1128 lines
40 KiB
Python
1128 lines
40 KiB
Python
"""
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A module for reading dvi files output by TeX. Several limitations make
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this not (currently) useful as a general-purpose dvi preprocessor, but
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it is currently used by the pdf backend for processing usetex text.
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Interface::
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with Dvi(filename, 72) as dvi:
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# iterate over pages:
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for page in dvi:
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w, h, d = page.width, page.height, page.descent
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for x, y, font, glyph, width in page.text:
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fontname = font.texname
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pointsize = font.size
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...
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for x, y, height, width in page.boxes:
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...
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"""
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from collections import namedtuple
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import enum
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from functools import lru_cache, partial, wraps
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import logging
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import os
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from pathlib import Path
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import re
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import struct
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import sys
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import textwrap
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import numpy as np
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from matplotlib import _api, cbook, rcParams
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_log = logging.getLogger(__name__)
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# Many dvi related files are looked for by external processes, require
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# additional parsing, and are used many times per rendering, which is why they
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# are cached using lru_cache().
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# Dvi is a bytecode format documented in
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# http://mirrors.ctan.org/systems/knuth/dist/texware/dvitype.web
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# http://texdoc.net/texmf-dist/doc/generic/knuth/texware/dvitype.pdf
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#
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# The file consists of a preamble, some number of pages, a postamble,
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# and a finale. Different opcodes are allowed in different contexts,
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# so the Dvi object has a parser state:
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#
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# pre: expecting the preamble
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# outer: between pages (followed by a page or the postamble,
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# also e.g. font definitions are allowed)
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# page: processing a page
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# post_post: state after the postamble (our current implementation
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# just stops reading)
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# finale: the finale (unimplemented in our current implementation)
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_dvistate = enum.Enum('DviState', 'pre outer inpage post_post finale')
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# The marks on a page consist of text and boxes. A page also has dimensions.
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Page = namedtuple('Page', 'text boxes height width descent')
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Text = namedtuple('Text', 'x y font glyph width')
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Box = namedtuple('Box', 'x y height width')
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# Opcode argument parsing
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#
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# Each of the following functions takes a Dvi object and delta,
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# which is the difference between the opcode and the minimum opcode
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# with the same meaning. Dvi opcodes often encode the number of
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# argument bytes in this delta.
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def _arg_raw(dvi, delta):
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"""Return *delta* without reading anything more from the dvi file."""
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return delta
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def _arg(nbytes, signed, dvi, _):
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"""
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Read *nbytes* bytes, returning the bytes interpreted as a signed integer
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if *signed* is true, unsigned otherwise.
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"""
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return dvi._arg(nbytes, signed)
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def _arg_slen(dvi, delta):
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"""
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Signed, length *delta*
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Read *delta* bytes, returning None if *delta* is zero, and the bytes
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interpreted as a signed integer otherwise.
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"""
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if delta == 0:
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return None
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return dvi._arg(delta, True)
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def _arg_slen1(dvi, delta):
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"""
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Signed, length *delta*+1
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Read *delta*+1 bytes, returning the bytes interpreted as signed.
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"""
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return dvi._arg(delta+1, True)
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def _arg_ulen1(dvi, delta):
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"""
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Unsigned length *delta*+1
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Read *delta*+1 bytes, returning the bytes interpreted as unsigned.
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"""
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return dvi._arg(delta+1, False)
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def _arg_olen1(dvi, delta):
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"""
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Optionally signed, length *delta*+1
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Read *delta*+1 bytes, returning the bytes interpreted as
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unsigned integer for 0<=*delta*<3 and signed if *delta*==3.
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"""
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return dvi._arg(delta + 1, delta == 3)
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_arg_mapping = dict(raw=_arg_raw,
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u1=partial(_arg, 1, False),
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u4=partial(_arg, 4, False),
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s4=partial(_arg, 4, True),
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slen=_arg_slen,
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olen1=_arg_olen1,
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slen1=_arg_slen1,
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ulen1=_arg_ulen1)
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def _dispatch(table, min, max=None, state=None, args=('raw',)):
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"""
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Decorator for dispatch by opcode. Sets the values in *table*
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from *min* to *max* to this method, adds a check that the Dvi state
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matches *state* if not None, reads arguments from the file according
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to *args*.
