<?php
/*******************************************************************************
* Software: PDF_ImageAlpha
* Version: 1.4
* Date: 2009-12-28
* Author: Valentin Schmidt
*
* Requirements: FPDF 1.6
*
* This script allows to use images (PNGs or JPGs) with alpha-channels.
* The alpha-channel can be either supplied as separate 8-bit PNG ("mask"),
* or, for PNGs, also an internal alpha-channel can be used.
* For the latter the GD 2.x extension is required.
*******************************************************************************/
require('../.inc/fpdf.php');
class PDF_ImageAlpha extends FPDF{
//Private properties
var $tmpFiles = array();
/*******************************************************************************
* *
* Public methods *
* *
*******************************************************************************/
function Image($file,$x,$y,$w=0,$h=0,$type='',$link='', $isMask=false, $maskImg=0)
{
//Put an image on the page
if(!isset($this->images[$file]))
{
//First use of image, get info
if($type=='')
{
$pos=strrpos($file,'.');
if(!$pos)
$this->Error('Image file has no extension and no type was specified: '.$file);
$type=substr($file,$pos+1);
}
$type=strtolower($type);
$mqr=get_magic_quotes_runtime();
set_magic_quotes_runtime(0);
if($type=='jpg' || $type=='jpeg')
$info=$this->_parsejpg($file);
elseif($type=='png'){
$info=$this->_parsepng($file);
if ($info=='alpha') return $this->ImagePngWithAlpha($file,$x,$y,$w,$h,$link);
}
else
{
//Allow for additional formats
$mtd='_parse'.$type;
if(!method_exists($this,$mtd))
$this->Error('Unsupported image type: '.$type);
$info=$this->$mtd($file);
}
set_magic_quotes_runtime($mqr);
if ($isMask){
$info['cs']="DeviceGray"; // try to force grayscale (instead of indexed)
}
$info['i']=count($this->images)+1;
if ($maskImg>0) $info['masked'] = $maskImg;###
$this->images[$file]=$info;
}
else
$info=$this->images[$file];
//Automatic width and height calculation if needed
if($w==0 && $h==0)
{
//Put image at 72 dpi
$w=$info['w']/$this->k;
$h=$info['h']/$this->k;
}
if($w==0)
$w=$h*$info['w']/$info['h'];
if($h==0)
$h=$w*$info['h']/$info['w'];
// embed hidden, ouside the canvas
if ((float)FPDF_VERSION>=1.7){
if ($isMask) $x = ($this->CurOrientation=='P'?$this->CurPageSize[0]:$this->CurPageSize[1]) + 10;
}else{
if ($isMask) $x = ($this->CurOrientation=='P'?$this->CurPageFormat[0]:$this->CurPageFormat[1]) + 10;
}
$this->_out(sprintf('q %.2f 0 0 %.2f %.2f %.2f cm /I%d Do Q',$w*$this->k,$h*$this->k,$x*$this->k,($this->h-($y+$h))*$this->k,$info['i']));
if($link)
$this->Link($x,$y,$w,$h,$link);
return $info['i'];
}
// needs GD 2.x extension
// pixel-wise operation, not very fast
function ImagePngWithAlpha($file,$x,$y,$w=0,$h=0,$link='')
{
$tmp_alpha = tempnam('.', 'mska');
$this->tmpFiles[] = $tmp_alpha;
$tmp_plain = tempnam('.', 'mskp');
$this->tmpFiles[] = $tmp_plain;
list($wpx, $hpx) = getimagesize($file);
$img = imagecreatefrompng($file);
$alpha_img = imagecreate( $wpx, $hpx );
// generate gray scale pallete
for($c=0;$c<256;$c++) ImageColorAllocate($alpha_img, $c, $c, $c);
// extract alpha channel
$xpx=0;
while ($xpx<$wpx){
$ypx = 0;
while ($ypx<$hpx){
$color_index = imagecolorat($img, $xpx, $ypx);
$alpha = 255-($color_index>>24)*255/127; // GD alpha component: 7 bit only, 0..127!
