"""

A module for reading dvi files output by TeX. Several limitations make

this not (currently) useful as a general-purpose dvi preprocessor, but

it is currently used by the pdf backend for processing usetex text.

Interface::

with Dvi(filename, 72) as dvi:

# iterate over pages:

for page in dvi:

w, h, d = page.width, page.height, page.descent

for x, y, font, glyph, width in page.text:

fontname = font.texname

pointsize = font.size

...

for x, y, height, width in page.boxes:

...

"""

from collections import namedtuple

import enum

from functools import lru_cache, partial, wraps

import logging

import os

from pathlib import Path

import re

import struct

import sys

import textwrap

import numpy as np

from matplotlib import _api, cbook, rcParams

_log = logging.getLogger(__name__)

# Many dvi related files are looked for by external processes, require

# additional parsing, and are used many times per rendering, which is why they

# are cached using lru_cache().

# Dvi is a bytecode format documented in

# http://mirrors.ctan.org/systems/knuth/dist/texware/dvitype.web

# http://texdoc.net/texmf-dist/doc/generic/knuth/texware/dvitype.pdf

#

# The file consists of a preamble, some number of pages, a postamble,

# and a finale. Different opcodes are allowed in different contexts,

# so the Dvi object has a parser state:

#

# pre: expecting the preamble

# outer: between pages (followed by a page or the postamble,

# also e.g. font definitions are allowed)

# page: processing a page

# post_post: state after the postamble (our current implementation

# just stops reading)

# finale: the finale (unimplemented in our current implementation)

_dvistate = enum.Enum('DviState', 'pre outer inpage post_post finale')

# The marks on a page consist of text and boxes. A page also has dimensions.

Page = namedtuple('Page', 'text boxes height width descent')

Text = namedtuple('Text', 'x y font glyph width')

Box = namedtuple('Box', 'x y height width')

# Opcode argument parsing

#

# Each of the following functions takes a Dvi object and delta,

# which is the difference between the opcode and the minimum opcode

# with the same meaning. Dvi opcodes often encode the number of

# argument bytes in this delta.

def _arg_raw(dvi, delta):

"""Return *delta* without reading anything more from the dvi file."""

return delta

def _arg(nbytes, signed, dvi, _):

"""

Read *nbytes* bytes, returning the bytes interpreted as a signed integer

if *signed* is true, unsigned otherwise.

"""

return dvi._arg(nbytes, signed)

def _arg_slen(dvi, delta):

"""

Signed, length *delta*

Read *delta* bytes, returning None if *delta* is zero, and the bytes

interpreted as a signed integer otherwise.

"""

if delta == 0:

return None

return dvi._arg(delta, True)

def _arg_slen1(dvi, delta):

"""

Signed, length *delta*+1

Read *delta*+1 bytes, returning the bytes interpreted as signed.

"""

return dvi._arg(delta+1, True)

def _arg_ulen1(dvi, delta):

"""

Unsigned length *delta*+1

Read *delta*+1 bytes, returning the bytes interpreted as unsigned.

"""

return dvi._arg(delta+1, False)

def _arg_olen1(dvi, delta):

"""

Optionally signed, length *delta*+1

Read *delta*+1 bytes, returning the bytes interpreted as

unsigned integer for 0<=*delta*<3 and signed if *delta*==3.

"""

return dvi._arg(delta + 1, delta == 3)

_arg_mapping = dict(raw=_arg_raw,

u1=partial(_arg, 1, False),

u4=partial(_arg, 4, False),

s4=partial(_arg, 4, True),

slen=_arg_slen,

olen1=_arg_olen1,

slen1=_arg_slen1,

ulen1=_arg_ulen1)

def _dispatch(table, min, max=None, state=None, args=('raw',)):

"""

Decorator for dispatch by opcode. Sets the values in *table*

from *min* to *max* to this method, adds a check that the Dvi state

matches *state* if not None, reads arguments from the file according

to *args*.