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*table*
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the dispatch table to be filled in
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*min*
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minimum opcode for calling this function
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*max*
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maximum opcode for calling this function, None if only *min* is allowed
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*state*
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state of the Dvi object in which these opcodes are allowed
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*args*
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sequence of argument specifications:
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``'raw'``: opcode minus minimum
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``'u1'``: read one unsigned byte
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``'u4'``: read four bytes, treat as an unsigned number
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``'s4'``: read four bytes, treat as a signed number
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``'slen'``: read (opcode - minimum) bytes, treat as signed
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``'slen1'``: read (opcode - minimum + 1) bytes, treat as signed
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``'ulen1'``: read (opcode - minimum + 1) bytes, treat as unsigned
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``'olen1'``: read (opcode - minimum + 1) bytes, treat as unsigned
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if under four bytes, signed if four bytes
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"""
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def decorate(method):
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get_args = [_arg_mapping[x] for x in args]
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@wraps(method)
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def wrapper(self, byte):
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if state is not None and self.state != state:
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raise ValueError("state precondition failed")
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return method(self, *[f(self, byte-min) for f in get_args])
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if max is None:
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table[min] = wrapper
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else:
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for i in range(min, max+1):
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assert table[i] is None
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table[i] = wrapper
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return wrapper
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return decorate
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class Dvi:
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"""
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A reader for a dvi ("device-independent") file, as produced by TeX.
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The current implementation can only iterate through pages in order,
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and does not even attempt to verify the postamble.
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This class can be used as a context manager to close the underlying
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file upon exit. Pages can be read via iteration. Here is an overly
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simple way to extract text without trying to detect whitespace::
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>>> with matplotlib.dviread.Dvi('input.dvi', 72) as dvi:
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... for page in dvi:
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... print(''.join(chr(t.glyph) for t in page.text))
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"""
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# dispatch table
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_dtable = [None] * 256
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_dispatch = partial(_dispatch, _dtable)
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def __init__(self, filename, dpi):
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"""
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Read the data from the file named *filename* and convert
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TeX's internal units to units of *dpi* per inch.
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*dpi* only sets the units and does not limit the resolution.
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Use None to return TeX's internal units.
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"""
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_log.debug('Dvi: %s', filename)
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self.file = open(filename, 'rb')
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self.dpi = dpi
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self.fonts = {}
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self.state = _dvistate.pre
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self.baseline = self._get_baseline(filename)
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def _get_baseline(self, filename):
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if dict.__getitem__(rcParams, 'text.latex.preview'):
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baseline = Path(filename).with_suffix(".baseline")
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if baseline.exists():
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height, depth, width = baseline.read_bytes().split()
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return float(depth)
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return None
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def __enter__(self):
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"""Context manager enter method, does nothing."""
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return self
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def __exit__(self, etype, evalue, etrace):
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"""
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Context manager exit method, closes the underlying file if it is open.
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"""
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self.close()
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def __iter__(self):
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"""
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Iterate through the pages of the file.
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Yields
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------
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Page
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Details of all the text and box objects on the page.
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The Page tuple contains lists of Text and Box tuples and
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the page dimensions, and the Text and Box tuples contain
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coordinates transformed into a standard Cartesian
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coordinate system at the dpi value given when initializing.
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The coordinates are floating point numbers, but otherwise
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precision is not lost and coordinate values are not clipped to
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integers.
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"""
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while self._read():
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yield self._output()
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def close(self):
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"""Close the underlying file if it is open."""
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if not self.file.closed:
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self.file.close()
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def _output(self):
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"""
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Output the text and boxes belonging to the most recent page.
