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<?php
# Written by scarfboy@gmail.com.
# Use at your own risk.
# See README for usage details.
#In case these are elsewhere
$path_to_latex = '/usr/bin/latex';
$path_to_dvips = '/usr/bin/dvips';
$path_to_convert = '/usr/bin/convert';
$imgfmt="png"; # used in extensions, and in parameters to convert. Should be either png or gif.
function phplatex_cleantmp($tempfname,$todir) {
# removes the various files that probably got created for a specific run, based on the run's filename.
global $imgfmt;
if (chdir($todir)===FALSE) { return '[directory access error, fix permissions (and empty tmp manually this time)]'; }
error_reporting(0); #at least one of these probably will not exist, but disable the error reporting related to that.
unlink($tempfname); #the longer/cleaner way would be check for existance for each
unlink($tempfname.".tex"); unlink($tempfname.".log");
unlink($tempfname.".aux"); unlink($tempfname.".dvi");
unlink($tempfname.".ps"); unlink($tempfname.".".$imgfmt);
error_reporting(E_ERROR | E_PARSE | E_WARNING | E_NOTICE);
#try-catch would have been nice. This is rather overkill too, the way I use it.
return '';
}
function phplatex_colorhex($r,$g,$b) {
#there has to be a better way of doing this. It's not even particularly clean.
$hex=array("","","");
if(strlen($hex[0]=dechex(round(min(255*$r,255))))==1){ $hex[0]="0".$hex[0]; }
if(strlen($hex[1]=dechex(round(min(255*$g,255))))==1){ $hex[1]="0".$hex[1]; }
if(strlen($hex[2]=dechex(round(min(255*$b,255))))==1){ $hex[2]="0".$hex[2]; }
return implode("",$hex);
}
function texify($string,$dpi='90',$fore="",$back="",$extraprelude="",$trans=FALSE) {
global $imgfmt,$path_to_latex,$path_to_dvips,$path_to_convert;
if ($dpi>300) $dpi=300;
# Figure out TeX string, either to get the right cache entry, or to compile
# Adds semi-common symbol packages (ams)
# used to include ,landscape in documentclass to avoid page wrapping, but it seems this sometimes implies 90 degree rotation
$totex = "\\documentclass[14pt]{extarticle}\n".
"\\usepackage{xcolor}\n".
"\\usepackage{amsmath}\n\\usepackage{amsfonts}\n\\usepackage{amssymb}\n".
$extraprelude."\n".
"\\pagestyle{empty}\n". #removes header/footer; necessary for trim
"\\begin{document}\n".
"\\color[HTML]{".$fore."}\n".
"\\pagecolor[HTML]{".$back."}\n".
$string."\n".
"\\end{document}\n";
$hashfn = sha1($totex).".".$dpi.".".$fore.".".$back.".".intval($trans); #file cache entry string: 40-char hash string plus size
$stralt = str_replace("&","&", preg_replace("/[\"\n]/","",$string)); # stuck in the alt and title attributes
# May need some extra safety.
$heredir = $_SERVER["DOCUMENT_ROOT"];
# Experiment: Tries to adjust vertical positioning, so that rendered TeX text looks natural enough inline with HTML text
# Only descenders are really a problem since HTML's leeway is upwards.
# Some things vary per font, e.g. the slash. In the default CM it is a descender, in Times and others it isn't.
# TODO: This can always use more work.
# TODO: Avoid using characters that are part of TeX commands.
$ascenders ="/(b|d|f|h|i|j|k|l|t|A|B|C|D|E|F|G|H|I|J|L|K|M|N|O|P|Q|R|S|T|U|V|W|X|Y|Z|\[|\]|\\{|\\}|\(|\)|\/|0|1|2|3|4|5|6|7|8|9|\\#|\*|\?|'|\\\\'|\\\\`|\\\\v)/";
$monoliners="/(a|c|e|m|n|o|r|s|u|v|w|x|z|-|=|\+|:|.)/";
$descenders="/(g|j|p|\/|q|y|Q|,|;|\[|\]|\\{|\\}|\(|\)|\#|\\\\LaTeX|\\\\TeX|\\\\c\{)/";
$deepdescenders="/(\[|\]|\\{|\\}|\(|\)|\\int)/";
error_reporting(0);
$ba = preg_match_all($ascenders, $string,$m);
$bm = preg_match_all($monoliners, $string,$m);
$bd = preg_match_all($descenders, $string,$m);
$dd = preg_match_all($deepdescenders, $string,$m);
error_reporting(E_ERROR | E_PARSE | E_WARNING | E_NOTICE);
if ($dd>0) $verticalalign="vertical-align: -25%"; # deep descenders: move down
else if ($bd>0 && $ba==0) $verticalalign="vertical-align: -15%"; # descenders: move down
else if ($bd==0 && $ba>0) $verticalalign="vertical-align: 0%"; # ascenders only: move up/do nothing?
