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<?php
namespace Mpdf\Gif;
/**
* GIF Util - (C) 2003 Yamasoft (S/C)
*
* All Rights Reserved
*
* This file can be freely copied, distributed, modified, updated by anyone under the only
* condition to leave the original address (Yamasoft, http://www.yamasoft.com) and this header.
*
* @link http://www.yamasoft.com
*/
class Image
{
var $m_disp;
var $m_bUser;
var $m_bTrans;
var $m_nDelay;
var $m_nTrans;
var $m_lpComm;
var $m_gih;
var $m_data;
var $m_lzw;
public function __construct()
{
unset($this->m_disp);
unset($this->m_bUser);
unset($this->m_bTrans);
unset($this->m_nDelay);
unset($this->m_nTrans);
unset($this->m_lpComm);
unset($this->m_data);
$this->m_gih = new ImageHeader();
$this->m_lzw = new Lzw();
}
function load($data, &$datLen)
{
$datLen = 0;
while (true) {
$b = ord($data[0]);
$data = substr($data, 1);
$datLen++;
switch ($b) {
case 0x21: // Extension
$len = 0;
if (!$this->skipExt($data, $len)) {
return false;
}
$datLen += $len;
break;
case 0x2C: // Image
// LOAD HEADER & COLOR TABLE
$len = 0;
if (!$this->m_gih->load($data, $len)) {
return false;
}
$data = substr($data, $len);
$datLen += $len;
// ALLOC BUFFER
$len = 0;
if (!($this->m_data = $this->m_lzw->deCompress($data, $len))) {
return false;
}
$data = substr($data, $len);
$datLen += $len;
if ($this->m_gih->m_bInterlace) {
$this->deInterlace();
}
return true;
case 0x3B: // EOF
default:
return false;
}
}
return false;
}
function skipExt(&$data, &$extLen)
{
$extLen = 0;
$b = ord($data[0]);
$data = substr($data, 1);
$extLen++;
switch ($b) {
case 0xF9: // Graphic Control
$b = ord($data[1]);
$this->m_disp = ($b & 0x1C) >> 2;
$this->m_bUser = ($b & 0x02) ? true : false;
$this->m_bTrans = ($b & 0x01) ? true : false;
$this->m_nDelay = $this->w2i(substr($data, 2, 2));
$this->m_nTrans = ord($data[4]);
break;
case 0xFE: // Comment
$this->m_lpComm = substr($data, 1, ord($data[0]));
break;
case 0x01: // Plain text
break;
case 0xFF: // Application
break;
}
// SKIP DEFAULT AS DEFS MAY CHANGE
$b = ord($data[0]);
$data = substr($data, 1);
$extLen++;
while ($b > 0) {
$data = substr($data, $b);
$extLen += $b;
$b = ord($data[0]);
$data = substr($data, 1);
$extLen++;
}
return true;
}
function w2i($str)
{
return ord(substr($str, 0, 1)) + (ord(substr($str, 1, 1)) << 8);
}
function deInterlace()
{
$data = $this->m_data;
for ($i = 0; $i < 4; $i++) {
switch ($i) {
case 0:
$s = 8;
$y = 0;
break;
case 1:
$s = 8;
$y = 4;
break;
case 2:
$s = 4;
$y = 2;
break;
case 3:
$s = 2;
$y = 1;
break;
}
for (; $y < $this->m_gih->m_nHeight; $y += $s) {
$lne = substr($this->m_data, 0, $this->m_gih->m_nWidth);
$this->m_data = substr($this->m_data, $this->m_gih->m_nWidth);
$data = substr($data, 0, $y * $this->m_gih->m_nWidth) .
$lne .
substr($data, ($y + 1) * $this->m_gih->m_nWidth);
}
}
$this->m_data = $data;
}
}
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