152 lines
No EOL
4.6 KiB
PHP
152 lines
No EOL
4.6 KiB
PHP
<?php namespace ProcessWire;
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// parsePng is a part of FPDF v1.81 - 2015-12-20
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// Author: Olivier PLATHEY
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// http://fpdf.org/
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software to use, copy, modify, distribute, sublicense, and/or sell
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// copies of the software, and to permit persons to whom the software is furnished
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// to do so.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED.
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///////////////////////////////////////////////////////////////////////////////////////////////////
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// PNG Inspector
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// original code from FPDF modified in April 2016 by Horst Nogajski
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// to be used for png image inspection in ProcessWire 3+ (http://processwire.com/)
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///////////////////////////////////////////////////////////////////////////////////////////////////
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class PWPNG {
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public $info = array();
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public $errors = array();
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protected $extended;
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public function __construct($extended = false) {
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$this->extended = $extended;
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}
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public function loadFile($lpszFileName) {
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// READ FILE
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if(!($fh = @fopen($lpszFileName, 'rb'))) {
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$this->Error('Can\'t open image file: '.basename($lpszFileName));
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return false;
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}
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$ret = (false === $this->_parsepngstream($fh, basename($lpszFileName))) ? false : true;
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fclose($fh);
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return $ret;
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}
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protected function _parsepngstream($f, $file) {
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// Check signature
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if($this->_readstream($f, 8) != chr(137) . 'PNG' . chr(13) . chr(10) . chr(26) . chr(10)) {
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$this->Error('Not a PNG file: '.$file);
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return false;
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}
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// Read header chunk
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$this->_readstream($f, 4);
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if($this->_readstream($f, 4) != 'IHDR') {
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$this->Error('Incorrect PNG file: '.$file);
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return false;
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}
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$w = $this->_readint($f);
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$h = $this->_readint($f);
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$bpc = ord($this->_readstream($f, 1));
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//if($bpc > 8) {
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// $this->Error('16-bit depth not supported: '.$file);
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//}
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$ct = ord($this->_readstream($f, 1));
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if($ct == 0 || $ct == 4) {
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$colspace = 'DeviceGray';
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} else if($ct == 2 || $ct == 6) {
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$colspace = 'DeviceRGB';
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} else if($ct == 3) {
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$colspace = 'Indexed';
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} else {
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$this->Error('Unknown color type: '.$file);
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$colspace = '';
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}
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if(ord($this->_readstream($f, 1)) != 0) $this->Error('Unknown compression method: '.$file);
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if(ord($this->_readstream($f, 1)) != 0) $this->Error('Unknown filter method: '.$file);
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$interlaced = ord($this->_readstream($f, 1)) != 0 ? true : false;
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$this->_readstream($f, 4);
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$dp = '/Predictor 15 /Colors '.($colspace=='DeviceRGB' ? 3 : 1).' /BitsPerComponent '.$bpc.' /Columns '.$w;
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// Scan chunks looking for palette, transparency and image data
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// http://www.w3.org/TR/2003/REC-PNG-20031110/#table53
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// http://www.libpng.org/pub/png/book/chapter11.html#png.ch11.div.6
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$pal = '';
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$trns = '';
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$counter = 0;
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do {
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$n = $this->_readint($f);
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$counter += $n;
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$type = $this->_readstream($f,4);
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if($type=='PLTE') {
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// Read palette
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$pal = $this->_readstream($f, $n);
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$this->_readstream($f,4);
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} else if($type == 'tRNS') {
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// Read transparency info
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$t = $this->_readstream($f,$n);
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if($ct == 0) {
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$trns = array(ord(substr($t,1,1)));
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} else if($ct == 2) {
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$trns = array(ord(substr($t, 1, 1)), ord(substr($t, 3, 1)), ord(substr($t, 5, 1)));
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} else {
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$pos = strpos($t, chr(0));
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if($pos !== false) $trns = array($pos);
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}
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$this->_readstream($f, 4);
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} else if($type == 'IEND' || $type == 'IDAT' || $counter >= 2048) {
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break;
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} else {
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$this->_readstream($f,$n+4);
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}
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} while($n);
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if($colspace == 'Indexed' && empty($pal)) $this->Error('Missing palette in '.$file);
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$this->info = array(
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'width' => $w,
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'height' => $h,
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'colspace' => $colspace,
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'channels' => $ct,
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'bits' => $bpc,
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'dp' => $dp,
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'palette' => (function_exists('utf8_encode') ? utf8_encode($pal) : $pal),
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'trans' => $trns,
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'alpha' => $ct >= 4 ? true : false,
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'interlace' => $interlaced,
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'errors' => $this->errors
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);
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return true;
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}
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protected function _readstream($f, $n) {
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// Read n bytes from stream
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$res = '';
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while($n > 0 && !feof($f)) {
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$s = fread($f, $n);
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if($s === false) {
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$this->Error('Error while reading stream');
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return '';
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}
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$n -= strlen($s);
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$res .= $s;
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}
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if($n > 0) $this->Error('Unexpected end of stream');
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return $res;
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}
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protected function _readint($f) {
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// Read a 4-byte integer from stream
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$a = unpack('Ni',$this->_readstream($f,4));
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return $a['i'];
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}
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protected function Error($msg) {
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$this->errors[] = $msg;
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}
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} |