369 lines
15 KiB
Python
369 lines
15 KiB
Python
r"""
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Support for embedded TeX expressions in Matplotlib.
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Requirements:
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* LaTeX.
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* \*Agg backends: dvipng>=1.6.
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* PS backend: PSfrag, dvips, and Ghostscript>=9.0.
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* PDF and SVG backends: if LuaTeX is present, it will be used to speed up some
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post-processing steps, but note that it is not used to parse the TeX string
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itself (only LaTeX is supported).
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To enable TeX rendering of all text in your Matplotlib figure, set
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:rc:`text.usetex` to True.
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TeX and dvipng/dvips processing results are cached
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in ~/.matplotlib/tex.cache for reuse between sessions.
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`TexManager.get_rgba` can also be used to directly obtain raster output as RGBA
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NumPy arrays.
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"""
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import functools
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import hashlib
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import logging
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import os
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from pathlib import Path
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import subprocess
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from tempfile import TemporaryDirectory
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import numpy as np
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import matplotlib as mpl
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from matplotlib import _api, cbook, dviread
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_log = logging.getLogger(__name__)
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def _usepackage_if_not_loaded(package, *, option=None):
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"""
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Output LaTeX code that loads a package (possibly with an option) if it
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hasn't been loaded yet.
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LaTeX cannot load twice a package with different options, so this helper
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can be used to protect against users loading arbitrary packages/options in
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their custom preamble.
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"""
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option = f"[{option}]" if option is not None else ""
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return (
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r"\makeatletter"
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r"\@ifpackageloaded{%(package)s}{}{\usepackage%(option)s{%(package)s}}"
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r"\makeatother"
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) % {"package": package, "option": option}
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class TexManager:
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"""
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Convert strings to dvi files using TeX, caching the results to a directory.
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The cache directory is called ``tex.cache`` and is located in the directory
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returned by `.get_cachedir`.
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Repeated calls to this constructor always return the same instance.
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"""
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texcache = _api.deprecate_privatize_attribute("3.8")
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_texcache = os.path.join(mpl.get_cachedir(), 'tex.cache')
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_grey_arrayd = {}
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_font_families = ('serif', 'sans-serif', 'cursive', 'monospace')
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_font_preambles = {
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'new century schoolbook': r'\renewcommand{\rmdefault}{pnc}',
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'bookman': r'\renewcommand{\rmdefault}{pbk}',
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'times': r'\usepackage{mathptmx}',
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'palatino': r'\usepackage{mathpazo}',
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'zapf chancery': r'\usepackage{chancery}',
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'cursive': r'\usepackage{chancery}',
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'charter': r'\usepackage{charter}',
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'serif': '',
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'sans-serif': '',
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'helvetica': r'\usepackage{helvet}',
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'avant garde': r'\usepackage{avant}',
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'courier': r'\usepackage{courier}',
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# Loading the type1ec package ensures that cm-super is installed, which
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# is necessary for Unicode computer modern. (It also allows the use of
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# computer modern at arbitrary sizes, but that's just a side effect.)
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'monospace': r'\usepackage{type1ec}',
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'computer modern roman': r'\usepackage{type1ec}',
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'computer modern sans serif': r'\usepackage{type1ec}',
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'computer modern typewriter': r'\usepackage{type1ec}',
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}
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_font_types = {
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'new century schoolbook': 'serif',
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'bookman': 'serif',
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'times': 'serif',
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'palatino': 'serif',
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'zapf chancery': 'cursive',
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'charter': 'serif',
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'helvetica': 'sans-serif',
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'avant garde': 'sans-serif',
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'courier': 'monospace',
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'computer modern roman': 'serif',
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'computer modern sans serif': 'sans-serif',
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'computer modern typewriter': 'monospace',
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}
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@functools.lru_cache # Always return the same instance.
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def __new__(cls):
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Path(cls._texcache).mkdir(parents=True, exist_ok=True)
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return object.__new__(cls)
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@classmethod
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def _get_font_family_and_reduced(cls):
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"""Return the font family name and whether the font is reduced."""