*table*

the dispatch table to be filled in

*min*

minimum opcode for calling this function

*max*

maximum opcode for calling this function, None if only *min* is allowed

*state*

state of the Dvi object in which these opcodes are allowed

*args*

sequence of argument specifications:

``'raw'``: opcode minus minimum

``'u1'``: read one unsigned byte

``'u4'``: read four bytes, treat as an unsigned number

``'s4'``: read four bytes, treat as a signed number

``'slen'``: read (opcode - minimum) bytes, treat as signed

``'slen1'``: read (opcode - minimum + 1) bytes, treat as signed

``'ulen1'``: read (opcode - minimum + 1) bytes, treat as unsigned

``'olen1'``: read (opcode - minimum + 1) bytes, treat as unsigned

if under four bytes, signed if four bytes

"""

def decorate(method):

get_args = [_arg_mapping[x] for x in args]

@wraps(method)

def wrapper(self, byte):

if state is not None and self.state != state:

raise ValueError("state precondition failed")

return method(self, *[f(self, byte-min) for f in get_args])

if max is None:

table[min] = wrapper

else:

for i in range(min, max+1):

assert table[i] is None

table[i] = wrapper

return wrapper

return decorate

class Dvi:

"""

A reader for a dvi ("device-independent") file, as produced by TeX.

The current implementation can only iterate through pages in order,

and does not even attempt to verify the postamble.

This class can be used as a context manager to close the underlying

file upon exit. Pages can be read via iteration. Here is an overly

simple way to extract text without trying to detect whitespace::

>>> with matplotlib.dviread.Dvi('input.dvi', 72) as dvi:

... for page in dvi:

... print(''.join(chr(t.glyph) for t in page.text))

"""

# dispatch table

_dtable = [None] * 256

_dispatch = partial(_dispatch, _dtable)

def __init__(self, filename, dpi):

"""

Read the data from the file named *filename* and convert

TeX's internal units to units of *dpi* per inch.

*dpi* only sets the units and does not limit the resolution.

Use None to return TeX's internal units.

"""

_log.debug('Dvi: %s', filename)

self.file = open(filename, 'rb')

self.dpi = dpi

self.fonts = {}

self.state = _dvistate.pre

self.baseline = self._get_baseline(filename)

def _get_baseline(self, filename):

if dict.__getitem__(rcParams, 'text.latex.preview'):

baseline = Path(filename).with_suffix(".baseline")

if baseline.exists():

height, depth, width = baseline.read_bytes().split()

return float(depth)

return None

def __enter__(self):

"""Context manager enter method, does nothing."""

return self

def __exit__(self, etype, evalue, etrace):

"""

Context manager exit method, closes the underlying file if it is open.

"""

self.close()

def __iter__(self):

"""

Iterate through the pages of the file.

Yields

------

Page

Details of all the text and box objects on the page.

The Page tuple contains lists of Text and Box tuples and

the page dimensions, and the Text and Box tuples contain

coordinates transformed into a standard Cartesian

coordinate system at the dpi value given when initializing.

The coordinates are floating point numbers, but otherwise

precision is not lost and coordinate values are not clipped to

integers.

"""

while self._read():

yield self._output()

def close(self):

"""Close the underlying file if it is open."""

if not self.file.closed:

self.file.close()

def _output(self):

"""

Output the text and boxes belonging to the most recent page.

page = dvi._output()

"""

minx, miny, maxx, maxy = np.inf, np.inf, -np.inf, -np.inf

maxy_pure = -np.inf

for elt in self.text + self.boxes:

if isinstance(elt, Box):

x, y, h, w = elt

e = 0 # zero depth

else: # glyph

x, y, font, g, w = elt

h, e = font._height_depth_of(g)

minx = min(minx, x)

miny = min(miny, y - h)

maxx = max(maxx, x + w)

maxy = max(maxy, y + e)

maxy_pure = max(maxy_pure, y)

if self._baseline_v is not None:

maxy_pure = self._baseline_v # This should normally be the case.

