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ppm (5)
  • >> ppm (5) ( Solaris man: Форматы файлов )
  • ppm (5) ( Разные man: Форматы файлов )
  • 
    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, proceding 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  pos-
         sible, 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 dif-
         ferent in the following ways:
    
         - 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.
    
         - 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 ASCII format.
    
    SEE ALSO
         giftoppm(1),   ilbmtoppm(1),    imgtoppm(1),    mtvtoppm(1),
         qrttoppm(1),  rasttoppm(1), tgatoppm(1), xwdtoppm(1), ppmto-
         gif(1), ppmtoilbm(1), ppmtopgm(1), ppmtops(1), ppmtorast(1),
         ppmtoxwd(1),    ppmarith(1),   ppmconvol(1),   ppmcscale(1),
         ppmhist(1),    ppmquant(1),    ppmrotate(1),    ppmscale(1),
         ppmshear(1), pnm(5), pgm(5), pbm(5)
    
    AUTHOR
         Copyright (C) 1989 by Jef Poskanzer.
    
         Permission  to  use,  copy,  modify,  and  distribute   this
         software  and  its documentation for any purpose and without
         fee is hereby granted, provided  that  the  above  copyright
         notice  appear  in  all  copies and that both that copyright
         notice and this permission notice appear in supporting docu-
         mentation.   This  software  is  provided  "as  is"  without
         express or implied warranty.
    
    
    
    


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