157 lines
4.1 KiB
Python
157 lines
4.1 KiB
Python
#
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# The Python Imaging Library.
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# $Id$
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#
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# PPM support for PIL
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#
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# History:
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# 96-03-24 fl Created
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# 98-03-06 fl Write RGBA images (as RGB, that is)
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#
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# Copyright (c) Secret Labs AB 1997-98.
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# Copyright (c) Fredrik Lundh 1996.
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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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from . import Image, ImageFile
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__version__ = "0.2"
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#
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# --------------------------------------------------------------------
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b_whitespace = b'\x20\x09\x0a\x0b\x0c\x0d'
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MODES = {
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# standard
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b"P4": "1",
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b"P5": "L",
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b"P6": "RGB",
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# extensions
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b"P0CMYK": "CMYK",
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# PIL extensions (for test purposes only)
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b"PyP": "P",
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b"PyRGBA": "RGBA",
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b"PyCMYK": "CMYK"
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}
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def _accept(prefix):
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return prefix[0:1] == b"P" and prefix[1] in b"0456y"
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##
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# Image plugin for PBM, PGM, and PPM images.
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class PpmImageFile(ImageFile.ImageFile):
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format = "PPM"
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format_description = "Pbmplus image"
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def _token(self, s=b""):
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while True: # read until next whitespace
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c = self.fp.read(1)
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if not c or c in b_whitespace:
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break
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if c > b'\x79':
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raise ValueError("Expected ASCII value, found binary")
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s = s + c
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if (len(s) > 9):
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raise ValueError("Expected int, got > 9 digits")
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return s
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def _open(self):
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# check magic
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s = self.fp.read(1)
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if s != b"P":
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raise SyntaxError("not a PPM file")
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mode = MODES[self._token(s)]
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if mode == "1":
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self.mode = "1"
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rawmode = "1;I"
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else:
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self.mode = rawmode = mode
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for ix in range(3):
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while True:
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while True:
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s = self.fp.read(1)
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if s not in b_whitespace:
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break
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if s == b"":
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raise ValueError("File does not extend beyond magic number")
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if s != b"#":
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break
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s = self.fp.readline()
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s = int(self._token(s))
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if ix == 0:
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xsize = s
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elif ix == 1:
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ysize = s
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if mode == "1":
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break
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elif ix == 2:
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# maxgrey
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if s > 255:
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if not mode == 'L':
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raise ValueError("Too many colors for band: %s" % s)
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if s < 2**16:
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self.mode = 'I'
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rawmode = 'I;16B'
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else:
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self.mode = 'I'
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rawmode = 'I;32B'
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self.size = xsize, ysize
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self.tile = [("raw",
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(0, 0, xsize, ysize),
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self.fp.tell(),
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(rawmode, 0, 1))]
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#
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# --------------------------------------------------------------------
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def _save(im, fp, filename):
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if im.mode == "1":
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rawmode, head = "1;I", b"P4"
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elif im.mode == "L":
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rawmode, head = "L", b"P5"
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elif im.mode == "I":
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if im.getextrema()[1] < 2**16:
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rawmode, head = "I;16B", b"P5"
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else:
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rawmode, head = "I;32B", b"P5"
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elif im.mode == "RGB":
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rawmode, head = "RGB", b"P6"
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elif im.mode == "RGBA":
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rawmode, head = "RGB", b"P6"
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else:
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raise IOError("cannot write mode %s as PPM" % im.mode)
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fp.write(head + ("\n%d %d\n" % im.size).encode('ascii'))
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if head == b"P6":
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fp.write(b"255\n")
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if head == b"P5":
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if rawmode == "L":
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fp.write(b"255\n")
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elif rawmode == "I;16B":
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fp.write(b"65535\n")
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elif rawmode == "I;32B":
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fp.write(b"2147483648\n")
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ImageFile._save(im, fp, [("raw", (0, 0)+im.size, 0, (rawmode, 0, 1))])
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# ALTERNATIVE: save via builtin debug function
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# im._dump(filename)
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#
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# --------------------------------------------------------------------
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Image.register_open(PpmImageFile.format, PpmImageFile, _accept)
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Image.register_save(PpmImageFile.format, _save)
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Image.register_extensions(PpmImageFile.format, [".pbm", ".pgm", ".ppm"])
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