
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* |
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* @author Sean Owen |
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*/ |
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final class FinderPatternFinder{ |
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private const MIN_SKIP = 2; |
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private const MAX_MODULES = 177; // 1 pixel/module times 3 modules/center |
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private const CENTER_QUORUM = 2; // support up to version 10 for mobile clients |
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private BitMatrix $bitMatrix; |
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/** @var \chillerlan\QRCode\Detector\FinderPattern[] */ |
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private array $possibleCenters; |
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private bool $hasSkipped = false; |
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/** |
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* <p>Creates a finder that will search the image for three finder patterns.</p> |
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* |
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* @param BitMatrix $bitMatrix image to search |
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*/ |
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public function __construct(BitMatrix $bitMatrix){ |
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$this->bitMatrix = $bitMatrix; |
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$this->possibleCenters = []; |
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} |
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/** |
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* @return \chillerlan\QRCode\Detector\FinderPattern[] |
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*/ |
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public function find():array{ |
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$dimension = $this->bitMatrix->getDimension(); |
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// We are looking for black/white/black/white/black modules in |
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// 1:1:3:1:1 ratio; this tracks the number of such modules seen so far |
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// Let's assume that the maximum version QR Code we support takes up 1/4 the height of the |
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// image, and then account for the center being 3 modules in size. This gives the smallest |
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// number of pixels the center could be, so skip this often. |
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$iSkip = (int)((3 * $dimension) / (4 * self::MAX_MODULES)); |
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if($iSkip < self::MIN_SKIP){ |
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$iSkip = self::MIN_SKIP; |
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} |
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$done = false; |
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for($i = $iSkip - 1; $i < $dimension && !$done; $i += $iSkip){ |
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// Get a row of black/white values |
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$stateCount = $this->getCrossCheckStateCount(); |
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$currentState = 0; |
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for($j = 0; $j < $dimension; $j++){ |
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// Black pixel |
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if($this->bitMatrix->get($j, $i)){ |
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// Counting white pixels |
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if(($currentState & 1) === 1){ |
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$currentState++; |
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} |
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$stateCount[$currentState]++; |
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} |
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// White pixel |
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else{ |
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// Counting black pixels |
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if(($currentState & 1) === 0){ |
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// A winner? |
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if($currentState === 4){ |
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// Yes |
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if($this->foundPatternCross($stateCount)){ |
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$confirmed = $this->handlePossibleCenter($stateCount, $i, $j); |
