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r"""
A module for parsing a subset of the TeX math syntax and rendering it to a
Matplotlib backend.
For a tutorial of its usage, see :doc:`/tutorials/text/mathtext`. This
document is primarily concerned with implementation details.
The module uses pyparsing_ to parse the TeX expression.
.. _pyparsing: https://pypi.org/project/pyparsing/
The Bakoma distribution of the TeX Computer Modern fonts, and STIX
fonts are supported. There is experimental support for using
arbitrary fonts, but results may vary without proper tweaking and
metrics for those fonts.
"""
from collections import namedtuple
import functools
from io import StringIO
import logging
import os
import types
import unicodedata
import numpy as np
from PIL import Image
from pyparsing import (
Combine, Empty, FollowedBy, Forward, Group, Literal, oneOf, OneOrMore,
Optional, ParseBaseException, ParseFatalException, ParserElement,
QuotedString, Regex, StringEnd, Suppress, ZeroOrMore)
from matplotlib import cbook, colors as mcolors, rcParams
from matplotlib.afm import AFM
from matplotlib.ft2font import FT2Image, KERNING_DEFAULT, LOAD_NO_HINTING
from matplotlib.font_manager import findfont, FontProperties, get_font
from matplotlib._mathtext_data import (latex_to_bakoma, latex_to_standard,
tex2uni, latex_to_cmex,
stix_virtual_fonts)
ParserElement.enablePackrat()
_log = logging.getLogger(__name__)
##############################################################################
# FONTS
def get_unicode_index(symbol, math=True):
r"""
Return the integer index (from the Unicode table) of *symbol*.
Parameters
----------
symbol : str
A single unicode character, a TeX command (e.g. r'\pi') or a Type1
symbol name (e.g. 'phi').
math : bool, default: True
If False, always treat as a single unicode character.
"""
# for a non-math symbol, simply return its unicode index
if not math:
return ord(symbol)
# From UTF #25: U+2212 minus sign is the preferred
# representation of the unary and binary minus sign rather than
# the ASCII-derived U+002D hyphen-minus, because minus sign is
# unambiguous and because it is rendered with a more desirable
# length, usually longer than a hyphen.
if symbol == '-':
return 0x2212
try: # This will succeed if symbol is a single unicode char
return ord(symbol)
except TypeError:
pass
try: # Is symbol a TeX symbol (i.e. \alpha)
return tex2uni[symbol.strip("\\")]
except KeyError as err:
raise ValueError(
"'{}' is not a valid Unicode character or TeX/Type1 symbol"
.format(symbol)) from err
class MathtextBackend:
"""
The base class for the mathtext backend-specific code. `MathtextBackend`
subclasses interface between mathtext and specific Matplotlib graphics
backends.
Subclasses need to override the following:
- :meth:`render_glyph`
- :meth:`render_rect_filled`
- :meth:`get_results`
And optionally, if you need to use a FreeType hinting style:
- :meth:`get_hinting_type`
"""
def __init__(self):
self.width = 0
self.height = 0
self.depth = 0
def set_canvas_size(self, w, h, d):
"""Set the dimension of the drawing canvas."""
self.width = w
self.height = h
self.depth = d
def render_glyph(self, ox, oy, info):
"""
Draw a glyph described by *info* to the reference point (*ox*,
*oy*).
"""
raise NotImplementedError()
def render_rect_filled(self, x1, y1, x2, y2):
"""
Draw a filled black rectangle from (*x1*, *y1*) to (*x2*, *y2*).
"""
raise NotImplementedError()
def get_results(self, box):
"""
Return a backend-specific tuple to return to the backend after
all processing is done.
"""
raise NotImplementedError()
def get_hinting_type(self):
"""
Get the FreeType hinting type to use with this particular
backend.
"""
return LOAD_NO_HINTING
class MathtextBackendAgg(MathtextBackend):
"""
Render glyphs and rectangles to an FTImage buffer, which is later
transferred to the Agg image by the Agg backend.
"""
def __init__(self):
self.ox = 0
self.oy = 0
self.image = None
self.mode = 'bbox'
self.bbox = [0, 0, 0, 0]
MathtextBackend.__init__(self)
def _update_bbox(self, x1, y1, x2, y2):
self.bbox = [min(self.bbox[0], x1),
min(self.bbox[1], y1),
max(self.bbox[2], x2),
max(self.bbox[3], y2)]
def set_canvas_size(self, w, h, d):
MathtextBackend.set_canvas_size(self, w, h, d)
if self.mode != 'bbox':
self.image = FT2Image(np.ceil(w), np.ceil(h + max(d, 0)))
def render_glyph(self, ox, oy, info):
if self.mode == 'bbox':
self._update_bbox(ox + info.metrics.xmin,
oy - info.metrics.ymax,
ox + info.metrics.xmax,
oy - info.metrics.ymin)
else:
info.font.draw_glyph_to_bitmap(
self.image, ox, oy - info.metrics.iceberg, info.glyph,
antialiased=rcParams['text.antialiased'])
def render_rect_filled(self, x1, y1, x2, y2):
if self.mode == 'bbox':
self._update_bbox(x1, y1, x2, y2)
else:
height = max(int(y2 - y1) - 1, 0)
if height == 0:
center = (y2 + y1) / 2.0
y = int(center - (height + 1) / 2.0)
else:
y = int(y1)
self.image.draw_rect_filled(int(x1), y, np.ceil(x2), y + height)
def get_results(self, box, used_characters):
self.mode = 'bbox'
orig_height = box.height
orig_depth = box.depth
ship(0, 0, box)
bbox = self.bbox
bbox = [bbox[0] - 1, bbox[1] - 1, bbox[2] + 1, bbox[3] + 1]
self.mode = 'render'
self.set_canvas_size(
bbox[2] - bbox[0],
(bbox[3] - bbox[1]) - orig_depth,
(bbox[3] - bbox[1]) - orig_height)
ship(-bbox[0], -bbox[1], box)
result = (self.ox,
self.oy,
self.width,
self.height + self.depth,
self.depth,
self.image,
used_characters)
self.image = None
return result
def get_hinting_type(self):
from matplotlib.backends import backend_agg
return backend_agg.get_hinting_flag()
class MathtextBackendBitmap(MathtextBackendAgg):
def get_results(self, box, used_characters):
ox, oy, width, height, depth, image, characters = \
MathtextBackendAgg.get_results(self, box, used_characters)
return image, depth
class MathtextBackendPs(MathtextBackend):
"""
Store information to write a mathtext rendering to the PostScript backend.
"""
_PSResult = namedtuple(
"_PSResult", "width height depth pswriter used_characters")
def __init__(self):
self.pswriter = StringIO()
self.lastfont = None
def render_glyph(self, ox, oy, info):
oy = self.height - oy + info.offset
postscript_name = info.postscript_name
fontsize = info.fontsize
if (postscript_name, fontsize) != self.lastfont:
self.lastfont = postscript_name, fontsize
self.pswriter.write(
f"/{postscript_name} findfont\n"
f"{fontsize} scalefont\n"
f"setfont\n")
self.pswriter.write(
f"{ox:f} {oy:f} moveto\n"
f"/{info.symbol_name} glyphshow\n")
def render_rect_filled(self, x1, y1, x2, y2):
ps = "%f %f %f %f rectfill\n" % (
x1, self.height - y2, x2 - x1, y2 - y1)
self.pswriter.write(ps)
def get_results(self, box, used_characters):
ship(0, 0, box)
return self._PSResult(self.width,
self.height + self.depth,
self.depth,
self.pswriter,
used_characters)
class MathtextBackendPdf(MathtextBackend):
"""Store information to write a mathtext rendering to the PDF backend."""
_PDFResult = namedtuple(
"_PDFResult", "width height depth glyphs rects used_characters")
def __init__(self):
self.glyphs = []
self.rects = []
def render_glyph(self, ox, oy, info):
filename = info.font.fname
oy = self.height - oy + info.offset
self.glyphs.append(
(ox, oy, filename, info.fontsize,
info.num, info.symbol_name))
def render_rect_filled(self, x1, y1, x2, y2):
self.rects.append((x1, self.height - y2, x2 - x1, y2 - y1))
def get_results(self, box, used_characters):
ship(0, 0, box)
return self._PDFResult(self.width,
self.height + self.depth,
self.depth,
self.glyphs,
self.rects,
used_characters)
class MathtextBackendSvg(MathtextBackend):
"""
Store information to write a mathtext rendering to the SVG
backend.
"""
def __init__(self):
self.svg_glyphs = []
self.svg_rects = []
def render_glyph(self, ox, oy, info):
oy = self.height - oy + info.offset
self.svg_glyphs.append(
(info.font, info.fontsize, info.num, ox, oy, info.metrics))
def render_rect_filled(self, x1, y1, x2, y2):
self.svg_rects.append(
(x1, self.height - y1 + 1, x2 - x1, y2 - y1))
def get_results(self, box, used_characters):
ship(0, 0, box)
svg_elements = types.SimpleNamespace(svg_glyphs=self.svg_glyphs,
svg_rects=self.svg_rects)
return (self.width,
self.height + self.depth,
self.depth,
svg_elements,
used_characters)
class MathtextBackendPath(MathtextBackend):
"""
Store information to write a mathtext rendering to the text path
machinery.
"""
def __init__(self):
self.glyphs = []
self.rects = []
def render_glyph(self, ox, oy, info):
oy = self.height - oy + info.offset
thetext = info.num
self.glyphs.append(
(info.font, info.fontsize, thetext, ox, oy))
def render_rect_filled(self, x1, y1, x2, y2):
self.rects.append((x1, self.height - y2, x2 - x1, y2 - y1))
def get_results(self, box, used_characters):
ship(0, 0, box)
return (self.width,
self.height + self.depth,
self.depth,
self.glyphs,
self.rects)
class MathtextBackendCairo(MathtextBackend):
"""
Store information to write a mathtext rendering to the Cairo
backend.
"""
def __init__(self):
self.glyphs = []
self.rects = []
def render_glyph(self, ox, oy, info):
oy = oy - info.offset - self.height
thetext = chr(info.num)
self.glyphs.append(
(info.font, info.fontsize, thetext, ox, oy))
def render_rect_filled(self, x1, y1, x2, y2):
self.rects.append(
(x1, y1 - self.height, x2 - x1, y2 - y1))
def get_results(self, box, used_characters):
ship(0, 0, box)
return (self.width,
self.height + self.depth,
self.depth,
self.glyphs,
self.rects)
class Fonts:
"""
An abstract base class for a system of fonts to use for mathtext.
The class must be able to take symbol keys and font file names and
return the character metrics. It also delegates to a backend class
to do the actual drawing.
"""
def __init__(self, default_font_prop, mathtext_backend):
"""
Parameters
----------
default_font_prop: `~.font_manager.FontProperties`
The default non-math font, or the base font for Unicode (generic)
font rendering.
mathtext_backend: `MathtextBackend` subclass
Backend to which rendering is actually delegated.
"""
self.default_font_prop = default_font_prop
self.mathtext_backend = mathtext_backend
self.used_characters = {}
def destroy(self):
"""
Fix any cyclical references before the object is about
to be destroyed.
"""
self.used_characters = None
def get_kern(self, font1, fontclass1, sym1, fontsize1,
font2, fontclass2, sym2, fontsize2, dpi):
r"""
Get the kerning distance for font between *sym1* and *sym2*.
*fontX*: one of the TeX font names::
tt, it, rm, cal, sf, bf or default/regular (non-math)
*fontclassX*: TODO
*symX*: a symbol in raw TeX form. e.g., '1', 'x' or '\sigma'
*fontsizeX*: the fontsize in points
*dpi*: the current dots-per-inch
"""
return 0.
def get_metrics(self, font, font_class, sym, fontsize, dpi, math=True):
r"""
*font*: one of the TeX font names::
tt, it, rm, cal, sf, bf or default/regular (non-math)
*font_class*: TODO
*sym*: a symbol in raw TeX form. e.g., '1', 'x' or '\sigma'
*fontsize*: font size in points
*dpi*: current dots-per-inch
*math*: whether sym is a math character
Returns an object with the following attributes:
- *advance*: The advance distance (in points) of the glyph.
- *height*: The height of the glyph in points.
- *width*: The width of the glyph in points.
- *xmin*, *xmax*, *ymin*, *ymax* - the ink rectangle of the glyph
- *iceberg* - the distance from the baseline to the top of
the glyph. This corresponds to TeX's definition of "height".
"""
info = self._get_info(font, font_class, sym, fontsize, dpi, math)
return info.metrics
def set_canvas_size(self, w, h, d):
"""
Set the size of the buffer used to render the math expression.
Only really necessary for the bitmap backends.
