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Public Member Functions | Protected Member Functions | Protected Attributes
PDF417 Class Reference

Class to create PDF417 barcode arrays for TCPDF class. More...

+ Collaboration diagram for PDF417:

Public Member Functions

 __construct ($code, $ecl=-1, $aspectratio=2, $macro=array())
 This is the class constructor.
 getBarcodeArray ()
 Returns a barcode array which is readable by TCPDF.

Protected Member Functions

 getErrorCorrectionLevel ($ecl, $numcw)
 Returns the error correction level (0-8) to be used.
 getErrorCorrection ($cw, $ecl)
 Returns the error correction codewords.
 getInputSequences ($code)
 Create array of sequences from input.
 getCompaction ($mode, $code, $addmode=true)
 Compact data by mode.

Protected Attributes

 $barcode_array = array()
 Barcode array to be returned which is readable by TCPDF.
 $start_pattern = '11111111010101000'
 Start pattern.
 $stop_pattern = '111111101000101001'
 Stop pattern.
 $textsubmodes
 Array of text Compaction Sub-Modes (values 0xFB - 0xFF are used for submode changers).
 $textlatch
 Array of switching codes for Text Compaction Sub-Modes.
 $clusters
 Clusters of codewords (0, 3, 6)
Values are hex equivalents of binary representation of bars (1 = bar, 0 = space).
 $rsfactors
 Array of factors of the Reed-Solomon polynomial equations used for error correction; one sub array for each correction level (0-8).

Detailed Description

Class to create PDF417 barcode arrays for TCPDF class.

PDF417 (ISO/IEC 15438:2006) is a 2-dimensional stacked bar code created by Symbol Technologies in 1991.

Definition at line 93 of file pdf417.php.

Constructor & Destructor Documentation

PDF417::__construct (   $code,
  $ecl = -1,
  $aspectratio = 2,
  $macro = array() 
)

This is the class constructor.

Creates a PDF417 object

Parameters
$code(string) code to represent using PDF417
$ecl(int) error correction level (0-8); default -1 = automatic correction level
$aspectratio(float) the width to height of the symbol (excluding quiet zones)
$macro(array) information for macro block

Definition at line 532 of file pdf417.php.

References $barcode_array, $row, $size, getCompaction(), getErrorCorrection(), getErrorCorrectionLevel(), and getInputSequences().