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if($confirmed){ |
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// Start examining every other line. Checking each line turned out to be too |
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// expensive and didn't improve performance. |
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$iSkip = 3; |
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if($this->hasSkipped){ |
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$done = $this->haveMultiplyConfirmedCenters(); |
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} |
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else{ |
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$rowSkip = $this->findRowSkip(); |
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if($rowSkip > $stateCount[2]){ |
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// Skip rows between row of lower confirmed center |
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// and top of presumed third confirmed center |
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// but back up a bit to get a full chance of detecting |
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// it, entire width of center of finder pattern |
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// Skip by rowSkip, but back off by $stateCount[2] (size of last center |
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// of pattern we saw) to be conservative, and also back off by iSkip which |
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// is about to be re-added |
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$i += $rowSkip - $stateCount[2] - $iSkip; |
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$j = $dimension - 1; |
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} |
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} |
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} |
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else{ |
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$stateCount = $this->doShiftCounts2($stateCount); |
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$currentState = 3; |
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continue; |
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} |
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// Clear state to start looking again |
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$currentState = 0; |
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$stateCount = $this->getCrossCheckStateCount(); |
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} |
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// No, shift counts back by two |
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else{ |
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$stateCount = $this->doShiftCounts2($stateCount); |
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$currentState = 3; |
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} |
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} |
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else{ |
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$stateCount[++$currentState]++; |
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} |
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} |
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// Counting white pixels |
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else{ |
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$stateCount[$currentState]++; |
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} |
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} |
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} |
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if($this->foundPatternCross($stateCount)){ |
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$confirmed = $this->handlePossibleCenter($stateCount, $i, $dimension); |
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if($confirmed){ |
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$iSkip = $stateCount[0]; |
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if($this->hasSkipped){ |
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// Found a third one |
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$done = $this->haveMultiplyConfirmedCenters(); |
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} |
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} |
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} |
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} |
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return $this->orderBestPatterns($this->selectBestPatterns()); |
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} |
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/** |
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* @return int[] |
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*/ |
