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#1 Le 11/08/2012, à 17:37
- Joalland
Comprendre un script perl
Hello,
Le script suivant (page internet où son créateur explique son fonctionnement) est censé convertir un fichier latex (.tex) en code html.
#!/usr/bin/perl -w
#==============================================================================
#
# CONVERT SIMPLE PLAIN TEXT TO HTML WITH TEX MATH SNIPPETS
#
# This program takes on standard input a simple text file containing TeX
# arbitrary math snippets (delimited by '$'s) and produces on standard
# output an HTML document with PNG images embedded in <IMG> tags.
#
# This program demonstrates conversion techniques and is not intended for
# production use.
#
# Todd S. Lehman
# February 2012
#
use strict;
#------------------------------------------------------------------------------
#
# RUN EXTERNAL COMMAND VIA BOURNE SHELL
#
sub run_command (@) {
my $origcmdline = join(" ", grep {defined} @_);
return if $origcmdline eq "";
my $cmdline = $origcmdline;
$cmdline =~ s/(["\\])/\\$1/g;
$cmdline = qq{/bin/sh -c "($cmdline) 2>&1"};
my $output = `$cmdline`;
my ($exit_value, $signal_num, $dumped_core) = ($?>>8, $?&127, $?&128);
$exit_value == 0 or die
"FAILED: $origcmdline\n" .
" \$! = $!\n" .
" \$@ = $@\n" .
" EXIT_VALUE = $exit_value\n" .
" SIGNAL_NUM = $signal_num\n" .
" DUMPED_CORE = $dumped_core\n" .
" OUTPUT = $output\n";
return $output;
}
#------------------------------------------------------------------------------
#
# ROUND NUMBER UP TO THE NEXT HIGHER MULTIPLE
#
sub round_up ($$) {
my ($num, $mod) = @_;
return $num + ($num % $mod == 0? 0 : ($mod - ($num % $mod)));
}
#------------------------------------------------------------------------------
#
# FETCH WIDTH AND HEIGHT FROM PNM FILE
#
sub pnm_width_height ($) {
my ($filename) = @_;
$filename =~ m/\.pnm$/ or die "$filename: not .pnm";
open(PNM, '<', $filename) or die "$filename: can't read";
my $line = <PNM>; # Skip first line.
do { $line = <PNM> }
while $line =~ m/^#/; # Read next line, skipping comments
close(PNM);
my ($width, $height) = ($line =~ m/^(\d+)\s+(\d+)$/);
defined($width) && defined($height)
or die "$filename: Couldn't read image size";
return ($width, $height);
}
#------------------------------------------------------------------------------
#
# COMPILE LATEX SNIPPET INTO HTML
#
# This routine caches results in the /tmp directory. Snippets are named and
# indexed by their SHA-1 hash.
#
sub tex_to_html ($$) {
my ($tex_template, $tex_snippet) = @_;
my $render_antialias_bits = 4;
my $render_oversample = 4;
my $display_oversample = 4;
my $oversample = $render_oversample * $display_oversample;
my $render_dpi = 96*1.2 * 72.27/72 * $oversample; # This is 1850.112 dpi.
# --- Generate SHA-1 hash of TeX input for caching.
(my $tex_input = $tex_template) =~ s{<SNIPPET>}{$tex_snippet};
my $hash = do { use Digest::SHA; uc(Digest::SHA::sha1_hex($tex_input)); };
my $file = "/tmp/tex-$hash";
# --- If the image has already been compiled, then simply return the
# cached result. Otherwise, continue and create the image.
if (open(HTML, '<', "$file.html")) {
my $html = do { local $/; <HTML> };
close(HTML);
return $html;
}
# --- Write TeX source and compile to PDF.
open(TEX, '>', "$file.tex") and print TEX $tex_input and close(TEX)
or die "$file.tex: can't write";
run_command(
"pdflatex",
"-halt-on-error",
"-output-directory=/tmp",
"-output-format=pdf",
"$file.tex",
">$file.err 2>&1"
);
# --- Convert PDF to PNM using Ghostscript.
run_command(
"gs",
"-q -dNOPAUSE -dBATCH",
"-dTextAlphaBits=$render_antialias_bits",
"-dGraphicsAlphaBits=$render_antialias_bits",
"-r$render_dpi",
"-sDEVICE=pnmraw",
"-sOutputFile=$file.pnm",
"$file.pdf"
);
my ($img_width, $img_height) = pnm_width_height("$file.pnm");
#print "# img_width=$img_width\n";
#print "# img_height=$img_height\n";
#print "# \n";
