Viewing file:  PcfFontFile.py (6.05 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
#
# THIS IS WORK IN PROGRESS
#
# The Python Imaging Library
# $Id$
#
# portable compiled font file parser
#
# history:
# 1997-08-19 fl created
# 2003-09-13 fl fixed loading of unicode fonts
#
# 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.
#
from PIL import Image
from PIL import FontFile
from PIL import _binary
# --------------------------------------------------------------------
# declarations
PCF_MAGIC = 0x70636601 # "\x01fcp"
PCF_PROPERTIES = (1 << 0)
PCF_ACCELERATORS = (1 << 1)
PCF_METRICS = (1 << 2)
PCF_BITMAPS = (1 << 3)
PCF_INK_METRICS = (1 << 4)
PCF_BDF_ENCODINGS = (1 << 5)
PCF_SWIDTHS = (1 << 6)
PCF_GLYPH_NAMES = (1 << 7)
PCF_BDF_ACCELERATORS = (1 << 8)
BYTES_PER_ROW = [
lambda bits: ((bits+7) >> 3),
lambda bits: ((bits+15) >> 3) & ~1,
lambda bits: ((bits+31) >> 3) & ~3,
lambda bits: ((bits+63) >> 3) & ~7,
]
i8 = _binary.i8
l16 = _binary.i16le
l32 = _binary.i32le
b16 = _binary.i16be
b32 = _binary.i32be
def sz(s, o):
return s[o:s.index(b"\0", o)]
##
# Font file plugin for the X11 PCF format.
class PcfFontFile(FontFile.FontFile):
name = "name"
def __init__(self, fp):
magic = l32(fp.read(4))
if magic != PCF_MAGIC:
raise SyntaxError("not a PCF file")
FontFile.FontFile.__init__(self)
count = l32(fp.read(4))
self.toc = {}
for i in range(count):
type = l32(fp.read(4))
self.toc[type] = l32(fp.read(4)), l32(fp.read(4)), l32(fp.read(4))
self.fp = fp
self.info = self._load_properties()
metrics = self._load_metrics()
bitmaps = self._load_bitmaps(metrics)
encoding = self._load_encoding()
#
# create glyph structure
for ch in range(256):
ix = encoding[ch]
if ix is not None:
x, y, l, r, w, a, d, f = metrics[ix]
glyph = (w, 0), (l, d-y, x+l, d), (0, 0, x, y), bitmaps[ix]
self.glyph[ch] = glyph
def _getformat(self, tag):
format, size, offset = self.toc[tag]
fp = self.fp
fp.seek(offset)
format = l32(fp.read(4))
if format & 4:
i16, i32 = b16, b32
else:
i16, i32 = l16, l32
return fp, format, i16, i32
def _load_properties(self):
#
# font properties
properties = {}
fp, format, i16, i32 = self._getformat(PCF_PROPERTIES)
nprops = i32(fp.read(4))
# read property description
p = []
for i in range(nprops):
p.append((i32(fp.read(4)), i8(fp.read(1)), i32(fp.read(4))))
if nprops & 3:
fp.seek(4 - (nprops & 3), 1) # pad
data = fp.read(i32(fp.read(4)))
for k, s, v in p:
k = sz(data, k)
if s:
v = sz(data, v)
properties[k] = v
return properties
def _load_metrics(self):
#
# font metrics
metrics = []
fp, format, i16, i32 = self._getformat(PCF_METRICS)
append = metrics.append
if (format & 0xff00) == 0x100:
# "compressed" metrics
for i in range(i16(fp.read(2))):
left = i8(fp.read(1)) - 128
right = i8(fp.read(1)) - 128
width = i8(fp.read(1)) - 128
ascent = i8(fp.read(1)) - 128
descent = i8(fp.read(1)) - 128
xsize = right - left
ysize = ascent + descent
append(
(xsize, ysize, left, right, width,
ascent, descent, 0)
)
else:
# "jumbo" metrics
for i in range(i32(fp.read(4))):
left = i16(fp.read(2))
right = i16(fp.read(2))
width = i16(fp.read(2))
ascent = i16(fp.read(2))
descent = i16(fp.read(2))
attributes = i16(fp.read(2))
xsize = right - left
ysize = ascent + descent
append(
(xsize, ysize, left, right, width,
ascent, descent, attributes)
)
return metrics
def _load_bitmaps(self, metrics):
#
# bitmap data
bitmaps = []
fp, format, i16, i32 = self._getformat(PCF_BITMAPS)
nbitmaps = i32(fp.read(4))
if nbitmaps != len(metrics):
raise IOError("Wrong number of bitmaps")
offsets = []
for i in range(nbitmaps):
offsets.append(i32(fp.read(4)))
bitmapSizes = []
for i in range(4):
bitmapSizes.append(i32(fp.read(4)))
# byteorder = format & 4 # non-zero => MSB
bitorder = format & 8 # non-zero => MSB
padindex = format & 3
bitmapsize = bitmapSizes[padindex]
offsets.append(bitmapsize)
data = fp.read(bitmapsize)
pad = BYTES_PER_ROW[padindex]
mode = "1;R"
if bitorder:
mode = "1"
for i in range(nbitmaps):
x, y, l, r, w, a, d, f = metrics[i]
b, e = offsets[i], offsets[i+1]
bitmaps.append(
Image.frombytes("1", (x, y), data[b:e], "raw", mode, pad(x))
)
return bitmaps
def _load_encoding(self):
# map character code to bitmap index
encoding = [None] * 256
fp, format, i16, i32 = self._getformat(PCF_BDF_ENCODINGS)
firstCol, lastCol = i16(fp.read(2)), i16(fp.read(2))
firstRow, lastRow = i16(fp.read(2)), i16(fp.read(2))
default = i16(fp.read(2))
nencoding = (lastCol - firstCol + 1) * (lastRow - firstRow + 1)
for i in range(nencoding):
encodingOffset = i16(fp.read(2))
if encodingOffset != 0xFFFF:
try:
encoding[i+firstCol] = encodingOffset
except IndexError:
break # only load ISO-8859-1 glyphs
return encoding
|