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 image image into which the points should map * @param points actual points in x1,y1,...,xn,yn form * * @throws NotFoundException if an endpoint is lies outside the image boundaries */ protected static function checkAndNudgePoints( $image, $points ) { $width = $image->getWidth(); $height = $image->getHeight(); // Check and nudge points from start until we see some that are OK: $nudged = true; for ($offset = 0; $offset < count($points) && $nudged; $offset += 2) { $x = (int)$points[$offset]; $y = (int)$points[$offset + 1]; if ($x < -1 || $x > $width || $y < -1 || $y > $height) { throw NotFoundException::getNotFoundInstance(); } $nudged = false; if ($x == -1) { $points[$offset] = 0.0; $nudged = true; } else if ($x == $width) { $points[$offset] = $width - 1; $nudged = true; } if ($y == -1) { $points[$offset + 1] = 0.0; $nudged = true; } else if ($y == $height) { $points[$offset + 1] = $height - 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 > $width || $y < -1 || $y > $height) { throw NotFoundException::getNotFoundInstance(); } $nudged = false; if ($x == -1) { $points[$offset] = 0.0; $nudged = true; } else if ($x == $width) { $points[$offset] = $width - 1; $nudged = true; } if ($y == -1) { $points[$offset + 1] = 0.0; $nudged = true; } else if ($y == $height) { $points[$offset + 1] = $height - 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. * * @param image image to sample * @param dimensionX width of {@link BitMatrix} to sample from image * @param dimensionY height of {@link BitMatrix} to sample from image * @param p1ToX point 1 preimage X * @param p1ToY point 1 preimage Y * @param p2ToX point 2 preimage X * @param p2ToY point 2 preimage Y * @param p3ToX point 3 preimage X * @param p3ToY point 3 preimage Y * @param p4ToX point 4 preimage X * @param p4ToY point 4 preimage Y * @param p1FromX point 1 image X * @param p1FromY point 1 image Y * @param p2FromX point 2 image X * @param p2FromY point 2 image Y * @param p3FromX point 3 image X * @param p3FromY point 3 image Y * @param p4FromX point 4 image X * @param p4FromY point 4 image Y * * @return {@link BitMatrix} representing a grid of points sampled from the image within a region * defined by the "from" parameters * @throws NotFoundException 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 abstract function sampleGrid( $image, $dimensionX, $dimensionY, $p1ToX, $p1ToY, $p2ToX, $p2ToY, $p3ToX, $p3ToY, $p4ToX, $p4ToY, $p1FromX, $p1FromY, $p2FromX, $p2FromY, $p3FromX, $p3FromY, $p4FromX, $p4FromY ); public abstract function sampleGrid_( $image, $dimensionX, $dimensionY, $transform ); }