{
$barcode_array = array();
if ((is_null($code)) OR ($code == '\0') OR ($code == '')) {
return false;
}
// get the input sequence array
$sequence = $this->getInputSequences($code);
$codewords = array(); // array of code-words
foreach($sequence as $seq) {
$cw = $this->getCompaction($seq[0], $seq[1], true);
$codewords = array_merge($codewords, $cw);
}
if ($codewords[0] == 900) {
// Text Alpha is the default mode, so remove the first code
array_shift($codewords);
}
// count number of codewords
$numcw = count($codewords);
if ($numcw > 925) {
// reached maximum data codeword capacity
return false;
}
// build macro control block codewords
if (!empty($macro)) {
$macrocw = array();
// beginning of macro control block
$macrocw[] = 928;
// segment index
$cw = $this->getCompaction(902, sprintf('%05d', $macro['segment_index']), false);
$macrocw = array_merge($macrocw, $cw);
// file ID
$cw = $this->getCompaction(900, $macro['file_id'], false);
$macrocw = array_merge($macrocw, $cw);
// optional fields
$optmodes = array(900,902,902,900,900,902,902);
$optsize = array(-1,2,4,-1,-1,-1,2);
foreach ($optmodes as $k => $omode) {
if (isset($macro['option_'.$k])) {
$macrocw[] = 923;
$macrocw[] = $k;
if ($optsize[$k] == 2) {
$macro['option_'.$k] = sprintf('%05d', $macro['option_'.$k]);
} elseif ($optsize[$k] == 4) {
$macro['option_'.$k] = sprintf('%010d', $macro['option_'.$k]);
}
$cw = $this->getCompaction($omode, $macro['option_'.$k], false);
$macrocw = array_merge($macrocw, $cw);
}
}
if ($macro['segment_index'] == ($macro['segment_total'] - 1)) {
// end of control block
$macrocw[] = 922;
}
// update total codewords
$numcw += count($macrocw);
}
// set error correction level
$ecl = $this->getErrorCorrectionLevel($ecl, $numcw);
// number of codewords for error correction
$errsize = (2 << $ecl);
// calculate number of columns (number of codewords per row) and rows
$nce = ($numcw + $errsize + 1);
$cols = round((sqrt(4761 + (68 * $aspectratio * ROWHEIGHT * $nce)) - 69) / 34);
// adjust cols
if ($cols < 1) {
$cols = 1;
} elseif ($cols > 30) {
$cols = 30;
}
$rows = ceil($nce / $cols);
$size = ($cols * $rows);
// adjust rows
if (($rows < 3) OR ($rows > 90)) {
if ($rows < 3) {
$rows = 3;
} elseif ($rows > 90) {
$rows = 90;
}
$cols = ceil($size / $rows);
$size = ($cols * $rows);
}
if ($size > 928) {
// set dimensions to get maximum capacity
if (abs($aspectratio - (17 * 29 / 32)) < abs($aspectratio - (17 * 16 / 58))) {
$cols = 29;
$rows = 32;
} else {
$cols = 16;
$rows = 58;
}
$size = 928;
}
// calculate padding
$pad = ($size - $nce);
if ($pad > 0) {
if (($size - $rows) == $nce) {
--$rows;
$size -= $rows;
} else {
// add pading
$codewords = array_merge($codewords, array_fill(0, $pad, 900));
}
}
if (!empty($macro)) {
// add macro section
$codewords = array_merge($codewords, $macrocw);
}
// Symbol Lenght Descriptor (number of data codewords including Symbol Lenght Descriptor and pad codewords)
$sld = $size - $errsize;
// add symbol length description
array_unshift($codewords, $sld);
// calculate error correction
$ecw = $this->getErrorCorrection($codewords, $ecl);
// add error correction codewords
$codewords = array_merge($codewords, $ecw);
// add horizontal quiet zones to start and stop patterns
$pstart = str_repeat('0', QUIETH).$this->start_pattern;
$pstop = $this->stop_pattern.str_repeat('0', QUIETH);
$barcode_array['num_rows'] = ($rows * ROWHEIGHT) + (2 * QUIETV);
$barcode_array['num_cols'] = (($cols + 2) * 17) + 35 + (2 * QUIETH);
$barcode_array['bcode'] = array();
// build rows for vertical quiet zone
if (QUIETV > 0) {
$empty_row = array_fill(0, $barcode_array['num_cols'], 0);
for ($i = 0; $i < QUIETV; ++$i) {
// add vertical quiet rows
$barcode_array['bcode'][] = $empty_row;
}
}
$k = 0; // codeword index
$cid = 0; // initial cluster
// for each row
for ($r = 0; $r < $rows; ++$r) {
// row start code
$row = $pstart;
switch ($cid) {
case 0: {
$L = ((30 * intval($r / 3)) + intval(($rows - 1) / 3));
break;
}
case 1: {
$L = ((30 * intval($r / 3)) + ($ecl * 3) + (($rows - 1) % 3));
break;
}
case 2: {
$L = ((30 * intval($r / 3)) + ($cols - 1));
break;
}
}
// left row indicator
$row .= sprintf('%17b', $this->clusters[$cid][$L]);
// for each column
for ($c = 0; $c < $cols; ++$c) {
$row .= sprintf('%17b', $this->clusters[$cid][$codewords[$k]]);
++$k;
}
switch ($cid) {
case 0: {
$L = ((30 * intval($r / 3)) + ($cols - 1));
break;
}
case 1: {
$L = ((30 * intval($r / 3)) + intval(($rows - 1) / 3));
break;
}
case 2: {
$L = ((30 * intval($r / 3)) + ($ecl * 3) + (($rows - 1) % 3));
break;
}
}
// right row indicator
$row .= sprintf('%17b', $this->clusters[$cid][$L]);
// row stop code
$row .= $pstop;
// convert the string to array
$arow = preg_split('//', $row, -1, PREG_SPLIT_NO_EMPTY);
// duplicate row to get the desired height
for ($h = 0; $h < ROWHEIGHT; ++$h) {
$barcode_array['bcode'][] = $arow;
}
++$cid;
if ($cid > 2) {
$cid = 0;
}
}
if (QUIETV > 0) {
for ($i = 0; $i < QUIETV; ++$i) {
// add vertical quiet rows
$barcode_array['bcode'][] = $empty_row;
}
}
$this->barcode_array = $barcode_array;
}

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Member Function Documentation

PDF417::getBarcodeArray ( )

Returns a barcode array which is readable by TCPDF.