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private function getCrossCheckStateCount():array{ |
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return [0, 0, 0, 0, 0]; |
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} |
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/** |
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* @param int[] $stateCount |
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* |
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* @return int[] |
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*/ |
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private function doShiftCounts2(array $stateCount):array{ |
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$stateCount[0] = $stateCount[2]; |
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$stateCount[1] = $stateCount[3]; |
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$stateCount[2] = $stateCount[4]; |
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$stateCount[3] = 1; |
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$stateCount[4] = 0; |
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return $stateCount; |
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} |
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/** |
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* Given a count of black/white/black/white/black pixels just seen and an end position, |
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* figures the location of the center of this run. |
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* |
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* @param int[] $stateCount |
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* |
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* @return float |
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*/ |
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private function centerFromEnd(array $stateCount, int $end):float{ |
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return (float)(($end - $stateCount[4] - $stateCount[3]) - $stateCount[2] / 2.0); |
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} |
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/** |
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* @param int[] $stateCount |
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* |
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* @return bool |
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*/ |
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private function foundPatternCross(array $stateCount):bool{ |
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// Allow less than 50% variance from 1-1-3-1-1 proportions |
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return $this->foundPatternVariance($stateCount, 2.0); |
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} |
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/** |
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* @param int[] $stateCount |
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* |
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* @return bool |
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*/ |
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private function foundPatternDiagonal(array $stateCount):bool{ |
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// Allow less than 75% variance from 1-1-3-1-1 proportions |
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return $this->foundPatternVariance($stateCount, 1.333); |
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} |
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/** |
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* @param int[] $stateCount count of black/white/black/white/black pixels just read |
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* |
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* @return bool true if the proportions of the counts is close enough to the 1/1/3/1/1 ratios |
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* used by finder patterns to be considered a match |
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*/ |
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private function foundPatternVariance(array $stateCount, float $variance):bool{ |
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$totalModuleSize = 0; |
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for($i = 0; $i < 5; $i++){ |
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$count = $stateCount[$i]; |
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if($count === 0){ |
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return false; |
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} |
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$totalModuleSize += $count; |
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} |
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if($totalModuleSize < 7){ |