"""
self.width, self.height, self.depth = np.ceil([w, h, d])
self.mathtext_backend.set_canvas_size(
self.width, self.height, self.depth)
def render_glyph(self, ox, oy, facename, font_class, sym, fontsize, dpi):
"""
Draw a glyph at
- *ox*, *oy*: position
- *facename*: One of the TeX face names
- *font_class*:
- *sym*: TeX symbol name or single character
- *fontsize*: fontsize in points
- *dpi*: The dpi to draw at.
"""
info = self._get_info(facename, font_class, sym, fontsize, dpi)
self.used_characters.setdefault(info.font.fname, set()).add(info.num)
self.mathtext_backend.render_glyph(ox, oy, info)
def render_rect_filled(self, x1, y1, x2, y2):
"""
Draw a filled rectangle from (*x1*, *y1*) to (*x2*, *y2*).
"""
self.mathtext_backend.render_rect_filled(x1, y1, x2, y2)
def get_xheight(self, font, fontsize, dpi):
"""
Get the xheight for the given *font* and *fontsize*.
"""
raise NotImplementedError()
def get_underline_thickness(self, font, fontsize, dpi):
"""
Get the line thickness that matches the given font. Used as a
base unit for drawing lines such as in a fraction or radical.
"""
raise NotImplementedError()
def get_used_characters(self):
"""
Get the set of characters that were used in the math
expression. Used by backends that need to subset fonts so
they know which glyphs to include.
"""
return self.used_characters
def get_results(self, box):
"""
Get the data needed by the backend to render the math
expression. The return value is backend-specific.
"""
result = self.mathtext_backend.get_results(
box, self.get_used_characters())
self.destroy()
return result
def get_sized_alternatives_for_symbol(self, fontname, sym):
"""
Override if your font provides multiple sizes of the same
symbol. Should return a list of symbols matching *sym* in
various sizes. The expression renderer will select the most
appropriate size for a given situation from this list.
"""
return [(fontname, sym)]
class TruetypeFonts(Fonts):
"""
A generic base class for all font setups that use Truetype fonts
(through FT2Font).
"""
def __init__(self, default_font_prop, mathtext_backend):
Fonts.__init__(self, default_font_prop, mathtext_backend)
self.glyphd = {}
self._fonts = {}
filename = findfont(default_font_prop)
default_font = get_font(filename)
self._fonts['default'] = default_font
self._fonts['regular'] = default_font
def destroy(self):
self.glyphd = None
Fonts.destroy(self)
def _get_font(self, font):
if font in self.fontmap:
basename = self.fontmap[font]
else:
basename = font
cached_font = self._fonts.get(basename)
if cached_font is None and os.path.exists(basename):
cached_font = get_font(basename)
self._fonts[basename] = cached_font
self._fonts[cached_font.postscript_name] = cached_font
self._fonts[cached_font.postscript_name.lower()] = cached_font
return cached_font
def _get_offset(self, font, glyph, fontsize, dpi):
if font.postscript_name == 'Cmex10':
return (glyph.height / 64 / 2) + (fontsize/3 * dpi/72)
return 0.
def _get_info(self, fontname, font_class, sym, fontsize, dpi, math=True):
key = fontname, font_class, sym, fontsize, dpi
bunch = self.glyphd.get(key)
if bunch is not None:
return bunch
font, num, symbol_name, fontsize, slanted = \
self._get_glyph(fontname, font_class, sym, fontsize, math)
font.set_size(fontsize, dpi)
glyph = font.load_char(
num,
flags=self.mathtext_backend.get_hinting_type())
xmin, ymin, xmax, ymax = [val/64.0 for val in glyph.bbox]
offset = self._get_offset(font, glyph, fontsize, dpi)
metrics = types.SimpleNamespace(
advance = glyph.linearHoriAdvance/65536.0,
height = glyph.height/64.0,
width = glyph.width/64.0,
xmin = xmin,
xmax = xmax,
ymin = ymin+offset,
ymax = ymax+offset,
# iceberg is the equivalent of TeX's "height"
iceberg = glyph.horiBearingY/64.0 + offset,
slanted = slanted
)
result = self.glyphd[key] = types.SimpleNamespace(
font = font,
fontsize = fontsize,
postscript_name = font.postscript_name,
metrics = metrics,
symbol_name = symbol_name,
num = num,
glyph = glyph,
offset = offset
)
return result
def get_xheight(self, fontname, fontsize, dpi):
font = self._get_font(fontname)
font.set_size(fontsize, dpi)
pclt = font.get_sfnt_table('pclt')
if pclt is None:
# Some fonts don't store the xHeight, so we do a poor man's xHeight
metrics = self.get_metrics(
fontname, rcParams['mathtext.default'], 'x', fontsize, dpi)
return metrics.iceberg
xHeight = (pclt['xHeight'] / 64.0) * (fontsize / 12.0) * (dpi / 100.0)
return xHeight
def get_underline_thickness(self, font, fontsize, dpi):
# This function used to grab underline thickness from the font
# metrics, but that information is just too un-reliable, so it
# is now hardcoded.
return ((0.75 / 12.0) * fontsize * dpi) / 72.0
def get_kern(self, font1, fontclass1, sym1, fontsize1,
font2, fontclass2, sym2, fontsize2, dpi):
if font1 == font2 and fontsize1 == fontsize2:
info1 = self._get_info(font1, fontclass1, sym1, fontsize1, dpi)
info2 = self._get_info(font2, fontclass2, sym2, fontsize2, dpi)
font = info1.font
return font.get_kerning(info1.num, info2.num, KERNING_DEFAULT) / 64
return Fonts.get_kern(self, font1, fontclass1, sym1, fontsize1,
font2, fontclass2, sym2, fontsize2, dpi)
class BakomaFonts(TruetypeFonts):
"""
Use the Bakoma TrueType fonts for rendering.
Symbols are strewn about a number of font files, each of which has
its own proprietary 8-bit encoding.
"""
_fontmap = {
'cal': 'cmsy10',
'rm': 'cmr10',
'tt': 'cmtt10',
'it': 'cmmi10',
'bf': 'cmb10',
'sf': 'cmss10',
'ex': 'cmex10',
}
def __init__(self, *args, **kwargs):
self._stix_fallback = StixFonts(*args, **kwargs)
TruetypeFonts.__init__(self, *args, **kwargs)
self.fontmap = {}
for key, val in self._fontmap.items():
fullpath = findfont(val)
self.fontmap[key] = fullpath
self.fontmap[val] = fullpath
_slanted_symbols = set(r"\int \oint".split())
def _get_glyph(self, fontname, font_class, sym, fontsize, math=True):
symbol_name = None
font = None
if fontname in self.fontmap and sym in latex_to_bakoma:
basename, num = latex_to_bakoma[sym]
slanted = (basename == "cmmi10") or sym in self._slanted_symbols
font = self._get_font(basename)
elif len(sym) == 1:
slanted = (fontname == "it")
font = self._get_font(fontname)
if font is not None:
num = ord(sym)
if font is not None:
gid = font.get_char_index(num)
if gid != 0:
symbol_name = font.get_glyph_name(gid)
if symbol_name is None:
return self._stix_fallback._get_glyph(
fontname, font_class, sym, fontsize, math)
return font, num, symbol_name, fontsize, slanted
# The Bakoma fonts contain many pre-sized alternatives for the
# delimiters. The AutoSizedChar class will use these alternatives
# and select the best (closest sized) glyph.
_size_alternatives = {
'(': [('rm', '('), ('ex', '\xa1'), ('ex', '\xb3'),
('ex', '\xb5'), ('ex', '\xc3')],
')': [('rm', ')'), ('ex', '\xa2'), ('ex', '\xb4'),
('ex', '\xb6'), ('ex', '\x21')],
'{': [('cal', '{'), ('ex', '\xa9'), ('ex', '\x6e'),
('ex', '\xbd'), ('ex', '\x28')],
'}': [('cal', '}'), ('ex', '\xaa'), ('ex', '\x6f'),
('ex', '\xbe'), ('ex', '\x29')],
# The fourth size of '[' is mysteriously missing from the BaKoMa
# font, so I've omitted it for both '[' and ']'
'[': [('rm', '['), ('ex', '\xa3'), ('ex', '\x68'),
('ex', '\x22')],
']': [('rm', ']'), ('ex', '\xa4'), ('ex', '\x69'),
('ex', '\x23')],
r'\lfloor': [('ex', '\xa5'), ('ex', '\x6a'),
('ex', '\xb9'), ('ex', '\x24')],
r'\rfloor': [('ex', '\xa6'), ('ex', '\x6b'),
('ex', '\xba'), ('ex', '\x25')],
r'\lceil': [('ex', '\xa7'), ('ex', '\x6c'),
('ex', '\xbb'), ('ex', '\x26')],
r'\rceil': [('ex', '\xa8'), ('ex', '\x6d'),
('ex', '\xbc'), ('ex', '\x27')],
r'\langle': [('ex', '\xad'), ('ex', '\x44'),
('ex', '\xbf'), ('ex', '\x2a')],
r'\rangle': [('ex', '\xae'), ('ex', '\x45'),
('ex', '\xc0'), ('ex', '\x2b')],
r'\__sqrt__': [('ex', '\x70'), ('ex', '\x71'),
('ex', '\x72'), ('ex', '\x73')],
r'\backslash': [('ex', '\xb2'), ('ex', '\x2f'),
('ex', '\xc2'), ('ex', '\x2d')],
r'/': [('rm', '/'), ('ex', '\xb1'), ('ex', '\x2e'),
('ex', '\xcb'), ('ex', '\x2c')],
r'\widehat': [('rm', '\x5e'), ('ex', '\x62'), ('ex', '\x63'),
('ex', '\x64')],
r'\widetilde': [('rm', '\x7e'), ('ex', '\x65'), ('ex', '\x66'),
('ex', '\x67')],
r'<': [('cal', 'h'), ('ex', 'D')],
r'>': [('cal', 'i'), ('ex', 'E')]
}
for alias, target in [(r'\leftparen', '('),
(r'\rightparent', ')'),
(r'\leftbrace', '{'),
(r'\rightbrace', '}'),
(r'\leftbracket', '['),
(r'\rightbracket', ']'),
(r'\{', '{'),
(r'\}', '}'),
(r'\[', '['),
(r'\]', ']')]:
_size_alternatives[alias] = _size_alternatives[target]
def get_sized_alternatives_for_symbol(self, fontname, sym):
return self._size_alternatives.get(sym, [(fontname, sym)])
class UnicodeFonts(TruetypeFonts):
"""
An abstract base class for handling Unicode fonts.
While some reasonably complete Unicode fonts (such as DejaVu) may
work in some situations, the only Unicode font I'm aware of with a
complete set of math symbols is STIX.
This class will "fallback" on the Bakoma fonts when a required
symbol can not be found in the font.
"""
use_cmex = True
def __init__(self, *args, **kwargs):
# This must come first so the backend's owner is set correctly
fallback_rc = rcParams['mathtext.fallback']
if rcParams['mathtext.fallback_to_cm'] is not None:
fallback_rc = ('cm' if rcParams['mathtext.fallback_to_cm']
else None)
font_class = {'stix': StixFonts,
'stixsans': StixSansFonts,
'cm': BakomaFonts
}.get(fallback_rc)
self.cm_fallback = font_class(*args, **kwargs) if font_class else None
TruetypeFonts.__init__(self, *args, **kwargs)
self.fontmap = {}
for texfont in "cal rm tt it bf sf".split():
prop = rcParams['mathtext.' + texfont]
font = findfont(prop)
self.fontmap[texfont] = font
prop = FontProperties('cmex10')
font = findfont(prop)
self.fontmap['ex'] = font
# include STIX sized alternatives for glyphs if fallback is STIX
if isinstance(self.cm_fallback, StixFonts):
stixsizedaltfonts = {
0: 'STIXGeneral',
1: 'STIXSizeOneSym',
2: 'STIXSizeTwoSym',
3: 'STIXSizeThreeSym',
4: 'STIXSizeFourSym',
5: 'STIXSizeFiveSym'}
for size, name in stixsizedaltfonts.items():
fullpath = findfont(name)
self.fontmap[size] = fullpath
self.fontmap[name] = fullpath
_slanted_symbols = set(r"\int \oint".split())
def _map_virtual_font(self, fontname, font_class, uniindex):
return fontname, uniindex
def _get_glyph(self, fontname, font_class, sym, fontsize, math=True):
found_symbol = False
if self.use_cmex:
uniindex = latex_to_cmex.get(sym)
if uniindex is not None:
fontname = 'ex'
found_symbol = True
if not found_symbol:
try:
uniindex = get_unicode_index(sym, math)
found_symbol = True
except ValueError:
uniindex = ord('?')