Returns
array barcode array readable by TCPDF;

Definition at line 731 of file pdf417.php.

References $barcode_array.

{
return $this->barcode_array;
}
PDF417::getCompaction (   $mode,
  $code,
  $addmode = true 
)
protected

Compact data by mode.

Parameters
$mode(int) compaction mode number
$code(string) data to compact
$addmode(boolean) if true add the mode codeword at first position
Returns
array of codewords

Definition at line 873 of file pdf417.php.

References $d, $rest, and $t.

Referenced by __construct().

{
$cw = array(); // array of codewords to return
switch($mode) {
case 900: { // Text Compaction mode latch
$submode = 0; // default Alpha sub-mode
$txtarr = array(); // array of characters and sub-mode switching characters
$codelen = strlen($code);
for ($i = 0; $i < $codelen; ++$i) {
$chval = ord($code{$i});
if (($k = array_search($chval, $this->textsubmodes[$submode])) !== false) {
// we are on the same sub-mode
$txtarr[] = $k;
} else {
// the sub-mode is changed
for ($s = 0; $s < 4; ++$s) {
// search new sub-mode
if (($s != $submode) AND (($k = array_search($chval, $this->textsubmodes[$s])) !== false)) {
// $s is the new submode
if (((($i + 1) == $codelen) OR ((($i + 1) < $codelen) AND (array_search(ord($code{($i + 1)}), $this->textsubmodes[$submode]) !== false))) AND (($s == 3) OR (($s == 0) AND ($submode == 1)))) {
// shift (temporary change only for this char)
if ($s == 3) {
// shift to puntuaction
$txtarr[] = 29;
} else {
// shift from lower to alpha
$txtarr[] = 27;
}
} else {
// latch
$txtarr = array_merge($txtarr, $this->textlatch[''.$submode.$s]);
// set new submode
$submode = $s;
}
// add characted code to array
$txtarr[] = $k;
break;
}
}
}
}
$txtarrlen = count($txtarr);
if (($txtarrlen % 2) != 0) {
// add padding
$txtarr[] = 29;
++$txtarrlen;
}
// calculate codewords
for ($i = 0; $i < $txtarrlen; $i += 2) {
$cw[] = (30 * $txtarr[$i]) + $txtarr[($i + 1)];
}
break;
}
case 901:
case 924: { // Byte Compaction mode latch
while (($codelen = strlen($code)) > 0) {
if ($codelen > 6) {
$rest = substr($code, 6);
$code = substr($code, 0, 6);
$sublen = 6;
} else {
$rest = '';
$sublen = strlen($code);
}
if ($sublen == 6) {
$t = bcmul(''.ord($code{0}), '1099511627776');
$t = bcadd($t, bcmul(''.ord($code{1}), '4294967296'));
$t = bcadd($t, bcmul(''.ord($code{2}), '16777216'));
$t = bcadd($t, bcmul(''.ord($code{3}), '65536'));
$t = bcadd($t, bcmul(''.ord($code{4}), '256'));
$t = bcadd($t, ''.ord($code{5}));
do {
$d = bcmod($t, '900');
$t = bcdiv($t, '900');
array_unshift($cw, $d);
} while ($t != '0');
} else {
for ($i = 0; $i < $sublen; ++$i) {
$cw[] = ord($code{$i});
}
}
$code = $rest;
}
break;
}
case 902: { // Numeric Compaction mode latch
while (($codelen = strlen($code)) > 0) {
if ($codelen > 44) {
$rest = substr($code, 44);
$code = substr($code, 0, 44);
} else {
$rest = '';
}
$t = '1'.$code;
do {
$d = bcmod($t, '900');
$t = bcdiv($t, '900');
array_unshift($cw, $d);
} while ($t != '0');
$code = $rest;
}
break;
}
case 913: { // Byte Compaction mode shift
$cw[] = ord($code);
break;
}
}
if ($addmode) {
// add the compaction mode codeword at the beginning
array_unshift($cw, $mode);
}
return $cw;
}

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PDF417::getErrorCorrection (   $cw,
  $ecl 
)
protected

Returns the error correction codewords.

