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