self._baseline_v = None

if not self.text and not self.boxes: # Avoid infs/nans from inf+/-inf.

return Page(text=[], boxes=[], width=0, height=0, descent=0)

if self.dpi is None:

# special case for ease of debugging: output raw dvi coordinates

return Page(text=self.text, boxes=self.boxes,

width=maxx-minx, height=maxy_pure-miny,

descent=maxy-maxy_pure)

# convert from TeX's "scaled points" to dpi units

d = self.dpi / (72.27 * 2**16)

if self.baseline is None:

descent = (maxy - maxy_pure) * d

else:

descent = self.baseline

text = [Text((x-minx)*d, (maxy-y)*d - descent, f, g, w*d)

for (x, y, f, g, w) in self.text]

boxes = [Box((x-minx)*d, (maxy-y)*d - descent, h*d, w*d)

for (x, y, h, w) in self.boxes]

return Page(text=text, boxes=boxes, width=(maxx-minx)*d,

height=(maxy_pure-miny)*d, descent=descent)

def _read(self):

"""

Read one page from the file. Return True if successful,

False if there were no more pages.

"""

# Pages appear to start with the sequence

# bop (begin of page)

# xxx comment

# down

# push

# down

# <push, push, xxx, right, xxx, pop, pop> # if using xcolor

# down

# push

# down (possibly multiple)

# push <= here, v is the baseline position.

# etc.

# (dviasm is useful to explore this structure.)

# Thus, we use the vertical position at the first time the stack depth

# reaches 3, while at least three "downs" have been executed, as the

# baseline (the "down" count is necessary to handle xcolor).

downs = 0

self._baseline_v = None

while True:

byte = self.file.read(1)[0]

self._dtable[byte](self, byte)

downs += self._dtable[byte].__name__ == "_down"

if (self._baseline_v is None

and len(getattr(self, "stack", [])) == 3

and downs >= 4):

self._baseline_v = self.v

if byte == 140: # end of page

return True

if self.state is _dvistate.post_post: # end of file

self.close()

return False

def _arg(self, nbytes, signed=False):

"""

Read and return an integer argument *nbytes* long.

Signedness is determined by the *signed* keyword.

"""

buf = self.file.read(nbytes)

value = buf[0]

if signed and value >= 0x80:

value = value - 0x100

for b in buf[1:]:

value = 0x100*value + b

return value

@_dispatch(min=0, max=127, state=_dvistate.inpage)

def _set_char_immediate(self, char):

self._put_char_real(char)

self.h += self.fonts[self.f]._width_of(char)

@_dispatch(min=128, max=131, state=_dvistate.inpage, args=('olen1',))

def _set_char(self, char):

self._put_char_real(char)

self.h += self.fonts[self.f]._width_of(char)

@_dispatch(132, state=_dvistate.inpage, args=('s4', 's4'))

def _set_rule(self, a, b):

self._put_rule_real(a, b)

self.h += b

@_dispatch(min=133, max=136, state=_dvistate.inpage, args=('olen1',))

def _put_char(self, char):

self._put_char_real(char)

def _put_char_real(self, char):

font = self.fonts[self.f]

if font._vf is None:

self.text.append(Text(self.h, self.v, font, char,

font._width_of(char)))

else:

scale = font._scale

for x, y, f, g, w in font._vf[char].text:

newf = DviFont(scale=_mul2012(scale, f._scale),

tfm=f._tfm, texname=f.texname, vf=f._vf)

self.text.append(Text(self.h + _mul2012(x, scale),

self.v + _mul2012(y, scale),

newf, g, newf._width_of(g)))

self.boxes.extend([Box(self.h + _mul2012(x, scale),

self.v + _mul2012(y, scale),

_mul2012(a, scale), _mul2012(b, scale))

for x, y, a, b in font._vf[char].boxes])

