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Diffstat (limited to 'vendor/chillerlan/php-qrcode/src/Detector/GridSampler.php')
| -rw-r--r-- | vendor/chillerlan/php-qrcode/src/Detector/GridSampler.php | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/vendor/chillerlan/php-qrcode/src/Detector/GridSampler.php b/vendor/chillerlan/php-qrcode/src/Detector/GridSampler.php new file mode 100644 index 000000000..f70bb0eca --- /dev/null +++ b/vendor/chillerlan/php-qrcode/src/Detector/GridSampler.php @@ -0,0 +1,181 @@ +<?php +/** + * Class GridSampler + * + * @created 17.01.2021 + * @author ZXing Authors + * @author Smiley <smiley@chillerlan.net> + * @copyright 2021 Smiley + * @license Apache-2.0 + */ + +namespace chillerlan\QRCode\Detector; + +use chillerlan\QRCode\Data\QRMatrix; +use chillerlan\QRCode\Decoder\BitMatrix; +use function array_fill, count, intdiv, sprintf; + +/** + * Implementations of this class can, given locations of finder patterns for a QR code in an + * image, sample the right points in the image to reconstruct the QR code, accounting for + * perspective distortion. It is abstracted since it is relatively expensive and should be allowed + * to take advantage of platform-specific optimized implementations, like Sun's Java Advanced + * Imaging library, but which may not be available in other environments such as J2ME, and vice + * versa. + * + * The implementation used can be controlled by calling #setGridSampler(GridSampler) + * with an instance of a class which implements this interface. + * + * @author Sean Owen + */ +final class GridSampler{ + + private array $points; + + /** + * Checks a set of points that have been transformed to sample points on an image against + * the image's dimensions to see if the point are even within the image. + * + * This method will actually "nudge" the endpoints back onto the image if they are found to be + * barely (less than 1 pixel) off the image. This accounts for imperfect detection of finder + * patterns in an image where the QR Code runs all the way to the image border. + * + * For efficiency, the method will check points from either end of the line until one is found + * to be within the image. Because the set of points are assumed to be linear, this is valid. + * + * @param int $dimension matrix width/height + * + * @throws \chillerlan\QRCode\Detector\QRCodeDetectorException if an endpoint is lies outside the image boundaries + */ + private function checkAndNudgePoints(int $dimension):void{ + $nudged = true; + $max = count($this->points); + + // Check and nudge points from start until we see some that are OK: + for($offset = 0; $offset < $max && $nudged; $offset += 2){ + $x = (int)$this->points[$offset]; + $y = (int)$this->points[($offset + 1)]; + + if($x < -1 || $x > $dimension || $y < -1 || $y > $dimension){ + throw new QRCodeDetectorException(sprintf('checkAndNudgePoints 1, x: %s, y: %s, d: %s', $x, $y, $dimension)); + } + + $nudged = false; + + if($x === -1){ + $this->points[$offset] = 0.0; + $nudged = true; + } + elseif($x === $dimension){ + $this->points[$offset] = ($dimension - 1); + $nudged = true; + } + + if($y === -1){ + $this->points[($offset + 1)] = 0.0; + $nudged = true; + } + elseif($y === $dimension){ + $this->points[($offset + 1)] = ($dimension - 1); + $nudged = true; + } + + } + + // Check and nudge points from end: + $nudged = true; + + for($offset = ($max - 2); $offset >= 0 && $nudged; $offset -= 2){ + $x = (int)$this->points[$offset]; + $y = (int)$this->points[($offset + 1)]; + + if($x < -1 || $x > $dimension || $y < -1 || $y > $dimension){ + throw new QRCodeDetectorException(sprintf('checkAndNudgePoints 2, x: %s, y: %s, d: %s', $x, $y, $dimension)); + } + + $nudged = false; + + if($x === -1){ + $this->points[$offset] = 0.0; + $nudged = true; + } + elseif($x === $dimension){ + $this->points[$offset] = ($dimension - 1); + $nudged = true; + } + + if($y === -1){ + $this->points[($offset + 1)] = 0.0; + $nudged = true; + } + elseif($y === $dimension){ + $this->points[($offset + 1)] = ($dimension - 1); + $nudged = true; + } + + } + + } + + /** + * Samples an image for a rectangular matrix of bits of the given dimension. The sampling + * transformation is determined by the coordinates of 4 points, in the original and transformed + * image space. + * + * @return \chillerlan\QRCode\Decoder\BitMatrix representing a grid of points sampled from the image within a region + * defined by the "from" parameters + * @throws \chillerlan\QRCode\Detector\QRCodeDetectorException if image can't be sampled, for example, if the transformation defined + * by the given points is invalid or results in sampling outside the image boundaries + */ + public function sampleGrid(BitMatrix $matrix, int $dimension, PerspectiveTransform $transform):BitMatrix{ + + if($dimension <= 0){ + throw new QRCodeDetectorException('invalid matrix size'); + } + + $bits = new BitMatrix($dimension); + $this->points = array_fill(0, (2 * $dimension), 0.0); + + for($y = 0; $y < $dimension; $y++){ + $max = count($this->points); + $iValue = ($y + 0.5); + + for($x = 0; $x < $max; $x += 2){ + $this->points[$x] = (($x / 2) + 0.5); + $this->points[($x + 1)] = $iValue; + } + // phpcs:ignore + [$this->points, ] = $transform->transformPoints($this->points); + // Quick check to see if points transformed to something inside the image; + // sufficient to check the endpoints + $this->checkAndNudgePoints($matrix->getSize()); + + // no need to try/catch as QRMatrix::set() will silently discard out of bounds values +# try{ + for($x = 0; $x < $max; $x += 2){ + // Black(-ish) pixel + $bits->set( + intdiv($x, 2), + $y, + $matrix->check((int)$this->points[$x], (int)$this->points[($x + 1)]), + QRMatrix::M_DATA + ); + } +# } +# catch(\Throwable $aioobe){//ArrayIndexOutOfBoundsException + // This feels wrong, but, sometimes if the finder patterns are misidentified, the resulting + // transform gets "twisted" such that it maps a straight line of points to a set of points + // whose endpoints are in bounds, but others are not. There is probably some mathematical + // way to detect this about the transformation that I don't know yet. + // This results in an ugly runtime exception despite our clever checks above -- can't have + // that. We could check each point's coordinates but that feels duplicative. We settle for + // catching and wrapping ArrayIndexOutOfBoundsException. +# throw new QRCodeDetectorException('ArrayIndexOutOfBoundsException'); +# } + + } + + return $bits; + } + +} |