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Python

r"""
This module supports embedded TeX expressions in matplotlib via dvipng
and dvips for the raster and postscript backends. The tex and
dvipng/dvips information is cached in ~/.matplotlib/tex.cache for reuse between
sessions
Requirements:
* latex
* \*Agg backends: dvipng>=1.6
* PS backend: psfrag, dvips, and Ghostscript>=8.60
Backends:
* \*Agg
* PS
* PDF
For raster output, you can get RGBA numpy arrays from TeX expressions
as follows::
texmanager = TexManager()
s = ('\TeX\ is Number '
'$\displaystyle\sum_{n=1}^\infty\frac{-e^{i\pi}}{2^n}$!')
Z = texmanager.get_rgba(s, fontsize=12, dpi=80, rgb=(1, 0, 0))
To enable tex rendering of all text in your matplotlib figure, set
:rc:`text.usetex` to True.
"""
import copy
import functools
import glob
import hashlib
import logging
import os
from pathlib import Path
import re
import subprocess
import numpy as np
import matplotlib as mpl
from matplotlib import cbook, dviread, rcParams
_log = logging.getLogger(__name__)
class TexManager:
"""
Convert strings to dvi files using TeX, caching the results to a directory.
Repeated calls to this constructor always return the same instance.
"""
cachedir = mpl.get_cachedir()
if cachedir is not None:
texcache = os.path.join(cachedir, 'tex.cache')
Path(texcache).mkdir(parents=True, exist_ok=True)
else:
# Should only happen in a restricted environment (such as Google App
# Engine). Deal with this gracefully by not creating a cache directory.
texcache = None
# Caches.
rgba_arrayd = {}
grey_arrayd = {}
serif = ('cmr', '')
sans_serif = ('cmss', '')
monospace = ('cmtt', '')
cursive = ('pzc', r'\usepackage{chancery}')
font_family = 'serif'
font_families = ('serif', 'sans-serif', 'cursive', 'monospace')
font_info = {
'new century schoolbook': ('pnc', r'\renewcommand{\rmdefault}{pnc}'),
'bookman': ('pbk', r'\renewcommand{\rmdefault}{pbk}'),
'times': ('ptm', r'\usepackage{mathptmx}'),
'palatino': ('ppl', r'\usepackage{mathpazo}'),
'zapf chancery': ('pzc', r'\usepackage{chancery}'),
'cursive': ('pzc', r'\usepackage{chancery}'),
'charter': ('pch', r'\usepackage{charter}'),
'serif': ('cmr', ''),
'sans-serif': ('cmss', ''),
'helvetica': ('phv', r'\usepackage{helvet}'),
'avant garde': ('pag', r'\usepackage{avant}'),
'courier': ('pcr', r'\usepackage{courier}'),
# Loading the type1ec package ensures that cm-super is installed, which
# is necessary for unicode computer modern. (It also allows the use of
# computer modern at arbitrary sizes, but that's just a side effect.)
'monospace': ('cmtt', r'\usepackage{type1ec}'),
'computer modern roman': ('cmr', r'\usepackage{type1ec}'),
'computer modern sans serif': ('cmss', r'\usepackage{type1ec}'),
'computer modern typewriter': ('cmtt', r'\usepackage{type1ec}')}
_rc_cache = None
_rc_cache_keys = (
('text.latex.preamble', 'text.latex.unicode', 'text.latex.preview',
'font.family') + tuple('font.' + n for n in font_families))
@functools.lru_cache() # Always return the same instance.
