Source code for PIL.PpmImagePlugin

#
# The Python Imaging Library.
# $Id$
#
# PPM support for PIL
#
# History:
#       96-03-24 fl     Created
#       98-03-06 fl     Write RGBA images (as RGB, that is)
#
# Copyright (c) Secret Labs AB 1997-98.
# Copyright (c) Fredrik Lundh 1996.
#
# See the README file for information on usage and redistribution.
#


from . import Image, ImageFile

__version__ = "0.2"

#
# --------------------------------------------------------------------

b_whitespace = b'\x20\x09\x0a\x0b\x0c\x0d'

MODES = {
    # standard
    b"P4": "1",
    b"P5": "L",
    b"P6": "RGB",
    # extensions
    b"P0CMYK": "CMYK",
    # PIL extensions (for test purposes only)
    b"PyP": "P",
    b"PyRGBA": "RGBA",
    b"PyCMYK": "CMYK"
}


def _accept(prefix):
    return prefix[0:1] == b"P" and prefix[1] in b"0456y"


##
# Image plugin for PBM, PGM, and PPM images.

[docs]class PpmImageFile(ImageFile.ImageFile): format = "PPM" format_description = "Pbmplus image" def _token(self, s=b""): while True: # read until next whitespace c = self.fp.read(1) if not c or c in b_whitespace: break if c > b'\x79': raise ValueError("Expected ASCII value, found binary") s = s + c if (len(s) > 9): raise ValueError("Expected int, got > 9 digits") return s def _open(self): # check magic s = self.fp.read(1) if s != b"P": raise SyntaxError("not a PPM file") mode = MODES[self._token(s)] if mode == "1": self.mode = "1" rawmode = "1;I" else: self.mode = rawmode = mode for ix in range(3): while True: while True: s = self.fp.read(1) if s not in b_whitespace: break if s == b"": raise ValueError( "File does not extend beyond magic number") if s != b"#": break s = self.fp.readline() s = int(self._token(s)) if ix == 0: xsize = s elif ix == 1: ysize = s if mode == "1": break elif ix == 2: # maxgrey if s > 255: if not mode == 'L': raise ValueError("Too many colors for band: %s" % s) if s < 2**16: self.mode = 'I' rawmode = 'I;16B' else: self.mode = 'I' rawmode = 'I;32B' self._size = xsize, ysize self.tile = [("raw", (0, 0, xsize, ysize), self.fp.tell(), (rawmode, 0, 1))]
# # -------------------------------------------------------------------- def _save(im, fp, filename): if im.mode == "1": rawmode, head = "1;I", b"P4" elif im.mode == "L": rawmode, head = "L", b"P5" elif im.mode == "I": if im.getextrema()[1] < 2**16: rawmode, head = "I;16B", b"P5" else: rawmode, head = "I;32B", b"P5" elif im.mode == "RGB": rawmode, head = "RGB", b"P6" elif im.mode == "RGBA": rawmode, head = "RGB", b"P6" else: raise IOError("cannot write mode %s as PPM" % im.mode) fp.write(head + ("\n%d %d\n" % im.size).encode('ascii')) if head == b"P6": fp.write(b"255\n") if head == b"P5": if rawmode == "L": fp.write(b"255\n") elif rawmode == "I;16B": fp.write(b"65535\n") elif rawmode == "I;32B": fp.write(b"2147483648\n") ImageFile._save(im, fp, [("raw", (0, 0)+im.size, 0, (rawmode, 0, 1))]) # ALTERNATIVE: save via builtin debug function # im._dump(filename) # # -------------------------------------------------------------------- Image.register_open(PpmImageFile.format, PpmImageFile, _accept) Image.register_save(PpmImageFile.format, _save) Image.register_extensions(PpmImageFile.format, [".pbm", ".pgm", ".ppm"])