#
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# The Python Imaging Library.
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# $Id$
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#
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# DCX file handling
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#
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# DCX is a container file format defined by Intel, commonly used
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# for fax applications. Each DCX file consists of a directory
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# (a list of file offsets) followed by a set of (usually 1-bit)
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# PCX files.
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#
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# History:
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# 1995-09-09 fl Created
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# 1996-03-20 fl Properly derived from PcxImageFile.
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# 1998-07-15 fl Renamed offset attribute to avoid name clash
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# 2002-07-30 fl Fixed file handling
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#
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# Copyright (c) 1997-98 by Secret Labs AB.
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# Copyright (c) 1995-96 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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__version__ = "0.2"
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import Image
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from PcxImagePlugin import PcxImageFile
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MAGIC = 0x3ADE68B1 # QUIZ: what's this value, then?
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def i32(c):
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return ord(c[0]) + (ord(c[1])<<8) + (ord(c[2])<<16) + (ord(c[3])<<24)
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def _accept(prefix):
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return i32(prefix) == MAGIC
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##
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# Image plugin for the Intel DCX format.
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class DcxImageFile(PcxImageFile):
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format = "DCX"
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format_description = "Intel DCX"
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def _open(self):
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# Header
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s = self.fp.read(4)
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if i32(s) != MAGIC:
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raise SyntaxError, "not a DCX file"
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# Component directory
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self._offset = []
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for i in range(1024):
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offset = i32(self.fp.read(4))
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if not offset:
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break
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self._offset.append(offset)
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self.__fp = self.fp
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self.seek(0)
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def seek(self, frame):
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if frame >= len(self._offset):
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raise EOFError("attempt to seek outside DCX directory")
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self.frame = frame
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self.fp = self.__fp
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self.fp.seek(self._offset[frame])
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PcxImageFile._open(self)
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def tell(self):
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return self.frame
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Image.register_open("DCX", DcxImageFile, _accept)
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Image.register_extension("DCX", ".dcx")
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