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from __future__ import annotations |
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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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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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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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Image.register_open(FitsImageFile.format, FitsImageFile, _accept) |
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Image.register_extensions(FitsImageFile.format, [".fit", ".fits"]) |
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