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return false; |
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} |
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$moduleSize = $totalModuleSize / 7.0; |
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$maxVariance = $moduleSize / $variance; |
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return |
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abs($moduleSize - $stateCount[0]) < $maxVariance |
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&& abs($moduleSize - $stateCount[1]) < $maxVariance |
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&& abs(3.0 * $moduleSize - $stateCount[2]) < 3 * $maxVariance |
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&& abs($moduleSize - $stateCount[3]) < $maxVariance |
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&& abs($moduleSize - $stateCount[4]) < $maxVariance; |
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} |
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/** |
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* After a vertical and horizontal scan finds a potential finder pattern, this method |
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* "cross-cross-cross-checks" by scanning down diagonally through the center of the possible |
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* finder pattern to see if the same proportion is detected. |
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* |
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* @param $centerI ; row where a finder pattern was detected |
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* @param $centerJ ; center of the section that appears to cross a finder pattern |
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* |
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* @return bool true if proportions are withing expected limits |
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*/ |
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private function crossCheckDiagonal(int $centerI, int $centerJ):bool{ |
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$stateCount = $this->getCrossCheckStateCount(); |
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// Start counting up, left from center finding black center mass |
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$i = 0; |
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while($centerI >= $i && $centerJ >= $i && $this->bitMatrix->get($centerJ - $i, $centerI - $i)){ |
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$stateCount[2]++; |
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$i++; |
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} |
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if($stateCount[2] === 0){ |
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return false; |
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} |
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// Continue up, left finding white space |
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while($centerI >= $i && $centerJ >= $i && !$this->bitMatrix->get($centerJ - $i, $centerI - $i)){ |
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$stateCount[1]++; |
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$i++; |
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} |
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if($stateCount[1] === 0){ |
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return false; |
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} |
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// Continue up, left finding black border |
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while($centerI >= $i && $centerJ >= $i && $this->bitMatrix->get($centerJ - $i, $centerI - $i)){ |
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$stateCount[0]++; |
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$i++; |
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} |
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if($stateCount[0] === 0){ |
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return false; |
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} |
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$dimension = $this->bitMatrix->getDimension(); |
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// Now also count down, right from center |
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$i = 1; |
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while($centerI + $i < $dimension && $centerJ + $i < $dimension && $this->bitMatrix->get($centerJ + $i, $centerI + $i)){ |
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$stateCount[2]++; |
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$i++; |
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} |
