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Mini Shell
Mini Shell
#
# 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 __future__ import annotations
import io
from typing import BinaryIO, Callable
from . import FontFile, Image
from ._binary import i8
from ._binary import i16be as b16
from ._binary import i16le as l16
from ._binary import i32be as b32
from ._binary import i32le as l32
# --------------------------------------------------------------------
# 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: list[Callable[[int], int]] = [
lambda bits: ((bits + 7) >> 3),
lambda bits: ((bits + 15) >> 3) & ~1,
lambda bits: ((bits + 31) >> 3) & ~3,
lambda bits: ((bits + 63) >> 3) & ~7,
]
def sz(s: bytes, o: int) -> bytes:
return s[o : s.index(b"\0", o)]
class PcfFontFile(FontFile.FontFile):
"""Font file plugin for the X11 PCF format."""
name = "name"
def __init__(self, fp: BinaryIO, charset_encoding: str = "iso8859-1"):
self.charset_encoding = charset_encoding
magic = l32(fp.read(4))
if magic != PCF_MAGIC:
msg = "not a PCF file"
raise SyntaxError(msg)
super().__init__()
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, ix in enumerate(encoding):
if ix is not None:
(
xsize,
ysize,
left,
right,
width,
ascent,
descent,
attributes,
) = metrics[ix]
self.glyph[ch] = (
(width, 0),
(left, descent - ysize, xsize + left, descent),
(0, 0, xsize, ysize),
bitmaps[ix],
)
def _getformat(
self, tag: int
) -> tuple[BinaryIO, int, Callable[[bytes], int], Callable[[bytes], int]]:
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) -> dict[bytes, bytes | int]:
#
# font properties
properties = {}
fp, format, i16, i32 = self._getformat(PCF_PROPERTIES)
nprops = i32(fp.read(4))
# read property description
p = [(i32(fp.read(4)), i8(fp.read(1)), i32(fp.read(4))) for _ in range(nprops)]
if nprops & 3:
fp.seek(4 - (nprops & 3), io.SEEK_CUR) # pad
data = fp.read(i32(fp.read(4)))
for k, s, v in p:
property_value: bytes | int = sz(data, v) if s else v
properties[sz(data, k)] = property_value
return properties
def _load_metrics(self) -> list[tuple[int, int, int, int, int, int, int, int]]:
#
# font metrics
metrics: list[tuple[int, int, int, int, int, int, int, int]] = []
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: list[tuple[int, int, int, int, int, int, int, int]]
) -> list[Image.Image]:
#
# bitmap data
fp, format, i16, i32 = self._getformat(PCF_BITMAPS)
nbitmaps = i32(fp.read(4))
if nbitmaps != len(metrics):
msg = "Wrong number of bitmaps"
raise OSError(msg)
offsets = [i32(fp.read(4)) for _ in range(nbitmaps)]
bitmap_sizes = [i32(fp.read(4)) for _ in range(4)]
# byteorder = format & 4 # non-zero => MSB
bitorder = format & 8 # non-zero => MSB
padindex = format & 3
bitmapsize = bitmap_sizes[padindex]
offsets.append(bitmapsize)
data = fp.read(bitmapsize)
pad = BYTES_PER_ROW[padindex]
mode = "1;R"
if bitorder:
mode = "1"
bitmaps = []
for i in range(nbitmaps):
xsize, ysize = metrics[i][:2]
b, e = offsets[i : i + 2]
bitmaps.append(
Image.frombytes("1", (xsize, ysize), data[b:e], "raw", mode, pad(xsize))
)
return bitmaps
def _load_encoding(self) -> list[int | None]:
fp, format, i16, i32 = self._getformat(PCF_BDF_ENCODINGS)
first_col, last_col = i16(fp.read(2)), i16(fp.read(2))
first_row, last_row = i16(fp.read(2)), i16(fp.read(2))
i16(fp.read(2)) # default
nencoding = (last_col - first_col + 1) * (last_row - first_row + 1)
# map character code to bitmap index
encoding: list[int | None] = [None] * min(256, nencoding)
encoding_offsets = [i16(fp.read(2)) for _ in range(nencoding)]
for i in range(first_col, len(encoding)):
try:
encoding_offset = encoding_offsets[
ord(bytearray([i]).decode(self.charset_encoding))
]
if encoding_offset != 0xFFFF:
encoding[i] = encoding_offset
except UnicodeDecodeError:
# character is not supported in selected encoding
pass
return encoding
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