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