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while($centerI + $i < $dimension && $centerJ + $i < $dimension && !$this->bitMatrix->get($centerJ + $i, $centerI + $i)){ |
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$stateCount[3]++; |
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$i++; |
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} |
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if($stateCount[3] === 0){ |
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return false; |
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} |
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while($centerI + $i < $dimension && $centerJ + $i < $dimension && $this->bitMatrix->get($centerJ + $i, $centerI + $i)){ |
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$stateCount[4]++; |
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$i++; |
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} |
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if($stateCount[4] === 0){ |
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return false; |
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} |
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return $this->foundPatternDiagonal($stateCount); |
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} |
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/** |
|
327
|
|
|
* <p>After a horizontal scan finds a potential finder pattern, this method |
|
328
|
|
|
* "cross-checks" by scanning down vertically through the center of the possible |
|
329
|
|
|
* finder pattern to see if the same proportion is detected.</p> |
|
330
|
|
|
* |
|
331
|
|
|
* @param int $startI ; row where a finder pattern was detected |
|
332
|
|
|
* @param int $centerJ ; center of the section that appears to cross a finder pattern |
|
333
|
|
|
* @param int $maxCount ; maximum reasonable number of modules that should be |
|
334
|
|
|
* observed in any reading state, based on the results of the horizontal scan |
|
335
|
|
|
* @param int $originalStateCountTotal |
|
336
|
|
|
* |
|
337
|
|
|
* @return float|null vertical center of finder pattern, or null if not found |
|
338
|
|
|
*/ |
|
339
|
|
|
private function crossCheckVertical(int $startI, int $centerJ, int $maxCount, int $originalStateCountTotal):?float{ |
|
340
|
|
|
$maxI = $this->bitMatrix->getDimension(); |
|
341
|
|
|
$stateCount = $this->getCrossCheckStateCount(); |
|
342
|
|
|
|
|
343
|
|
|
// Start counting up from center |
|
344
|
|
|
$i = $startI; |
|
345
|
|
|
while($i >= 0 && $this->bitMatrix->get($centerJ, $i)){ |
|
346
|
|
|
$stateCount[2]++; |
|
347
|
|
|
$i--; |
|
348
|
|
|
} |
|
349
|
|
|
|
|
350
|
|
|
if($i < 0){ |
|
351
|
|
|
return null; |
|
352
|
|
|
} |
|
353
|
|
|
|
|
354
|
|
|
while($i >= 0 && !$this->bitMatrix->get($centerJ, $i) && $stateCount[1] <= $maxCount){ |
|
355
|
|
|
$stateCount[1]++; |
|
356
|
|
|
$i--; |
|
357
|
|
|
} |
|
358
|
|
|
|
|
359
|
|
|
// If already too many modules in this state or ran off the edge: |
|
360
|
|
|
if($i < 0 || $stateCount[1] > $maxCount){ |
|
361
|
|
|
return null; |
|
362
|
|
|
} |
|
363
|
|
|
|
|
364
|
|
|
while($i >= 0 && $this->bitMatrix->get($centerJ, $i) && $stateCount[0] <= $maxCount){ |
|
365
|
|
|
$stateCount[0]++; |
|
366
|
|
|
$i--; |
|
367
|
|
|
} |
|
368
|
|
|
|
|
369
|
|
|
if($stateCount[0] > $maxCount){ |
|
370
|
|
|
return null; |
|
371
|
|
|
} |
|
372
|
|
|
|
|
373
|
|
|
// Now also count down from center |
|
374
|
|
|
$i = $startI + 1; |
|
375
|
|
|
while($i < $maxI && $this->bitMatrix->get($centerJ, $i)){ |
|
376
|
|
|
$stateCount[2]++; |
|
377
|
|
|
$i++; |
|
378
|
|
|
} |
|
379
|
|
|
|
|
380
|
|
|
if($i === $maxI){ |
|
381
|
|
|
return null; |
|
382
|
|
|
} |
|
383
|
|
|
|
|
384
|
|
|
while($i < $maxI && !$this->bitMatrix->get($centerJ, $i) && $stateCount[3] < $maxCount){ |
|
385
|
|
|
$stateCount[3]++; |
|
386
|
|
|
$i++; |
|
387
|
|
|
} |
|
388
|
|
|
|
|
389
|
|
|
if($i === $maxI || $stateCount[3] >= $maxCount){ |
|
390
|
|
|
return null; |
|
391
|
|
|
} |
|
392
|
|
|
|
|
393
|
|
|
while($i < $maxI && $this->bitMatrix->get($centerJ, $i) && $stateCount[4] < $maxCount){ |
|
394
|
|
|
$stateCount[4]++; |
|
395
|
|
|
$i++; |
|
396
|
|
|
} |
|
397
|
|
|
|
|
398
|
|
|
if($stateCount[4] >= $maxCount){ |
|
399
|
|
|
return null; |
|
400
|
|
|
} |
|
401
|
|
|
|
|
402
|
|
|
// If we found a finder-pattern-like section, but its size is more than 40% different than |
|
403
|
|
|
// the original, assume it's a false positive |
|
404
|
|
|
$stateCountTotal = $stateCount[0] + $stateCount[1] + $stateCount[2] + $stateCount[3] + $stateCount[4]; |
|
405
|
|
|
|
|
406
|
|
|
if(5 * abs($stateCountTotal - $originalStateCountTotal) >= 2 * $originalStateCountTotal){ |
|
407
|
|
|
return null; |
|
408
|
|
|
} |
|
409
|
|
|
|
|
410
|
|
|
if(!$this->foundPatternCross($stateCount)){ |
|
411
|
|
|
return null; |
|
412
|
|
|
} |
|
413
|
|
|
|
|
414
|
|
|
return $this->centerFromEnd($stateCount, $i); |
|
415
|
|
|
} |
|
416
|
|
|
|
|
417
|
|
|
/** |
|
418
|
|
|
