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- <?php
- /*
- * Copyright 2007 ZXing authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- namespace Zxing\Common;
- use Zxing\NotFoundException;
- /**
- * 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 {@link #setGridSampler(GridSampler)}
- * with an instance of a class which implements this interface.
- *
- * @author Sean Owen
- */
- abstract class GridSampler
- {
- /**
- * @var mixed|\Zxing\Common\DefaultGridSampler|null
- */
- private static $gridSampler;
- /**
- * Sets the implementation of GridSampler used by the library. One global
- * instance is stored, which may sound problematic. But, the implementation provided
- * ought to be appropriate for the entire platform, and all uses of this library
- * in the whole lifetime of the JVM. For instance, an Android activity can swap in
- * an implementation that takes advantage of native platform libraries.
- *
- * @param $newGridSampler The platform-specific object to install.
- */
- public static function setGridSampler($newGridSampler): void
- {
- self::$gridSampler = $newGridSampler;
- }
- /**
- * @return GridSampler the current implementation of GridSampler
- */
- public static function getInstance()
- {
- if (!self::$gridSampler) {
- self::$gridSampler = new DefaultGridSampler();
- }
- return self::$gridSampler;
- }
- /**
- * <p>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.</p>
- *
- * <p>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.</p>
- *
- * <p>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.</p>
- *
- * @param image $image into which the points should map
- * @param actual $points 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; $offset < (is_countable($points) ? count($points) : 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;
- $nudged = true;
- } elseif ($x == $width) {
- $points[$offset] = $width - 1;
- $nudged = true;
- }
- if ($y == -1) {
- $points[$offset + 1] = 0.0;
- $nudged = true;
- } elseif ($y == $height) {
- $points[$offset + 1] = $height - 1;
- $nudged = true;
- }
- }
- // Check and nudge points from end:
- $nudged = true;
- for ($offset = (is_countable($points) ? count($points) : 0) - 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;
- $nudged = true;
- } elseif ($x == $width) {
- $points[$offset] = $width - 1;
- $nudged = true;
- }
- if ($y == -1) {
- $points[$offset + 1] = 0.0;
- $nudged = true;
- } elseif ($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 width $dimensionX of {@link BitMatrix} to sample from image
- * @param height $dimensionY of {@link BitMatrix} to sample from image
- * @param point $p1ToX 1 preimage X
- * @param point $p1ToY 1 preimage Y
- * @param point $p2ToX 2 preimage X
- * @param point $p2ToY 2 preimage Y
- * @param point $p3ToX 3 preimage X
- * @param point $p3ToY 3 preimage Y
- * @param point $p4ToX 4 preimage X
- * @param point $p4ToY 4 preimage Y
- * @param point $p1FromX 1 image X
- * @param point $p1FromY 1 image Y
- * @param point $p2FromX 2 image X
- * @param point $p2FromY 2 image Y
- * @param point $p3FromX 3 image X
- * @param point $p3FromY 3 image Y
- * @param point $p4FromX 4 image X
- * @param point $p4FromY 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
- */
- abstract public function sampleGrid(
- $image,
- $dimensionX,
- $dimensionY,
- $p1ToX,
- $p1ToY,
- $p2ToX,
- $p2ToY,
- $p3ToX,
- $p3ToY,
- $p4ToX,
- $p4ToY,
- $p1FromX,
- $p1FromY,
- $p2FromX,
- $p2FromY,
- $p3FromX,
- $p3FromY,
- $p4FromX,
- $p4FromY
- );
- abstract public function sampleGrid_(
- $image,
- $dimensionX,
- $dimensionY,
- $transform
- );
- }
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