74 lines
2.0 KiB
Python
74 lines
2.0 KiB
Python
|
#
|
||
|
|
# 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.
|
||
|
|
#
|
||
|
|
|
||
|
|
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"
|
||
|
|
# rawmode = "I;16S"
|
||
|
|
elif number_of_bits == 32:
|
||
|
|
self.mode = "I"
|
||
|
|
elif number_of_bits in (-32, -64):
|
||
|
|
self.mode = "F"
|
||
|
|
# rawmode = "F" if number_of_bits == -32 else "F;64F"
|
||
|
|
|
||
|
|
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"])
|