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ff = mpl.rcParams['font.family']
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ff_val = ff[0].lower() if len(ff) == 1 else None
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if len(ff) == 1 and ff_val in cls._font_families:
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return ff_val, False
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elif len(ff) == 1 and ff_val in cls._font_preambles:
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return cls._font_types[ff_val], True
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else:
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_log.info('font.family must be one of (%s) when text.usetex is '
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'True. serif will be used by default.',
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', '.join(cls._font_families))
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return 'serif', False
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@classmethod
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def _get_font_preamble_and_command(cls):
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requested_family, is_reduced_font = cls._get_font_family_and_reduced()
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preambles = {}
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for font_family in cls._font_families:
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if is_reduced_font and font_family == requested_family:
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preambles[font_family] = cls._font_preambles[
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mpl.rcParams['font.family'][0].lower()]
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else:
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for font in mpl.rcParams['font.' + font_family]:
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if font.lower() in cls._font_preambles:
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preambles[font_family] = \
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cls._font_preambles[font.lower()]
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_log.debug(
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'family: %s, font: %s, info: %s',
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font_family, font,
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cls._font_preambles[font.lower()])
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break
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else:
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_log.debug('%s font is not compatible with usetex.',
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font)
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else:
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_log.info('No LaTeX-compatible font found for the %s font'
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'family in rcParams. Using default.',
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font_family)
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preambles[font_family] = cls._font_preambles[font_family]
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# The following packages and commands need to be included in the latex
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# file's preamble:
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cmd = {preambles[family]
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for family in ['serif', 'sans-serif', 'monospace']}
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if requested_family == 'cursive':
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cmd.add(preambles['cursive'])
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cmd.add(r'\usepackage{type1cm}')
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preamble = '\n'.join(sorted(cmd))
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fontcmd = (r'\sffamily' if requested_family == 'sans-serif' else
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r'\ttfamily' if requested_family == 'monospace' else
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r'\rmfamily')
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return preamble, fontcmd
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@classmethod
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def get_basefile(cls, tex, fontsize, dpi=None):
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"""
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Return a filename based on a hash of the string, fontsize, and dpi.
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"""
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src = cls._get_tex_source(tex, fontsize) + str(dpi)
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filehash = hashlib.md5(src.encode('utf-8')).hexdigest()
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filepath = Path(cls._texcache)
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num_letters, num_levels = 2, 2
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for i in range(0, num_letters*num_levels, num_letters):
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filepath = filepath / Path(filehash[i:i+2])
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filepath.mkdir(parents=True, exist_ok=True)
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return os.path.join(filepath, filehash)
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@classmethod
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def get_font_preamble(cls):
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"""
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Return a string containing font configuration for the tex preamble.
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"""
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font_preamble, command = cls._get_font_preamble_and_command()
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return font_preamble
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@classmethod
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def get_custom_preamble(cls):
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"""Return a string containing user additions to the tex preamble."""
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return mpl.rcParams['text.latex.preamble']
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@classmethod
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def _get_tex_source(cls, tex, fontsize):
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"""Return the complete TeX source for processing a TeX string."""
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font_preamble, fontcmd = cls._get_font_preamble_and_command()
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baselineskip = 1.25 * fontsize
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return "\n".join([
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r"\documentclass{article}",
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r"% Pass-through \mathdefault, which is used in non-usetex mode",
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r"% to use the default text font but was historically suppressed",
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r"% in usetex mode.",
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r"\newcommand{\mathdefault}[1]{#1}",
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font_preamble,
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r"\usepackage[utf8]{inputenc}",
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r"\DeclareUnicodeCharacter{2212}{\ensuremath{-}}",
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r"% geometry is loaded before the custom preamble as ",
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r"% convert_psfrags relies on a custom preamble to change the ",
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r"% geometry.",
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r"\usepackage[papersize=72in, margin=1in]{geometry}",
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cls.get_custom_preamble(),
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r"% Use `underscore` package to take care of underscores in text.",
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r"% The [strings] option allows to use underscores in file names.",
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_usepackage_if_not_loaded("underscore", option="strings"),
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r"% Custom packages (e.g. newtxtext) may already have loaded ",
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r"% textcomp with different options.",
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_usepackage_if_not_loaded("textcomp"),
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r"\pagestyle{empty}",
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r"\begin{document}",
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r"% The empty hbox ensures that a page is printed even for empty",
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r"% inputs, except when using psfrag which gets confused by it.",
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r"% matplotlibbaselinemarker is used by dviread to detect the",
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r"% last line's baseline.",
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rf"\fontsize{{{fontsize}}}{{{baselineskip}}}%",
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r"\ifdefined\psfrag\else\hbox{}\fi%",
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rf"{{{fontcmd} {tex}}}%",
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r"\end{document}",
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])
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@classmethod
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def make_tex(cls, tex, fontsize):
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"""
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Generate a tex file to render the tex string at a specific font size.
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Return the file name.
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"""
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texfile = cls.get_basefile(tex, fontsize) + ".tex"
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Path(texfile).write_text(cls._get_tex_source(tex, fontsize),
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encoding='utf-8')
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return texfile
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@classmethod
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def _run_checked_subprocess(cls, command, tex, *, cwd=None):
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_log.debug(cbook._pformat_subprocess(command))
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try:
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report = subprocess.check_output(
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command, cwd=cwd if cwd is not None else cls._texcache,
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stderr=subprocess.STDOUT)
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except FileNotFoundError as exc:
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raise RuntimeError(
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f'Failed to process string with tex because {command[0]} '
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'could not be found') from exc
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except subprocess.CalledProcessError as exc:
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raise RuntimeError(
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'{prog} was not able to process the following string:\n'
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'{tex!r}\n\n'
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'Here is the full command invocation and its output:\n\n'
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'{format_command}\n\n'
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'{exc}\n\n'.format(
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prog=command[0],
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format_command=cbook._pformat_subprocess(command),
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tex=tex.encode('unicode_escape'),
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exc=exc.output.decode('utf-8', 'backslashreplace'))
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) from None
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_log.debug(report)
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return report
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@classmethod
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def make_dvi(cls, tex, fontsize):
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"""
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Generate a dvi file containing latex's layout of tex string.