@_dispatch(137, state=_dvistate.inpage, args=('s4', 's4'))

def _put_rule(self, a, b):

self._put_rule_real(a, b)

def _put_rule_real(self, a, b):

if a > 0 and b > 0:

self.boxes.append(Box(self.h, self.v, a, b))

@_dispatch(138)

def _nop(self, _):

pass

@_dispatch(139, state=_dvistate.outer, args=('s4',)*11)

def _bop(self, c0, c1, c2, c3, c4, c5, c6, c7, c8, c9, p):

self.state = _dvistate.inpage

self.h, self.v, self.w, self.x, self.y, self.z = 0, 0, 0, 0, 0, 0

self.stack = []

self.text = [] # list of Text objects

self.boxes = [] # list of Box objects

@_dispatch(140, state=_dvistate.inpage)

def _eop(self, _):

self.state = _dvistate.outer

del self.h, self.v, self.w, self.x, self.y, self.z, self.stack

@_dispatch(141, state=_dvistate.inpage)

def _push(self, _):

self.stack.append((self.h, self.v, self.w, self.x, self.y, self.z))

@_dispatch(142, state=_dvistate.inpage)

def _pop(self, _):

self.h, self.v, self.w, self.x, self.y, self.z = self.stack.pop()

@_dispatch(min=143, max=146, state=_dvistate.inpage, args=('slen1',))

def _right(self, b):

self.h += b

@_dispatch(min=147, max=151, state=_dvistate.inpage, args=('slen',))

def _right_w(self, new_w):

if new_w is not None:

self.w = new_w

self.h += self.w

@_dispatch(min=152, max=156, state=_dvistate.inpage, args=('slen',))

def _right_x(self, new_x):

if new_x is not None:

self.x = new_x

self.h += self.x

@_dispatch(min=157, max=160, state=_dvistate.inpage, args=('slen1',))

def _down(self, a):

self.v += a

@_dispatch(min=161, max=165, state=_dvistate.inpage, args=('slen',))

def _down_y(self, new_y):

if new_y is not None:

self.y = new_y

self.v += self.y

@_dispatch(min=166, max=170, state=_dvistate.inpage, args=('slen',))

def _down_z(self, new_z):

if new_z is not None:

self.z = new_z

self.v += self.z

@_dispatch(min=171, max=234, state=_dvistate.inpage)

def _fnt_num_immediate(self, k):

self.f = k

@_dispatch(min=235, max=238, state=_dvistate.inpage, args=('olen1',))

def _fnt_num(self, new_f):

self.f = new_f

@_dispatch(min=239, max=242, args=('ulen1',))

def _xxx(self, datalen):

special = self.file.read(datalen)

_log.debug(

'Dvi._xxx: encountered special: %s',

''.join([chr(ch) if 32 <= ch < 127 else '<%02x>' % ch

for ch in special]))

@_dispatch(min=243, max=246, args=('olen1', 'u4', 'u4', 'u4', 'u1', 'u1'))

def _fnt_def(self, k, c, s, d, a, l):

self._fnt_def_real(k, c, s, d, a, l)

def _fnt_def_real(self, k, c, s, d, a, l):

n = self.file.read(a + l)

fontname = n[-l:].decode('ascii')

tfm = _tfmfile(fontname)

if tfm is None:

raise FileNotFoundError("missing font metrics file: %s" % fontname)

if c != 0 and tfm.checksum != 0 and c != tfm.checksum:

raise ValueError('tfm checksum mismatch: %s' % n)

vf = _vffile(fontname)

self.fonts[k] = DviFont(scale=s, tfm=tfm, texname=n, vf=vf)

@_dispatch(247, state=_dvistate.pre, args=('u1', 'u4', 'u4', 'u4', 'u1'))

def _pre(self, i, num, den, mag, k):

self.file.read(k) # comment in the dvi file

if i != 2:

raise ValueError("Unknown dvi format %d" % i)

if num != 25400000 or den != 7227 * 2**16:

raise ValueError("Nonstandard units in dvi file")

