ppmcolormask
produce mask of areas of a certain color in a PPM file
see also :
pgmtoppm - pnmcomp - pbmmask
Synopsis
ppmcolormask
color [ppmfile]
add an example, a script, a trick and tips
examples
source
colors="rgbi:1/0/0 rgbi:1/0/1 rgbi:0/0/1
rgbi:0/1/1 rgbi:0/1/0 rgbi:1/1/0 rgbi:.5/0/0 rgbi:.5/0/.5
rgbi:0/0/.5 rgbi:0/.5/.5 rgbi:0/.5/0 rgbi:.5/.5/0"
i=0
for color in $colors; do
cmask[$i]="$tmpdir/cmask$i.pbm"
ppmcolormask $color $cutout | pnminvert > ${cmask[$i]}
description
Reads a PPM
file as input. Produces a PBM (bitmap) file as output. The
output file is the same dimensions as the input file and is
black in all places where the input file is the color
color, and white everywhere else.
The output of
ppmcolormask is useful as an alpha mask input to
pnmcomp. Note that you can generate such an alpha
mask automatically as you convert to PNG format with
pnmtopng(1). Use its -transparent option.
ppmfile
is the input file. If you don’t specify
ppmfile, the input is from Standard Input.
The output goes
to Standard Output.
You can specify
color five ways:
o
An X11-style color name (e.g. black).
o
An X11-style hexadecimal specifier: rgb:r/g/b, where r g
and b are each 1- to 4-digit hexadecimal numbers.
o
An X11-style decimal specifier: rgbi:r/g/b, where r g
and b are floating point numbers between 0 and 1.
o
For backwards compatibility, an old-X11-style
hexadecimal number: #rgb, #rrggbb, #rrrgggbbb, or
#rrrrggggbbbb.
o
For backwards compatibility, a triplet of numbers
separated by commas: r,g,b, where r g and b are floating
point numbers between 0 and 1. (This style was added before
MIT came up with the similar rgbi style.)
see also
pgmtoppm ,
pnmcomp , pbmmask , ppm
author
Bryan Henderson
(bryanh@giraffe-data.com)