pgm(5)

NAME

pgm - portable graymap file format

DESCRIPTION

The portable graymap format is a lowest common denominator grayscale file format. The definition is as follows:

     Here is an example of a small graymap in this format:
     P2
     # feep.pgm
     24 7
     15
     0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
     0  3  3  3  3  0  0  7  7  7  7  0  0 11 11 11 11  0  0 15 15 15 15  0
     0  3  0  0  0  0  0  7  0  0  0  0  0 11  0  0  0  0  0 15  0  0 15  0
     0  3  3  3  0  0  0  7  7  7  0  0  0 11 11 11  0  0  0 15 15 15 15  0
     0  3  0  0  0  0  0  7  0  0  0  0  0 11  0  0  0  0  0 15  0  0  0  0
     0  3  0  0  0  0  0  7  7  7  7  0  0 11 11 11 11  0  0 15  0  0  0  0
     0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  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 graymap.

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:

Note that this raw format can only be used for maxvals less than or equal to 255. If you use the pgm 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

fitstopgm(1), fstopgm(1), hipstopgm(1), lispmtopgm(1), psidtopgm(1), rawtopgm(1), pgmbentley(1), pgmcrater(1), pgmedge(1), pgmenhance(1), pgmhist(1), pgmnorm(1), pgmoil(1), pgmramp(1), pgmtexture(1), pgmtofits(1), pgmtofs(1), pgmtolispm(1), pgmtopbm(1), pnm(5), pbm(5), ppm(5)

AUTHOR

Copyright (C) 1989, 1991 by Jef Poskanzer.