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- #
- # 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.
- #
-
- import io
-
- 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 = [
- 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, o):
- 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, charset_encoding="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):
- 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), io.SEEK_CUR) # 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):
- msg = "Wrong number of bitmaps"
- raise OSError(msg)
-
- offsets = []
- for i in range(nbitmaps):
- offsets.append(i32(fp.read(4)))
-
- bitmap_sizes = []
- for i in range(4):
- bitmap_sizes.append(i32(fp.read(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"
-
- 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):
- 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 = [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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