view docs/tutorial/mypandocfilters/graphviz-file.py @ 6202:fe8e88ea296d

evolve: use util.unlinkpath() via vfs

Internally vfs.unlinkpath() does the path join and calls util.unlinkpath(). So
the new form is equivalent, just shorter.

This method exists in 4.8, so the new code shouldn't have any compatibility
issues.

#!/usr/bin/env python

"""
Pandoc filter to process code blocks with class "graphviz" into
graphviz-generated images.

Needs pygraphviz
"""

import os
import sys

import pygraphviz

from pandocfilters import toJSONFilter, Para, Image, get_filename4code, get_caption, get_extension, get_value

def graphviz(key, value, format, _):
    if key == 'CodeBlock':
        [[ident, classes, keyvals], file] = value
        if "graphviz-file" in classes:
            caption, typef, keyvals = get_caption(keyvals)
            prog, keyvals = get_value(keyvals, u"prog", u"dot")
            filetype = get_extension(format, "svg", html="svg", latex="pdf")
            with open(file) as f:
                code = f.read()
            dest = get_filename4code("graphviz", code, filetype)

            if not os.path.isfile(dest):
                g = pygraphviz.AGraph(string=code)
                g.layout()
                g.draw(dest, prog=prog)
                sys.stderr.write('Created image ' + dest + '\n')

            return Para([Image([ident, ['graphviz'], keyvals], caption, [dest, typef])])

if __name__ == "__main__":
    toJSONFilter(graphviz)