* <p>Like {@link #crossCheckVertical(int, int, int, int)}, and in fact is basically identical, |
|
419
|
|
|
* except it reads horizontally instead of vertically. This is used to cross-cross |
|
420
|
|
|
* check a vertical cross check and locate the real center of the alignment pattern.</p> |
|
421
|
|
|
*/ |
|
422
|
|
|
private function crossCheckHorizontal(int $startJ, int $centerI, int $maxCount, int $originalStateCountTotal):?float{ |
|
423
|
|
|
$maxJ = $this->bitMatrix->getDimension(); |
|
424
|
|
|
$stateCount = $this->getCrossCheckStateCount(); |
|
425
|
|
|
|
|
426
|
|
|
$j = $startJ; |
|
427
|
|
|
while($j >= 0 && $this->bitMatrix->get($j, $centerI)){ |
|
428
|
|
|
$stateCount[2]++; |
|
429
|
|
|
$j--; |
|
430
|
|
|
} |
|
431
|
|
|
|
|
432
|
|
|
if($j < 0){ |
|
433
|
|
|
return null; |
|
434
|
|
|
} |
|
435
|
|
|
|
|
436
|
|
|
while($j >= 0 && !$this->bitMatrix->get($j, $centerI) && $stateCount[1] <= $maxCount){ |
|
437
|
|
|
$stateCount[1]++; |
|
438
|
|
|
$j--; |
|
439
|
|
|
} |
|
440
|
|
|
|
|
441
|
|
|
if($j < 0 || $stateCount[1] > $maxCount){ |
|
442
|
|
|
return null; |
|
443
|
|
|
} |
|
444
|
|
|
|
|
445
|
|
|
while($j >= 0 && $this->bitMatrix->get($j, $centerI) && $stateCount[0] <= $maxCount){ |
|
446
|
|
|
$stateCount[0]++; |
|
447
|
|
|
$j--; |
|
448
|
|
|
} |
|
449
|
|
|
|
|
450
|
|
|
if($stateCount[0] > $maxCount){ |
|
451
|
|
|
return null; |
|
452
|
|
|
} |
|
453
|
|
|
|
|
454
|
|
|
$j = $startJ + 1; |
|
455
|
|
|
while($j < $maxJ && $this->bitMatrix->get($j, $centerI)){ |
|
456
|
|
|
$stateCount[2]++; |
|
457
|
|
|
$j++; |
|
458
|
|
|
} |
|
459
|
|
|
|
|
460
|
|
|
if($j === $maxJ){ |
|
461
|
|
|
return null; |
|
462
|
|
|
} |
|
463
|
|
|
|
|
464
|
|
|
while($j < $maxJ && !$this->bitMatrix->get($j, $centerI) && $stateCount[3] < $maxCount){ |
|
465
|
|
|
$stateCount[3]++; |
|
466
|
|
|
$j++; |
|
467
|
|
|
} |
|
468
|
|
|
|
|
469
|
|
|
if($j === $maxJ || $stateCount[3] >= $maxCount){ |
|
470
|
|
|
return null; |
|
471
|
|
|
} |
|
472
|
|
|
|
|
473
|
|
|
while($j < $maxJ && $this->bitMatrix->get($j, $centerI) && $stateCount[4] < $maxCount){ |
|
474
|
|
|
$stateCount[4]++; |
|
475
|
|
|
$j++; |
|
476
|
|
|
} |
|
477
|
|
|
|
|
478
|
|
|
if($stateCount[4] >= $maxCount){ |
|
479
|
|
|
return null; |
|
480
|
|
|
} |
|
481
|
|
|
|
|
482
|
|
|
// If we found a finder-pattern-like section, but its size is significantly different than |
|
483
|
|
|
// the original, assume it's a false positive |
|
484
|
|
|
$stateCountTotal = $stateCount[0] + $stateCount[1] + $stateCount[2] + $stateCount[3] + $stateCount[4]; |
|
485
|
|
|
|
|
486
|
|
|
if(5 * abs($stateCountTotal - $originalStateCountTotal) >= $originalStateCountTotal){ |
|
487
|
|
|
return null; |
|
488
|
|
|
} |
|
489
|
|
|
|
|
490
|
|
|
if(!$this->foundPatternCross($stateCount)){ |
|
491
|
|
|
return null; |
|
492
|
|
|
} |
|
493
|
|
|
|
|
494
|
|
|
return $this->centerFromEnd($stateCount, $j); |
|
495
|
|
|
} |
|
496
|
|
|
|
|
497
|
|
|
/** |
|
498
|
|
|
* <p>This is called when a horizontal scan finds a possible alignment pattern. It will |
|
499
|
|
|
* cross check with a vertical scan, and if successful, will, ah, cross-cross-check |
|
500
|
|
|
* with another horizontal scan. This is needed primarily to locate the real horizontal |
|
501
|
|
|
* center of the pattern in cases of extreme skew. |
|
502
|
|
|
* And then we cross-cross-cross check with another diagonal scan.</p> |
|
503
|
|
|
* |
|
504
|
|
|
* <p>If that succeeds the finder pattern location is added to a list that tracks |
|
505
|
|
|
* the number of times each location has been nearly-matched as a finder pattern. |
|
506
|
|
|
* Each additional find is more evidence that the location is in fact a finder |
|
507
|
|
|
* pattern center |
|
508
|
|
|
* |
|
509
|
|
|
* @param int[] $stateCount reading state module counts from horizontal scan |
|
510
|
|
|
* @param int $i row where finder pattern may be found |
|
511
|
|
|
* @param int $j end of possible finder pattern in row |
|
512
|
|
|
* |
|
513
|
|
|
* @return bool if a finder pattern candidate was found this time |
|
514
|
|
|
*/ |
|
515
|
|
|
private function handlePossibleCenter(array $stateCount, int $i, int $j):bool{ |
|
516
|
|
|
$stateCountTotal = $stateCount[0] + $stateCount[1] + $stateCount[2] + $stateCount[3] + $stateCount[4]; |
|
517
|
|
|
$centerJ = $this->centerFromEnd($stateCount, $j); |
|
518
|
|
|
$centerI = $this->crossCheckVertical($i, (int)$centerJ, $stateCount[2], $stateCountTotal); |
|
519
|
|
|
|
|
520
|
|
|
if($centerI !== null){ |
|
521
|
|
|
// Re-cross check |
|
522
|
|
|
$centerJ = $this->crossCheckHorizontal((int)$centerJ, (int)$centerI, $stateCount[2], $stateCountTotal); |
|
523
|
|
|
if($centerJ !== null && ($this->crossCheckDiagonal((int)$centerI, (int)$centerJ))){ |
|
524
|
|
|
$estimatedModuleSize = $stateCountTotal / 7.0; |
|
525
|
|
|
$found = false; |
|
526
|
|
|
|
|
527
|
|
|
for($index = 0; $index < count($this->possibleCenters); $index++){ |
|
|
|
|
|
|
528
|
|
|