_log.warning(
"No TeX to unicode mapping for {!a}.".format(sym))
fontname, uniindex = self._map_virtual_font(
fontname, font_class, uniindex)
new_fontname = fontname
# Only characters in the "Letter" class should be italicized in 'it'
# mode. Greek capital letters should be Roman.
if found_symbol:
if fontname == 'it' and uniindex < 0x10000:
char = chr(uniindex)
if (unicodedata.category(char)[0] != "L"
or unicodedata.name(char).startswith("GREEK CAPITAL")):
new_fontname = 'rm'
slanted = (new_fontname == 'it') or sym in self._slanted_symbols
found_symbol = False
font = self._get_font(new_fontname)
if font is not None:
glyphindex = font.get_char_index(uniindex)
if glyphindex != 0:
found_symbol = True
if not found_symbol:
if self.cm_fallback:
if (fontname in ('it', 'regular')
and isinstance(self.cm_fallback, StixFonts)):
fontname = 'rm'
g = self.cm_fallback._get_glyph(fontname, font_class,
sym, fontsize)
fname = g[0].family_name
if fname in list(BakomaFonts._fontmap.values()):
fname = "Computer Modern"
_log.info("Substituting symbol %s from %s", sym, fname)
return g
else:
if (fontname in ('it', 'regular')
and isinstance(self, StixFonts)):
return self._get_glyph('rm', font_class, sym, fontsize)
_log.warning("Font {!r} does not have a glyph for {!a} "
"[U+{:x}], substituting with a dummy "
"symbol.".format(new_fontname, sym, uniindex))
fontname = 'rm'
font = self._get_font(fontname)
uniindex = 0xA4 # currency char, for lack of anything better
glyphindex = font.get_char_index(uniindex)
slanted = False
symbol_name = font.get_glyph_name(glyphindex)
return font, uniindex, symbol_name, fontsize, slanted
def get_sized_alternatives_for_symbol(self, fontname, sym):
if self.cm_fallback:
return self.cm_fallback.get_sized_alternatives_for_symbol(
fontname, sym)
return [(fontname, sym)]
class DejaVuFonts(UnicodeFonts):
use_cmex = False
def __init__(self, *args, **kwargs):
# This must come first so the backend's owner is set correctly
if isinstance(self, DejaVuSerifFonts):
self.cm_fallback = StixFonts(*args, **kwargs)
else:
self.cm_fallback = StixSansFonts(*args, **kwargs)
self.bakoma = BakomaFonts(*args, **kwargs)
TruetypeFonts.__init__(self, *args, **kwargs)
self.fontmap = {}
# Include Stix sized alternatives for glyphs
self._fontmap.update({
1: 'STIXSizeOneSym',
2: 'STIXSizeTwoSym',
3: 'STIXSizeThreeSym',
4: 'STIXSizeFourSym',
5: 'STIXSizeFiveSym',
})
for key, name in self._fontmap.items():
fullpath = findfont(name)
self.fontmap[key] = fullpath
self.fontmap[name] = fullpath
def _get_glyph(self, fontname, font_class, sym, fontsize, math=True):
# Override prime symbol to use Bakoma.
if sym == r'\prime':
return self.bakoma._get_glyph(
fontname, font_class, sym, fontsize, math)
else:
# check whether the glyph is available in the display font
uniindex = get_unicode_index(sym)
font = self._get_font('ex')
if font is not None:
glyphindex = font.get_char_index(uniindex)
if glyphindex != 0:
return super()._get_glyph(
'ex', font_class, sym, fontsize, math)
# otherwise return regular glyph
return super()._get_glyph(
fontname, font_class, sym, fontsize, math)
class DejaVuSerifFonts(DejaVuFonts):
"""
A font handling class for the DejaVu Serif fonts
If a glyph is not found it will fallback to Stix Serif
"""
_fontmap = {
'rm': 'DejaVu Serif',
'it': 'DejaVu Serif:italic',
'bf': 'DejaVu Serif:weight=bold',
'sf': 'DejaVu Sans',
'tt': 'DejaVu Sans Mono',
'ex': 'DejaVu Serif Display',
0: 'DejaVu Serif',
}
class DejaVuSansFonts(DejaVuFonts):
"""
A font handling class for the DejaVu Sans fonts
If a glyph is not found it will fallback to Stix Sans
"""
_fontmap = {
'rm': 'DejaVu Sans',
'it': 'DejaVu Sans:italic',
'bf': 'DejaVu Sans:weight=bold',
'sf': 'DejaVu Sans',
'tt': 'DejaVu Sans Mono',
'ex': 'DejaVu Sans Display',
0: 'DejaVu Sans',
}
class StixFonts(UnicodeFonts):
"""
A font handling class for the STIX fonts.
In addition to what UnicodeFonts provides, this class:
- supports "virtual fonts" which are complete alpha numeric
character sets with different font styles at special Unicode
code points, such as "Blackboard".
- handles sized alternative characters for the STIXSizeX fonts.
"""
_fontmap = {
'rm': 'STIXGeneral',
'it': 'STIXGeneral:italic',
'bf': 'STIXGeneral:weight=bold',
'nonunirm': 'STIXNonUnicode',
'nonuniit': 'STIXNonUnicode:italic',
'nonunibf': 'STIXNonUnicode:weight=bold',
0: 'STIXGeneral',
1: 'STIXSizeOneSym',
2: 'STIXSizeTwoSym',
3: 'STIXSizeThreeSym',
4: 'STIXSizeFourSym',
5: 'STIXSizeFiveSym',
}
use_cmex = False
cm_fallback = False
_sans = False
def __init__(self, *args, **kwargs):
TruetypeFonts.__init__(self, *args, **kwargs)
self.fontmap = {}
for key, name in self._fontmap.items():
fullpath = findfont(name)
self.fontmap[key] = fullpath
self.fontmap[name] = fullpath
def _map_virtual_font(self, fontname, font_class, uniindex):
# Handle these "fonts" that are actually embedded in
# other fonts.
mapping = stix_virtual_fonts.get(fontname)
if (self._sans and mapping is None
and fontname not in ('regular', 'default')):
mapping = stix_virtual_fonts['sf']
doing_sans_conversion = True
else:
doing_sans_conversion = False
if mapping is not None:
if isinstance(mapping, dict):
try:
mapping = mapping[font_class]
except KeyError:
mapping = mapping['rm']
# Binary search for the source glyph
lo = 0
hi = len(mapping)
while lo < hi:
mid = (lo+hi)//2
range = mapping[mid]
if uniindex < range[0]:
hi = mid
elif uniindex <= range[1]:
break
else:
lo = mid + 1
if range[0] <= uniindex <= range[1]:
uniindex = uniindex - range[0] + range[3]
fontname = range[2]
elif not doing_sans_conversion:
# This will generate a dummy character
uniindex = 0x1
fontname = rcParams['mathtext.default']
# Handle private use area glyphs
if fontname in ('it', 'rm', 'bf') and 0xe000 <= uniindex <= 0xf8ff:
fontname = 'nonuni' + fontname
return fontname, uniindex
@functools.lru_cache()
def get_sized_alternatives_for_symbol(self, fontname, sym):
fixes = {
'\\{': '{', '\\}': '}', '\\[': '[', '\\]': ']',
'<': '\N{MATHEMATICAL LEFT ANGLE BRACKET}',
'>': '\N{MATHEMATICAL RIGHT ANGLE BRACKET}',
}
sym = fixes.get(sym, sym)
try:
uniindex = get_unicode_index(sym)
except ValueError:
return [(fontname, sym)]
alternatives = [(i, chr(uniindex)) for i in range(6)
if self._get_font(i).get_char_index(uniindex) != 0]
# The largest size of the radical symbol in STIX has incorrect
# metrics that cause it to be disconnected from the stem.
if sym == r'\__sqrt__':
alternatives = alternatives[:-1]
return alternatives
class StixSansFonts(StixFonts):
"""
A font handling class for the STIX fonts (that uses sans-serif
characters by default).
"""
_sans = True
class StandardPsFonts(Fonts):
"""
Use the standard postscript fonts for rendering to backend_ps
Unlike the other font classes, BakomaFont and UnicodeFont, this
one requires the Ps backend.
"""
basepath = str(cbook._get_data_path('fonts/afm'))
fontmap = {
'cal': 'pzcmi8a', # Zapf Chancery
'rm': 'pncr8a', # New Century Schoolbook
'tt': 'pcrr8a', # Courier
'it': 'pncri8a', # New Century Schoolbook Italic
'sf': 'phvr8a', # Helvetica
'bf': 'pncb8a', # New Century Schoolbook Bold
None: 'psyr', # Symbol
}
def __init__(self, default_font_prop):
Fonts.__init__(self, default_font_prop, MathtextBackendPs())
self.glyphd = {}
self.fonts = {}
filename = findfont(default_font_prop, fontext='afm',
directory=self.basepath)
if filename is None:
filename = findfont('Helvetica', fontext='afm',
directory=self.basepath)
with open(filename, 'rb') as fd:
default_font = AFM(fd)
default_font.fname = filename
self.fonts['default'] = default_font
self.fonts['regular'] = default_font
self.pswriter = StringIO()
def _get_font(self, font):
if font in self.fontmap:
basename = self.fontmap[font]
else:
basename = font
cached_font = self.fonts.get(basename)
if cached_font is None:
fname = os.path.join(self.basepath, basename + ".afm")
with open(fname, 'rb') as fd:
cached_font = AFM(fd)
cached_font.fname = fname
self.fonts[basename] = cached_font
self.fonts[cached_font.get_fontname()] = cached_font
return cached_font
def _get_info(self, fontname, font_class, sym, fontsize, dpi, math=True):
"""Load the cmfont, metrics and glyph with caching."""
key = fontname, sym, fontsize, dpi
tup = self.glyphd.get(key)
if tup is not None:
return tup
# Only characters in the "Letter" class should really be italicized.
# This class includes greek letters, so we're ok
if (fontname == 'it' and
(len(sym) > 1
or not unicodedata.category(sym).startswith("L"))):
fontname = 'rm'
found_symbol = False
if sym in latex_to_standard:
fontname, num = latex_to_standard[sym]
glyph = chr(num)
found_symbol = True
elif len(sym) == 1:
glyph = sym
num = ord(glyph)
found_symbol = True
else:
_log.warning(
"No TeX to built-in Postscript mapping for {!r}".format(sym))
slanted = (fontname == 'it')
font = self._get_font(fontname)
if found_symbol:
try:
symbol_name = font.get_name_char(glyph)
except KeyError:
_log.warning(
"No glyph in standard Postscript font {!r} for {!r}"
.format(font.get_fontname(), sym))
found_symbol = False
if not found_symbol:
glyph = '?'
num = ord(glyph)
symbol_name = font.get_name_char(glyph)
offset = 0
scale = 0.001 * fontsize
xmin, ymin, xmax, ymax = [val * scale
for val in font.get_bbox_char(glyph)]
metrics = types.SimpleNamespace(
advance = font.get_width_char(glyph) * scale,
width = font.get_width_char(glyph) * scale,
height = font.get_height_char(glyph) * scale,
xmin = xmin,
xmax = xmax,
ymin = ymin+offset,
ymax = ymax+offset,
# iceberg is the equivalent of TeX's "height"
iceberg = ymax + offset,
slanted = slanted
)
self.glyphd[key] = types.SimpleNamespace(
font = font,
fontsize = fontsize,
postscript_name = font.get_fontname(),
metrics = metrics,
symbol_name = symbol_name,
num = num,
glyph = glyph,
offset = offset
)
return self.glyphd[key]
def get_kern(self, font1, fontclass1, sym1, fontsize1,
font2, fontclass2, sym2, fontsize2, dpi):
if font1 == font2 and fontsize1 == fontsize2:
info1 = self._get_info(font1, fontclass1, sym1, fontsize1, dpi)
info2 = self._get_info(font2, fontclass2, sym2, fontsize2, dpi)
font = info1.font
return (font.get_kern_dist(info1.glyph, info2.glyph)
* 0.001 * fontsize1)
return Fonts.get_kern(self, font1, fontclass1, sym1, fontsize1,
font2, fontclass2, sym2, fontsize2, dpi)
def get_xheight(self, font, fontsize, dpi):
font = self._get_font(font)
return font.get_xheight() * 0.001 * fontsize
def get_underline_thickness(self, font, fontsize, dpi):
font = self._get_font(font)
return font.get_underline_thickness() * 0.001 * fontsize
##############################################################################
# TeX-LIKE BOX MODEL
# The following is based directly on the document 'woven' from the
# TeX82 source code. This information is also available in printed
# form:
#
# Knuth, Donald E.. 1986. Computers and Typesetting, Volume B:
# TeX: The Program. Addison-Wesley Professional.
#
# The most relevant "chapters" are:
# Data structures for boxes and their friends
# Shipping pages out (Ship class)
# Packaging (hpack and vpack)
# Data structures for math mode
# Subroutines for math mode
# Typesetting math formulas
#
# Many of the docstrings below refer to a numbered "node" in that
# book, e.g., node123
#
# Note that (as TeX) y increases downward, unlike many other parts of
# matplotlib.
# How much text shrinks when going to the next-smallest level. GROW_FACTOR
# must be the inverse of SHRINK_FACTOR.
SHRINK_FACTOR = 0.7
GROW_FACTOR = 1.0 / SHRINK_FACTOR
# The number of different sizes of chars to use, beyond which they will not
# get any smaller
NUM_SIZE_LEVELS = 6
class FontConstantsBase:
"""
A set of constants that controls how certain things, such as sub-
and superscripts are laid out. These are all metrics that can't
be reliably retrieved from the font metrics in the font itself.
