74 lines
2.0 KiB
Python
74 lines
2.0 KiB
Python
#
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# The Python Imaging Library
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# $Id$
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#
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# FITS file handling
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#
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# Copyright (c) 1998-2003 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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import math
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from . import Image, ImageFile
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def _accept(prefix):
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return prefix[:6] == b"SIMPLE"
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class FitsImageFile(ImageFile.ImageFile):
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format = "FITS"
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format_description = "FITS"
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def _open(self):
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headers = {}
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while True:
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header = self.fp.read(80)
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if not header:
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msg = "Truncated FITS file"
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raise OSError(msg)
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keyword = header[:8].strip()
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if keyword == b"END":
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break
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value = header[8:].split(b"/")[0].strip()
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if value.startswith(b"="):
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value = value[1:].strip()
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if not headers and (not _accept(keyword) or value != b"T"):
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msg = "Not a FITS file"
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raise SyntaxError(msg)
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headers[keyword] = value
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naxis = int(headers[b"NAXIS"])
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if naxis == 0:
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msg = "No image data"
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raise ValueError(msg)
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elif naxis == 1:
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self._size = 1, int(headers[b"NAXIS1"])
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else:
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self._size = int(headers[b"NAXIS1"]), int(headers[b"NAXIS2"])
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number_of_bits = int(headers[b"BITPIX"])
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if number_of_bits == 8:
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self.mode = "L"
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elif number_of_bits == 16:
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self.mode = "I"
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# rawmode = "I;16S"
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elif number_of_bits == 32:
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self.mode = "I"
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elif number_of_bits in (-32, -64):
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self.mode = "F"
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# rawmode = "F" if number_of_bits == -32 else "F;64F"
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offset = math.ceil(self.fp.tell() / 2880) * 2880
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self.tile = [("raw", (0, 0) + self.size, offset, (self.mode, 0, -1))]
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# --------------------------------------------------------------------
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# Registry
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Image.register_open(FitsImageFile.format, FitsImageFile, _accept)
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Image.register_extensions(FitsImageFile.format, [".fit", ".fits"])
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