tex2pic

#!/usr/bin/env python

def tex2pic(
        texequation,
        outfname = None,
        verbose = False,
        fmt='pdf',
        resolution=300):

    import subprocess
    import tempfile
    import os
    import shutil

    head = r"""% latex file create by sandbox.py
    \documentclass[border=1pt]{standalone}
    \begin{document}
    $\displaystyle
    """

    foot = r"""
    $
    \end{document}
    """

    # overwriting options if contradictions
    if outfname:
        fmt = os.path.splitext(outfname)[1][1:]
    else:
        verbose = 0

    # create temporary directory and filenames
    tmpdir = tempfile.mkdtemp()
    tmptex = os.path.join(tmpdir,"texeq.tex")
    tmppdf = os.path.join(tmpdir,"texeq.pdf")
    tmpout = os.path.join(tmpdir,"texeq."+fmt)

    # write the tmp texfile
    with open(tmptex,'w') as f:
        f.write(head)
        f.write(texequation)
        f.write(foot)

    # compile the tex file in tmpdir
    stdout = None if verbose else open(os.devnull,'w')
    popen = subprocess.Popen("pdflatex -interaction=nonstopmode -pdf %s"%tmptex,
                shell=True,cwd=tmpdir,stdout=stdout,stderr=stdout)
    popen.wait()
    if not verbose: stdout.close()

    # exit if not compiled
    if popen.returncode != 0:
        print("Compilation failed. Run again with -v to detect errors in your formula.")
        exit()

    # convert in tmpdir
    formats = {'jpg':'jpg','jpeg':'jpg','png':'png','tiff':'tiff','ppm':''}
    if fmt in formats.keys():
        convertcmd = "pdftoppm -r %d -%s %s > %s" %(resolution,formats[fmt],tmppdf,tmpout)
        subprocess.check_call(convertcmd,shell=True)

    # return the actual output
    if outfname:
        shutil.copy(tmpout,outfname)
    else:
        with open(tmpout,'r') as f:
            print(f.read())

    # remove tmp files
    shutil.rmtree(tmpdir)


if __name__ == '__main__':
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument('texequation')
    parser.add_argument('-v','--verbose',action='count', help='print compilation output of pdflatex if output not to stdout')
    parser.add_argument('-o','--output',help='the output file which will be generated')
    parser.add_argument('-f','--format',default='pdf',help='format of output (if --output not set)')
    parser.add_argument('-r','--resolution',default='300',type=int,help='resolution as in -r option of pdftoppm')
    args = parser.parse_args()

    tex2pic(args.texequation,
            outfname=args.output,
            verbose=args.verbose,
            fmt=args.format,
            resolution=args.resolution)