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- ppm(5) AMIGA (27 September 1991) ppm(5)
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- NAME
- ppm - portable pixmap file format
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- 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.
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- - Whitespace.
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- - A height, again in ASCII decimal.
-
- - Whitespace.
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- - The maximum color-component value, again in ASCII decimal.
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- - 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
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- Page 1 (printed 3/1/94)
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- ppm(5) AMIGA (27 September 1991) ppm(5)
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- the RAWBITS option at compile time. This variant is
- different in the following ways:
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- - The "magic number" is "P6" instead of "P3".
-
- - The pixel values are stored as plain bytes, instead of
- ASCII decimal.
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- - 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)
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- AUTHOR
- Copyright (C) 1989, 1991 by Jef Poskanzer.
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- Page 2 (printed 3/1/94)
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