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