ppm(5)                 UNIX System V(27 September 1991)                  ppm(5)


NAME
      ppm - portable pixmap file format

DESCRIPTION
      The portable pixmap format is a lowest common denominator color image
      file format.  The definition is as follows:

      - A "magic number" for identifying the file type.  A ppm file's magic
        number is the two characters "P3".

      - Whitespace (blanks, TABs, CRs, LFs).

      - A width, formatted as ASCII characters in decimal.

      - Whitespace.

      - A height, again in ASCII decimal.

      - Whitespace.

      - The maximum color-component value, again in ASCII decimal.

      - Whitespace.

      - Width * height pixels, each three ASCII decimal values between 0 and
        the specified maximum value, starting at the top-left corner of the
        pixmap, proceeding in normal English reading order.  The three values
        for each pixel represent red, green, and blue, respectively; a value of
        0 means that color is off, and the maximum value means that color is
        maxxed out.

      - Characters from a "#" to the next end-of-line are ignored (comments).

      - No line should be longer than 70 characters.

      Here is an example of a small pixmap in this format:
      P3
      # feep.ppm
      4 4
      15
       0  0  0    0  0  0    0  0  0   15  0 15
       0  0  0    0 15  7    0  0  0    0  0  0
       0  0  0    0  0  0    0 15  7    0  0  0
      15  0 15    0  0  0    0  0  0    0  0  0

      Programs that read this format should be as lenient as possible,
      accepting anything that looks remotely like a pixmap.

      There is also a variant on the format, available by setting the RAWBITS
      option at compile time.  This variant is different in the following ways:




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ppm(5)                 UNIX System V(27 September 1991)                  ppm(5)


      - The "magic number" is "P6" instead of "P3".

      - The pixel values are stored as plain bytes, instead of ASCII decimal.

      - Whitespace is not allowed in the pixels area, and only a single
        character of whitespace (typically a newline) is allowed after the
        maxval.

      - The files are smaller and many times faster to read and write.

      Note that this raw format can only be used for maxvals less than or equal
      to 255.  If you use the ppm library and try to write a file with a larger
      maxval, it will automatically fall back on the slower but more general
      plain format.

SEE ALSO
      giftoppm(1), gouldtoppm(1), ilbmtoppm(1), imgtoppm(1), mtvtoppm(1),
      pcxtoppm(1), pgmtoppm(1), pi1toppm(1), picttoppm(1), pjtoppm(1),
      qrttoppm(1), rawtoppm(1), rgb3toppm(1), sldtoppm(1), spctoppm(1),
      sputoppm(1), tgatoppm(1), ximtoppm(1), xpmtoppm(1), yuvtoppm(1),
      ppmtoacad(1), ppmtogif(1), ppmtoicr(1), ppmtoilbm(1), ppmtopcx(1),
      ppmtopgm(1), ppmtopi1(1), ppmtopict(1), ppmtopj(1), ppmtopuzz(1),
      ppmtorgb3(1), ppmtosixel(1), ppmtotga(1), ppmtouil(1), ppmtoxpm(1),
      ppmtoyuv(1), ppmdither(1), ppmforge(1), ppmhist(1), ppmmake(1),
      ppmpat(1), ppmquant(1), ppmquantall(1), ppmrelief(1), pnm(5), pgm(5),
      pbm(5)

AUTHOR
      Copyright (C) 1989, 1991 by Jef Poskanzer.

























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