ppmtopgm (1)
convert a portable pixmap into a portable graymap
SYNOPSIS
DESCRIPTION
Reads a portable pixmap as input.
Produces a portable graymap as output.
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
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 ALSO
AUTHOR
Copyright (C) 1989 by Jef Poskanzer.
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