Source code for matplotlib.dviread

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.


  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
# 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),

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*.

        the dispatch table to be filled in

        minimum opcode for calling this function

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

        state of the Dvi object in which these opcodes are allowed

        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]

        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
            for i in range(min, max+1):
                assert table[i] is None
                table[i] = wrapper
        return wrapper
    return decorate

[docs]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()
[docs] 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 =[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 = 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 = _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 = + 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): # 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}")
[docs]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 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 # (, # 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
[docs]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: 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 =[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 = 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
[docs]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 = 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 =*lh) self.checksum, self.design_size = \ struct.unpack('!2I', header2[:8]) # there is also encoding information etc. char_info =*(ec-bc+1)) widths =*nw) heights =*nh) depths =*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')
[docs]class PsfontsMap: """ A 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:``, :file:``, or :file:``. The file :file:`` is used by :program:`dvips`, :file:`` by :program:`pdfTeX`, and :file:`` by :program:`dvipdfm`. :file:`` 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('')) >>> 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) 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. # # 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 # The font names are probably unquoted: w = next(words) texname ='eff2') or'eff1') w = next(words) psname ='eff2') or'eff1') for w in words: # Any effects are almost always quoted: eff ='eff1') or'eff2') if eff: effects = eff continue # Encoding files usually have the .enc suffix # and almost never need quoting: enc = ('enc4') or'enc3') or'enc2') or'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 ='file2') or'file1') effects_dict = {} for match in effects_re.finditer(effects): slant ='slant') if slant: effects_dict['slant'] = float(slant) else: effects_dict['extend'] = float('extend')) self._font[texname] = PsFont( texname=texname, psname=psname, effects=effects_dict, encoding=encoding, filename=filename)
[docs]@_api.deprecated("3.3") class Encoding: r""" Parse a \*.enc file referenced from a 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: raise ValueError("Cannot locate beginning of encoding in {}" .format(file)) data = data[beginning:] end = data.find(b']') if end < 0: raise ValueError("Cannot locate end of encoding in {}" .format(file)) data = data[:end] return re.findall(br'/([^][{}<>\s]+)', data)
# Note: this function should ultimately replace the Encoding class, which # appears to be mostly broken: because it uses b''.join(), there is no # whitespace left between glyph names (only slashes) so the final re.findall # returns a single string with all glyph names. However this does not appear # to bother backend_pdf, so that needs to be investigated more. (The fixed # version below is necessary for textpath/backend_svg, though.) def _parse_enc(path): r""" Parses a \*.enc file referenced from a style file. The format this class understands is a very limited subset of PostScript. Parameters ---------- path : os.PathLike Returns ------- list The nth entry of the list is the PostScript glyph name of the nth glyph. """ no_comments = re.sub("%.*", "", Path(path).read_text(encoding="ascii")) array ="(?s)\[(.*)\]", no_comments).group(1) lines = [line for line in array.split() if line] if all(line.startswith("/") for line in lines): return [line[1:] for line in lines] else: raise ValueError( "Failed to parse {} as Postscript encoding".format(path))
[docs]@lru_cache() def find_tex_file(filename, format=None): """ Find a file in the texmf tree. Calls :program:`kpsewhich` which is an interface to the kpathsea library [1]_. Most existing TeX distributions on Unix-like systems use kpathsea. It is also available as part of MikTeX, a popular distribution on Windows. *If the file is not found, an empty string is returned*. Parameters ---------- filename : str or path-like format : str or bytes Used as the value of the ``--format`` option to :program:`kpsewhich`. Could be e.g. 'tfm' or 'vf' to limit the search to that type of files. References ---------- .. [1] `Kpathsea documentation <>`_ The library that :program:`kpsewhich` is part of. """ # we expect these to always be ascii encoded, but use utf-8 # out of caution if isinstance(filename, bytes): filename = filename.decode('utf-8', errors='replace') if isinstance(format, bytes): format = format.decode('utf-8', errors='replace') if == 'nt': # On Windows only, kpathsea can use utf-8 for cmd args and output. # The `command_line_encoding` environment variable is set to force it # to always use utf-8 encoding. See Matplotlib issue #11848. kwargs = {'env': {**os.environ, 'command_line_encoding': 'utf-8'}, 'encoding': 'utf-8'} else: # On POSIX, run through the equivalent of os.fsdecode(). kwargs = {'encoding': sys.getfilesystemencoding(), 'errors': 'surrogatescape'} cmd = ['kpsewhich'] if format is not None: cmd += ['--format=' + format] cmd += [filename] try: result = cbook._check_and_log_subprocess(cmd, _log, **kwargs) except (FileNotFoundError, RuntimeError): return '' return result.rstrip('\n')
@lru_cache() def _fontfile(cls, suffix, texname): filename = find_tex_file(texname + suffix) return cls(filename) if filename else None _tfmfile = partial(_fontfile, Tfm, ".tfm") _vffile = partial(_fontfile, Vf, ".vf") if __name__ == '__main__': from argparse import ArgumentParser import itertools parser = ArgumentParser() parser.add_argument("filename") parser.add_argument("dpi", nargs="?", type=float, default=None) args = parser.parse_args() with Dvi(args.filename, args.dpi) as dvi: fontmap = PsfontsMap(find_tex_file('')) for page in dvi: print('=== new page ===') for font, group in itertools.groupby( page.text, lambda text: text.font): print('font', font.texname, 'scaled', font._scale / 2 ** 20) for text in group: print(text.x, text.y, text.glyph, chr(text.glyph) if chr(text.glyph).isprintable() else ".", text.width) for x, y, w, h in page.boxes: print(x, y, 'BOX', w, h)