def __new__(cls):
self = object.__new__(cls)
self._reinit()
return self
def _reinit(self):
if self.texcache is None:
raise RuntimeError('Cannot create TexManager, as there is no '
'cache directory available')
Path(self.texcache).mkdir(parents=True, exist_ok=True)
ff = rcParams['font.family']
if len(ff) == 1 and ff[0].lower() in self.font_families:
self.font_family = ff[0].lower()
elif isinstance(ff, str) and ff.lower() in self.font_families:
self.font_family = ff.lower()
else:
_log.info('font.family must be one of (%s) when text.usetex is '
'True. serif will be used by default.',
', '.join(self.font_families))
self.font_family = 'serif'
fontconfig = [self.font_family]
for font_family in self.font_families:
font_family_attr = font_family.replace('-', '_')
for font in rcParams['font.' + font_family]:
if font.lower() in self.font_info:
setattr(self, font_family_attr,
self.font_info[font.lower()])
_log.debug('family: %s, font: %s, info: %s',
font_family, font, self.font_info[font.lower()])
break
else:
_log.debug('%s font is not compatible with usetex.',
font_family)
else:
_log.info('No LaTeX-compatible font found for the %s font '
'family in rcParams. Using default.', font_family)
setattr(self, font_family_attr, self.font_info[font_family])
fontconfig.append(getattr(self, font_family_attr)[0])
# Add a hash of the latex preamble to self._fontconfig so that the
# correct png is selected for strings rendered with same font and dpi
# even if the latex preamble changes within the session
preamble_bytes = self.get_custom_preamble().encode('utf-8')
fontconfig.append(hashlib.md5(preamble_bytes).hexdigest())
self._fontconfig = ''.join(fontconfig)
# The following packages and commands need to be included in the latex
# file's preamble:
cmd = [self.serif[1], self.sans_serif[1], self.monospace[1]]
if self.font_family == 'cursive':
cmd.append(self.cursive[1])
self._font_preamble = '\n'.join(
[r'\usepackage{type1cm}'] + cmd + [r'\usepackage{textcomp}'])
def get_basefile(self, tex, fontsize, dpi=None):
"""
Return a filename based on a hash of the string, fontsize, and dpi.
"""
s = ''.join([tex, self.get_font_config(), '%f' % fontsize,
self.get_custom_preamble(), str(dpi or '')])
return os.path.join(
self.texcache, hashlib.md5(s.encode('utf-8')).hexdigest())
def get_font_config(self):
"""Reinitializes self if relevant rcParams on have changed."""
if self._rc_cache is None:
self._rc_cache = dict.fromkeys(self._rc_cache_keys)
changed = [par for par in self._rc_cache_keys
if rcParams[par] != self._rc_cache[par]]
if changed:
_log.debug('following keys changed: %s', changed)
for k in changed:
_log.debug('%-20s: %-10s -> %-10s',
k, self._rc_cache[k], rcParams[k])
# deepcopy may not be necessary, but feels more future-proof
self._rc_cache[k] = copy.deepcopy(rcParams[k])
_log.debug('RE-INIT\nold fontconfig: %s', self._fontconfig)
self._reinit()
_log.debug('fontconfig: %s', self._fontconfig)
return self._fontconfig
def get_font_preamble(self):
"""
Return a string containing font configuration for the tex preamble.
"""
return self._font_preamble
def get_custom_preamble(self):
"""Return a string containing user additions to the tex preamble."""
return rcParams['text.latex.preamble']
def make_tex(self, tex, fontsize):
"""
Generate a tex file to render the tex string at a specific font size.
Return the file name.
"""
basefile = self.get_basefile(tex, fontsize)
texfile = '%s.tex' % basefile
custom_preamble = self.get_custom_preamble()
fontcmd = {'sans-serif': r'{\sffamily %s}',
'monospace': r'{\ttfamily %s}'}.get(self.font_family,
r'{\rmfamily %s}')
tex = fontcmd % tex
unicode_preamble = "\n".join([
r"\usepackage[utf8]{inputenc}",
r"\DeclareUnicodeCharacter{2212}{\ensuremath{-}}",
]) if rcParams["text.latex.unicode"] else ""
s = r"""
\documentclass{article}
%s
%s
%s
\usepackage[papersize={72in,72in},body={70in,70in},margin={1in,1in}]{geometry}
\pagestyle{empty}
\begin{document}
\fontsize{%f}{%f}%s
\end{document}
""" % (self._font_preamble, unicode_preamble, custom_preamble,
fontsize, fontsize * 1.25, tex)
with open(texfile, 'wb') as fh:
if rcParams['text.latex.unicode']:
fh.write(s.encode('utf8'))
else:
try:
fh.write(s.encode('ascii'))
except UnicodeEncodeError:
_log.info("You are using unicode and latex, but have not "
"enabled the 'text.latex.unicode' rcParam.")