# --- Read dimensions file written by TeX during processing.
#
# Example of file contents:
# snippetdepth = 6.50009pt
# snippetheight = 13.53899pt
# snippetwidth = 145.4777pt
# pagewidth = 153.4777pt
# pageheight = 28.03908pt
# pagemargin = 4.0pt
my $dimensions = {};
do {
open(DIMENSIONS, '<', "$file.dimensions")
or die "$file.dimensions: can't read";
while (<DIMENSIONS>) {
if (m/^(\S+)\s+=\s+(-?[0-9\.]+)pt$/) {
my ($value, $length) = ($1, $2);
$length = $length / 72.27 * $render_dpi;
$dimensions->{$value} = $length;
} else {
die "$file.dimensions: invalid line: $_";
}
}
close(DIMENSIONS);
};
#foreach (keys %$dimensions) { print "# $_=$dimensions->{$_}px\n"; }
#print "# \n";
# --- Crop bottom, then measure how much was cropped.
run_command("pnmcrop -white -bottom $file.pnm >$file.bottomcrop.pnm");
my ($img_width_bottomcrop, $img_height_bottomcrop) =
pnm_width_height("$file.bottomcrop.pnm");
my $bottomcrop = $img_height - $img_height_bottomcrop;
#printf "# Cropping bottom: %d pixels - %d pixels = %d pixels cropped\n",
# $img_height, $img_height_bottomcrop, $bottomcrop;
# --- Crop top and sides, then measure how much was cropped from the top.
run_command("pnmcrop -white $file.bottomcrop.pnm >$file.crop.pnm");
my ($cropped_img_width, $cropped_img_height) =
pnm_width_height("$file.crop.pnm");
my $topcrop = $img_height_bottomcrop - $cropped_img_height;
#printf "# Cropping top: %d pixels - %d pixels = %d pixels cropped\n",
# $img_height_bottomcrop, $cropped_img_height, $topcrop;
# --- Pad image with specific values on all four sides, in preparation for
# downsampling.
# Calculate bottom padding.
my $snippet_depth =
int($dimensions->{snippetdepth} + $dimensions->{pagemargin} + .5)
- $bottomcrop;
my $padded_snippet_depth = round_up($snippet_depth, $oversample);
my $increase_snippet_depth = $padded_snippet_depth - $snippet_depth;
my $bottom_padding = $increase_snippet_depth;
#printf "# Padding snippet depth: %d pixels + %d pixels = %d pixels\n",
# $snippet_depth, $increase_snippet_depth, $padded_snippet_depth;
# --- Next calculate top padding, which depends on bottom padding.
my $padded_img_height = round_up(
$cropped_img_height + $bottom_padding,
$oversample);
my $top_padding =
$padded_img_height - ($cropped_img_height + $bottom_padding);
#printf "# Padding top: %d pixels + %d pixels = %d pixels\n",
# $cropped_img_height, $top_padding, $padded_img_height;
# --- Calculate left and right side padding. Distribute padding evenly.
my $padded_img_width = round_up($cropped_img_width, $oversample);
my $left_padding = int(($padded_img_width - $cropped_img_width) / 2);
my $right_padding = ($padded_img_width - $cropped_img_width)
- $left_padding;
#printf "# Padding left = $left_padding pixels\n";
#printf "# Padding right = $right_padding pixels\n";
# --- Pad the final image.
run_command(
"pnmpad",
"-white",
"-bottom=$bottom_padding",
"-top=$top_padding",
"-left=$left_padding",
"-right=$right_padding",
"$file.crop.pnm",
">$file.pad.pnm"
);
# --- Sanity check of final size.
my ($final_pnm_width, $final_pnm_height) =
pnm_width_height("$file.pad.pnm");
$final_pnm_width % $oversample == 0
or die "$final_pnm_width is not a multiple of $oversample";
$final_pnm_height % $oversample == 0
or die "$final_pnm_height is not a multiple of $oversample";
# --- Convert PNM to PNG.
my $final_png_width = $final_pnm_width / $render_oversample;
my $final_png_height = $final_pnm_height / $render_oversample;
run_command(
"cat $file.pad.pnm",
"| ppmtopgm",
"| pamscale -reduce $render_oversample",
"| pnmgamma .3",
"| pnmtopng -compression 9",
"> $file.png"
);
# --- Convert PNG to HTML.
my $html_img_width = $final_png_width / $display_oversample;
my $html_img_height = $final_png_height / $display_oversample;
my $html_img_vertical_align = sprintf("%.0f",
-$padded_snippet_depth / $oversample);
(my $html_img_title = $tex_snippet) =~
s{([&<>'"])}{sprintf("&#%d;",ord($1))}eg;
my $png_data_base64 = do {
open(PNG, '<', "$file.png") or die "$file.png: can't open";
binmode PNG;
my $png_data = do { local $/; <PNG> };
close(PNG);
use MIME::Base64;
MIME::Base64::encode_base64($png_data);
};
#$png_data_base64 =~ s/\s+//g;
my $html =
qq{<img\n} .
qq{ width=$html_img_width} .
qq{ height=$html_img_height} .
qq{ style="vertical-align:${html_img_vertical_align}px;"} .
qq{ title="$html_img_title"} .
