DataMask | <p>Encapsulates data masks for the data bits in a QR code, per ISO 18004:2006 6.8. Implementations of this class can un-mask a raw BitMatrix. For simplicity, they will unmask the entire BitMatrix, including areas used for finder patterns, timing patterns, etc. These areas should be unused after the point they are unmasked anyway.</p> |
DataMask000 | 000: mask bits for which (x + y) mod 2 == 0 |
DataMask001 | 001: mask bits for which x mod 2 == 0 |
DataMask010 | 010: mask bits for which y mod 3 == 0 |
DataMask011 | 011: mask bits for which (x + y) mod 3 == 0 |
DataMask100 | 100: mask bits for which (x/2 + y/3) mod 2 == 0 |
DataMask101 | 101: mask bits for which xy mod 2 + xy mod 3 == 0 |
DataMask110 | 110: mask bits for which (xy mod 2 + xy mod 3) mod 2 == 0 |
DataMask111 | 111: mask bits for which ((x+y)mod 2 + xy mod 3) mod 2 == 0 |
<?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\Qrcode\Decoder;
use Zxing\Common\BitMatrix;
/**
* <p>Encapsulates data masks for the data bits in a QR code, per ISO 18004:2006 6.8. Implementations
* of this class can un-mask a raw BitMatrix. For simplicity, they will unmask the entire BitMatrix,
* including areas used for finder patterns, timing patterns, etc. These areas should be unused
* after the point they are unmasked anyway.</p>
*
* <p>Note that the diagram in section 6.8.1 is misleading since it indicates that i is column position
* and j is row position. In fact, as the text says, i is row position and j is column position.</p>
*
* @author Sean Owen
*/
abstract class DataMask
{
/**
* See ISO 18004:2006 6.8.1
*/
private static $DATA_MASKS = [];
public function __construct()
{
}
public static function Init()
{
self::$DATA_MASKS = [
new DataMask000(),
new DataMask001(),
new DataMask010(),
new DataMask011(),
new DataMask100(),
new DataMask101(),
new DataMask110(),
new DataMask111(),
];
}
/**
* @param reference a value between 0 and 7 indicating one of the eight possible
* data mask patterns a QR Code may use
*
* @return DataMask encapsulating the data mask pattern
*/
public static function forReference($reference)
{
if ($reference < 0 || $reference > 7) {
throw new \InvalidArgumentException();
}
return self::$DATA_MASKS[$reference];
}
/**
* <p>Implementations of this method reverse the data masking process applied to a QR Code and
* make its bits ready to read.</p>
*
* @param bits representation of QR Code bits
* @param dimension dimension of QR Code, represented by bits, being unmasked
*/
final public function unmaskBitMatrix($bits, $dimension)
{
for ($i = 0; $i < $dimension; $i++) {
for ($j = 0; $j < $dimension; $j++) {
if ($this->isMasked($i, $j)) {
$bits->flip($j, $i);
}
}
}
}
abstract public function isMasked($i, $j);
}
DataMask::Init();
/**
* 000: mask bits for which (x + y) mod 2 == 0
*/
final class DataMask000 extends DataMask
{
// @Override
public function isMasked($i, $j)
{
return (($i + $j) & 0x01) == 0;
}
}
/**
* 001: mask bits for which x mod 2 == 0
*/
final class DataMask001 extends DataMask
{
//@Override
public function isMasked($i, $j)
{
return ($i & 0x01) == 0;
}
}
/**
* 010: mask bits for which y mod 3 == 0
*/
final class DataMask010 extends DataMask
{
//@Override
public function isMasked($i, $j)
{
return $j % 3 == 0;
}
}
/**
* 011: mask bits for which (x + y) mod 3 == 0
*/
final class DataMask011 extends DataMask
{
//@Override
public function isMasked($i, $j)
{
return ($i + $j) % 3 == 0;
}
}
/**
* 100: mask bits for which (x/2 + y/3) mod 2 == 0
*/
final class DataMask100 extends DataMask
{
//@Override
public function isMasked($i, $j)
{
return (int)(((int)($i / 2) + (int)($j / 3)) & 0x01) == 0;
}
}
/**
* 101: mask bits for which xy mod 2 + xy mod 3 == 0
*/
final class DataMask101 extends DataMask
{
//@Override
public function isMasked($i, $j)
{
$temp = $i * $j;
return ($temp & 0x01) + ($temp % 3) == 0;
}
}
/**
* 110: mask bits for which (xy mod 2 + xy mod 3) mod 2 == 0
*/
final class DataMask110 extends DataMask
{
//@Override
public function isMasked($i, $j)
{
$temp = $i * $j;
return ((($temp & 0x01) + ($temp % 3)) & 0x01) == 0;
}
}
/**
* 111: mask bits for which ((x+y)mod 2 + xy mod 3) mod 2 == 0
*/
final class DataMask111 extends DataMask
{
//@Override
public function isMasked($i, $j)
{
return (((($i + $j) & 0x01) + (($i * $j) % 3)) & 0x01) == 0;
}
}