$center = $this->possibleCenters[$index]; |
|
529
|
|
|
// Look for about the same center and module size: |
|
530
|
|
|
if($center->aboutEquals($estimatedModuleSize, $centerI, $centerJ)){ |
|
531
|
|
|
$this->possibleCenters[$index] = $center->combineEstimate($centerI, $centerJ, $estimatedModuleSize); |
|
532
|
|
|
$found = true; |
|
533
|
|
|
break; |
|
534
|
|
|
} |
|
535
|
|
|
} |
|
536
|
|
|
|
|
537
|
|
|
if(!$found){ |
|
538
|
|
|
$point = new FinderPattern($centerJ, $centerI, $estimatedModuleSize); |
|
539
|
|
|
$this->possibleCenters[] = $point; |
|
540
|
|
|
} |
|
541
|
|
|
|
|
542
|
|
|
return true; |
|
543
|
|
|
} |
|
544
|
|
|
} |
|
545
|
|
|
|
|
546
|
|
|
return false; |
|
547
|
|
|
} |
|
548
|
|
|
|
|
549
|
|
|
/** |
|
550
|
|
|
* @return int number of rows we could safely skip during scanning, based on the first |
|
551
|
|
|
* two finder patterns that have been located. In some cases their position will |
|
552
|
|
|
* allow us to infer that the third pattern must lie below a certain point farther |
|
553
|
|
|
* down in the image. |
|
554
|
|
|
*/ |
|
555
|
|
|
private function findRowSkip():int{ |
|
556
|
|
|
$max = count($this->possibleCenters); |
|
557
|
|
|
|
|
558
|
|
|
if($max <= 1){ |
|
559
|
|
|
return 0; |
|
560
|
|
|
} |
|
561
|
|
|
|
|
562
|
|
|
$firstConfirmedCenter = null; |
|
563
|
|
|
|
|
564
|
|
|
foreach($this->possibleCenters as $center){ |
|
565
|
|
|
|
|
566
|
|
|
if($center->getCount() >= self::CENTER_QUORUM){ |
|
567
|
|
|
|
|
568
|
|
|
if($firstConfirmedCenter === null){ |
|
569
|
|
|
$firstConfirmedCenter = $center; |
|
570
|
|
|
} |
|
571
|
|
|
else{ |
|
572
|
|
|
// We have two confirmed centers |
|
573
|
|
|
// How far down can we skip before resuming looking for the next |
|
574
|
|
|
// pattern? In the worst case, only the difference between the |
|
575
|
|
|
// difference in the x / y coordinates of the two centers. |
|
576
|
|
|
// This is the case where you find top left last. |
|
577
|
|
|
$this->hasSkipped = true; |
|
578
|
|
|
|
|
579
|
|
|
return (int)((abs($firstConfirmedCenter->getX() - $center->getX()) - |
|
|
|
|
|
|
580
|
|
|
abs($firstConfirmedCenter->getY() - $center->getY())) / 2); |
|
581
|
|
|
} |
|
582
|
|
|
} |
|
583
|
|
|
} |
|
584
|
|
|
|
|
585
|
|
|
return 0; |
|
586
|
|
|
} |
|
587
|
|
|
|
|
588
|
|
|
/** |
|
589
|
|
|
* @return bool true if we have found at least 3 finder patterns that have been detected |
|
590
|
|
|
* at least {@link #CENTER_QUORUM} times each, and, the estimated module size of the |
|
591
|
|
|
* candidates is "pretty similar" |
|
592
|
|
|
*/ |
|
593
|
|
|
private function haveMultiplyConfirmedCenters():bool{ |
|
594
|
|
|
$confirmedCount = 0; |
|
595
|
|
|
$totalModuleSize = 0.0; |
|
596
|
|
|
$max = count($this->possibleCenters); |
|
597
|
|
|
|
|
598
|
|
|
foreach($this->possibleCenters as $pattern){ |
|
599
|
|
|
if($pattern->getCount() >= self::CENTER_QUORUM){ |
|
600
|
|
|
$confirmedCount++; |
|
601
|
|
|
$totalModuleSize += $pattern->getEstimatedModuleSize(); |
|
602
|
|
|
} |
|
603
|
|
|
} |
|
604
|
|
|
|
|
605
|
|
|
if($confirmedCount < 3){ |
|
606
|
|
|
return false; |
|
607
|
|
|
} |
|
608
|
|
|
// OK, we have at least 3 confirmed centers, but, it's possible that one is a "false positive" |
|
609
|
|
|
// and that we need to keep looking. We detect this by asking if the estimated module sizes |
|
610
|
|
|
// vary too much. We arbitrarily say that when the total deviation from average exceeds |
|
611
|
|
|
// 5% of the total module size estimates, it's too much. |
|
612
|
|
|
$average = $totalModuleSize / (float)$max; |
|
613
|
|
|
$totalDeviation = 0.0; |
|
614
|
|
|
|
|
615
|
|
|
foreach($this->possibleCenters as $pattern){ |
|
616
|
|
|
$totalDeviation += abs($pattern->getEstimatedModuleSize() - $average); |
|
617
|
|
|
} |
|
618
|
|
|
|
|
619
|
|
|
return $totalDeviation <= 0.05 * $totalModuleSize; |
|
620
|
|
|
} |
|
621
|
|
|
|
|
622
|
|
|
/** |
|
623
|
|
|
* @return \chillerlan\QRCode\Detector\FinderPattern[] the 3 best {@link FinderPattern}s from our list of candidates. The "best" are |
|
624
|
|
|
* those that have been detected at least {@link #CENTER_QUORUM} times, and whose module |
|
625
|
|
|
* size differs from the average among those patterns the least |
|
626
|
|
|
* @throws \RuntimeException if 3 such finder patterns do not exist |
|
627
|
|
|
*/ |
|
628
|
|
|
private function selectBestPatterns():array{ |
|
629
|
|
|
$startSize = count($this->possibleCenters); |
|
630
|
|
|
|
|
631
|
|
|
if($startSize < 3){ |
|
632
|
|
|
throw new RuntimeException('could not find enough finder patterns'); |
|
633
|
|
|
} |
|
634
|
|
|
|
|
635
|
|
|
usort( |
|
636
|
|
|
$this->possibleCenters, |
|
637
|
|
|
fn(FinderPattern $a, FinderPattern $b) => $a->getEstimatedModuleSize() <=> $b->getEstimatedModuleSize() |
|
638
|
|
|
); |
|
639
|
|
|
|
|
640
|
|
|
$distortion = PHP_FLOAT_MAX; |
|
641
|
|
|
$bestPatterns = []; |
|
642
|
|
|
|
|
643
|
|
|
for($i = 0; $i < $startSize - 2; $i++){ |
|