imagesetpixel($alpha_img, $xpx, $ypx, $alpha);
++$ypx;
}
++$xpx;
}
imagepng($alpha_img, $tmp_alpha);
imagedestroy($alpha_img);
// extract image without alpha channel
$plain_img = imagecreatetruecolor ( $wpx, $hpx );
imagecopy ($plain_img, $img, 0, 0, 0, 0, $wpx, $hpx );
imagepng($plain_img, $tmp_plain);
imagedestroy($plain_img);
//first embed mask image (w, h, x, will be ignored)
$maskImg = $this->Image($tmp_alpha, 0,0,0,0, 'PNG', '', true);
//embed image, masked with previously embedded mask
$this->Image($tmp_plain,$x,$y,$w,$h,'PNG',$link, false, $maskImg);
}
function Close()
{
parent::Close();
// clean up tmp files
foreach($this->tmpFiles as $tmp) @unlink($tmp);
}
/*******************************************************************************
* *
* Private methods *
* *
*******************************************************************************/
function _putimages()
{
$filter=($this->compress) ? '/Filter /FlateDecode ' : '';
reset($this->images);
while(list($file,$info)=each($this->images))
{
$this->_newobj();
$this->images[$file]['n']=$this->n;
$this->_out('<</Type /XObject');
$this->_out('/Subtype /Image');
$this->_out('/Width '.$info['w']);
$this->_out('/Height '.$info['h']);
if (isset($info["masked"])) $this->_out('/SMask '.($this->n-1).' 0 R'); ###
if($info['cs']=='Indexed')
$this->_out('/ColorSpace [/Indexed /DeviceRGB '.(strlen($info['pal'])/3-1).' '.($this->n+1).' 0 R]');
else
{
$this->_out('/ColorSpace /'.$info['cs']);
if($info['cs']=='DeviceCMYK')
$this->_out('/Decode [1 0 1 0 1 0 1 0]');
}
$this->_out('/BitsPerComponent '.$info['bpc']);
if(isset($info['f']))
$this->_out('/Filter /'.$info['f']);
if(isset($info['parms']))
$this->_out($info['parms']);
if(isset($info['trns']) && is_array($info['trns']))
{
$trns='';
for($i=0;$i<count($info['trns']);$i++)
$trns.=$info['trns'][$i].' '.$info['trns'][$i].' ';
$this->_out('/Mask ['.$trns.']');
}
$this->_out('/Length '.strlen($info['data']).'>>');
$this->_putstream($info['data']);
unset($this->images[$file]['data']);
$this->_out('endobj');
//Palette
if($info['cs']=='Indexed')
{
$this->_newobj();
$pal=($this->compress) ? gzcompress($info['pal']) : $info['pal'];
$this->_out('<<'.$filter.'/Length '.strlen($pal).'>>');
$this->_putstream($pal);
$this->_out('endobj');
}
}
}
// this method overwriing the original version is only needed to make the Image method support PNGs with alpha channels.
// if you only use the ImagePngWithAlpha method for such PNGs, you can remove it from this script.
function _parsepng($file)
{
//Extract info from a PNG file
$f=fopen($file,'rb');
if(!$f)
$this->Error('Can\'t open image file: '.$file);
//Check signature
if(fread($f,8)!=chr(137).'PNG'.chr(13).chr(10).chr(26).chr(10))
$this->Error('Not a PNG file: '.$file);
//Read header chunk
fread($f,4);
if(fread($f,4)!='IHDR')
$this->Error('Incorrect PNG file: '.$file);
$w=$this->_readint($f);
$h=$this->_readint($f);
$bpc=ord(fread($f,1));
if($bpc>8)
$this->Error('16-bit depth not supported: '.$file);
$ct=ord(fread($f,1));
if($ct==0)
$colspace='DeviceGray';
elseif($ct==2)
$colspace='DeviceRGB';
elseif($ct==3)
$colspace='Indexed';
else {
fclose($f); // the only changes are
return 'alpha'; // made in those 2 lines
}
if(ord(fread($f,1))!=0)
$this->Error('Unknown compression method: '.$file);
if(ord(fread($f,1))!=0)
$this->Error('Unknown filter method: '.$file);
if(ord(fread($f,1))!=0)
$this->Error('Interlacing not supported: '.$file);
fread($f,4);
$parms='/DecodeParms <</Predictor 15 /Colors '.($ct==2 ? 3 : 1).' /BitsPerComponent '.$bpc.' /Columns '.$w.'>>';
//Scan chunks looking for palette, transparency and image data
$pal='';
$trns='';
$data='';
do
{
$n=$this->_readint($f);
$type=fread($f,4);
if($type=='PLTE')
{
//Read palette
$pal=fread($f,$n);
fread($f,4);
}
elseif($type=='tRNS')
{
//Read transparency info
$t=fread($f,$n);
if($ct==0)
$trns=array(ord(substr($t,1,1)));
elseif($ct==2)
$trns=array(ord(substr($t,1,1)),ord(substr($t,3,1)),ord(substr($t,5,1)));
else
{
$pos=strpos($t,chr(0));
if($pos!==false)
$trns=array($pos);
}
fread($f,4);
}
elseif($type=='IDAT')
{
//Read image data block
$data.=fread($f,$n);
fread($f,4);
}
elseif($type=='IEND')
break;
else
fread($f,$n+4);
}
while($n);
if($colspace=='Indexed' && empty($pal))
$this->Error('Missing palette in '.$file);
fclose($f);
return array('w'=>$w,'h'=>$h,'cs'=>$colspace,'bpc'=>$bpc,'f'=>'FlateDecode','parms'=>$parms,'pal'=>$pal,'trns'=>$trns,'data'=>$data);
}
}
?>
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