"""
# Percentage of x-height of additional horiz. space after sub/superscripts
script_space = 0.05
# Percentage of x-height that sub/superscripts drop below the baseline
subdrop = 0.4
# Percentage of x-height that superscripts are raised from the baseline
sup1 = 0.7
# Percentage of x-height that subscripts drop below the baseline
sub1 = 0.3
# Percentage of x-height that subscripts drop below the baseline when a
# superscript is present
sub2 = 0.5
# Percentage of x-height that sub/supercripts are offset relative to the
# nucleus edge for non-slanted nuclei
delta = 0.025
# Additional percentage of last character height above 2/3 of the
# x-height that supercripts are offset relative to the subscript
# for slanted nuclei
delta_slanted = 0.2
# Percentage of x-height that supercripts and subscripts are offset for
# integrals
delta_integral = 0.1
class ComputerModernFontConstants(FontConstantsBase):
script_space = 0.075
subdrop = 0.2
sup1 = 0.45
sub1 = 0.2
sub2 = 0.3
delta = 0.075
delta_slanted = 0.3
delta_integral = 0.3
class STIXFontConstants(FontConstantsBase):
script_space = 0.1
sup1 = 0.8
sub2 = 0.6
delta = 0.05
delta_slanted = 0.3
delta_integral = 0.3
class STIXSansFontConstants(FontConstantsBase):
script_space = 0.05
sup1 = 0.8
delta_slanted = 0.6
delta_integral = 0.3
class DejaVuSerifFontConstants(FontConstantsBase):
pass
class DejaVuSansFontConstants(FontConstantsBase):
pass
# Maps font family names to the FontConstantBase subclass to use
_font_constant_mapping = {
'DejaVu Sans': DejaVuSansFontConstants,
'DejaVu Sans Mono': DejaVuSansFontConstants,
'DejaVu Serif': DejaVuSerifFontConstants,
'cmb10': ComputerModernFontConstants,
'cmex10': ComputerModernFontConstants,
'cmmi10': ComputerModernFontConstants,
'cmr10': ComputerModernFontConstants,
'cmss10': ComputerModernFontConstants,
'cmsy10': ComputerModernFontConstants,
'cmtt10': ComputerModernFontConstants,
'STIXGeneral': STIXFontConstants,
'STIXNonUnicode': STIXFontConstants,
'STIXSizeFiveSym': STIXFontConstants,
'STIXSizeFourSym': STIXFontConstants,
'STIXSizeThreeSym': STIXFontConstants,
'STIXSizeTwoSym': STIXFontConstants,
'STIXSizeOneSym': STIXFontConstants,
# Map the fonts we used to ship, just for good measure
'Bitstream Vera Sans': DejaVuSansFontConstants,
'Bitstream Vera': DejaVuSansFontConstants,
}
def _get_font_constant_set(state):
constants = _font_constant_mapping.get(
state.font_output._get_font(state.font).family_name,
FontConstantsBase)
# STIX sans isn't really its own fonts, just different code points
# in the STIX fonts, so we have to detect this one separately.
if (constants is STIXFontConstants and
isinstance(state.font_output, StixSansFonts)):
return STIXSansFontConstants
return constants
class MathTextWarning(Warning):
pass
class Node:
"""A node in the TeX box model."""
def __init__(self):
self.size = 0
def __repr__(self):
return self.__class__.__name__
def get_kerning(self, next):
return 0.0
def shrink(self):
"""
Shrinks one level smaller. There are only three levels of
sizes, after which things will no longer get smaller.
"""
self.size += 1
def grow(self):
"""
Grows one level larger. There is no limit to how big
something can get.
"""
self.size -= 1
def render(self, x, y):
pass
class Box(Node):
"""A node with a physical location."""
def __init__(self, width, height, depth):
Node.__init__(self)
self.width = width
self.height = height
self.depth = depth
def shrink(self):
Node.shrink(self)
if self.size < NUM_SIZE_LEVELS:
self.width *= SHRINK_FACTOR
self.height *= SHRINK_FACTOR
self.depth *= SHRINK_FACTOR
def grow(self):
Node.grow(self)
self.width *= GROW_FACTOR
self.height *= GROW_FACTOR
self.depth *= GROW_FACTOR
def render(self, x1, y1, x2, y2):
pass
class Vbox(Box):
"""A box with only height (zero width)."""
def __init__(self, height, depth):
Box.__init__(self, 0., height, depth)
class Hbox(Box):
"""A box with only width (zero height and depth)."""
def __init__(self, width):
Box.__init__(self, width, 0., 0.)
class Char(Node):
"""
A single character.
Unlike TeX, the font information and metrics are stored with each `Char`
to make it easier to lookup the font metrics when needed. Note that TeX
boxes have a width, height, and depth, unlike Type1 and TrueType which use
a full bounding box and an advance in the x-direction. The metrics must
be converted to the TeX model, and the advance (if different from width)
must be converted into a `Kern` node when the `Char` is added to its parent
`Hlist`.
"""
def __init__(self, c, state, math=True):
Node.__init__(self)
self.c = c
self.font_output = state.font_output
self.font = state.font
self.font_class = state.font_class
self.fontsize = state.fontsize
self.dpi = state.dpi
self.math = math
# The real width, height and depth will be set during the
# pack phase, after we know the real fontsize
self._update_metrics()
def __repr__(self):
return '`%s`' % self.c
def _update_metrics(self):
metrics = self._metrics = self.font_output.get_metrics(
self.font, self.font_class, self.c, self.fontsize, self.dpi,
self.math)
if self.c == ' ':
self.width = metrics.advance
else:
self.width = metrics.width
self.height = metrics.iceberg
self.depth = -(metrics.iceberg - metrics.height)
def is_slanted(self):
return self._metrics.slanted
def get_kerning(self, next):
"""
Return the amount of kerning between this and the given character.
This method is called when characters are strung together into `Hlist`
to create `Kern` nodes.
"""
advance = self._metrics.advance - self.width
kern = 0.
if isinstance(next, Char):
kern = self.font_output.get_kern(
self.font, self.font_class, self.c, self.fontsize,
next.font, next.font_class, next.c, next.fontsize,
self.dpi)
return advance + kern
def render(self, x, y):
"""
Render the character to the canvas
"""
self.font_output.render_glyph(
x, y,
self.font, self.font_class, self.c, self.fontsize, self.dpi)
def shrink(self):
Node.shrink(self)
if self.size < NUM_SIZE_LEVELS:
self.fontsize *= SHRINK_FACTOR
self.width *= SHRINK_FACTOR
self.height *= SHRINK_FACTOR
self.depth *= SHRINK_FACTOR
def grow(self):
Node.grow(self)
self.fontsize *= GROW_FACTOR
self.width *= GROW_FACTOR
self.height *= GROW_FACTOR
self.depth *= GROW_FACTOR
class Accent(Char):
"""
The font metrics need to be dealt with differently for accents,
since they are already offset correctly from the baseline in
TrueType fonts.
"""
def _update_metrics(self):
metrics = self._metrics = self.font_output.get_metrics(
self.font, self.font_class, self.c, self.fontsize, self.dpi)
self.width = metrics.xmax - metrics.xmin
self.height = metrics.ymax - metrics.ymin
self.depth = 0
def shrink(self):
Char.shrink(self)
self._update_metrics()
def grow(self):
Char.grow(self)
self._update_metrics()
def render(self, x, y):
"""
Render the character to the canvas.
"""
self.font_output.render_glyph(
x - self._metrics.xmin, y + self._metrics.ymin,
self.font, self.font_class, self.c, self.fontsize, self.dpi)
class List(Box):
"""A list of nodes (either horizontal or vertical)."""
def __init__(self, elements):
Box.__init__(self, 0., 0., 0.)
self.shift_amount = 0. # An arbitrary offset
self.children = elements # The child nodes of this list
# The following parameters are set in the vpack and hpack functions
self.glue_set = 0. # The glue setting of this list
self.glue_sign = 0 # 0: normal, -1: shrinking, 1: stretching
self.glue_order = 0 # The order of infinity (0 - 3) for the glue
def __repr__(self):
return '[%s <%.02f %.02f %.02f %.02f> %s]' % (
super().__repr__(),
self.width, self.height,
self.depth, self.shift_amount,
' '.join([repr(x) for x in self.children]))
@staticmethod
def _determine_order(totals):
"""
Determine the highest order of glue used by the members of this list.
Helper function used by vpack and hpack.
"""
for i in range(len(totals))[::-1]:
if totals[i] != 0:
return i
return 0
def _set_glue(self, x, sign, totals, error_type):
o = self._determine_order(totals)
self.glue_order = o
self.glue_sign = sign
if totals[o] != 0.:
self.glue_set = x / totals[o]
else:
self.glue_sign = 0
self.glue_ratio = 0.
if o == 0:
if len(self.children):
_log.warning("%s %s: %r",
error_type, self.__class__.__name__, self)
def shrink(self):
for child in self.children:
child.shrink()
Box.shrink(self)
if self.size < NUM_SIZE_LEVELS:
self.shift_amount *= SHRINK_FACTOR
self.glue_set *= SHRINK_FACTOR
def grow(self):
for child in self.children:
child.grow()
Box.grow(self)
self.shift_amount *= GROW_FACTOR
self.glue_set *= GROW_FACTOR
class Hlist(List):
"""A horizontal list of boxes."""
def __init__(self, elements, w=0., m='additional', do_kern=True):
List.__init__(self, elements)
if do_kern:
self.kern()
self.hpack()
def kern(self):
"""
Insert `Kern` nodes between `Char` nodes to set kerning.
The `Char` nodes themselves determine the amount of kerning they need
(in `~Char.get_kerning`), and this function just creates the correct
linked list.
"""
new_children = []
num_children = len(self.children)
if num_children:
for i in range(num_children):
elem = self.children[i]
if i < num_children - 1:
next = self.children[i + 1]
else:
next = None
new_children.append(elem)
kerning_distance = elem.get_kerning(next)
if kerning_distance != 0.:
kern = Kern(kerning_distance)
new_children.append(kern)
self.children = new_children
# This is a failed experiment to fake cross-font kerning.
# def get_kerning(self, next):
# if len(self.children) >= 2 and isinstance(self.children[-2], Char):
# if isinstance(next, Char):
# print "CASE A"
# return self.children[-2].get_kerning(next)
# elif (isinstance(next, Hlist) and len(next.children)
# and isinstance(next.children[0], Char)):
# print "CASE B"
# result = self.children[-2].get_kerning(next.children[0])
# print result
# return result
# return 0.0
def hpack(self, w=0., m='additional'):
r"""
Compute the dimensions of the resulting boxes, and adjust the glue if
one of those dimensions is pre-specified. The computed sizes normally
enclose all of the material inside the new box; but some items may
stick out if negative glue is used, if the box is overfull, or if a
``\vbox`` includes other boxes that have been shifted left.
Parameters
----------
w : float, default: 0
A width.
m : {'exactly', 'additional'}, default: 'additional'
Whether to produce a box whose width is 'exactly' *w*; or a box
with the natural width of the contents, plus *w* ('additional').
Notes
-----
The defaults produce a box with the natural width of the contents.
"""
# I don't know why these get reset in TeX. Shift_amount is pretty
# much useless if we do.
# self.shift_amount = 0.
h = 0.
d = 0.
x = 0.
total_stretch = [0.] * 4
total_shrink = [0.] * 4
for p in self.children:
if isinstance(p, Char):
x += p.width
h = max(h, p.height)
d = max(d, p.depth)
elif isinstance(p, Box):
x += p.width
if not np.isinf(p.height) and not np.isinf(p.depth):
s = getattr(p, 'shift_amount', 0.)
h = max(h, p.height - s)
d = max(d, p.depth + s)
elif isinstance(p, Glue):
glue_spec = p.glue_spec
x += glue_spec.width
total_stretch[glue_spec.stretch_order] += glue_spec.stretch
total_shrink[glue_spec.shrink_order] += glue_spec.shrink
elif isinstance(p, Kern):
x += p.width
self.height = h
self.depth = d
if m == 'additional':
w += x
self.width = w
x = w - x
if x == 0.:
self.glue_sign = 0
self.glue_order = 0
self.glue_ratio = 0.
return
if x > 0.:
self._set_glue(x, 1, total_stretch, "Overfull")
else:
self._set_glue(x, -1, total_shrink, "Underfull")
class Vlist(List):
"""A vertical list of boxes."""
def __init__(self, elements, h=0., m='additional'):
List.__init__(self, elements)
self.vpack()
def vpack(self, h=0., m='additional', l=np.inf):
"""
Compute the dimensions of the resulting boxes, and to adjust the glue
if one of those dimensions is pre-specified.
