NAME¶
ppmcolormask - produce mask of areas of a certain color in a PPM file
SYNOPSIS¶
ppmcolormask color [
ppmfile]
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(1),
pnmcomp(1),
pbmmask(1),
ppm(5)
AUTHOR¶
Bryan Henderson (bryanh@giraffe-data.com)