Source code for bdflib.reader
# bdflib, a library for working with BDF font files
# Copyright (C) 2009-2022, Timothy Allen
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from bdflib import model
def _read_glyph(iterable, font):
glyphName = ""
codepoint = -1
bbX = 0
bbY = 0
bbW = 0
bbH = 0
advance = 0
hex_data = []
for key, values in iterable:
if key == b"STARTCHAR":
glyphName = values
elif key == b"ENCODING":
codepoint = int(values.split()[0])
elif key == b"DWIDTH":
advance = int(values.split()[0])
elif key == b"BBX":
bbW, bbH, bbX, bbY = map(int, values.split())
elif key == b"BITMAP":
# The next bbH lines describe the font bitmap.
hex_data = [next(iterable)[0] for _ in range(bbH)]
assert next(iterable)[0] == b"ENDCHAR"
break
int_data = []
for row in hex_data:
paddingbits = len(row) * 4 - bbW
int_data.append(int(row, 16) >> paddingbits)
# Make the list indices match the coordinate system
int_data.reverse()
font.new_glyph_from_data(
glyphName, int_data, bbX, bbY, bbW, bbH, advance, codepoint
)
def _unquote_property_value(value):
if value.startswith(b'"'):
# Must be a string. Remove the outer quotes and un-escape embedded
# quotes.
return value[1:-1].replace(b'""', b'"')
else:
# No quotes, must be an integer.
return int(value)
def _next_token(iterable, comments):
"""
Yields only non-whitespace, non-comment lines.
"""
for line in iterable:
parts = iter(line.strip().split(None, 1))
key = next(parts, None)
if not key:
continue
elif key == b"COMMENT":
comments.append(next(parts, b""))
else:
yield key, next(parts, None)
[docs]def read_bdf(raw_iterable):
"""
Read a BDF-format font from the given source.
:param raw_iterable: Each item should be a single line of the BDF file,
ASCII encoded.
:type raw_iterable: iterable of :class:`bytes`
:returns: the resulting font object
:rtype: :class:`.Font`
If you want to read an actual file, make sure you use the 'b' flag so
you get bytes instead of text::
font = bdflib.reader.read_bdf(open(path, 'rb'))
"""
name = b""
pointSize = 0
resX = 0
resY = 0
comments = []
font = None
iterable = _next_token(raw_iterable, comments)
for key, values in iterable:
if key == b"FONT":
name = values
elif key == b"SIZE":
pointSize, resX, resY = values.split()
pointSize = int(pointSize)
resX = int(resX)
resY = int(resY)
elif key == b"FONTBOUNDINGBOX":
# We don't care about the font bounding box, but it's the last
# header to come before the variable-length fields for which we
# need a font object around.
font = model.Font(name, pointSize, resX, resY)
elif key == b"STARTPROPERTIES":
assert font is not None
propertyCount = int(values)
for _ in range(propertyCount):
key, values = next(iterable)
font[key] = _unquote_property_value(values)
key, values = next(iterable)
assert key == b"ENDPROPERTIES"
elif key == b"CHARS":
for _ in range(int(values)):
_read_glyph(iterable, font)
break
assert next(iterable)[0] == b"ENDFONT"
# Set font comments
for c in comments:
font.add_comment(c)
return font