Parameters
----------
h : float, default: 0
A height.
m : {'exactly', 'additional'}, default: 'additional'
Whether to produce a box whose height is 'exactly' *w*; or a box
with the natural height of the contents, plus *w* ('additional').
l : float, default: np.inf
The maximum height.
Notes
-----
The defaults produce a box with the natural height of the contents.
"""
# I don't know why these get reset in TeX. Shift_amount is pretty
# much useless if we do.
# self.shift_amount = 0.
w = 0.
d = 0.
x = 0.
total_stretch = [0.] * 4
total_shrink = [0.] * 4
for p in self.children:
if isinstance(p, Box):
x += d + p.height
d = p.depth
if not np.isinf(p.width):
s = getattr(p, 'shift_amount', 0.)
w = max(w, p.width + s)
elif isinstance(p, Glue):
x += d
d = 0.
glue_spec = p.glue_spec
x += glue_spec.width
total_stretch[glue_spec.stretch_order] += glue_spec.stretch
total_shrink[glue_spec.shrink_order] += glue_spec.shrink
elif isinstance(p, Kern):
x += d + p.width
d = 0.
elif isinstance(p, Char):
raise RuntimeError(
"Internal mathtext error: Char node found in Vlist")
self.width = w
if d > l:
x += d - l
self.depth = l
else:
self.depth = d
if m == 'additional':
h += x
self.height = h
x = h - x
if x == 0:
self.glue_sign = 0
self.glue_order = 0
self.glue_ratio = 0.
return
if x > 0.:
self._set_glue(x, 1, total_stretch, "Overfull")
else:
self._set_glue(x, -1, total_shrink, "Underfull")
class Rule(Box):
"""
A solid black rectangle.
It has *width*, *depth*, and *height* fields just as in an `Hlist`.
However, if any of these dimensions is inf, the actual value will be
determined by running the rule up to the boundary of the innermost
enclosing box. This is called a "running dimension". The width is never
running in an `Hlist`; the height and depth are never running in a `Vlist`.
"""
def __init__(self, width, height, depth, state):
Box.__init__(self, width, height, depth)
self.font_output = state.font_output
def render(self, x, y, w, h):
self.font_output.render_rect_filled(x, y, x + w, y + h)
class Hrule(Rule):
"""Convenience class to create a horizontal rule."""
def __init__(self, state, thickness=None):
if thickness is None:
thickness = state.font_output.get_underline_thickness(
state.font, state.fontsize, state.dpi)
height = depth = thickness * 0.5
Rule.__init__(self, np.inf, height, depth, state)
class Vrule(Rule):
"""Convenience class to create a vertical rule."""
def __init__(self, state):
thickness = state.font_output.get_underline_thickness(
state.font, state.fontsize, state.dpi)
Rule.__init__(self, thickness, np.inf, np.inf, state)
_GlueSpec = namedtuple(
"_GlueSpec", "width stretch stretch_order shrink shrink_order")
_GlueSpec._named = {
'fil': _GlueSpec(0., 1., 1, 0., 0),
'fill': _GlueSpec(0., 1., 2, 0., 0),
'filll': _GlueSpec(0., 1., 3, 0., 0),
'neg_fil': _GlueSpec(0., 0., 0, 1., 1),
'neg_fill': _GlueSpec(0., 0., 0, 1., 2),
'neg_filll': _GlueSpec(0., 0., 0, 1., 3),
'empty': _GlueSpec(0., 0., 0, 0., 0),
'ss': _GlueSpec(0., 1., 1, -1., 1),
}
class Glue(Node):
"""
Most of the information in this object is stored in the underlying
``_GlueSpec`` class, which is shared between multiple glue objects.
(This is a memory optimization which probably doesn't matter anymore, but
it's easier to stick to what TeX does.)
"""
@cbook.deprecated("3.3")
@property
def glue_subtype(self):
return "normal"
@cbook._delete_parameter("3.3", "copy")
def __init__(self, glue_type, copy=False):
Node.__init__(self)
if isinstance(glue_type, str):
glue_spec = _GlueSpec._named[glue_type]
elif isinstance(glue_type, _GlueSpec):
glue_spec = glue_type
else:
raise ValueError("glue_type must be a glue spec name or instance")
self.glue_spec = glue_spec
def shrink(self):
Node.shrink(self)
if self.size < NUM_SIZE_LEVELS:
g = self.glue_spec
self.glue_spec = g._replace(width=g.width * SHRINK_FACTOR)
def grow(self):
Node.grow(self)
g = self.glue_spec
self.glue_spec = g._replace(width=g.width * GROW_FACTOR)
@cbook.deprecated("3.3")
class GlueSpec:
"""See `Glue`."""
def __init__(self, width=0., stretch=0., stretch_order=0,
shrink=0., shrink_order=0):
self.width = width
self.stretch = stretch
self.stretch_order = stretch_order
self.shrink = shrink
self.shrink_order = shrink_order
def copy(self):
return GlueSpec(
self.width,
self.stretch,
self.stretch_order,
self.shrink,
self.shrink_order)
@classmethod
def factory(cls, glue_type):
return cls._types[glue_type]
with cbook._suppress_matplotlib_deprecation_warning():
GlueSpec._types = {k: GlueSpec(**v._asdict())
for k, v in _GlueSpec._named.items()}
# Some convenient ways to get common kinds of glue
@cbook.deprecated("3.3", alternative="Glue('fil')")
class Fil(Glue):
def __init__(self):
Glue.__init__(self, 'fil')
@cbook.deprecated("3.3", alternative="Glue('fill')")
class Fill(Glue):
def __init__(self):
Glue.__init__(self, 'fill')
@cbook.deprecated("3.3", alternative="Glue('filll')")
class Filll(Glue):
def __init__(self):
Glue.__init__(self, 'filll')
@cbook.deprecated("3.3", alternative="Glue('neg_fil')")
class NegFil(Glue):
def __init__(self):
Glue.__init__(self, 'neg_fil')
@cbook.deprecated("3.3", alternative="Glue('neg_fill')")
class NegFill(Glue):
def __init__(self):
Glue.__init__(self, 'neg_fill')
@cbook.deprecated("3.3", alternative="Glue('neg_filll')")
class NegFilll(Glue):
def __init__(self):
Glue.__init__(self, 'neg_filll')
@cbook.deprecated("3.3", alternative="Glue('ss')")
class SsGlue(Glue):
def __init__(self):
Glue.__init__(self, 'ss')
class HCentered(Hlist):
"""
A convenience class to create an `Hlist` whose contents are
centered within its enclosing box.
"""
def __init__(self, elements):
super().__init__([Glue('ss'), *elements, Glue('ss')], do_kern=False)
class VCentered(Vlist):
"""
A convenience class to create a `Vlist` whose contents are
centered within its enclosing box.
"""
def __init__(self, elements):
super().__init__([Glue('ss'), *elements, Glue('ss')])
class Kern(Node):
"""
A `Kern` node has a width field to specify a (normally
negative) amount of spacing. This spacing correction appears in
horizontal lists between letters like A and V when the font
designer said that it looks better to move them closer together or
further apart. A kern node can also appear in a vertical list,
when its *width* denotes additional spacing in the vertical
direction.
"""
height = 0
depth = 0
def __init__(self, width):
Node.__init__(self)
self.width = width
def __repr__(self):
return "k%.02f" % self.width
def shrink(self):
Node.shrink(self)
if self.size < NUM_SIZE_LEVELS:
self.width *= SHRINK_FACTOR
def grow(self):
Node.grow(self)
self.width *= GROW_FACTOR
class SubSuperCluster(Hlist):
"""
A hack to get around that fact that this code does a two-pass parse like
TeX. This lets us store enough information in the hlist itself, namely the
nucleus, sub- and super-script, such that if another script follows that
needs to be attached, it can be reconfigured on the fly.
"""
def __init__(self):
self.nucleus = None
self.sub = None
self.super = None
Hlist.__init__(self, [])
class AutoHeightChar(Hlist):
"""
A character as close to the given height and depth as possible.
When using a font with multiple height versions of some characters (such as
the BaKoMa fonts), the correct glyph will be selected, otherwise this will
always just return a scaled version of the glyph.
"""
def __init__(self, c, height, depth, state, always=False, factor=None):
alternatives = state.font_output.get_sized_alternatives_for_symbol(
state.font, c)
xHeight = state.font_output.get_xheight(
state.font, state.fontsize, state.dpi)
state = state.copy()
target_total = height + depth
for fontname, sym in alternatives:
state.font = fontname
char = Char(sym, state)
# Ensure that size 0 is chosen when the text is regular sized but
# with descender glyphs by subtracting 0.2 * xHeight
if char.height + char.depth >= target_total - 0.2 * xHeight:
break
shift = 0
if state.font != 0:
if factor is None:
factor = target_total / (char.height + char.depth)
state.fontsize *= factor
char = Char(sym, state)
shift = (depth - char.depth)
Hlist.__init__(self, [char])
self.shift_amount = shift
class AutoWidthChar(Hlist):
"""
A character as close to the given width as possible.
When using a font with multiple width versions of some characters (such as
the BaKoMa fonts), the correct glyph will be selected, otherwise this will
always just return a scaled version of the glyph.
"""
def __init__(self, c, width, state, always=False, char_class=Char):
alternatives = state.font_output.get_sized_alternatives_for_symbol(
state.font, c)
state = state.copy()
for fontname, sym in alternatives:
state.font = fontname
char = char_class(sym, state)
if char.width >= width:
break
factor = width / char.width
state.fontsize *= factor
char = char_class(sym, state)
Hlist.__init__(self, [char])
self.width = char.width
class Ship:
"""
Ship boxes to output once they have been set up, this sends them to output.
Since boxes can be inside of boxes inside of boxes, the main work of `Ship`
is done by two mutually recursive routines, `hlist_out` and `vlist_out`,
which traverse the `Hlist` nodes and `Vlist` nodes inside of horizontal
and vertical boxes. The global variables used in TeX to store state as it
processes have become member variables here.
"""
def __call__(self, ox, oy, box):
self.max_push = 0 # Deepest nesting of push commands so far
self.cur_s = 0
self.cur_v = 0.
self.cur_h = 0.
self.off_h = ox
self.off_v = oy + box.height
self.hlist_out(box)
@staticmethod
def clamp(value):
if value < -1000000000.:
return -1000000000.
if value > 1000000000.:
return 1000000000.
return value
def hlist_out(self, box):
cur_g = 0
cur_glue = 0.
glue_order = box.glue_order
glue_sign = box.glue_sign
base_line = self.cur_v
left_edge = self.cur_h
self.cur_s += 1
self.max_push = max(self.cur_s, self.max_push)
clamp = self.clamp
for p in box.children:
if isinstance(p, Char):
p.render(self.cur_h + self.off_h, self.cur_v + self.off_v)
self.cur_h += p.width
elif isinstance(p, Kern):
self.cur_h += p.width
elif isinstance(p, List):
# node623
if len(p.children) == 0:
self.cur_h += p.width
else:
edge = self.cur_h
self.cur_v = base_line + p.shift_amount
if isinstance(p, Hlist):
self.hlist_out(p)
else:
# p.vpack(box.height + box.depth, 'exactly')
self.vlist_out(p)
self.cur_h = edge + p.width
self.cur_v = base_line
elif isinstance(p, Box):
# node624
rule_height = p.height
rule_depth = p.depth
rule_width = p.width
if np.isinf(rule_height):
rule_height = box.height
if np.isinf(rule_depth):
rule_depth = box.depth
if rule_height > 0 and rule_width > 0:
self.cur_v = base_line + rule_depth
p.render(self.cur_h + self.off_h,
self.cur_v + self.off_v,
rule_width, rule_height)
self.cur_v = base_line
self.cur_h += rule_width
elif isinstance(p, Glue):
# node625
glue_spec = p.glue_spec
rule_width = glue_spec.width - cur_g
if glue_sign != 0: # normal
if glue_sign == 1: # stretching
if glue_spec.stretch_order == glue_order:
cur_glue += glue_spec.stretch
cur_g = round(clamp(box.glue_set * cur_glue))
elif glue_spec.shrink_order == glue_order:
cur_glue += glue_spec.shrink
cur_g = round(clamp(box.glue_set * cur_glue))
rule_width += cur_g
self.cur_h += rule_width
self.cur_s -= 1
def vlist_out(self, box):
cur_g = 0
cur_glue = 0.
glue_order = box.glue_order
glue_sign = box.glue_sign
self.cur_s += 1
self.max_push = max(self.max_push, self.cur_s)
left_edge = self.cur_h
self.cur_v -= box.height
top_edge = self.cur_v
clamp = self.clamp
for p in box.children:
if isinstance(p, Kern):
self.cur_v += p.width
elif isinstance(p, List):
if len(p.children) == 0:
self.cur_v += p.height + p.depth
else:
self.cur_v += p.height
self.cur_h = left_edge + p.shift_amount
save_v = self.cur_v
p.width = box.width
if isinstance(p, Hlist):
self.hlist_out(p)
else:
self.vlist_out(p)
self.cur_v = save_v + p.depth
self.cur_h = left_edge
elif isinstance(p, Box):
rule_height = p.height
rule_depth = p.depth
rule_width = p.width
if np.isinf(rule_width):
rule_width = box.width
rule_height += rule_depth
if rule_height > 0 and rule_depth > 0:
self.cur_v += rule_height
p.render(self.cur_h + self.off_h,
self.cur_v + self.off_v,
rule_width, rule_height)
elif isinstance(p, Glue):
glue_spec = p.glue_spec
rule_height = glue_spec.width - cur_g
if glue_sign != 0: # normal
if glue_sign == 1: # stretching
if glue_spec.stretch_order == glue_order:
cur_glue += glue_spec.stretch
cur_g = round(clamp(box.glue_set * cur_glue))
elif glue_spec.shrink_order == glue_order: # shrinking
cur_glue += glue_spec.shrink
cur_g = round(clamp(box.glue_set * cur_glue))
rule_height += cur_g
self.cur_v += rule_height
elif isinstance(p, Char):
raise RuntimeError(
"Internal mathtext error: Char node found in vlist")
self.cur_s -= 1
ship = Ship()
##############################################################################
# PARSER
def Error(msg):
"""Helper class to raise parser errors."""
def raise_error(s, loc, toks):
raise ParseFatalException(s, loc, msg)
empty = Empty()
empty.setParseAction(raise_error)
return empty
class Parser:
"""
A pyparsing-based parser for strings containing math expressions.