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Return the file name.
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"""
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basefile = cls.get_basefile(tex, fontsize)
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dvifile = '%s.dvi' % basefile
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if not os.path.exists(dvifile):
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texfile = Path(cls.make_tex(tex, fontsize))
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# Generate the dvi in a temporary directory to avoid race
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# conditions e.g. if multiple processes try to process the same tex
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# string at the same time. Having tmpdir be a subdirectory of the
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# final output dir ensures that they are on the same filesystem,
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# and thus replace() works atomically. It also allows referring to
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# the texfile with a relative path (for pathological MPLCONFIGDIRs,
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# the absolute path may contain characters (e.g. ~) that TeX does
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# not support; n.b. relative paths cannot traverse parents, or it
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# will be blocked when `openin_any = p` in texmf.cnf).
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cwd = Path(dvifile).parent
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with TemporaryDirectory(dir=cwd) as tmpdir:
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tmppath = Path(tmpdir)
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cls._run_checked_subprocess(
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["latex", "-interaction=nonstopmode", "--halt-on-error",
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f"--output-directory={tmppath.name}",
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f"{texfile.name}"], tex, cwd=cwd)
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(tmppath / Path(dvifile).name).replace(dvifile)
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return dvifile
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@classmethod
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def make_png(cls, tex, fontsize, dpi):
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"""
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Generate a png file containing latex's rendering of tex string.
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Return the file name.
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"""
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basefile = cls.get_basefile(tex, fontsize, dpi)
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pngfile = '%s.png' % basefile
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# see get_rgba for a discussion of the background
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if not os.path.exists(pngfile):
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dvifile = cls.make_dvi(tex, fontsize)
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cmd = ["dvipng", "-bg", "Transparent", "-D", str(dpi),
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"-T", "tight", "-o", pngfile, dvifile]
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# When testing, disable FreeType rendering for reproducibility; but
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# dvipng 1.16 has a bug (fixed in f3ff241) that breaks --freetype0
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# mode, so for it we keep FreeType enabled; the image will be
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# slightly off.
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if (getattr(mpl, "_called_from_pytest", False) and
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mpl._get_executable_info("dvipng").raw_version != "1.16"):
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cmd.insert(1, "--freetype0")
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cls._run_checked_subprocess(cmd, tex)
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return pngfile
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@classmethod
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def get_grey(cls, tex, fontsize=None, dpi=None):
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"""Return the alpha channel."""
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if not fontsize:
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fontsize = mpl.rcParams['font.size']
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if not dpi:
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dpi = mpl.rcParams['savefig.dpi']
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key = cls._get_tex_source(tex, fontsize), dpi
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alpha = cls._grey_arrayd.get(key)
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if alpha is None:
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pngfile = cls.make_png(tex, fontsize, dpi)
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rgba = mpl.image.imread(os.path.join(cls._texcache, pngfile))
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cls._grey_arrayd[key] = alpha = rgba[:, :, -1]
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return alpha
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@classmethod
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def get_rgba(cls, tex, fontsize=None, dpi=None, rgb=(0, 0, 0)):
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r"""
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Return latex's rendering of the tex string as an RGBA array.
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Examples
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--------
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>>> texmanager = TexManager()
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>>> s = r"\TeX\ is $\displaystyle\sum_n\frac{-e^{i\pi}}{2^n}$!"
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>>> Z = texmanager.get_rgba(s, fontsize=12, dpi=80, rgb=(1, 0, 0))
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"""
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alpha = cls.get_grey(tex, fontsize, dpi)
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rgba = np.empty((*alpha.shape, 4))
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rgba[..., :3] = mpl.colors.to_rgb(rgb)
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rgba[..., -1] = alpha
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return rgba
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@classmethod
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def get_text_width_height_descent(cls, tex, fontsize, renderer=None):
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"""Return width, height and descent of the text."""
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if tex.strip() == '':
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return 0, 0, 0
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dvifile = cls.make_dvi(tex, fontsize)
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dpi_fraction = renderer.points_to_pixels(1.) if renderer else 1
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with dviread.Dvi(dvifile, 72 * dpi_fraction) as dvi:
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page, = dvi
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# A total height (including the descent) needs to be returned.
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return page.width, page.height + page.descent, page.descent
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