|
| 1 | +import logging |
| 2 | +from functools import partial |
| 3 | + |
| 4 | +from matplotlib.dviread import Dvi, _dvistate |
| 5 | +from matplotlib import _dviread |
| 6 | + |
| 7 | + |
| 8 | +_log = logging.getLogger(__name__) |
| 9 | + |
| 10 | + |
| 11 | +class Vf(Dvi): |
| 12 | + r""" |
| 13 | + A virtual font (\*.vf file) containing subroutines for dvi files. |
| 14 | +
|
| 15 | + Parameters |
| 16 | + ---------- |
| 17 | + filename : str or path-like |
| 18 | +
|
| 19 | + Notes |
| 20 | + ----- |
| 21 | + The virtual font format is a derivative of dvi: |
| 22 | + http://mirrors.ctan.org/info/knuth/virtual-fonts |
| 23 | + This class reuses some of the machinery of `Dvi` |
| 24 | + but replaces the `_read` loop and dispatch mechanism. |
| 25 | +
|
| 26 | + Examples |
| 27 | + -------- |
| 28 | + :: |
| 29 | +
|
| 30 | + vf = Vf(filename) |
| 31 | + glyph = vf[code] |
| 32 | + glyph.text, glyph.boxes, glyph.width |
| 33 | + """ |
| 34 | + |
| 35 | + def __init__(self, filename): |
| 36 | + super().__init__(filename, 0) |
| 37 | + try: |
| 38 | + self._first_font = None |
| 39 | + self._chars = {} |
| 40 | + self._read() |
| 41 | + finally: |
| 42 | + self.close() |
| 43 | + |
| 44 | + def __getitem__(self, code): |
| 45 | + return self._chars[code] |
| 46 | + |
| 47 | + def _read(self): |
| 48 | + """ |
| 49 | + Read one page from the file. Return True if successful, |
| 50 | + False if there were no more pages. |
| 51 | + """ |
| 52 | + packet_char, packet_ends = None, None |
| 53 | + packet_len, packet_width = None, None |
| 54 | + while True: |
| 55 | + byte = self.file.read(1)[0] |
| 56 | + # If we are in a packet, execute the dvi instructions |
| 57 | + if self.state is _dvistate.inpage: |
| 58 | + byte_at = self.file.tell()-1 |
| 59 | + if byte_at == packet_ends: |
| 60 | + self._finalize_packet(packet_char, packet_width) |
| 61 | + packet_len, packet_char, packet_width = None, None, None |
| 62 | + # fall through to out-of-packet code |
| 63 | + elif byte_at > packet_ends: |
| 64 | + raise ValueError("Packet length mismatch in vf file") |
| 65 | + else: |
| 66 | + if byte in (139, 140) or byte >= 243: |
| 67 | + raise ValueError( |
| 68 | + "Inappropriate opcode %d in vf file" % byte) |
| 69 | + Dvi._dtable[byte](self, byte) |
| 70 | + continue |
| 71 | + |
| 72 | + # We are outside a packet |
| 73 | + if byte < 242: # a short packet (length given by byte) |
| 74 | + packet_len = byte |
| 75 | + packet_char, packet_width = self._arg(1), self._arg(3) |
| 76 | + packet_ends = self._init_packet(byte) |
| 77 | + self.state = _dvistate.inpage |
| 78 | + elif byte == 242: # a long packet |
| 79 | + packet_len, packet_char, packet_width = \ |
| 80 | + [self._arg(x) for x in (4, 4, 4)] |
| 81 | + self._init_packet(packet_len) |
| 82 | + elif 243 <= byte <= 246: |
| 83 | + k = self._arg(byte - 242, byte == 246) |
| 84 | + c, s, d, a, l = [self._arg(x) for x in (4, 4, 4, 1, 1)] |
| 85 | + self._fnt_def_real(k, c, s, d, a, l) |
| 86 | + if self._first_font is None: |
| 87 | + self._first_font = k |
| 88 | + elif byte == 247: # preamble |
| 89 | + i, k = self._arg(1), self._arg(1) |
| 90 | + x = self.file.read(k) |
| 91 | + cs, ds = self._arg(4), self._arg(4) |
| 92 | + self._pre(i, x, cs, ds) |
| 93 | + elif byte == 248: # postamble (just some number of 248s) |
| 94 | + break |
| 95 | + else: |
| 96 | + raise ValueError("Unknown vf opcode %d" % byte) |
| 97 | + |
| 98 | + def _init_packet(self, pl): |
| 99 | + if self.state != _dvistate.outer: |
| 100 | + raise ValueError("Misplaced packet in vf file") |
| 101 | + self.h, self.v, self.w, self.x, self.y, self.z = 0, 0, 0, 0, 0, 0 |
| 102 | + self.stack, self.text, self.boxes = [], [], [] |
| 103 | + self.f = self._first_font |
| 104 | + return self.file.tell() + pl |
| 105 | + |
| 106 | + def _finalize_packet(self, packet_char, packet_width): |
| 107 | + self._chars[packet_char] = _dviread.Page( |
| 108 | + text=self.text, boxes=self.boxes, width=packet_width, |
| 109 | + height=None, descent=None) |
| 110 | + self.state = _dvistate.outer |
| 111 | + |
| 112 | + def _pre(self, i, x, cs, ds): |
| 113 | + if self.state is not _dvistate.pre: |
| 114 | + raise ValueError("pre command in middle of vf file") |
| 115 | + if i != 202: |
| 116 | + raise ValueError("Unknown vf format %d" % i) |
| 117 | + if len(x): |
| 118 | + _log.debug('vf file comment: %s', x) |
| 119 | + self.state = _dvistate.outer |
| 120 | + # cs = checksum, ds = design size |
| 121 | + |
| 122 | + |
| 123 | +_vffile = partial(_dviread._fontfile, Vf, ".vf") |
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