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page = dvi._output()
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"""
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minx, miny, maxx, maxy = np.inf, np.inf, -np.inf, -np.inf
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maxy_pure = -np.inf
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for elt in self.text + self.boxes:
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if isinstance(elt, Box):
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x, y, h, w = elt
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e = 0 # zero depth
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else: # glyph
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x, y, font, g, w = elt
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h, e = font._height_depth_of(g)
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minx = min(minx, x)
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miny = min(miny, y - h)
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maxx = max(maxx, x + w)
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maxy = max(maxy, y + e)
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maxy_pure = max(maxy_pure, y)
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if self._baseline_v is not None:
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maxy_pure = self._baseline_v # This should normally be the case.
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self._baseline_v = None
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if not self.text and not self.boxes: # Avoid infs/nans from inf+/-inf.
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return Page(text=[], boxes=[], width=0, height=0, descent=0)
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if self.dpi is None:
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# special case for ease of debugging: output raw dvi coordinates
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return Page(text=self.text, boxes=self.boxes,
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width=maxx-minx, height=maxy_pure-miny,
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descent=maxy-maxy_pure)
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# convert from TeX's "scaled points" to dpi units
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d = self.dpi / (72.27 * 2**16)
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if self.baseline is None:
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descent = (maxy - maxy_pure) * d
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else:
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descent = self.baseline
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text = [Text((x-minx)*d, (maxy-y)*d - descent, f, g, w*d)
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for (x, y, f, g, w) in self.text]
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boxes = [Box((x-minx)*d, (maxy-y)*d - descent, h*d, w*d)
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for (x, y, h, w) in self.boxes]
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return Page(text=text, boxes=boxes, width=(maxx-minx)*d,
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height=(maxy_pure-miny)*d, descent=descent)
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def _read(self):
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"""
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Read one page from the file. Return True if successful,
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False if there were no more pages.
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"""
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# Pages appear to start with the sequence
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# bop (begin of page)
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# xxx comment
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# down
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# push
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# down
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# <push, push, xxx, right, xxx, pop, pop> # if using xcolor
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# down
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# push
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# down (possibly multiple)
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# push <= here, v is the baseline position.
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# etc.
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# (dviasm is useful to explore this structure.)
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# Thus, we use the vertical position at the first time the stack depth
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# reaches 3, while at least three "downs" have been executed, as the
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# baseline (the "down" count is necessary to handle xcolor).
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downs = 0
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self._baseline_v = None
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while True:
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byte = self.file.read(1)[0]
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self._dtable[byte](self, byte)
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downs += self._dtable[byte].__name__ == "_down"
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if (self._baseline_v is None
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and len(getattr(self, "stack", [])) == 3
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and downs >= 4):
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self._baseline_v = self.v
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if byte == 140: # end of page
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return True
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if self.state is _dvistate.post_post: # end of file
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self.close()
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return False
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def _arg(self, nbytes, signed=False):
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"""
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Read and return an integer argument *nbytes* long.
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Signedness is determined by the *signed* keyword.
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"""
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buf = self.file.read(nbytes)
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value = buf[0]
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if signed and value >= 0x80:
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value = value - 0x100
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for b in buf[1:]:
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value = 0x100*value + b
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return value
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@_dispatch(min=0, max=127, state=_dvistate.inpage)
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def _set_char_immediate(self, char):
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self._put_char_real(char)
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self.h += self.fonts[self.f]._width_of(char)
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@_dispatch(min=128, max=131, state=_dvistate.inpage, args=('olen1',))
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def _set_char(self, char):
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self._put_char_real(char)
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self.h += self.fonts[self.f]._width_of(char)
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@_dispatch(132, state=_dvistate.inpage, args=('s4', 's4'))