qq{ src="data:image/png;base64,\n$png_data_base64" />};
open(HTML, '>', "$file.html") and print HTML $html and close(HTML)
or die "$file.html: can't write";
# --- Clean up and return result to caller.
run_command(
"rm -f",
"${file}{.*,}.{tex,aux,dvi,err,log,dimensions,pdf,pnm,png}"
);
return $html;
}
#------------------------------------------------------------------------------
#
# MAIN CONTROL
#
binmode(STDIN, ":utf8");
binmode(STDOUT, ":utf8");
binmode(STDERR, ":utf8");
my $tex_template = do { local $/; <DATA> };
my $input = do { local $/; <STDIN> };
(my $html = $input) =~ s{\$(.*?)\$}{tex_to_html($tex_template,$1)}seg;
$html =~ s{([^\s<>]*<img.*?>[^\s<>]*)}
{<span style="white-space:nowrap;">$1</span>}sg;
print <<EOT;
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title></title>
</head>
<body>
<p>
$html
</p>
</body>
</html>
EOT
exit(0);
#------------------------------------------------------------------------------
#
# LATEX TEMPLATE
#
__DATA__
\documentclass[10pt]{article}
\pagestyle{empty}
\setlength{\topskip}{0pt}
\setlength{\parindent}{0pt}
\setlength{\abovedisplayskip}{0pt}
\setlength{\belowdisplayskip}{0pt}
\usepackage{geometry}
\usepackage{amsmath}
\newsavebox{\snippetbox}
\newlength{\snippetwidth}
\newlength{\snippetheight}
\newlength{\snippetdepth}
\newlength{\pagewidth}
\newlength{\pageheight}
\newlength{\pagemargin}
\begin{lrbox}{\snippetbox}%
$<SNIPPET>$%
\end{lrbox}
\settowidth{\snippetwidth}{\usebox{\snippetbox}}
\settoheight{\snippetheight}{\usebox{\snippetbox}}
\settodepth{\snippetdepth}{\usebox{\snippetbox}}
\setlength\pagemargin{4pt}
\setlength\pagewidth\snippetwidth
\addtolength\pagewidth\pagemargin
\addtolength\pagewidth\pagemargin
\setlength\pageheight\snippetheight
\addtolength{\pageheight}{\snippetdepth}
\addtolength\pageheight\pagemargin
\addtolength\pageheight\pagemargin
\newwrite\foo
\immediate\openout\foo=\jobname.dimensions
\immediate\write\foo{snippetdepth = \the\snippetdepth}
\immediate\write\foo{snippetheight = \the\snippetheight}
\immediate\write\foo{snippetwidth = \the\snippetwidth}
\immediate\write\foo{pagewidth = \the\pagewidth}
\immediate\write\foo{pageheight = \the\pageheight}
\immediate\write\foo{pagemargin = \the\pagemargin}
\closeout\foo
\geometry{paperwidth=\pagewidth,paperheight=\pageheight,margin=\pagemargin}
\begin{document}%
\usebox{\snippetbox}%
\end{document}Pour faire simple, je n'arrive pas à l'utiliser. 
J’essaie :
./script.pl fichier.tex dans le terminal et rien ne se passe ( un nouvelle invite de commande n'apparait pas, j'imagine que le script tourne en boucle)
Si une âme charitable pouvait m'aider, j'en serais assez heureux. 
Merci.
Hors ligne
#2 Le 11/08/2012, à 17:55
- pingouinux
Re : Comprendre un script perl
Bonjour,
D'après le commentaire en tête du script, il semble qu'il faille l'utiliser ainsi :
./script.pl <fichier.tex Hors ligne
#3 Le 11/08/2012, à 19:09
- Joalland
Re : Comprendre un script perl
Merci pour ta réponse, le script ne tourne plus en boucle. La commande ne me fait qu'afficher mon fichier.tex dans le terminal par contre.
il semble au fait qu'il faille utiliser un fichier .txt contenant des balises tex ($) (exemple: "Ceci est le symbole de la racine de deux : $sqrt(2)$."
Mais j'obtiens maintenant l'erreur suivante :
FAILED: cat /tmp/tex-B728807E73EA03E586F0263C9A498650C0C76305.pad.pnm | ppmtopgm | pamscale -reduce 4 | pnmgamma .3 | pnmtopng -compression 9 > /tmp/tex-B728807E73EA03E586F0263C9A498650C0C76305.png
$! =
$@ =
EXIT_VALUE = 1
SIGNAL_NUM = 0
DUMPED_CORE = 0
OUTPUT = /bin/sh: 1: pamscale: not found
pnmgamma: EOF / read error reading magic number
pnmtopng: EOF / read error reading magic numberQue faire ? Je suis relativement désespéré.
Hors ligne
#4 Le 12/08/2012, à 11:32
- ludovic889
Re : Comprendre un script perl
pamscale: not found
il faut l'installer !
c'est le paquet netpbm on dirait
oui c'est ça, c'est d'ailleurs indiqué sur la page initiale !
Dernière modification par ludovic889 (Le 12/08/2012, à 11:41)
Ce n'est pas grave de ne pas avoir l'heure si on a le temps.
Hors ligne