else if ($bd==0 && $ba==0) $verticalalign="vertical-align: 0%"; # neither vertical-align: 0%
else $verticalalign="vertical-align: -15%"; # both ascender and regular descender
# check if image for that TeX in the cache, return img HTML if it exists
if (file_exists($heredir.'/lateximages/'.$hashfn.'.'.$imgfmt))
return '<img style="'.$verticalalign.'" title="'.$stralt.'" alt="'.$stralt.'" src="/lateximages/'.$hashfn.'.'.$imgfmt.'">';
# otherwise try to make and store:
# chdir to have superfluous files be created in just one place, tmp/ (you probably want to occasionally clean this yourself)
error_reporting(0); # TODO: fetch current value so we can restore it
if (chdir($_SERVER["DOCUMENT_ROOT"] . "/tmp")===FALSE) { return '[tmp directory access error, please fix permissions]'; } #I should think about some more specific errors, e.g. check whether file creation is allowed
error_reporting(E_ERROR | E_PARSE | E_WARNING | E_NOTICE);
$tfn = tempnam(getcwd(), 'PTX'); # unique base path in tmp dir
#write temporary .tex file
if ( ($tex = fopen($tfn.'.tex', "w"))==FALSE) { return '[tex file access error] '.phplatex_cleantmp($tfn,$heredir); }
fwrite($tex, $totex);
fclose($tex);
# Run latex to create a .dvi. Have it try to fix minor errors instead of breaking/pausing on them.
exec($path_to_latex.' --interaction=nonstopmode '.$tfn.'.tex');
if (!file_exists($tfn.".dvi")) {
$log = file_get_contents($tfn.'.log'); #The log always exists, but now it's actually interesting since it'll contain an error
return '[latex error, code follows]<pre>'.$totex.'</pre><p><b>Log file:</b><pre>'.$log.'</pre></p> '.phplatex_cleantmp($tfn,$heredir);
}
# DVI -> PostScript. Since dvips uses lpr, which may be configured to actually print by default, force writing to a file with -o
exec($path_to_dvips.' '.$tfn.'.dvi -o '.$tfn.'.ps');
if ( !file_exists($tfn.'.ps')) {
return '[dvi2ps error] '.phplatex_cleantmp($tfn,$heredir);
}
# PostScript -> image. Also trim based on corner pixel and set transparent color.
$convert_cmd = $path_to_convert;
if ($trans) {
$convert_cmd .= ' -transparent-color "#'.$back.'" -transparent "#'.$back.'"';
}
$convert_cmd .= ' -colorspace RGB -density '.$dpi.' -trim +page '.$tfn.'.ps '.$tfn.'.'.$imgfmt;
exec($convert_cmd);
#Note: +page OR -page +0+0 OR +repage moves the image to the cropped area (kills offset)
#Older code tried: exec('/usr/bin/mogrify -density 90 -trim +page -format $imgfmt '.$tfn.'.ps');
# It seems some versions of convert may not have -trim. Old versions?
if (!file_exists($tfn.'.'.$imgfmt)) {
return '[image convert error] '.phplatex_cleantmp($tfn,$heredir);
}
# Copy result image to chache.
copy($tfn.'.'.$imgfmt, $heredir.'/lateximages/'.$hashfn.'.'.$imgfmt);
# Clean up temporary files, and return link to just-created image
return phplatex_cleantmp($tfn,$heredir).'<img style="'.$verticalalign.'" title="'.$stralt.'" alt="LaTeX formula: '.$stralt.'" src="/lateximages/'.$hashfn.'.'.$imgfmt.'">';
}
?>
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