# meaning: TeX always uses those exact values, so it

# should be enough for us to support those

# (There are 72.27 pt to an inch so 7227 pt =

# 7227 * 2**16 sp to 100 in. The numerator is multiplied

# by 10^5 to get units of 10**-7 meters.)

if mag != 1000:

raise ValueError("Nonstandard magnification in dvi file")

# meaning: LaTeX seems to frown on setting \mag, so

# I think we can assume this is constant

self.state = _dvistate.outer

@_dispatch(248, state=_dvistate.outer)

def _post(self, _):

self.state = _dvistate.post_post

# TODO: actually read the postamble and finale?

# currently post_post just triggers closing the file

@_dispatch(249)

def _post_post(self, _):

raise NotImplementedError

@_dispatch(min=250, max=255)

def _malformed(self, offset):

raise ValueError(f"unknown command: byte {250 + offset}")

class DviFont:

"""

Encapsulation of a font that a DVI file can refer to.

This class holds a font's texname and size, supports comparison,

and knows the widths of glyphs in the same units as the AFM file.

There are also internal attributes (for use by dviread.py) that

are *not* used for comparison.

The size is in Adobe points (converted from TeX points).

Parameters

----------

scale : float

Factor by which the font is scaled from its natural size.

tfm : Tfm

TeX font metrics for this font

texname : bytes

Name of the font as used internally by TeX and friends, as an ASCII

bytestring. This is usually very different from any external font

names; `PsfontsMap` can be used to find the external name of the font.

vf : Vf

A TeX "virtual font" file, or None if this font is not virtual.

Attributes

----------

texname : bytes

size : float

Size of the font in Adobe points, converted from the slightly

smaller TeX points.

widths : list

Widths of glyphs in glyph-space units, typically 1/1000ths of

the point size.

"""

__slots__ = ('texname', 'size', 'widths', '_scale', '_vf', '_tfm')

def __init__(self, scale, tfm, texname, vf):

_api.check_isinstance(bytes, texname=texname)

self._scale = scale

self._tfm = tfm

self.texname = texname

self._vf = vf

self.size = scale * (72.0 / (72.27 * 2**16))

try:

nchars = max(tfm.width) + 1

except ValueError:

nchars = 0

self.widths = [(1000*tfm.width.get(char, 0)) >> 20

for char in range(nchars)]

def __eq__(self, other):

return (type(self) == type(other)

and self.texname == other.texname and self.size == other.size)

def __ne__(self, other):

return not self.__eq__(other)

def __repr__(self):

return "<{}: {}>".format(type(self).__name__, self.texname)

def _width_of(self, char):

"""Width of char in dvi units."""

width = self._tfm.width.get(char, None)

if width is not None:

return _mul2012(width, self._scale)

_log.debug('No width for char %d in font %s.', char, self.texname)

return 0

def _height_depth_of(self, char):

"""Height and depth of char in dvi units."""

result = []

for metric, name in ((self._tfm.height, "height"),

(self._tfm.depth, "depth")):

value = metric.get(char, None)

if value is None:

_log.debug('No %s for char %d in font %s',

name, char, self.texname)

result.append(0)

else:

result.append(_mul2012(value, self._scale))

# cmsyXX (symbols font) glyph 0 ("minus") has a nonzero descent

# so that TeX aligns equations properly

# (https://tex.stackexchange.com/questions/526103/),

# but we actually care about the rasterization depth to align

# the dvipng-generated images.

if re.match(br'^cmsy\d+$', self.texname) and char == 0:

result[-1] = 0

return result

class Vf(Dvi):

r"""

A virtual font (\*.vf file) containing subroutines for dvi files.

Parameters

----------

filename : str or path-like

Notes

-----

The virtual font format is a derivative of dvi:

http://mirrors.ctan.org/info/knuth/virtual-fonts

This class reuses some of the machinery of `Dvi`

but replaces the `_read` loop and dispatch mechanism.

