ppmtopgm(1)ppmtopgm(1)NAMEppmtopgm - convert a portable pixmap into a portable graymap
SYNOPSISppmtopgm [ppmfile]
DESCRIPTION
Reads a portable pixmap as input. Produces a portable graymap as out‐
put. The quantization formula used is .299 r + .587 g + .114 b.
Note that although there is a pgmtoppm program, it is not necessary for
simple conversions from pgm to ppm, because any ppm program can read
pgm (and pbm ) files automagically. pgmtoppm is for colorizing a pgm
file. Also, see ppmtorgb3 for a different way of converting color to
gray.
QUOTE
Cold-hearted orb that rules the night
Removes the colors from our sight
Red is gray, and yellow white
But we decide which is right
And which is a quantization error.
SEE ALSOpgmtoppm(1), ppmtorgb3(1), rgb3toppm(1), ppm(5), pgm(5)AUTHOR
Copyright (C) 1989 by Jef Poskanzer.
23 December 1988 ppmtopgm(1)