raise
return texfile
_re_vbox = re.compile(
r"MatplotlibBox:\(([\d.]+)pt\+([\d.]+)pt\)x([\d.]+)pt")
def make_tex_preview(self, tex, fontsize):
"""
Generate a tex file to render the tex string at a specific font size.
It uses the preview.sty to determine the dimension (width, height,
descent) of the output.
Return the file name.
"""
basefile = self.get_basefile(tex, fontsize)
texfile = '%s.tex' % basefile
custom_preamble = self.get_custom_preamble()
fontcmd = {'sans-serif': r'{\sffamily %s}',
'monospace': r'{\ttfamily %s}'}.get(self.font_family,
r'{\rmfamily %s}')
tex = fontcmd % tex
unicode_preamble = "\n".join([
r"\usepackage[utf8]{inputenc}",
r"\DeclareUnicodeCharacter{2212}{\ensuremath{-}}",
]) if rcParams["text.latex.unicode"] else ""
# newbox, setbox, immediate, etc. are used to find the box
# extent of the rendered text.
s = r"""
\documentclass{article}
%s
%s
%s
\usepackage[active,showbox,tightpage]{preview}
\usepackage[papersize={72in,72in},body={70in,70in},margin={1in,1in}]{geometry}
%% we override the default showbox as it is treated as an error and makes
%% the exit status not zero
\def\showbox#1%%
{\immediate\write16{MatplotlibBox:(\the\ht#1+\the\dp#1)x\the\wd#1}}
\begin{document}
\begin{preview}
{\fontsize{%f}{%f}%s}
\end{preview}
\end{document}
""" % (self._font_preamble, unicode_preamble, custom_preamble,
fontsize, fontsize * 1.25, tex)
with open(texfile, 'wb') as fh:
if rcParams['text.latex.unicode']:
fh.write(s.encode('utf8'))
else:
try:
fh.write(s.encode('ascii'))
except UnicodeEncodeError:
_log.info("You are using unicode and latex, but have not "
"enabled the 'text.latex.unicode' rcParam.")
raise
return texfile
def _run_checked_subprocess(self, command, tex):
_log.debug(cbook._pformat_subprocess(command))
try:
report = subprocess.check_output(command,
cwd=self.texcache,
stderr=subprocess.STDOUT)
except FileNotFoundError as exc:
raise RuntimeError(
'Failed to process string with tex because {} could not be '
'found'.format(command[0])) from exc
except subprocess.CalledProcessError as exc:
raise RuntimeError(
'{prog} was not able to process the following string:\n'
'{tex!r}\n\n'
'Here is the full report generated by {prog}:\n'
'{exc}\n\n'.format(
prog=command[0],
tex=tex.encode('unicode_escape'),
exc=exc.output.decode('utf-8'))) from exc
_log.debug(report)
return report
def make_dvi(self, tex, fontsize):
"""
Generate a dvi file containing latex's layout of tex string.
Return the file name.
"""
if rcParams['text.latex.preview']:
return self.make_dvi_preview(tex, fontsize)
basefile = self.get_basefile(tex, fontsize)
dvifile = '%s.dvi' % basefile
if not os.path.exists(dvifile):
texfile = self.make_tex(tex, fontsize)
with cbook._lock_path(texfile):
self._run_checked_subprocess(
["latex", "-interaction=nonstopmode", "--halt-on-error",
texfile], tex)
for fname in glob.glob(basefile + '*'):
if not fname.endswith(('dvi', 'tex')):
try:
os.remove(fname)
except OSError:
pass
return dvifile
def make_dvi_preview(self, tex, fontsize):
"""
Generate a dvi file containing latex's layout of tex string.