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def _set_rule(self, a, b):
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self._put_rule_real(a, b)
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self.h += b
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@_dispatch(min=133, max=136, state=_dvistate.inpage, args=('olen1',))
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def _put_char(self, char):
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self._put_char_real(char)
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def _put_char_real(self, char):
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font = self.fonts[self.f]
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if font._vf is None:
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self.text.append(Text(self.h, self.v, font, char,
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font._width_of(char)))
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else:
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scale = font._scale
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for x, y, f, g, w in font._vf[char].text:
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newf = DviFont(scale=_mul2012(scale, f._scale),
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tfm=f._tfm, texname=f.texname, vf=f._vf)
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self.text.append(Text(self.h + _mul2012(x, scale),
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self.v + _mul2012(y, scale),
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newf, g, newf._width_of(g)))
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self.boxes.extend([Box(self.h + _mul2012(x, scale),
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self.v + _mul2012(y, scale),
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_mul2012(a, scale), _mul2012(b, scale))
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for x, y, a, b in font._vf[char].boxes])
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@_dispatch(137, state=_dvistate.inpage, args=('s4', 's4'))
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def _put_rule(self, a, b):
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self._put_rule_real(a, b)
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def _put_rule_real(self, a, b):
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if a > 0 and b > 0:
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self.boxes.append(Box(self.h, self.v, a, b))
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@_dispatch(138)
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def _nop(self, _):
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pass
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@_dispatch(139, state=_dvistate.outer, args=('s4',)*11)
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def _bop(self, c0, c1, c2, c3, c4, c5, c6, c7, c8, c9, p):
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self.state = _dvistate.inpage
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self.h, self.v, self.w, self.x, self.y, self.z = 0, 0, 0, 0, 0, 0
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self.stack = []
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self.text = [] # list of Text objects
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self.boxes = [] # list of Box objects
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@_dispatch(140, state=_dvistate.inpage)
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def _eop(self, _):
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self.state = _dvistate.outer
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del self.h, self.v, self.w, self.x, self.y, self.z, self.stack
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|
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@_dispatch(141, state=_dvistate.inpage)
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def _push(self, _):
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self.stack.append((self.h, self.v, self.w, self.x, self.y, self.z))
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@_dispatch(142, state=_dvistate.inpage)
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def _pop(self, _):
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self.h, self.v, self.w, self.x, self.y, self.z = self.stack.pop()
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|
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@_dispatch(min=143, max=146, state=_dvistate.inpage, args=('slen1',))
|
|
def _right(self, b):
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self.h += b
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|
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@_dispatch(min=147, max=151, state=_dvistate.inpage, args=('slen',))
|
|
def _right_w(self, new_w):
|
|
if new_w is not None:
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self.w = new_w
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self.h += self.w
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|
|
|
@_dispatch(min=152, max=156, state=_dvistate.inpage, args=('slen',))
|
|
def _right_x(self, new_x):
|
|
if new_x is not None:
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self.x = new_x
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self.h += self.x
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@_dispatch(min=157, max=160, state=_dvistate.inpage, args=('slen1',))
|
|
def _down(self, a):
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self.v += a
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|
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@_dispatch(min=161, max=165, state=_dvistate.inpage, args=('slen',))
|
|
def _down_y(self, new_y):
|
|
if new_y is not None:
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self.y = new_y
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self.v += self.y
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|
|
|
@_dispatch(min=166, max=170, state=_dvistate.inpage, args=('slen',))
|
|
def _down_z(self, new_z):
|
|
if new_z is not None:
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|
self.z = new_z
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|
self.v += self.z
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|
|
|
@_dispatch(min=171, max=234, state=_dvistate.inpage)
|
|
def _fnt_num_immediate(self, k):
|
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self.f = k
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|
|
|
@_dispatch(min=235, max=238, state=_dvistate.inpage, args=('olen1',))
|
|
def _fnt_num(self, new_f):
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self.f = new_f
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|
|
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@_dispatch(min=239, max=242, args=('ulen1',))
|
|
def _xxx(self, datalen):
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|
special = self.file.read(datalen)
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|
_log.debug(
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'Dvi._xxx: encountered special: %s',
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''.join([chr(ch) if 32 <= ch < 127 else '<%02x>' % ch
|
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for ch in special]))
|
|
|
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@_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)
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|
|
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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:
|
|
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 psfonts.map 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 = re.search(r"(?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))
|
|
|
|
|
|
@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 <http://www.tug.org/kpathsea/>`_
|
|
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 os.name == '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('pdftex.map'))
|
|
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)
|