spot/python/spot/aux.py
Alexandre Duret-Lutz e18616e788 work around recent GraphViz bug in SVG scaling
See https://gitlab.com/graphviz/graphviz/issues/1605.

* python/spot/aux.py (str_to_svg): Invert the scale parameters
if they are both greater than one.
2019-10-19 15:40:00 +02:00

119 lines
3.6 KiB
Python

# -*- coding: utf-8 -*-
# Copyright (C) 2016, 2019 Laboratoire de Recherche et Développement de l'Epita
# (LRDE).
#
# This file is part of Spot, a model checking library.
#
# Spot is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# Spot is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
# License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
Auxiliary functions for Spot's Python bindings
"""
from functools import lru_cache
import subprocess
import sys
import os
import errno
import contextlib
import re
def extend(*classes):
"""
Decorator that extends all the given classes with the contents
of the class currently being defined.
"""
def wrap(this):
for cls in classes:
for (name, val) in this.__dict__.items():
if name not in ('__dict__', '__weakref__') \
and not (name == '__doc__' and val is None):
setattr(cls, name, val)
return classes[0]
return wrap
# Work around a bug introduced in GraphViz 2.42.x, where the scale
# parameter is inverted. https://gitlab.com/graphviz/graphviz/issues/1605
# In our case, the scale parameters should both be <= 1, so we can
# detect when that is not the case.
svgscale_regex = re.compile('transform="scale\(([\d.]+) ([\d.]+)\) rotate')
def _gvfix(matchobj):
xs = float(matchobj.group(1))
ys = float(matchobj.group(2))
if xs >= 1 and ys >= 1:
xs = 1/xs
ys = 1/ys
return 'transform="scale({} {}) rotate'.format(xs, ys)
# Add a small LRU cache so that when we display automata into a
# interactive widget, we avoid some repeated calls to dot for
# identical inputs.
@lru_cache(maxsize=64)
def str_to_svg(str):
"""
Send some text to dot for conversion to SVG.
"""
try:
dot = subprocess.Popen(['dot', '-Tsvg'],
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
except FileNotFoundError:
print("The command 'dot' seems to be missing on your system.\n"
"Please install the GraphViz package "
"and make sure 'dot' is in your PATH.", file=sys.stderr)
raise
stdout, stderr = dot.communicate(str)
if stderr:
print("Calling 'dot' for the conversion to SVG produced the message:\n"
+ stderr.decode('utf-8'), file=sys.stderr)
ret = dot.wait()
if ret:
raise subprocess.CalledProcessError(ret, 'dot')
out = stdout.decode('utf-8')
return svgscale_regex.sub(_gvfix, out)
def ostream_to_svg(ostr):
"""
Encode an ostringstream as utf-8 and send it to dot for cocnversion to SVG.
"""
return str_to_svg(ostr.str().encode('utf-8'))
def rm_f(filename):
"""
Remove filename if it exists.
"""
try:
os.remove(filename)
except OSError as e:
if e.errno != errno.ENOENT:
raise
@contextlib.contextmanager
def tmpdir():
cwd = os.getcwd()
tmpdir = os.environ.get('SPOT_TMPDIR') or os.environ.get('TMPDIR') or '.'
try:
os.chdir(tmpdir)
yield
finally:
os.chdir(cwd)