It calls make_tex_preview() method and store the size information
(width, height, descent) in a separate file.
Return the file name.
"""
basefile = self.get_basefile(tex, fontsize)
dvifile = '%s.dvi' % basefile
baselinefile = '%s.baseline' % basefile
if not os.path.exists(dvifile) or not os.path.exists(baselinefile):
texfile = self.make_tex_preview(tex, fontsize)
report = self._run_checked_subprocess(
["latex", "-interaction=nonstopmode", "--halt-on-error",
texfile], tex)
# find the box extent information in the latex output
# file and store them in ".baseline" file
m = TexManager._re_vbox.search(report.decode("utf-8"))
with open(basefile + '.baseline', "w") as fh:
fh.write(" ".join(m.groups()))
for fname in glob.glob(basefile + '*'):
if not fname.endswith(('dvi', 'tex', 'baseline')):
try:
os.remove(fname)
except OSError:
pass
return dvifile
def make_png(self, tex, fontsize, dpi):
"""
Generate a png file containing latex's rendering of tex string.
Return the file name.
"""
basefile = self.get_basefile(tex, fontsize, dpi)
pngfile = '%s.png' % basefile
# see get_rgba for a discussion of the background
if not os.path.exists(pngfile):
dvifile = self.make_dvi(tex, fontsize)
self._run_checked_subprocess(
["dvipng", "-bg", "Transparent", "-D", str(dpi),
"-T", "tight", "-o", pngfile, dvifile], tex)
return pngfile
def get_grey(self, tex, fontsize=None, dpi=None):
"""Return the alpha channel."""
from matplotlib import _png
key = tex, self.get_font_config(), fontsize, dpi
alpha = self.grey_arrayd.get(key)
if alpha is None:
pngfile = self.make_png(tex, fontsize, dpi)
with open(os.path.join(self.texcache, pngfile), "rb") as file:
X = _png.read_png(file)
self.grey_arrayd[key] = alpha = X[:, :, -1]
return alpha
def get_rgba(self, tex, fontsize=None, dpi=None, rgb=(0, 0, 0)):
"""Return latex's rendering of the tex string as an rgba array."""
if not fontsize:
fontsize = rcParams['font.size']
if not dpi:
dpi = rcParams['savefig.dpi']
r, g, b = rgb
key = tex, self.get_font_config(), fontsize, dpi, tuple(rgb)
Z = self.rgba_arrayd.get(key)
if Z is None:
alpha = self.get_grey(tex, fontsize, dpi)
Z = np.dstack([r, g, b, alpha])
self.rgba_arrayd[key] = Z
return Z
def get_text_width_height_descent(self, tex, fontsize, renderer=None):
"""Return width, height and descent of the text."""
if tex.strip() == '':
return 0, 0, 0
dpi_fraction = renderer.points_to_pixels(1.) if renderer else 1
if rcParams['text.latex.preview']:
# use preview.sty
basefile = self.get_basefile(tex, fontsize)
baselinefile = '%s.baseline' % basefile
if not os.path.exists(baselinefile):
dvifile = self.make_dvi_preview(tex, fontsize)
with open(baselinefile) as fh:
l = fh.read().split()
height, depth, width = [float(l1) * dpi_fraction for l1 in l]
return width, height + depth, depth
else:
# use dviread. It sometimes returns a wrong descent.
dvifile = self.make_dvi(tex, fontsize)
with dviread.Dvi(dvifile, 72 * dpi_fraction) as dvi:
page, = dvi
# A total height (including the descent) needs to be returned.
return page.width, page.height + page.descent, page.descent