Parameters
$cw(array) array of codewords including Symbol Lenght Descriptor and pad
$ecl(int) error correction level 0-8
Returns
array of error correction codewords

Definition at line 780 of file pdf417.php.

References $d.

Referenced by __construct().

{
// get error correction coefficients
$ecc = $this->rsfactors[$ecl];
// number of error correction factors
$eclsize = (2 << $ecl);
// maximum index for $rsfactors[$ecl]
$eclmaxid = ($eclsize - 1);
// initialize array of error correction codewords
$ecw = array_fill(0, $eclsize, 0);
// for each data codeword
foreach($cw as $k => $d) {
$t1 = ($d + $ecw[$eclmaxid]) % 929;
for ($j = $eclmaxid; $j > 0; --$j) {
$t2 = ($t1 * $ecc[$j]) % 929;
$t3 = 929 - $t2;
$ecw[$j] = ($ecw[($j - 1)] + $t3) % 929;
}
$t2 = ($t1 * $ecc[0]) % 929;
$t3 = 929 - $t2;
$ecw[0] = $t3 % 929;
}
foreach($ecw as $j => $e) {
if ($e != 0) {
$ecw[$j] = 929 - $e;
}
}
$ecw = array_reverse($ecw);
return $ecw;
}

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PDF417::getErrorCorrectionLevel (   $ecl,
  $numcw 
)
protected

Returns the error correction level (0-8) to be used.

Parameters
$ecl(int) error correction level
$numcw(int) number of data codewords
Returns
int error correction level

Definition at line 742 of file pdf417.php.

Referenced by __construct().

{
// get maximum correction level
$maxecl = 8; // starting error level
$maxerrsize = (928 - $numcw); // available codewords for error
while ($maxecl > 0) {
$errsize = (2 << $ecl);
if ($maxerrsize >= $errsize) {
break;
}
--$maxecl;
}
// check for automatic levels
if (($ecl < 0) OR ($ecl > 8)) {
if ($numcw < 41) {
$ecl = 2;
} elseif ($numcw < 161) {
$ecl = 3;
} elseif ($numcw < 321) {
$ecl = 4;
} elseif ($numcw < 864) {
$ecl = 5;
} else {
$ecl = $maxecl;
}
}
if ($ecl > $maxecl) {
$ecl = $maxecl;
}
return $ecl;
}

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PDF417::getInputSequences (   $code)
protected

Create array of sequences from input.

Parameters
$code(string) code
Returns
bidimensional array containing characters and classification

Definition at line 816 of file pdf417.php.

Referenced by __construct().

{
$sequence_array = array(); // array to be returned
$numseq = array();
// get numeric sequences
preg_match_all('/([0-9]{13,44})/', $code, $numseq, PREG_OFFSET_CAPTURE);
$numseq[1][] = array('', strlen($code));
$offset = 0;
foreach($numseq[1] as $seq) {
$seqlen = strlen($seq[0]);
if ($seq[1] > 0) {
// extract text sequence before the number sequence
$prevseq = substr($code, $offset, ($seq[1] - $offset));
$textseq = array();
// get text sequences
preg_match_all('/([\x09\x0a\x0d\x20-\x7e]{5,})/', $prevseq, $textseq, PREG_OFFSET_CAPTURE);
$textseq[1][] = array('', strlen($prevseq));
$txtoffset = 0;
foreach($textseq[1] as $txtseq) {
$txtseqlen = strlen($txtseq[0]);
if ($txtseq[1] > 0) {
// extract byte sequence before the text sequence
$prevtxtseq = substr($prevseq, $txtoffset, ($txtseq[1] - $txtoffset));
if (strlen($prevtxtseq) > 0) {
// add BYTE sequence
if ((strlen($prevtxtseq) == 1) AND ((count($sequence_array) > 0) AND ($sequence_array[(count($sequence_array) - 1)][0] == 900))) {
$sequence_array[] = array(913, $prevtxtseq);
} elseif ((strlen($prevtxtseq) % 6) == 0) {
$sequence_array[] = array(924, $prevtxtseq);
} else {
$sequence_array[] = array(901, $prevtxtseq);
}
}
}
if ($txtseqlen > 0) {
// add numeric sequence
$sequence_array[] = array(900, $txtseq[0]);
}
$txtoffset = $txtseq[1] + $txtseqlen;
}
}
if ($seqlen > 0) {
// add numeric sequence
$sequence_array[] = array(902, $seq[0]);
}
$offset = $seq[1] + $seqlen;
}
return $sequence_array;
}

