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79 lines
1.8 KiB
Python
79 lines
1.8 KiB
Python
#
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# The Python Imaging Library.
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# $Id$
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#
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# Basic McIdas support for PIL
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#
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# History:
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# 1997-05-05 fl Created (8-bit images only)
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# 2009-03-08 fl Added 16/32-bit support.
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#
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# Thanks to Richard Jones and Craig Swank for specs and samples.
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#
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# Copyright (c) Secret Labs AB 1997.
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# Copyright (c) Fredrik Lundh 1997.
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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 __future__ import annotations
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import struct
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from . import Image, ImageFile
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def _accept(prefix: bytes) -> bool:
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return prefix.startswith(b"\x00\x00\x00\x00\x00\x00\x00\x04")
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##
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# Image plugin for McIdas area images.
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class McIdasImageFile(ImageFile.ImageFile):
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format = "MCIDAS"
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format_description = "McIdas area file"
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def _open(self) -> None:
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# parse area file directory
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assert self.fp is not None
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s = self.fp.read(256)
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if not _accept(s) or len(s) != 256:
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msg = "not an McIdas area file"
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raise SyntaxError(msg)
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self.area_descriptor_raw = s
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self.area_descriptor = w = [0, *struct.unpack("!64i", s)]
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# get mode
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if w[11] == 1:
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mode = rawmode = "L"
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elif w[11] == 2:
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mode = rawmode = "I;16B"
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elif w[11] == 4:
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# FIXME: add memory map support
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mode = "I"
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rawmode = "I;32B"
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else:
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msg = "unsupported McIdas format"
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raise SyntaxError(msg)
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self._mode = mode
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self._size = w[10], w[9]
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offset = w[34] + w[15]
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stride = w[15] + w[10] * w[11] * w[14]
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self.tile = [
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ImageFile._Tile("raw", (0, 0) + self.size, offset, (rawmode, stride, 1))
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]
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# --------------------------------------------------------------------
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# registry
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Image.register_open(McIdasImageFile.format, McIdasImageFile, _accept)
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# no default extension
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