Pillow/src/PIL/BdfFontFile.py

123 lines
3.2 KiB
Python

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