GridSampler::checkAndNudgePoints() - Code Metrics - Inspection of ":shower:" - chillerlan/php-qrcode - Measure and Improve Code Quality continuously with Scrutinizer

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by smiley

created 2022-05-26 21:07 UTC

GridSampler::checkAndNudgePoints() D

↳ Parent: GridSampler

Complexity

Conditions	21
Paths	111

Size

Total Lines	61
Code Lines	40

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	21
eloc	40
c	1
b	0
f	0
nc	111
nop	2
dl	0
loc	61
rs	4.075

How to fix Long Method Complexity

<?php
/**
 * Class GridSampler
 *
 * @created      17.01.2021
 * @author       ZXing Authors
 * @author       Smiley <[email protected]>
 * @copyright    2021 Smiley
 * @license      Apache-2.0
 */

namespace chillerlan\QRCode\Detector;

use chillerlan\QRCode\Data\QRMatrix;
use chillerlan\QRCode\Decoder\BitMatrix;
use Throwable;
use function array_fill, count, 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{

	/**
	 * 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 \chillerlan\QRCode\Decoder\BitMatrix $matrix image into which the points should map
	 * @param float[]                              $points actual points in x1,y1,...,xn,yn form
	 *
	 * @throws \chillerlan\QRCode\Detector\QRCodeDetectorException if an endpoint is lies outside the image boundaries
	 */
	private function checkAndNudgePoints(BitMatrix $matrix, array $points):void{
		$dimension = $matrix->size();
		$nudged    = true;
		$max       = count($points);

		// Check and nudge points from start until we see some that are OK:
		for($offset = 0; $offset < $max && $nudged; $offset += 2){
			$x = (int)$points[$offset];
			$y = (int)$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){
				$points[$offset] = 0.0;
				$nudged          = true;
			}
			elseif($x === $dimension){
				$points[$offset] = $dimension - 1;
				$nudged          = true;
			}
			if($y === -1){
				$points[$offset + 1] = 0.0;
				$nudged              = true;
			}
			elseif($y === $dimension){
				$points[$offset + 1] = $dimension - 1;
				$nudged              = true;
			}
		}
		// Check and nudge points from end:
		$nudged = true;

		for($offset = count($points) - 2; $offset >= 0 && $nudged; $offset -= 2){
			$x = (int)$points[$offset];
			$y = (int)$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){
				$points[$offset] = 0.0;
				$nudged          = true;
			}
			elseif($x === $dimension){
				$points[$offset] = $dimension - 1;
				$nudged          = true;
			}
			if($y === -1){
				$points[$offset + 1] = 0.0;
				$nudged              = true;
			}
			elseif($y === $dimension){
				$points[$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);
		$points = array_fill(0, 2 * $dimension, 0.0);

		for($y = 0; $y < $dimension; $y++){
			$max    = count($points);
			$iValue = $y + 0.5;

			for($x = 0; $x < $max; $x += 2){
				$points[$x]     = ($x / 2) + 0.5;
				$points[$x + 1] = $iValue;
			}

			$transform->transformPoints($points);
			// Quick check to see if points transformed to something inside the image;
			// sufficient to check the endpoints
			$this->checkAndNudgePoints($matrix, $points);

			try{
				for($x = 0; $x < $max; $x += 2){
					// Black(-ish) pixel
					$bits->set($x / 2, $y, $matrix->check((int)$points[$x], (int)$points[$x + 1]), QRMatrix::M_DATA);
				}
			}
			// @codeCoverageIgnoreStart
			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');
			}
			// @codeCoverageIgnoreEnd