644
|
|
|
$fpi = $this->possibleCenters[$i]; |
|
645
|
|
|
$minModuleSize = $fpi->getEstimatedModuleSize(); |
|
646
|
|
|
|
|
647
|
|
|
for($j = $i + 1; $j < $startSize - 1; $j++){ |
|
648
|
|
|
$fpj = $this->possibleCenters[$j]; |
|
649
|
|
|
$squares0 = $fpi->getSquaredDistance($fpj); |
|
650
|
|
|
|
|
651
|
|
|
for($k = $j + 1; $k < $startSize; $k++){ |
|
652
|
|
|
$fpk = $this->possibleCenters[$k]; |
|
653
|
|
|
$maxModuleSize = $fpk->getEstimatedModuleSize(); |
|
654
|
|
|
|
|
655
|
|
|
// module size is not similar |
|
656
|
|
|
if($maxModuleSize > $minModuleSize * 1.4){ |
|
657
|
|
|
continue; |
|
658
|
|
|
} |
|
659
|
|
|
|
|
660
|
|
|
$a = $squares0; |
|
661
|
|
|
$b = $fpj->getSquaredDistance($fpk); |
|
662
|
|
|
$c = $fpi->getSquaredDistance($fpk); |
|
663
|
|
|
|
|
664
|
|
|
// sorts ascending - inlined |
|
665
|
|
|
if($a < $b){ |
|
666
|
|
|
if($b > $c){ |
|
667
|
|
|
if($a < $c){ |
|
668
|
|
|
$temp = $b; |
|
669
|
|
|
$b = $c; |
|
670
|
|
|
$c = $temp; |
|
671
|
|
|
} |
|
672
|
|
|
else{ |
|
673
|
|
|
$temp = $a; |
|
674
|
|
|
$a = $c; |
|
675
|
|
|
$c = $b; |
|
676
|
|
|
$b = $temp; |
|
677
|
|
|
} |
|
678
|
|
|
} |
|
679
|
|
|
} |
|
680
|
|
|
else{ |
|
681
|
|
|
if($b < $c){ |
|
682
|
|
|
if($a < $c){ |
|
683
|
|
|
$temp = $a; |
|
684
|
|
|
$a = $b; |
|
685
|
|
|
$b = $temp; |
|
686
|
|
|
} |
|
687
|
|
|
else{ |
|
688
|
|
|
$temp = $a; |
|
689
|
|
|
$a = $b; |
|
690
|
|
|
$b = $c; |
|
691
|
|
|
$c = $temp; |
|
692
|
|
|
} |
|
693
|
|
|
} |
|
694
|
|
|
else{ |
|
695
|
|
|
$temp = $a; |
|
696
|
|
|
$a = $c; |
|
697
|
|
|
$c = $temp; |
|
698
|
|
|
} |
|
699
|
|
|
} |
|
700
|
|
|
|
|
701
|
|
|
// a^2 + b^2 = c^2 (Pythagorean theorem), and a = b (isosceles triangle). |
|
702
|
|
|
// Since any right triangle satisfies the formula c^2 - b^2 - a^2 = 0, |
|
703
|
|
|
// we need to check both two equal sides separately. |
|
704
|
|
|
// The value of |c^2 - 2 * b^2| + |c^2 - 2 * a^2| increases as dissimilarity |
|
705
|
|
|
// from isosceles right triangle. |
|
706
|
|
|
$d = abs($c - 2 * $b) + abs($c - 2 * $a); |
|
707
|
|
|
|
|
708
|
|
|
if($d < $distortion){ |
|
709
|
|
|
$distortion = $d; |
|
710
|
|
|
$bestPatterns = [$fpi, $fpj, $fpk]; |
|
711
|
|
|
} |
|
712
|
|
|
} |
|
713
|
|
|
} |
|
714
|
|
|
} |
|
715
|
|
|
|
|
716
|
|
|
if($distortion === PHP_FLOAT_MAX){ |
|
717
|
|
|
throw new RuntimeException('finder patterns may be too distorted'); |
|
718
|
|
|
} |
|
719
|
|
|
|
|
720
|
|
|
return $bestPatterns; |
|
721
|
|
|
} |
|
722
|
|
|
|
|
723
|
|
|
/** |
|
724
|
|
|
* Orders an array of three ResultPoints in an order [A,B,C] such that AB is less than AC |
|
725
|
|
|
* and BC is less than AC, and the angle between BC and BA is less than 180 degrees. |
|
726
|
|
|
* |
|
727
|
|
|
* @param \chillerlan\QRCode\Detector\FinderPattern[] $patterns array of three FinderPattern to order |
|
728
|
|
|
* |
|
729
|
|
|
* @return \chillerlan\QRCode\Detector\FinderPattern[] |
|
730
|
|
|
*/ |
|
731
|
|
|
private function orderBestPatterns(array $patterns):array{ |
|
732
|
|
|
|
|
733
|
|
|
// Find distances between pattern centers |
|
734
|
|
|
$zeroOneDistance = $patterns[0]->getDistance($patterns[1]); |
|
735
|
|
|
$oneTwoDistance = $patterns[1]->getDistance($patterns[2]); |
|
736
|
|
|
$zeroTwoDistance = $patterns[0]->getDistance($patterns[2]); |
|
737
|
|
|
|
|
738
|
|
|
// Assume one closest to other two is B; A and C will just be guesses at first |
|
739
|
|
|
if($oneTwoDistance >= $zeroOneDistance && $oneTwoDistance >= $zeroTwoDistance){ |
|
740
|
|
|
[$pointB, $pointA, $pointC] = $patterns; |
|
741
|
|
|
} |
|
742
|
|
|
elseif($zeroTwoDistance >= $oneTwoDistance && $zeroTwoDistance >= $zeroOneDistance){ |
|
743
|
|
|
[$pointA, $pointB, $pointC] = $patterns; |
|
744
|
|
|
} |
|
745
|
|
|
else{ |
|
746
|
|
|
[$pointA, $pointC, $pointB] = $patterns; |
|
747
|
|
|
} |
|
748
|
|
|
|
|
749
|
|
|
// Use cross product to figure out whether A and C are correct or flipped. |
|
750
|
|
|
// This asks whether BC x BA has a positive z component, which is the arrangement |
|
751
|
|
|
// we want for A, B, C. If it's negative, then we've got it flipped around and |
|
752
|
|
|
// should swap A and C. |
|
753
|
|
|
if($this->crossProductZ($pointA, $pointB, $pointC) < 0.0){ |
|
754
|
|
|
$temp = $pointA; |
|
755
|
|
|
$pointA = $pointC; |
|
756
|
|
|
$pointC = $temp; |
|
757
|
|
|
} |
|
758
|
|
|
|
|
759
|
|
|
return [$pointA, $pointB, $pointC]; |
|
760
|
|
|
} |
|
761
|
|
|
|
|
762
|
|
|
/** |
|
763
|
|
|
* Returns the z component of the cross product between vectors BC and BA. |
|
764
|
|
|
*/ |
|
765
|
|
|
private function crossProductZ(FinderPattern $pointA, FinderPattern $pointB, FinderPattern $pointC):float{ |
|
766
|
|
|
$bX = $pointB->getX(); |
|
767
|
|
|
$bY = $pointB->getY(); |
|
768
|
|
|
|
|
769
|
|
|
return (($pointC->getX() - $bX) * ($pointA->getY() - $bY)) - (($pointC->getY() - $bY) * ($pointA->getX() - $bX)); |
|
770
|
|
|
} |
|
771
|
|
|
|
|
772
|
|
|
} |
|
773
|
|
|
|