#!/usr/bin/env python3 ''' NAME latex2img - Converts LaTeX source to PNG or SVG file SYNOPSIS latex2img [options] INFILE DESCRIPTION This filter reads LaTeX source text from the input file INFILE (or stdin if INFILE is -) and renders it to PNG image file. Typically used to render math equations. Requires latex(1), dvipng(1) and/or dvisvgm(1) commands and LaTeX math packages. OPTIONS -D DPI Set the output resolution for PNG images to DPI dots per inch. Use this option to scale the output PNG image size. -o OUTFILE The file name of the output file. If not specified the output file is named like INFILE but with an extension matching the chosen output image format, .png for PNG images and .svg for SVG images. -m Skip if the output image file is newer than the INFILE. Compares timestamps on INFILE and OUTFILE. If INFILE is - (stdin) then compares MD5 checksum stored in file named like OUTFILE but with a .md5 file name extension. The .md5 file is created if the -m option is used and the INFILE is - (stdin). -v Verbosely print processing information to stderr. --help, -h Print this documentation. --version Print program version number. SEE ALSO latex(1), dvipng(1), dvisvgm(1) AUTHOR Written by Stuart Rackham, The code was inspired by Kjell Magne Fauske's code: http://fauskes.net/nb/htmleqII/ See also: http://www.amk.ca/python/code/mt-math http://code.google.com/p/latexmath2png/ COPYING Copyright (C) 2002-2013 Stuart Rackham. Copyright (C) 2013-2020 AsciiDoc Contributors. Free use of this software is granted under the terms of the GNU General Public License version 2 (GPLv2). ''' import os import sys import tempfile from hashlib import md5 VERSION = '0.2.0' # Include LaTeX packages and commands here. TEX_HEADER = r'''\documentclass{article} \usepackage{amsmath} \usepackage{amsthm} \usepackage{amssymb} \usepackage{bm} \newcommand{\mx}[1]{\mathbf{\bm{#1}}} % Matrix command \newcommand{\vc}[1]{\mathbf{\bm{#1}}} % Vector command \newcommand{\T}{\text{T}} % Transpose \pagestyle{empty} \begin{document}''' TEX_FOOTER = r'''\end{document}''' # Globals. verbose = False class EApp(Exception): pass # Application specific exception. def print_stderr(line): sys.stderr.write(line + os.linesep) def print_verbose(line): if verbose: print_stderr(line) def write_file(filename, data, mode='w', encoding='utf-8'): if 'b' in mode: encoding = None with open(filename, mode, encoding=encoding) as f: f.write(data) def read_file(filename, mode='r', encoding='utf-8'): if 'b' in mode: encoding = None with open(filename, mode, encoding=encoding) as f: return f.read() def run(cmd): global verbose if verbose: cmd += ' 1>&2' else: cmd += ' 2>%s 1>&2' % os.devnull print_verbose('executing: %s' % cmd) if os.system(cmd): raise EApp('failed command: %s' % cmd) def latex2img(infile, outfile, imgfmt, dpi, modified): ''' Convert LaTeX input file infile to image file named outfile. ''' outfile = os.path.abspath(outfile) outdir = os.path.dirname(outfile) if not os.path.isdir(outdir): raise EApp('directory does not exist: %s' % outdir) texfile = tempfile.mktemp(suffix='.tex', dir=os.path.dirname(outfile)) basefile = os.path.splitext(texfile)[0] dvifile = basefile + '.dvi' temps = [basefile + ext for ext in ('.tex', '.dvi', '.aux', '.log')] skip = False if infile == '-': tex = sys.stdin.read() if modified: checksum = md5((tex + imgfmt + str(dpi)).encode('utf-8')).digest() md5_file = os.path.splitext(outfile)[0] + '.md5' if os.path.isfile(md5_file) and os.path.isfile(outfile) and \ checksum == read_file(md5_file, 'rb'): skip = True else: if not os.path.isfile(infile): raise EApp('input file does not exist: %s' % infile) tex = read_file(infile) if modified and os.path.isfile(outfile) and \ os.path.getmtime(infile) <= os.path.getmtime(outfile): skip = True if skip: print_verbose('skipped: no change: %s' % outfile) return tex = '%s\n%s\n%s\n' % (TEX_HEADER, tex.strip(), TEX_FOOTER) print_verbose('tex:\n%s' % tex) write_file(texfile, tex) saved_pwd = os.getcwd() os.chdir(outdir) try: # Compile LaTeX document to DVI file. run('latex %s' % texfile) if imgfmt == 'svg': # Convert DVI file to SVG. cmd = 'dvisvgm' cmd += ' --no-fonts' cmd += ' --scale=1.4' cmd += ' --exact' cmd += ' -o "%s" "%s"' % (outfile, dvifile) else: # Convert DVI file to PNG. cmd = 'dvipng' if dpi: cmd += ' -D %s' % dpi cmd += ' -T tight -x 1000 -z 9 -bg Transparent --truecolor' cmd += ' -o "%s" "%s" ' % (outfile, dvifile) run(cmd) finally: os.chdir(saved_pwd) for f in temps: if os.path.isfile(f): print_verbose('deleting: %s' % f) os.remove(f) if 'md5_file' in locals(): print_verbose('writing: %s' % md5_file) write_file(md5_file, checksum, 'wb') def usage(msg=''): if msg: print_stderr(msg) print_stderr( '\n' 'usage:\n' ' latex2img [options] INFILE\n' '\n' 'options:\n' ' -D DPI\n' ' -o OUTFILE\n' ' -f FORMAT\n' ' -m\n' ' -v\n' ' --help\n' ' --version' ) def main(): # Process command line options. global verbose dpi = None outfile = None imgfmt = 'png' modified = False import getopt opts, args = getopt.getopt(sys.argv[1:], 'D:o:mhvf:', ['help', 'version']) for o, v in opts: if o in ('--help', '-h'): print(__doc__) sys.exit(0) if o == '--version': print(('latex2img version %s' % (VERSION,))) sys.exit(0) if o == '-D': dpi = v if o == '-o': outfile = v if o == '-m': modified = True if o == '-v': verbose = True if o == '-f': imgfmt = v if len(args) != 1: usage() sys.exit(1) infile = args[0] if dpi and not dpi.isdigit(): usage('invalid DPI') sys.exit(1) if imgfmt not in {'png', 'svg'}: usage('Invalid image format. Valid values are "png" or "svg".') sys.exit(1) if outfile is None: if infile == '-': usage('OUTFILE must be specified') sys.exit(1) outfile = os.path.splitext(infile)[0] + '.' + imgfmt # Do the work. latex2img(infile, outfile, imgfmt, dpi, modified) # Print something to suppress asciidoc 'no output from filter' warnings. if infile == '-': sys.stdout.write(' ') if __name__ == "__main__": try: main() except SystemExit: raise except KeyboardInterrupt: sys.exit(1) except Exception as e: print_stderr("%s: %s" % (os.path.basename(sys.argv[0]), str(e))) sys.exit(1)