		}

		return $bits;
	}

}


1			<?php
2			/**
3			* Class GridSampler
4			*
5			* @created 17.01.2021
6			* @author ZXing Authors
7			* @author Smiley <[email protected]>
8			* @copyright 2021 Smiley
9			* @license Apache-2.0
10			*/
11
12			namespace chillerlan\QRCode\Detector;
13
14			use chillerlan\QRCode\Data\QRMatrix;
15			use chillerlan\QRCode\Decoder\BitMatrix;
16			use Throwable;
17			use function array_fill, count, sprintf;
18
19			/**
20			* Implementations of this class can, given locations of finder patterns for a QR code in an
21			* image, sample the right points in the image to reconstruct the QR code, accounting for
22			* perspective distortion. It is abstracted since it is relatively expensive and should be allowed
23			* to take advantage of platform-specific optimized implementations, like Sun's Java Advanced
24			* Imaging library, but which may not be available in other environments such as J2ME, and vice
25			* versa.
26			*
27			* The implementation used can be controlled by calling #setGridSampler(GridSampler)
28			* with an instance of a class which implements this interface.
29			*
30			* @author Sean Owen
31			*/
32			final class GridSampler{
33
34			/**
35			* Checks a set of points that have been transformed to sample points on an image against
36			* the image's dimensions to see if the point are even within the image.
37			*
38			* This method will actually "nudge" the endpoints back onto the image if they are found to be
39			* barely (less than 1 pixel) off the image. This accounts for imperfect detection of finder
40			* patterns in an image where the QR Code runs all the way to the image border.
41			*
42			* For efficiency, the method will check points from either end of the line until one is found
43			* to be within the image. Because the set of points are assumed to be linear, this is valid.
44			*
45			* @param \chillerlan\QRCode\Decoder\BitMatrix $matrix image into which the points should map
46			* @param float[] $points actual points in x1,y1,...,xn,yn form
47			*
48			* @throws \chillerlan\QRCode\Detector\QRCodeDetectorException if an endpoint is lies outside the image boundaries
49			*/
50			private function checkAndNudgePoints(BitMatrix $matrix, array $points):void{
51			$dimension = $matrix->size();
52			$nudged = true;
53			$max = count($points);
54
55			// Check and nudge points from start until we see some that are OK:
56			for($offset = 0; $offset < $max && $nudged; $offset += 2){
57			$x = (int)$points[$offset];
58			$y = (int)$points[$offset + 1];
59
60			if($x < -1 \|\| $x > $dimension \|\| $y < -1 \|\| $y > $dimension){
61			throw new QRCodeDetectorException(sprintf('checkAndNudgePoints 1, x: %s, y: %s, d: %s', $x, $y, $dimension));
62			}
63
64			$nudged = false;
65
66			if($x === -1){
67			$points[$offset] = 0.0;
68			$nudged = true;
69			}
70			elseif($x === $dimension){
71			$points[$offset] = $dimension - 1;
72			$nudged = true;
73			}
74			if($y === -1){
75			$points[$offset + 1] = 0.0;
76			$nudged = true;
77			}
78			elseif($y === $dimension){
79			$points[$offset + 1] = $dimension - 1;
80			$nudged = true;
81			}
82			}
83			// Check and nudge points from end:
84			$nudged = true;
85
86			for($offset = count($points) - 2; $offset >= 0 && $nudged; $offset -= 2){
87			$x = (int)$points[$offset];
88			$y = (int)$points[$offset + 1];
89
90			if($x < -1 \|\| $x > $dimension \|\| $y < -1 \|\| $y > $dimension){
91			throw new QRCodeDetectorException(sprintf('checkAndNudgePoints 2, x: %s, y: %s, d: %s', $x, $y, $dimension));
92			}
93
94			$nudged = false;
95
96			if($x === -1){
97			$points[$offset] = 0.0;
98			$nudged = true;
99			}
100			elseif($x === $dimension){
101			$points[$offset] = $dimension - 1;
102			$nudged = true;
103			}
104			if($y === -1){
105			$points[$offset + 1] = 0.0;
106			$nudged = true;
107			}
108			elseif($y === $dimension){
109			$points[$offset + 1] = $dimension - 1;
110			$nudged = true;
111			}
112			}
113			}
114
115			/**
116			* Samples an image for a rectangular matrix of bits of the given dimension. The sampling
117			* transformation is determined by the coordinates of 4 points, in the original and transformed
118			* image space.
119			*
120			* @return \chillerlan\QRCode\Decoder\BitMatrix representing a grid of points sampled from the image within a region
121			* defined by the "from" parameters
122			* @throws \chillerlan\QRCode\Detector\QRCodeDetectorException if image can't be sampled, for example, if the transformation defined
123			* by the given points is invalid or results in sampling outside the image boundaries
124			*/
125			public function sampleGrid(BitMatrix $matrix, int $dimension, PerspectiveTransform $transform):BitMatrix{
126
127			if($dimension <= 0){
128			throw new QRCodeDetectorException('invalid matrix size');
129			}
130
131			$bits = new BitMatrix($dimension);
132			$points = array_fill(0, 2 * $dimension, 0.0);
133
134			for($y = 0; $y < $dimension; $y++){
135			$max = count($points);
136			$iValue = $y + 0.5;
137
138			for($x = 0; $x < $max; $x += 2){
139			$points[$x] = ($x / 2) + 0.5;
140			$points[$x + 1] = $iValue;
141			}
142
143			$transform->transformPoints($points);
144			// Quick check to see if points transformed to something inside the image;
145			// sufficient to check the endpoints
146			$this->checkAndNudgePoints($matrix, $points);
147
148			try{
149			for($x = 0; $x < $max; $x += 2){
150			// Black(-ish) pixel
151			$bits->set($x / 2, $y, $matrix->check((int)$points[$x], (int)$points[$x + 1]), QRMatrix::M_DATA);
152			}
153			}
154			// @codeCoverageIgnoreStart
155			catch(Throwable $aioobe){//ArrayIndexOutOfBoundsException
156			// This feels wrong, but, sometimes if the finder patterns are misidentified, the resulting
157			// transform gets "twisted" such that it maps a straight line of points to a set of points
158			// whose endpoints are in bounds, but others are not. There is probably some mathematical
159			// way to detect this about the transformation that I don't know yet.
160			// This results in an ugly runtime exception despite our clever checks above -- can't have
161			// that. We could check each point's coordinates but that feels duplicative. We settle for
162			// catching and wrapping ArrayIndexOutOfBoundsException.
163			throw new QRCodeDetectorException('ArrayIndexOutOfBoundsException');
164			}
165			// @codeCoverageIgnoreEnd
166
167			}
168
169			return $bits;
170			}
171
172			}
173

chillerlan / php-qrcode

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GridSampler::checkAndNudgePoints() D

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