134 lines
3.4 KiB
Python
134 lines
3.4 KiB
Python
#
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# The Python Imaging Library
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# $Id$
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#
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# bitmap distribution font (bdf) file parser
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#
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# history:
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# 1996-05-16 fl created (as bdf2pil)
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# 1997-08-25 fl converted to FontFile driver
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# 2001-05-25 fl removed bogus __init__ call
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# 2002-11-20 fl robustification (from Kevin Cazabon, Dmitry Vasiliev)
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# 2003-04-22 fl more robustification (from Graham Dumpleton)
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#
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# Copyright (c) 1997-2003 by Secret Labs AB.
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# Copyright (c) 1997-2003 by Fredrik Lundh.
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#
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# See the README file for information on usage and redistribution.
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#
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"""
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Parse X Bitmap Distribution Format (BDF)
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"""
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from __future__ import annotations
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from typing import BinaryIO
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from . import FontFile, Image
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bdf_slant = {
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"R": "Roman",
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"I": "Italic",
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"O": "Oblique",
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"RI": "Reverse Italic",
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"RO": "Reverse Oblique",
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"OT": "Other",
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}
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bdf_spacing = {"P": "Proportional", "M": "Monospaced", "C": "Cell"}
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def bdf_char(
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f: BinaryIO,
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) -> (
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tuple[
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str,
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int,
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tuple[tuple[int, int], tuple[int, int, int, int], tuple[int, int, int, int]],
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Image.Image,
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]
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| None
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):
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# skip to STARTCHAR
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while True:
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s = f.readline()
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if not s:
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return None
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if s[:9] == b"STARTCHAR":
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break
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id = s[9:].strip().decode("ascii")
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# load symbol properties
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props = {}
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while True:
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s = f.readline()
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if not s or s[:6] == b"BITMAP":
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break
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i = s.find(b" ")
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props[s[:i].decode("ascii")] = s[i + 1 : -1].decode("ascii")
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# load bitmap
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bitmap = bytearray()
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while True:
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s = f.readline()
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if not s or s[:7] == b"ENDCHAR":
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break
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bitmap += s[:-1]
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# The word BBX
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# followed by the width in x (BBw), height in y (BBh),
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# and x and y displacement (BBxoff0, BByoff0)
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# of the lower left corner from the origin of the character.
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width, height, x_disp, y_disp = (int(p) for p in props["BBX"].split())
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# The word DWIDTH
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# followed by the width in x and y of the character in device pixels.
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dwx, dwy = (int(p) for p in props["DWIDTH"].split())
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bbox = (
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(dwx, dwy),
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(x_disp, -y_disp - height, width + x_disp, -y_disp),
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(0, 0, width, height),
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)
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try:
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im = Image.frombytes("1", (width, height), bitmap, "hex", "1")
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except ValueError:
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# deal with zero-width characters
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im = Image.new("1", (width, height))
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return id, int(props["ENCODING"]), bbox, im
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class BdfFontFile(FontFile.FontFile):
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"""Font file plugin for the X11 BDF format."""
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def __init__(self, fp: BinaryIO) -> None:
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super().__init__()
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s = fp.readline()
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if s[:13] != b"STARTFONT 2.1":
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msg = "not a valid BDF file"
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raise SyntaxError(msg)
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props = {}
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comments = []
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while True:
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s = fp.readline()
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if not s or s[:13] == b"ENDPROPERTIES":
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break
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i = s.find(b" ")
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props[s[:i].decode("ascii")] = s[i + 1 : -1].decode("ascii")
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if s[:i] in [b"COMMENT", b"COPYRIGHT"]:
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if s.find(b"LogicalFontDescription") < 0:
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comments.append(s[i + 1 : -1].decode("ascii"))
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while True:
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c = bdf_char(fp)
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if not c:
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break
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id, ch, (xy, dst, src), im = c
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if 0 <= ch < len(self.glyph):
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self.glyph[ch] = xy, dst, src, im
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