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Field Documentation

PDF417::$barcode_array = array()
protected

Barcode array to be returned which is readable by TCPDF.

Definition at line 99 of file pdf417.php.

Referenced by __construct(), and getBarcodeArray().

PDF417::$clusters
protected

Clusters of codewords (0, 3, 6)
Values are hex equivalents of binary representation of bars (1 = bar, 0 = space).


The codewords numbered from 900 to 928 have special meaning, some enable to switch between modes in order to optimise the code:

  • 900 : Switch to "Text" mode
  • 901 : Switch to "Byte" mode
  • 902 : Switch to "Numeric" mode
  • 903 - 912 : Reserved
  • 913 : Switch to "Octet" only for the next codeword
  • 914 - 920 : Reserved
  • 921 : Initialization
  • 922 : Terminator codeword for Macro PDF control block
  • 923 : Sequence tag to identify the beginning of optional fields in the Macro PDF control block
  • 924 : Switch to "Byte" mode (If the total number of byte is multiple of 6)
  • 925 : Identifier for a user defined Extended Channel Interpretation (ECI)
  • 926 : Identifier for a general purpose ECI format
  • 927 : Identifier for an ECI of a character set or code page
  • 928 : Macro marker codeword to indicate the beginning of a Macro PDF Control Block

Definition at line 156 of file pdf417.php.

PDF417::$rsfactors
protected

Array of factors of the Reed-Solomon polynomial equations used for error correction; one sub array for each correction level (0-8).

Definition at line 445 of file pdf417.php.

PDF417::$start_pattern = '11111111010101000'
protected

Start pattern.

Definition at line 105 of file pdf417.php.

PDF417::$stop_pattern = '111111101000101001'
protected

Stop pattern.

Definition at line 111 of file pdf417.php.

PDF417::$textlatch
protected
Initial value:
array(
'01' => array(27), '02' => array(28), '03' => array(28,25),
'10' => array(28,28), '12' => array(28), '13' => array(28,25),
'20' => array(28), '21' => array(27), '23' => array(25),
'30' => array(29), '31' => array(29,27), '32' => array(29,28)
)

Array of switching codes for Text Compaction Sub-Modes.

Definition at line 128 of file pdf417.php.

PDF417::$textsubmodes
protected
Initial value:
array(
array(0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f,0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5a,0x20,0xFD,0xFE,0xFF),
array(0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x6b,0x6c,0x6d,0x6e,0x6f,0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7a,0x20,0xFD,0xFE,0xFF),
array(0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x26,0x0d,0x09,0x2c,0x3a,0x23,0x2d,0x2e,0x24,0x2f,0x2b,0x25,0x2a,0x3d,0x5e,0xFB,0x20,0xFD,0xFE,0xFF),
array(0x3b,0x3c,0x3e,0x40,0x5b,0x5c,0x5d,0x5f,0x60,0x7e,0x21,0x0d,0x09,0x2c,0x3a,0x0a,0x2d,0x2e,0x24,0x2f,0x22,0x7c,0x2a,0x28,0x29,0x3f,0x7b,0x7d,0x27,0xFF)
)

Array of text Compaction Sub-Modes (values 0xFB - 0xFF are used for submode changers).

Definition at line 117 of file pdf417.php.

The documentation for this class was generated from the following file: