Viewing file:  BitMatrix.php (7.55 KB) -rwxr-x---
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
<?php
declare(strict_types = 1);
namespace BaconQrCode\Common;
use BaconQrCode\Exception\InvalidArgumentException;
use SplFixedArray;
/**
* Bit matrix.
*
* Represents a 2D matrix of bits. In function arguments below, and throughout
* the common module, x is the column position, and y is the row position. The
* ordering is always x, y. The origin is at the top-left.
*/
class BitMatrix
{
/**
* Width of the bit matrix.
*
* @var int
*/
private $width;
/**
* Height of the bit matrix.
*
* @var int
*/
private $height;
/**
* Size in bits of each individual row.
*
* @var int
*/
private $rowSize;
/**
* Bits representation.
*
* @var SplFixedArray<int>
*/
private $bits;
/**
* @throws InvalidArgumentException if a dimension is smaller than zero
*/
public function __construct(int $width, int $height = null)
{
if (null === $height) {
$height = $width;
}
if ($width < 1 || $height < 1) {
throw new InvalidArgumentException('Both dimensions must be greater than zero');
}
$this->width = $width;
$this->height = $height;
$this->rowSize = ($width + 31) >> 5;
$this->bits = SplFixedArray::fromArray(array_fill(0, $this->rowSize * $height, 0));
}
/**
* Gets the requested bit, where true means black.
*/
public function get(int $x, int $y) : bool
{
$offset = $y * $this->rowSize + ($x >> 5);
return 0 !== (BitUtils::unsignedRightShift($this->bits[$offset], ($x & 0x1f)) & 1);
}
/**
* Sets the given bit to true.
*/
public function set(int $x, int $y) : void
{
$offset = $y * $this->rowSize + ($x >> 5);
$this->bits[$offset] = $this->bits[$offset] | (1 << ($x & 0x1f));
}
/**
* Flips the given bit.
*/
public function flip(int $x, int $y) : void
{
$offset = $y * $this->rowSize + ($x >> 5);
$this->bits[$offset] = $this->bits[$offset] ^ (1 << ($x & 0x1f));
}
/**
* Clears all bits (set to false).
*/
public function clear() : void
{
$max = count($this->bits);
for ($i = 0; $i < $max; ++$i) {
$this->bits[$i] = 0;
}
}
/**
* Sets a square region of the bit matrix to true.
*
* @throws InvalidArgumentException if left or top are negative
* @throws InvalidArgumentException if width or height are smaller than 1
* @throws InvalidArgumentException if region does not fit into the matix
*/
public function setRegion(int $left, int $top, int $width, int $height) : void
{
if ($top < 0 || $left < 0) {
throw new InvalidArgumentException('Left and top must be non-negative');
}
if ($height < 1 || $width < 1) {
throw new InvalidArgumentException('Width and height must be at least 1');
}
$right = $left + $width;
$bottom = $top + $height;
if ($bottom > $this->height || $right > $this->width) {
throw new InvalidArgumentException('The region must fit inside the matrix');
}
for ($y = $top; $y < $bottom; ++$y) {
$offset = $y * $this->rowSize;
for ($x = $left; $x < $right; ++$x) {
$index = $offset + ($x >> 5);
$this->bits[$index] = $this->bits[$index] | (1 << ($x & 0x1f));
}
}
}
/**
* A fast method to retrieve one row of data from the matrix as a BitArray.
*/
public function getRow(int $y, BitArray $row = null) : BitArray
{
if (null === $row || $row->getSize() < $this->width) {
$row = new BitArray($this->width);
}
$offset = $y * $this->rowSize;
for ($x = 0; $x < $this->rowSize; ++$x) {
$row->setBulk($x << 5, $this->bits[$offset + $x]);
}
return $row;
}
/**
* Sets a row of data from a BitArray.
*/
public function setRow(int $y, BitArray $row) : void
{
$bits = $row->getBitArray();
for ($i = 0; $i < $this->rowSize; ++$i) {
$this->bits[$y * $this->rowSize + $i] = $bits[$i];
}
}
/**
* This is useful in detecting the enclosing rectangle of a 'pure' barcode.
*
* @return int[]|null
*/
public function getEnclosingRectangle() : ?array
{
$left = $this->width;
$top = $this->height;
$right = -1;
$bottom = -1;
for ($y = 0; $y < $this->height; ++$y) {
for ($x32 = 0; $x32 < $this->rowSize; ++$x32) {
$bits = $this->bits[$y * $this->rowSize + $x32];
if (0 !== $bits) {
if ($y < $top) {
$top = $y;
}
if ($y > $bottom) {
$bottom = $y;
}
if ($x32 * 32 < $left) {
$bit = 0;
while (($bits << (31 - $bit)) === 0) {
$bit++;
}
if (($x32 * 32 + $bit) < $left) {
$left = $x32 * 32 + $bit;
}
}
}
if ($x32 * 32 + 31 > $right) {
$bit = 31;
while (0 === BitUtils::unsignedRightShift($bits, $bit)) {
--$bit;
}
if (($x32 * 32 + $bit) > $right) {
$right = $x32 * 32 + $bit;
}
}
}
}
$width = $right - $left;
$height = $bottom - $top;
if ($width < 0 || $height < 0) {
return null;
}
return [$left, $top, $width, $height];
}
/**
* Gets the most top left set bit.
*
* This is useful in detecting a corner of a 'pure' barcode.
*
* @return int[]|null
*/
public function getTopLeftOnBit() : ?array
{
$bitsOffset = 0;
while ($bitsOffset < count($this->bits) && 0 === $this->bits[$bitsOffset]) {
++$bitsOffset;
}
if (count($this->bits) === $bitsOffset) {
return null;
}
$x = intdiv($bitsOffset, $this->rowSize);
$y = ($bitsOffset % $this->rowSize) << 5;
$bits = $this->bits[$bitsOffset];
$bit = 0;
while (0 === ($bits << (31 - $bit))) {
++$bit;
}
$x += $bit;
return [$x, $y];
}
/**
* Gets the most bottom right set bit.
*
* This is useful in detecting a corner of a 'pure' barcode.
*
* @return int[]|null
*/
public function getBottomRightOnBit() : ?array
{
$bitsOffset = count($this->bits) - 1;
while ($bitsOffset >= 0 && 0 === $this->bits[$bitsOffset]) {
--$bitsOffset;
}
if ($bitsOffset < 0) {
return null;
}
$x = intdiv($bitsOffset, $this->rowSize);
$y = ($bitsOffset % $this->rowSize) << 5;
$bits = $this->bits[$bitsOffset];
$bit = 0;
while (0 === BitUtils::unsignedRightShift($bits, $bit)) {
--$bit;
}
$x += $bit;
return [$x, $y];
}
/**
* Gets the width of the matrix,
*/
public function getWidth() : int
{
return $this->width;
}
/**
* Gets the height of the matrix.
*/
public function getHeight() : int
{
return $this->height;
}
}
|