sandbox/latex_directive/latex_directive.py

   1 """
   2 Implement latex directive.
   3
   4 """
   5 import os
   6 import shutil
   7 import sha
   8 import tempfile
   9 import subprocess
  10
  11 from docutils import nodes
  12 from docutils.parsers.rst.directives import register_directive, flag
  13 from docutils.parsers.rst.roles import register_canonical_role
  14
  15
  16 def latex_math(tex):
  17     """ Process `tex` and produce image nodes. """
  18     image_names = latex_snippet_to_png(tex)
  19
  20     the_nodes = []
  21     alt = tex
  22     for pageno, name in enumerate(image_names):
  23
  24         the_nodes.append(nodes.image(uri=name, alt=alt))
  25         alt = ''
  26
  27     return the_nodes
  28
  29
  30 def latex_directive(name, arguments, options, content, lineno,
  31                     content_offset, block_text, state, state_machine):
  32     """ Latex directive. """
  33     tex = '\n'.join(content)
  34
  35     return latex_math(tex)
  36
  37 latex_directive.content = True
  38
  39
  40 def latex_role(role, rawtext, text, lineno, inliner,
  41                options={}, content=[]):
  42     """ Latex role. """
  43
  44     i = rawtext.find('`')
  45     tex = rawtext[i+1:-1]
  46     return latex_math(tex), []
  47
  48 def register():
  49     register_directive('latex', latex_directive)
  50     register_canonical_role('latex', latex_role)
  51
  52
  53
  54 def call_command_in_dir(app, args, targetdir):
  55
  56     cwd = os.getcwd()
  57     try:
  58         os.chdir(targetdir)
  59         print args
  60         print ' '.join(args)
  61         p = subprocess.Popen(app + ' ' + ' '.join(args), shell=True)
  62         sts = os.waitpid(p.pid, 0)
  63
  64         # FIXME -- should we raise an exception of status is non-zero?
  65
  66     finally:
  67         # Restore working directory
  68         os.chdir(cwd)
  69
  70 latex_template = r'''
  71 \documentclass[12pt]{article}
  72 \pagestyle{empty}
  73 %(prologue)s
  74 \begin{document}
  75 %(raw)s
  76 \end{document}
  77 '''
  78 max_pages = 10
  79 MAX_RUN_TIME = 5 # seconds
  80 latex_name_template = 'latex2png_%s'
  81 latex = "latex"
  82 dvipng = "dvipng"
  83 latex_args = ("--interaction=nonstopmode", "%s.tex")
  84 dvipng_args = ("-bgTransparent", "-Ttight", "--noghostscript", "-l%s" % max_pages, "%s.dvi")
  85
  86 def latex_snippet_to_png(inputtex, prologue=''):
  87     """ Convert a latex snippet into a png. """
  88
  89     tex = latex_template % { 'raw': inputtex, 'prologue': prologue }
  90     namebase = latex_name_template % sha.new(tex).hexdigest()
  91     dst = namebase + '%d.png'
  92
  93     tmpdir = tempfile.mkdtemp()
  94     try:
  95         data = open("%s/%s.tex" % (tmpdir, namebase), "w")
  96         data.write(tex)
  97         data.close()
  98         args = list(latex_args)
  99         args[-1] = args[-1] % namebase
 100         res = call_command_in_dir(latex, args, tmpdir)
 101         if not res is None:
 102             # FIXME need to return some sort of error
 103             return []
 104         args = list(dvipng_args)
 105         args[-1] = args[-1] % namebase
 106         res = call_command_in_dir(dvipng, args, tmpdir)
 107         if not res is None:
 108             # FIXME need to return some sort of error
 109             return []
 110
 111         page = 1
 112         pagenames = []
 113         while os.access("%s/%s%d.png" % (tmpdir, namebase, page), os.R_OK):
 114             pagename = dst % page
 115             shutil.copyfile("%s/%s%d.png" % (tmpdir, namebase, page), pagename)
 116             page += 1
 117             pagenames.append(pagename)
 118     finally:
 119         # FIXME do some tidy up here
 120         pass
 121
 122     return pagenames
 123