Examples

--------

::

vf = Vf(filename)

glyph = vf[code]

glyph.text, glyph.boxes, glyph.width

"""

def __init__(self, filename):

super().__init__(filename, 0)

try:

self._first_font = None

self._chars = {}

self._read()

finally:

self.close()

def __getitem__(self, code):

return self._chars[code]

def _read(self):

"""

Read one page from the file. Return True if successful,

False if there were no more pages.

"""

packet_char, packet_ends = None, None

packet_len, packet_width = None, None

while True:

byte = self.file.read(1)[0]

# If we are in a packet, execute the dvi instructions

if self.state is _dvistate.inpage:

byte_at = self.file.tell()-1

if byte_at == packet_ends:

self._finalize_packet(packet_char, packet_width)

packet_len, packet_char, packet_width = None, None, None

# fall through to out-of-packet code

elif byte_at > packet_ends:

raise ValueError("Packet length mismatch in vf file")

else:

if byte in (139, 140) or byte >= 243:

raise ValueError(

"Inappropriate opcode %d in vf file" % byte)

Dvi._dtable[byte](self, byte)

continue

# We are outside a packet

if byte < 242: # a short packet (length given by byte)

packet_len = byte

packet_char, packet_width = self._arg(1), self._arg(3)

packet_ends = self._init_packet(byte)

self.state = _dvistate.inpage

elif byte == 242: # a long packet

packet_len, packet_char, packet_width = \

[self._arg(x) for x in (4, 4, 4)]

self._init_packet(packet_len)

elif 243 <= byte <= 246:

k = self._arg(byte - 242, byte == 246)

c, s, d, a, l = [self._arg(x) for x in (4, 4, 4, 1, 1)]

self._fnt_def_real(k, c, s, d, a, l)

if self._first_font is None:

self._first_font = k

elif byte == 247: # preamble

i, k = self._arg(1), self._arg(1)

x = self.file.read(k)

cs, ds = self._arg(4), self._arg(4)

self._pre(i, x, cs, ds)

elif byte == 248: # postamble (just some number of 248s)

break

else:

raise ValueError("Unknown vf opcode %d" % byte)

def _init_packet(self, pl):

if self.state != _dvistate.outer:

raise ValueError("Misplaced packet in vf file")

self.h, self.v, self.w, self.x, self.y, self.z = 0, 0, 0, 0, 0, 0

self.stack, self.text, self.boxes = [], [], []

self.f = self._first_font

return self.file.tell() + pl

def _finalize_packet(self, packet_char, packet_width):

self._chars[packet_char] = Page(

text=self.text, boxes=self.boxes, width=packet_width,

height=None, descent=None)

self.state = _dvistate.outer

def _pre(self, i, x, cs, ds):

if self.state is not _dvistate.pre:

raise ValueError("pre command in middle of vf file")

if i != 202:

raise ValueError("Unknown vf format %d" % i)

if len(x):

_log.debug('vf file comment: %s', x)

self.state = _dvistate.outer

# cs = checksum, ds = design size

def _fix2comp(num):

"""Convert from two's complement to negative."""

assert 0 <= num < 2**32

if num & 2**31:

return num - 2**32

else:

return num

def _mul2012(num1, num2):

"""Multiply two numbers in 20.12 fixed point format."""

# Separated into a function because >> has surprising precedence

return (num1*num2) >> 20

class Tfm:

"""

A TeX Font Metric file.

This implementation covers only the bare minimum needed by the Dvi class.

Parameters

----------

filename : str or path-like

Attributes

----------

checksum : int

Used for verifying against the dvi file.

design_size : int

Design size of the font (unknown units)

width, height, depth : dict

Dimensions of each character, need to be scaled by the factor

specified in the dvi file. These are dicts because indexing may

not start from 0.