Raw text may also appear outside of pairs of ``$``.
The grammar is based directly on that in TeX, though it cuts a few corners.
"""
_math_style_dict = dict(displaystyle=0, textstyle=1,
scriptstyle=2, scriptscriptstyle=3)
_binary_operators = set('''
+ * -
\\pm \\sqcap \\rhd
\\mp \\sqcup \\unlhd
\\times \\vee \\unrhd
\\div \\wedge \\oplus
\\ast \\setminus \\ominus
\\star \\wr \\otimes
\\circ \\diamond \\oslash
\\bullet \\bigtriangleup \\odot
\\cdot \\bigtriangledown \\bigcirc
\\cap \\triangleleft \\dagger
\\cup \\triangleright \\ddagger
\\uplus \\lhd \\amalg'''.split())
_relation_symbols = set('''
= < > :
\\leq \\geq \\equiv \\models
\\prec \\succ \\sim \\perp
\\preceq \\succeq \\simeq \\mid
\\ll \\gg \\asymp \\parallel
\\subset \\supset \\approx \\bowtie
\\subseteq \\supseteq \\cong \\Join
\\sqsubset \\sqsupset \\neq \\smile
\\sqsubseteq \\sqsupseteq \\doteq \\frown
\\in \\ni \\propto \\vdash
\\dashv \\dots \\dotplus \\doteqdot'''.split())
_arrow_symbols = set('''
\\leftarrow \\longleftarrow \\uparrow
\\Leftarrow \\Longleftarrow \\Uparrow
\\rightarrow \\longrightarrow \\downarrow
\\Rightarrow \\Longrightarrow \\Downarrow
\\leftrightarrow \\longleftrightarrow \\updownarrow
\\Leftrightarrow \\Longleftrightarrow \\Updownarrow
\\mapsto \\longmapsto \\nearrow
\\hookleftarrow \\hookrightarrow \\searrow
\\leftharpoonup \\rightharpoonup \\swarrow
\\leftharpoondown \\rightharpoondown \\nwarrow
\\rightleftharpoons \\leadsto'''.split())
_spaced_symbols = _binary_operators | _relation_symbols | _arrow_symbols
_punctuation_symbols = set(r', ; . ! \ldotp \cdotp'.split())
_overunder_symbols = set(r'''
\sum \prod \coprod \bigcap \bigcup \bigsqcup \bigvee
\bigwedge \bigodot \bigotimes \bigoplus \biguplus
'''.split())
_overunder_functions = set(
"lim liminf limsup sup max min".split())
_dropsub_symbols = set(r'''\int \oint'''.split())
_fontnames = set("rm cal it tt sf bf default bb frak scr regular".split())
_function_names = set("""
arccos csc ker min arcsin deg lg Pr arctan det lim sec arg dim
liminf sin cos exp limsup sinh cosh gcd ln sup cot hom log tan
coth inf max tanh""".split())
_ambi_delim = set("""
| \\| / \\backslash \\uparrow \\downarrow \\updownarrow \\Uparrow
\\Downarrow \\Updownarrow . \\vert \\Vert \\\\|""".split())
_left_delim = set(r"( [ \{ < \lfloor \langle \lceil".split())
_right_delim = set(r") ] \} > \rfloor \rangle \rceil".split())
def __init__(self):
p = types.SimpleNamespace()
# All forward declarations are here
p.accent = Forward()
p.ambi_delim = Forward()
p.apostrophe = Forward()
p.auto_delim = Forward()
p.binom = Forward()
p.bslash = Forward()
p.c_over_c = Forward()
p.customspace = Forward()
p.end_group = Forward()
p.float_literal = Forward()
p.font = Forward()
p.frac = Forward()
p.dfrac = Forward()
p.function = Forward()
p.genfrac = Forward()
p.group = Forward()
p.int_literal = Forward()
p.latexfont = Forward()
p.lbracket = Forward()
p.left_delim = Forward()
p.lbrace = Forward()
p.main = Forward()
p.math = Forward()
p.math_string = Forward()
p.non_math = Forward()
p.operatorname = Forward()
p.overline = Forward()
p.placeable = Forward()
p.rbrace = Forward()
p.rbracket = Forward()
p.required_group = Forward()
p.right_delim = Forward()
p.right_delim_safe = Forward()
p.simple = Forward()
p.simple_group = Forward()
p.single_symbol = Forward()
p.accentprefixed = Forward()
p.space = Forward()
p.sqrt = Forward()
p.start_group = Forward()
p.subsuper = Forward()
p.subsuperop = Forward()
p.symbol = Forward()
p.symbol_name = Forward()
p.token = Forward()
p.unknown_symbol = Forward()
# Set names on everything -- very useful for debugging
for key, val in vars(p).items():
if not key.startswith('_'):
val.setName(key)
p.float_literal <<= Regex(r"[-+]?([0-9]+\.?[0-9]*|\.[0-9]+)")
p.int_literal <<= Regex("[-+]?[0-9]+")
p.lbrace <<= Literal('{').suppress()
p.rbrace <<= Literal('}').suppress()
p.lbracket <<= Literal('[').suppress()
p.rbracket <<= Literal(']').suppress()
p.bslash <<= Literal('\\')
p.space <<= oneOf(list(self._space_widths))
p.customspace <<= (
Suppress(Literal(r'\hspace'))
- ((p.lbrace + p.float_literal + p.rbrace)
| Error(r"Expected \hspace{n}"))
)
unicode_range = "\U00000080-\U0001ffff"
p.single_symbol <<= Regex(
r"([a-zA-Z0-9 +\-*/<>=:,.;!\?&'@()\[\]|%s])|(\\[%%${}\[\]_|])" %
unicode_range)
p.accentprefixed <<= Suppress(p.bslash) + oneOf(self._accentprefixed)
p.symbol_name <<= (
Combine(p.bslash + oneOf(list(tex2uni)))
+ FollowedBy(Regex("[^A-Za-z]").leaveWhitespace() | StringEnd())
)
p.symbol <<= (p.single_symbol | p.symbol_name).leaveWhitespace()
p.apostrophe <<= Regex("'+")
p.c_over_c <<= (
Suppress(p.bslash)
+ oneOf(list(self._char_over_chars))
)
p.accent <<= Group(
Suppress(p.bslash)
+ oneOf([*self._accent_map, *self._wide_accents])
- p.placeable
)
p.function <<= (
Suppress(p.bslash)
+ oneOf(list(self._function_names))
)
p.start_group <<= Optional(p.latexfont) + p.lbrace
p.end_group <<= p.rbrace.copy()
p.simple_group <<= Group(p.lbrace + ZeroOrMore(p.token) + p.rbrace)
p.required_group <<= Group(p.lbrace + OneOrMore(p.token) + p.rbrace)
p.group <<= Group(
p.start_group + ZeroOrMore(p.token) + p.end_group
)
p.font <<= Suppress(p.bslash) + oneOf(list(self._fontnames))
p.latexfont <<= (
Suppress(p.bslash)
+ oneOf(['math' + x for x in self._fontnames])
)
p.frac <<= Group(
Suppress(Literal(r"\frac"))
- ((p.required_group + p.required_group)
| Error(r"Expected \frac{num}{den}"))
)
p.dfrac <<= Group(
Suppress(Literal(r"\dfrac"))
- ((p.required_group + p.required_group)
| Error(r"Expected \dfrac{num}{den}"))
)
p.binom <<= Group(
Suppress(Literal(r"\binom"))
- ((p.required_group + p.required_group)
| Error(r"Expected \binom{num}{den}"))
)
p.ambi_delim <<= oneOf(list(self._ambi_delim))
p.left_delim <<= oneOf(list(self._left_delim))
p.right_delim <<= oneOf(list(self._right_delim))
p.right_delim_safe <<= oneOf([*(self._right_delim - {'}'}), r'\}'])
p.genfrac <<= Group(
Suppress(Literal(r"\genfrac"))
- (((p.lbrace
+ Optional(p.ambi_delim | p.left_delim, default='')
+ p.rbrace)
+ (p.lbrace
+ Optional(p.ambi_delim | p.right_delim_safe, default='')
+ p.rbrace)
+ (p.lbrace + p.float_literal + p.rbrace)
+ p.simple_group + p.required_group + p.required_group)
| Error("Expected "
r"\genfrac{ldelim}{rdelim}{rulesize}{style}{num}{den}"))
)
p.sqrt <<= Group(
Suppress(Literal(r"\sqrt"))
- ((Optional(p.lbracket + p.int_literal + p.rbracket, default=None)
+ p.required_group)
| Error("Expected \\sqrt{value}"))
)
p.overline <<= Group(
Suppress(Literal(r"\overline"))
- (p.required_group | Error("Expected \\overline{value}"))
)
p.unknown_symbol <<= Combine(p.bslash + Regex("[A-Za-z]*"))
p.operatorname <<= Group(
Suppress(Literal(r"\operatorname"))
- ((p.lbrace + ZeroOrMore(p.simple | p.unknown_symbol) + p.rbrace)
| Error("Expected \\operatorname{value}"))
)
p.placeable <<= (
p.accentprefixed # Must be before accent so named symbols that are
# prefixed with an accent name work
| p.accent # Must be before symbol as all accents are symbols
| p.symbol # Must be third to catch all named symbols and single
# chars not in a group
| p.c_over_c
| p.function
| p.group
| p.frac
| p.dfrac
| p.binom
| p.genfrac
| p.sqrt
| p.overline
| p.operatorname
)
p.simple <<= (
p.space
| p.customspace
| p.font
| p.subsuper
)
p.subsuperop <<= oneOf(["_", "^"])
p.subsuper <<= Group(
(Optional(p.placeable)
+ OneOrMore(p.subsuperop - p.placeable)
+ Optional(p.apostrophe))
| (p.placeable + Optional(p.apostrophe))
| p.apostrophe
)
p.token <<= (
p.simple
| p.auto_delim
| p.unknown_symbol # Must be last
)
p.auto_delim <<= (
Suppress(Literal(r"\left"))
- ((p.left_delim | p.ambi_delim)
| Error("Expected a delimiter"))
+ Group(ZeroOrMore(p.simple | p.auto_delim))
+ Suppress(Literal(r"\right"))
- ((p.right_delim | p.ambi_delim)
| Error("Expected a delimiter"))
)
p.math <<= OneOrMore(p.token)
p.math_string <<= QuotedString('$', '\\', unquoteResults=False)
p.non_math <<= Regex(r"(?:(?:\\[$])|[^$])*").leaveWhitespace()
p.main <<= (
p.non_math + ZeroOrMore(p.math_string + p.non_math) + StringEnd()
)
# Set actions
for key, val in vars(p).items():
if not key.startswith('_'):
if hasattr(self, key):
val.setParseAction(getattr(self, key))
self._expression = p.main
self._math_expression = p.math
def parse(self, s, fonts_object, fontsize, dpi):
"""
Parse expression *s* using the given *fonts_object* for
output, at the given *fontsize* and *dpi*.
Returns the parse tree of `Node` instances.
