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1#
2# The Python Imaging Library.
3# $Id$
4#
5# Basic McIdas support for PIL
6#
7# History:
8# 1997-05-05 fl Created (8-bit images only)
9# 2009-03-08 fl Added 16/32-bit support.
10#
11# Thanks to Richard Jones and Craig Swank for specs and samples.
12#
13# Copyright (c) Secret Labs AB 1997.
14# Copyright (c) Fredrik Lundh 1997.
15#
16# See the README file for information on usage and redistribution.
17#
18from __future__ import annotations
20import struct
22from . import Image, ImageFile
25def _accept(prefix: bytes) -> bool:
26 return prefix[:8] == b"\x00\x00\x00\x00\x00\x00\x00\x04"
29##
30# Image plugin for McIdas area images.
33class McIdasImageFile(ImageFile.ImageFile):
34 format = "MCIDAS"
35 format_description = "McIdas area file"
37 def _open(self) -> None:
38 # parse area file directory
39 assert self.fp is not None
41 s = self.fp.read(256)
42 if not _accept(s) or len(s) != 256:
43 msg = "not an McIdas area file"
44 raise SyntaxError(msg)
46 self.area_descriptor_raw = s
47 self.area_descriptor = w = [0] + list(struct.unpack("!64i", s))
49 # get mode
50 if w[11] == 1:
51 mode = rawmode = "L"
52 elif w[11] == 2:
53 # FIXME: add memory map support
54 mode = "I"
55 rawmode = "I;16B"
56 elif w[11] == 4:
57 # FIXME: add memory map support
58 mode = "I"
59 rawmode = "I;32B"
60 else:
61 msg = "unsupported McIdas format"
62 raise SyntaxError(msg)
64 self._mode = mode
65 self._size = w[10], w[9]
67 offset = w[34] + w[15]
68 stride = w[15] + w[10] * w[11] * w[14]
70 self.tile = [("raw", (0, 0) + self.size, offset, (rawmode, stride, 1))]
73# --------------------------------------------------------------------
74# registry
76Image.register_open(McIdasImageFile.format, McIdasImageFile, _accept)
78# no default extension