"""

__slots__ = ('checksum', 'design_size', 'width', 'height', 'depth')

def __init__(self, filename):

_log.debug('opening tfm file %s', filename)

with open(filename, 'rb') as file:

header1 = file.read(24)

lh, bc, ec, nw, nh, nd = \

struct.unpack('!6H', header1[2:14])

_log.debug('lh=%d, bc=%d, ec=%d, nw=%d, nh=%d, nd=%d',

lh, bc, ec, nw, nh, nd)

header2 = file.read(4*lh)

self.checksum, self.design_size = \

struct.unpack('!2I', header2[:8])

# there is also encoding information etc.

char_info = file.read(4*(ec-bc+1))

widths = file.read(4*nw)

heights = file.read(4*nh)

depths = file.read(4*nd)

self.width, self.height, self.depth = {}, {}, {}

widths, heights, depths = \

[struct.unpack('!%dI' % (len(x)/4), x)

for x in (widths, heights, depths)]

for idx, char in enumerate(range(bc, ec+1)):

byte0 = char_info[4*idx]

byte1 = char_info[4*idx+1]

self.width[char] = _fix2comp(widths[byte0])

self.height[char] = _fix2comp(heights[byte1 >> 4])

self.depth[char] = _fix2comp(depths[byte1 & 0xf])

PsFont = namedtuple('PsFont', 'texname psname effects encoding filename')

class PsfontsMap:

"""

A psfonts.map formatted file, mapping TeX fonts to PS fonts.

Parameters

----------

filename : str or path-like

Notes

-----

For historical reasons, TeX knows many Type-1 fonts by different

names than the outside world. (For one thing, the names have to

fit in eight characters.) Also, TeX's native fonts are not Type-1

but Metafont, which is nontrivial to convert to PostScript except

as a bitmap. While high-quality conversions to Type-1 format exist

and are shipped with modern TeX distributions, we need to know

which Type-1 fonts are the counterparts of which native fonts. For

these reasons a mapping is needed from internal font names to font

file names.

A texmf tree typically includes mapping files called e.g.

:file:`psfonts.map`, :file:`pdftex.map`, or :file:`dvipdfm.map`.

The file :file:`psfonts.map` is used by :program:`dvips`,

:file:`pdftex.map` by :program:`pdfTeX`, and :file:`dvipdfm.map`

by :program:`dvipdfm`. :file:`psfonts.map` might avoid embedding

the 35 PostScript fonts (i.e., have no filename for them, as in

the Times-Bold example above), while the pdf-related files perhaps

only avoid the "Base 14" pdf fonts. But the user may have

configured these files differently.

Examples

--------

>>> map = PsfontsMap(find_tex_file('pdftex.map'))

>>> entry = map[b'ptmbo8r']

>>> entry.texname

b'ptmbo8r'

>>> entry.psname

b'Times-Bold'

>>> entry.encoding

'/usr/local/texlive/2008/texmf-dist/fonts/enc/dvips/base/8r.enc'

>>> entry.effects

{'slant': 0.16700000000000001}

>>> entry.filename

"""

__slots__ = ('_font', '_filename')

# Create a filename -> PsfontsMap cache, so that calling

# `PsfontsMap(filename)` with the same filename a second time immediately

# returns the same object.

@lru_cache()

def __new__(cls, filename):

self = object.__new__(cls)

self._font = {}

self._filename = os.fsdecode(filename)

with open(filename, 'rb') as file:

self._parse(file)

return self

def __getitem__(self, texname):

assert isinstance(texname, bytes)

try:

result = self._font[texname]

except KeyError:

fmt = ('A PostScript file for the font whose TeX name is "{0}" '

'could not be found in the file "{1}". The dviread module '

'can only handle fonts that have an associated PostScript '

'font file. '

'This problem can often be solved by installing '

'a suitable PostScript font package in your (TeX) '

'package manager.')

msg = fmt.format(texname.decode('ascii'), self._filename)

msg = textwrap.fill(msg, break_on_hyphens=False,

break_long_words=False)

_log.info(msg)

raise

fn, enc = result.filename, result.encoding

if fn is not None and not fn.startswith(b'/'):

fn = find_tex_file(fn)

if enc is not None and not enc.startswith(b'/'):

enc = find_tex_file(result.encoding)

return result._replace(filename=fn, encoding=enc)

def _parse(self, file):

"""

Parse the font mapping file.