"""
self._state_stack = [
self.State(fonts_object, 'default', 'rm', fontsize, dpi)]
self._em_width_cache = {}
try:
result = self._expression.parseString(s)
except ParseBaseException as err:
raise ValueError("\n".join(["",
err.line,
" " * (err.column - 1) + "^",
str(err)])) from err
self._state_stack = None
self._em_width_cache = {}
self._expression.resetCache()
return result[0]
# The state of the parser is maintained in a stack. Upon
# entering and leaving a group { } or math/non-math, the stack
# is pushed and popped accordingly. The current state always
# exists in the top element of the stack.
class State:
"""
Stores the state of the parser.
States are pushed and popped from a stack as necessary, and
the "current" state is always at the top of the stack.
"""
def __init__(self, font_output, font, font_class, fontsize, dpi):
self.font_output = font_output
self._font = font
self.font_class = font_class
self.fontsize = fontsize
self.dpi = dpi
def copy(self):
return Parser.State(
self.font_output,
self.font,
self.font_class,
self.fontsize,
self.dpi)
@property
def font(self):
return self._font
@font.setter
def font(self, name):
if name in ('rm', 'it', 'bf'):
self.font_class = name
self._font = name
def get_state(self):
"""Get the current `State` of the parser."""
return self._state_stack[-1]
def pop_state(self):
"""Pop a `State` off of the stack."""
self._state_stack.pop()
def push_state(self):
"""Push a new `State` onto the stack, copying the current state."""
self._state_stack.append(self.get_state().copy())
def main(self, s, loc, toks):
return [Hlist(toks)]
def math_string(self, s, loc, toks):
return self._math_expression.parseString(toks[0][1:-1])
def math(self, s, loc, toks):
hlist = Hlist(toks)
self.pop_state()
return [hlist]
def non_math(self, s, loc, toks):
s = toks[0].replace(r'\$', '$')
symbols = [Char(c, self.get_state(), math=False) for c in s]
hlist = Hlist(symbols)
# We're going into math now, so set font to 'it'
self.push_state()
self.get_state().font = rcParams['mathtext.default']
return [hlist]
def _make_space(self, percentage):
# All spaces are relative to em width
state = self.get_state()
key = (state.font, state.fontsize, state.dpi)
width = self._em_width_cache.get(key)
if width is None:
metrics = state.font_output.get_metrics(
state.font, rcParams['mathtext.default'], 'm', state.fontsize,
state.dpi)
width = metrics.advance
self._em_width_cache[key] = width
return Kern(width * percentage)
_space_widths = {
r'\,': 0.16667, # 3/18 em = 3 mu
r'\thinspace': 0.16667, # 3/18 em = 3 mu
r'\/': 0.16667, # 3/18 em = 3 mu
r'\>': 0.22222, # 4/18 em = 4 mu
r'\:': 0.22222, # 4/18 em = 4 mu
r'\;': 0.27778, # 5/18 em = 5 mu
r'\ ': 0.33333, # 6/18 em = 6 mu
r'~': 0.33333, # 6/18 em = 6 mu, nonbreakable
r'\enspace': 0.5, # 9/18 em = 9 mu
r'\quad': 1, # 1 em = 18 mu
r'\qquad': 2, # 2 em = 36 mu
r'\!': -0.16667, # -3/18 em = -3 mu
}
def space(self, s, loc, toks):
assert len(toks) == 1
num = self._space_widths[toks[0]]
box = self._make_space(num)
return [box]
def customspace(self, s, loc, toks):
return [self._make_space(float(toks[0]))]
def symbol(self, s, loc, toks):
c = toks[0]
try:
char = Char(c, self.get_state())
except ValueError as err:
raise ParseFatalException(s, loc,
"Unknown symbol: %s" % c) from err
if c in self._spaced_symbols:
# iterate until we find previous character, needed for cases
# such as ${ -2}$, $ -2$, or $ -2$.
prev_char = next((c for c in s[:loc][::-1] if c != ' '), '')
# Binary operators at start of string should not be spaced
if (c in self._binary_operators and
(len(s[:loc].split()) == 0 or prev_char == '{' or
prev_char in self._left_delim)):
return [char]
else:
return [Hlist([self._make_space(0.2),
char,
self._make_space(0.2)],
do_kern=True)]
elif c in self._punctuation_symbols:
# Do not space commas between brackets
if c == ',':
prev_char = next((c for c in s[:loc][::-1] if c != ' '), '')
next_char = next((c for c in s[loc + 1:] if c != ' '), '')
if prev_char == '{' and next_char == '}':
return [char]
# Do not space dots as decimal separators
if c == '.' and s[loc - 1].isdigit() and s[loc + 1].isdigit():
return [char]
else:
return [Hlist([char, self._make_space(0.2)], do_kern=True)]
return [char]
accentprefixed = symbol
def unknown_symbol(self, s, loc, toks):
c = toks[0]
raise ParseFatalException(s, loc, "Unknown symbol: %s" % c)
_char_over_chars = {
# The first 2 entries in the tuple are (font, char, sizescale) for
# the two symbols under and over. The third element is the space
# (in multiples of underline height)
r'AA': (('it', 'A', 1.0), (None, '\\circ', 0.5), 0.0),
}
def c_over_c(self, s, loc, toks):
sym = toks[0]
state = self.get_state()
thickness = state.font_output.get_underline_thickness(
state.font, state.fontsize, state.dpi)
under_desc, over_desc, space = \
self._char_over_chars.get(sym, (None, None, 0.0))
if under_desc is None:
raise ParseFatalException("Error parsing symbol")
over_state = state.copy()
if over_desc[0] is not None:
over_state.font = over_desc[0]
over_state.fontsize *= over_desc[2]
over = Accent(over_desc[1], over_state)
under_state = state.copy()
if under_desc[0] is not None:
under_state.font = under_desc[0]
under_state.fontsize *= under_desc[2]
under = Char(under_desc[1], under_state)
width = max(over.width, under.width)
over_centered = HCentered([over])
over_centered.hpack(width, 'exactly')
under_centered = HCentered([under])
under_centered.hpack(width, 'exactly')
return Vlist([
over_centered,
Vbox(0., thickness * space),
under_centered
])
_accent_map = {
r'hat': r'\circumflexaccent',
r'breve': r'\combiningbreve',
r'bar': r'\combiningoverline',
r'grave': r'\combininggraveaccent',
r'acute': r'\combiningacuteaccent',
r'tilde': r'\combiningtilde',
r'dot': r'\combiningdotabove',
r'ddot': r'\combiningdiaeresis',
r'vec': r'\combiningrightarrowabove',
r'"': r'\combiningdiaeresis',
r"`": r'\combininggraveaccent',
r"'": r'\combiningacuteaccent',
r'~': r'\combiningtilde',
r'.': r'\combiningdotabove',
r'^': r'\circumflexaccent',
r'overrightarrow': r'\rightarrow',
r'overleftarrow': r'\leftarrow',
r'mathring': r'\circ',
}
_wide_accents = set(r"widehat widetilde widebar".split())
# make a lambda and call it to get the namespace right
_accentprefixed = (lambda am: [
p for p in tex2uni
if any(p.startswith(a) and a != p for a in am)
])(set(_accent_map))
def accent(self, s, loc, toks):
assert len(toks) == 1
state = self.get_state()
thickness = state.font_output.get_underline_thickness(
state.font, state.fontsize, state.dpi)
if len(toks[0]) != 2:
raise ParseFatalException("Error parsing accent")
accent, sym = toks[0]
if accent in self._wide_accents:
accent_box = AutoWidthChar(
'\\' + accent, sym.width, state, char_class=Accent)
else:
accent_box = Accent(self._accent_map[accent], state)
if accent == 'mathring':
accent_box.shrink()
accent_box.shrink()
centered = HCentered([Hbox(sym.width / 4.0), accent_box])
centered.hpack(sym.width, 'exactly')
return Vlist([
centered,
Vbox(0., thickness * 2.0),
Hlist([sym])
])
def function(self, s, loc, toks):
self.push_state()
state = self.get_state()
state.font = 'rm'
hlist = Hlist([Char(c, state) for c in toks[0]])
self.pop_state()
hlist.function_name = toks[0]
return hlist
def operatorname(self, s, loc, toks):
self.push_state()
state = self.get_state()
state.font = 'rm'
# Change the font of Chars, but leave Kerns alone
for c in toks[0]:
if isinstance(c, Char):
c.font = 'rm'
c._update_metrics()
self.pop_state()
return Hlist(toks[0])
def start_group(self, s, loc, toks):
self.push_state()
# Deal with LaTeX-style font tokens
if len(toks):
self.get_state().font = toks[0][4:]
return []
def group(self, s, loc, toks):
grp = Hlist(toks[0])
return [grp]
required_group = simple_group = group
def end_group(self, s, loc, toks):
self.pop_state()
return []
def font(self, s, loc, toks):
assert len(toks) == 1
name = toks[0]
self.get_state().font = name
return []
def is_overunder(self, nucleus):
if isinstance(nucleus, Char):
return nucleus.c in self._overunder_symbols
elif isinstance(nucleus, Hlist) and hasattr(nucleus, 'function_name'):
return nucleus.function_name in self._overunder_functions
return False
def is_dropsub(self, nucleus):
if isinstance(nucleus, Char):
return nucleus.c in self._dropsub_symbols
return False
def is_slanted(self, nucleus):
if isinstance(nucleus, Char):
return nucleus.is_slanted()
return False
def is_between_brackets(self, s, loc):
return False
def subsuper(self, s, loc, toks):
assert len(toks) == 1
nucleus = None
sub = None
super = None
# Pick all of the apostrophes out, including first apostrophes that
# have been parsed as characters
napostrophes = 0
new_toks = []
for tok in toks[0]:
if isinstance(tok, str) and tok not in ('^', '_'):
napostrophes += len(tok)
elif isinstance(tok, Char) and tok.c == "'":
napostrophes += 1
else:
new_toks.append(tok)
toks = new_toks
if len(toks) == 0:
assert napostrophes
nucleus = Hbox(0.0)
elif len(toks) == 1:
if not napostrophes:
return toks[0] # .asList()
else:
nucleus = toks[0]
elif len(toks) in (2, 3):
# single subscript or superscript
nucleus = toks[0] if len(toks) == 3 else Hbox(0.0)
op, next = toks[-2:]
if op == '_':
sub = next
else:
super = next
elif len(toks) in (4, 5):
# subscript and superscript
nucleus = toks[0] if len(toks) == 5 else Hbox(0.0)
op1, next1, op2, next2 = toks[-4:]
if op1 == op2:
if op1 == '_':
raise ParseFatalException("Double subscript")
else:
raise ParseFatalException("Double superscript")
if op1 == '_':
sub = next1
super = next2
else:
super = next1
sub = next2
else:
raise ParseFatalException(
"Subscript/superscript sequence is too long. "
"Use braces { } to remove ambiguity.")
state = self.get_state()
rule_thickness = state.font_output.get_underline_thickness(
state.font, state.fontsize, state.dpi)
xHeight = state.font_output.get_xheight(
state.font, state.fontsize, state.dpi)
if napostrophes:
if super is None:
super = Hlist([])
for i in range(napostrophes):
super.children.extend(self.symbol(s, loc, ['\\prime']))
# kern() and hpack() needed to get the metrics right after
# extending
super.kern()
super.hpack()
# Handle over/under symbols, such as sum or integral
if self.is_overunder(nucleus):
vlist = []
shift = 0.
width = nucleus.width
if super is not None:
super.shrink()
width = max(width, super.width)
if sub is not None:
sub.shrink()
width = max(width, sub.width)
if super is not None:
hlist = HCentered([super])
hlist.hpack(width, 'exactly')
vlist.extend([hlist, Kern(rule_thickness * 3.0)])
hlist = HCentered([nucleus])
hlist.hpack(width, 'exactly')
vlist.append(hlist)
if sub is not None:
hlist = HCentered([sub])
hlist.hpack(width, 'exactly')
vlist.extend([Kern(rule_thickness * 3.0), hlist])
shift = hlist.height
vlist = Vlist(vlist)
vlist.shift_amount = shift + nucleus.depth
result = Hlist([vlist])
return [result]
# We remove kerning on the last character for consistency (otherwise
# it will compute kerning based on non-shrunk characters and may put
# them too close together when superscripted)
# We change the width of the last character to match the advance to
# consider some fonts with weird metrics: e.g. stix's f has a width of
# 7.75 and a kerning of -4.0 for an advance of 3.72, and we want to put
# the superscript at the advance
last_char = nucleus
if isinstance(nucleus, Hlist):
new_children = nucleus.children
if len(new_children):
# remove last kern
if (isinstance(new_children[-1], Kern) and
hasattr(new_children[-2], '_metrics')):
new_children = new_children[:-1]
last_char = new_children[-1]
if hasattr(last_char, '_metrics'):
last_char.width = last_char._metrics.advance
# create new Hlist without kerning
nucleus = Hlist(new_children, do_kern=False)
else:
if isinstance(nucleus, Char):
last_char.width = last_char._metrics.advance
nucleus = Hlist([nucleus])
# Handle regular sub/superscripts
constants = _get_font_constant_set(state)
lc_height = last_char.height
lc_baseline = 0
if self.is_dropsub(last_char):
lc_baseline = last_char.depth
# Compute kerning for sub and super
superkern = constants.delta * xHeight
subkern = constants.delta * xHeight
if self.is_slanted(last_char):
superkern += constants.delta * xHeight
superkern += (constants.delta_slanted *
(lc_height - xHeight * 2. / 3.))
if self.is_dropsub(last_char):
subkern = (3 * constants.delta -
constants.delta_integral) * lc_height
superkern = (3 * constants.delta +
constants.delta_integral) * lc_height
else:
subkern = 0
if super is None:
# node757
x = Hlist([Kern(subkern), sub])
x.shrink()
if self.is_dropsub(last_char):
shift_down = lc_baseline + constants.subdrop * xHeight
else:
shift_down = constants.sub1 * xHeight
x.shift_amount = shift_down
else:
x = Hlist([Kern(superkern), super])
x.shrink()
if self.is_dropsub(last_char):
shift_up = lc_height - constants.subdrop * xHeight
else:
shift_up = constants.sup1 * xHeight
if sub is None:
x.shift_amount = -shift_up
else: # Both sub and superscript
y = Hlist([Kern(subkern), sub])
y.shrink()
if self.is_dropsub(last_char):
shift_down = lc_baseline + constants.subdrop * xHeight
else:
shift_down = constants.sub2 * xHeight
# If sub and superscript collide, move super up
clr = (2.0 * rule_thickness -
((shift_up - x.depth) - (y.height - shift_down)))
if clr > 0.:
shift_up += clr
x = Vlist([
x,
Kern((shift_up - x.depth) - (y.height - shift_down)),
y])
x.shift_amount = shift_down
if not self.is_dropsub(last_char):
x.width += constants.script_space * xHeight
result = Hlist([nucleus, x])
return [result]
def _genfrac(self, ldelim, rdelim, rule, style, num, den):
state = self.get_state()
thickness = state.font_output.get_underline_thickness(
state.font, state.fontsize, state.dpi)
rule = float(rule)
# If style != displaystyle == 0, shrink the num and den
if style != self._math_style_dict['displaystyle']:
num.shrink()
den.shrink()
cnum = HCentered([num])
cden = HCentered([den])
width = max(num.width, den.width)
cnum.hpack(width, 'exactly')
cden.hpack(width, 'exactly')
vlist = Vlist([cnum, # numerator
Vbox(0, thickness * 2.0), # space
Hrule(state, rule), # rule
Vbox(0, thickness * 2.0), # space
cden # denominator
])
# Shift so the fraction line sits in the middle of the
# equals sign
metrics = state.font_output.get_metrics(
state.font, rcParams['mathtext.default'],
'=', state.fontsize, state.dpi)
shift = (cden.height -
((metrics.ymax + metrics.ymin) / 2 -
thickness * 3.0))
vlist.shift_amount = shift
result = [Hlist([vlist, Hbox(thickness * 2.)])]
if ldelim or rdelim:
if ldelim == '':
ldelim = '.'
if rdelim == '':
rdelim = '.'
return self._auto_sized_delimiter(ldelim, result, rdelim)
return result
def genfrac(self, s, loc, toks):
assert len(toks) == 1
assert len(toks[0]) == 6
return self._genfrac(*tuple(toks[0]))
def frac(self, s, loc, toks):
assert len(toks) == 1
assert len(toks[0]) == 2
state = self.get_state()
thickness = state.font_output.get_underline_thickness(
state.font, state.fontsize, state.dpi)
num, den = toks[0]
return self._genfrac('', '', thickness,
self._math_style_dict['textstyle'], num, den)
def dfrac(self, s, loc, toks):
assert len(toks) == 1
assert len(toks[0]) == 2
state = self.get_state()
thickness = state.font_output.get_underline_thickness(
state.font, state.fontsize, state.dpi)
num, den = toks[0]
return self._genfrac('', '', thickness,
self._math_style_dict['displaystyle'], num, den)
def binom(self, s, loc, toks):
assert len(toks) == 1
assert len(toks[0]) == 2
num, den = toks[0]
return self._genfrac('(', ')', 0.0,
self._math_style_dict['textstyle'], num, den)
def sqrt(self, s, loc, toks):
root, body = toks[0]
state = self.get_state()
thickness = state.font_output.get_underline_thickness(
state.font, state.fontsize, state.dpi)
# Determine the height of the body, and add a little extra to
# the height so it doesn't seem cramped
height = body.height - body.shift_amount + thickness * 5.0
depth = body.depth + body.shift_amount
check = AutoHeightChar(r'\__sqrt__', height, depth, state, always=True)
height = check.height - check.shift_amount
depth = check.depth + check.shift_amount
# Put a little extra space to the left and right of the body
padded_body = Hlist([Hbox(2 * thickness), body, Hbox(2 * thickness)])
rightside = Vlist([Hrule(state), Glue('fill'), padded_body])
# Stretch the glue between the hrule and the body
rightside.vpack(height + (state.fontsize * state.dpi) / (100.0 * 12.0),
'exactly', depth)
# Add the root and shift it upward so it is above the tick.
# The value of 0.6 is a hard-coded hack ;)
if root is None:
root = Box(check.width * 0.5, 0., 0.)
else:
root = Hlist([Char(x, state) for x in root])
root.shrink()
root.shrink()
root_vlist = Vlist([Hlist([root])])
root_vlist.shift_amount = -height * 0.6
hlist = Hlist([root_vlist, # Root
# Negative kerning to put root over tick
Kern(-check.width * 0.5),
check, # Check
rightside]) # Body
return [hlist]
def overline(self, s, loc, toks):
assert len(toks) == 1
assert len(toks[0]) == 1
body = toks[0][0]
state = self.get_state()
thickness = state.font_output.get_underline_thickness(
state.font, state.fontsize, state.dpi)
height = body.height - body.shift_amount + thickness * 3.0
depth = body.depth + body.shift_amount
# Place overline above body
rightside = Vlist([Hrule(state), Glue('fill'), Hlist([body])])
# Stretch the glue between the hrule and the body
rightside.vpack(height + (state.fontsize * state.dpi) / (100.0 * 12.0),
'exactly', depth)
hlist = Hlist([rightside])
return [hlist]
def _auto_sized_delimiter(self, front, middle, back):
state = self.get_state()
if len(middle):
height = max(x.height for x in middle)
depth = max(x.depth for x in middle)
factor = None
else:
height = 0
depth = 0
factor = 1.0
parts = []
# \left. and \right. aren't supposed to produce any symbols
if front != '.':
parts.append(
AutoHeightChar(front, height, depth, state, factor=factor))
parts.extend(middle)
if back != '.':
parts.append(
AutoHeightChar(back, height, depth, state, factor=factor))
hlist = Hlist(parts)
return hlist
def auto_delim(self, s, loc, toks):
front, middle, back = toks
return self._auto_sized_delimiter(front, middle.asList(), back)
##############################################################################
# MAIN
class MathTextParser:
_parser = None
_backend_mapping = {
'bitmap': MathtextBackendBitmap,
'agg': MathtextBackendAgg,
'ps': MathtextBackendPs,
'pdf': MathtextBackendPdf,
'svg': MathtextBackendSvg,
'path': MathtextBackendPath,
'cairo': MathtextBackendCairo,
'macosx': MathtextBackendAgg,
}
_font_type_mapping = {
'cm': BakomaFonts,
'dejavuserif': DejaVuSerifFonts,
'dejavusans': DejaVuSansFonts,
'stix': StixFonts,
'stixsans': StixSansFonts,
'custom': UnicodeFonts,
}
def __init__(self, output):
"""Create a MathTextParser for the given backend *output*."""
self._output = output.lower()
def parse(self, s, dpi=72, prop=None):
"""
Parse the given math expression *s* at the given *dpi*. If *prop* is
provided, it is a `.FontProperties` object specifying the "default"
font to use in the math expression, used for all non-math text.
The results are cached, so multiple calls to `parse`
with the same expression should be fast.
"""
# lru_cache can't decorate parse() directly because the ps.useafm and
# mathtext.fontset rcParams also affect the parse (e.g. by affecting
# the glyph metrics).
return self._parse_cached(
s, dpi, prop, rcParams['ps.useafm'], rcParams['mathtext.fontset'])
@functools.lru_cache(50)
def _parse_cached(self, s, dpi, prop, ps_useafm, fontset):
if prop is None:
prop = FontProperties()
if self._output == 'ps' and ps_useafm:
font_output = StandardPsFonts(prop)
else:
backend = self._backend_mapping[self._output]()
fontset_class = cbook._check_getitem(
self._font_type_mapping, fontset=fontset)
font_output = fontset_class(prop, backend)
fontsize = prop.get_size_in_points()
# This is a class variable so we don't rebuild the parser
# with each request.
if self._parser is None:
self.__class__._parser = Parser()
box = self._parser.parse(s, font_output, fontsize, dpi)
font_output.set_canvas_size(box.width, box.height, box.depth)
return font_output.get_results(box)
def to_mask(self, texstr, dpi=120, fontsize=14):
r"""
Parameters
----------
texstr : str
A valid mathtext string, e.g., r'IQ: $\sigma_i=15$'.
dpi : float
The dots-per-inch setting used to render the text.
fontsize : int
The font size in points
Returns
-------
array : 2D uint8 alpha
Mask array of rasterized tex.
depth : int
Offset of the baseline from the bottom of the image, in pixels.
"""
assert self._output == "bitmap"
prop = FontProperties(size=fontsize)
ftimage, depth = self.parse(texstr, dpi=dpi, prop=prop)
return np.asarray(ftimage), depth
def to_rgba(self, texstr, color='black', dpi=120, fontsize=14):
r"""
Parameters
----------
texstr : str
A valid mathtext string, e.g., r'IQ: $\sigma_i=15$'.
color : color
The text color.
dpi : float
The dots-per-inch setting used to render the text.
fontsize : int
The font size in points.
Returns
-------
array : (M, N, 4) array
RGBA color values of rasterized tex, colorized with *color*.
depth : int
Offset of the baseline from the bottom of the image, in pixels.
"""
x, depth = self.to_mask(texstr, dpi=dpi, fontsize=fontsize)
r, g, b, a = mcolors.to_rgba(color)
RGBA = np.zeros((x.shape[0], x.shape[1], 4), dtype=np.uint8)
RGBA[:, :, 0] = 255 * r
RGBA[:, :, 1] = 255 * g
RGBA[:, :, 2] = 255 * b
RGBA[:, :, 3] = x
return RGBA, depth
def to_png(self, filename, texstr, color='black', dpi=120, fontsize=14):
r"""
Render a tex expression to a PNG file.
Parameters
----------
filename
A writable filename or fileobject.
texstr : str
A valid mathtext string, e.g., r'IQ: $\sigma_i=15$'.
color : color
The text color.
dpi : float
The dots-per-inch setting used to render the text.
fontsize : int
The font size in points.
Returns
-------
int
Offset of the baseline from the bottom of the image, in pixels.
"""
rgba, depth = self.to_rgba(
texstr, color=color, dpi=dpi, fontsize=fontsize)
Image.fromarray(rgba).save(filename, format="png")
return depth
def get_depth(self, texstr, dpi=120, fontsize=14):
r"""
Parameters
----------
texstr : str
A valid mathtext string, e.g., r'IQ: $\sigma_i=15$'.
dpi : float
The dots-per-inch setting used to render the text.
Returns
-------
int
Offset of the baseline from the bottom of the image, in pixels.
"""
assert self._output == "bitmap"
prop = FontProperties(size=fontsize)
ftimage, depth = self.parse(texstr, dpi=dpi, prop=prop)
return depth
def math_to_image(s, filename_or_obj, prop=None, dpi=None, format=None):
"""
Given a math expression, renders it in a closely-clipped bounding
box to an image file.
Parameters
----------
s : str
A math expression. The math portion must be enclosed in dollar signs.
filename_or_obj : str or path-like or file-like
Where to write the image data.
prop : `.FontProperties`, optional
The size and style of the text.
dpi : float, optional
The output dpi. If not set, the dpi is determined as for
`.Figure.savefig`.
format : str, optional
The output format, e.g., 'svg', 'pdf', 'ps' or 'png'. If not set, the
format is determined as for `.Figure.savefig`.
"""
from matplotlib import figure
# backend_agg supports all of the core output formats
from matplotlib.backends import backend_agg
if prop is None:
prop = FontProperties()
parser = MathTextParser('path')
width, height, depth, _, _ = parser.parse(s, dpi=72, prop=prop)
fig = figure.Figure(figsize=(width / 72.0, height / 72.0))
fig.text(0, depth/height, s, fontproperties=prop)
backend_agg.FigureCanvasAgg(fig)
fig.savefig(filename_or_obj, dpi=dpi, format=format)
return depth
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