The format is, AFAIK: texname fontname [effects and filenames]

Effects are PostScript snippets like ".177 SlantFont",

filenames begin with one or two less-than signs. A filename

ending in enc is an encoding file, other filenames are font

files. This can be overridden with a left bracket: <[foobar

indicates an encoding file named foobar.

There is some difference between <foo.pfb and <<bar.pfb in

subsetting, but I have no example of << in my TeX installation.

"""

# If the map file specifies multiple encodings for a font, we

# follow pdfTeX in choosing the last one specified. Such

# entries are probably mistakes but they have occurred.

# http://tex.stackexchange.com/questions/10826/

# http://article.gmane.org/gmane.comp.tex.pdftex/4914

empty_re = re.compile(br'%|\s*$')

word_re = re.compile(

br'''(?x) (?:

"<\[ (?P<enc1> [^"]+ )" | # quoted encoding marked by [

"< (?P<enc2> [^"]+.enc)" | # quoted encoding, ends in .enc

"<<? (?P<file1> [^"]+ )" | # quoted font file name

" (?P<eff1> [^"]+ )" | # quoted effects or font name

<\[ (?P<enc3> \S+ ) | # encoding marked by [

< (?P<enc4> \S+ .enc) | # encoding, ends in .enc

<<? (?P<file2> \S+ ) | # font file name

(?P<eff2> \S+ ) # effects or font name

)''')

effects_re = re.compile(

br'''(?x) (?P<slant> -?[0-9]*(?:\.[0-9]+)) \s* SlantFont

| (?P<extend>-?[0-9]*(?:\.[0-9]+)) \s* ExtendFont''')

lines = (line.strip()

for line in file

if not empty_re.match(line))

for line in lines:

effects, encoding, filename = b'', None, None

words = word_re.finditer(line)

# The named groups are mutually exclusive and are

# referenced below at an estimated order of probability of

# occurrence based on looking at my copy of pdftex.map.

# The font names are probably unquoted:

w = next(words)

texname = w.group('eff2') or w.group('eff1')

w = next(words)

psname = w.group('eff2') or w.group('eff1')

for w in words:

# Any effects are almost always quoted:

eff = w.group('eff1') or w.group('eff2')

if eff:

effects = eff

continue

# Encoding files usually have the .enc suffix

# and almost never need quoting:

enc = (w.group('enc4') or w.group('enc3') or

w.group('enc2') or w.group('enc1'))

if enc:

if encoding is not None:

_log.debug('Multiple encodings for %s = %s',

texname, psname)

encoding = enc

continue

# File names are probably unquoted:

filename = w.group('file2') or w.group('file1')

effects_dict = {}

for match in effects_re.finditer(effects):

slant = match.group('slant')

if slant:

effects_dict['slant'] = float(slant)

else:

effects_dict['extend'] = float(match.group('extend'))

self._font[texname] = PsFont(

texname=texname, psname=psname, effects=effects_dict,

encoding=encoding, filename=filename)

@_api.deprecated("3.3")

class Encoding:

r"""

Parse a \*.enc file referenced from a psfonts.map style file.

The format this class understands is a very limited subset of PostScript.

Usage (subject to change)::

for name in Encoding(filename):

whatever(name)

Parameters

----------

filename : str or path-like

Attributes

----------

encoding : list

List of character names

"""

__slots__ = ('encoding',)

def __init__(self, filename):

with open(filename, 'rb') as file:

_log.debug('Parsing TeX encoding %s', filename)

self.encoding = self._parse(file)

_log.debug('Result: %s', self.encoding)

def __iter__(self):

yield from self.encoding

@staticmethod

def _parse(file):

lines = (line.split(b'%', 1)[0].strip() for line in file)

data = b''.join(lines)

beginning = data.find(b'[')

if beginning < 0: