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<H1>ppmcolormask</H1>
Section: User Commands (1)<BR>Updated: 14 April 2000<BR><A HREF="#index">Index</A>
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
<A NAME="ixAAB"></A>
<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>
ppmcolormask - produce mask of areas of a certain color in a PPM file
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<B>ppmcolormask</B>
<I>color</I>
[<I>ppmfile</I>]
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
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
<I>color</I>,
and white everywhere else.
<P>
The output of
<B>ppmcolormask</B>
is useful as an alpha mask input to
<B>pnmcomp</B>.
Note that you can generate such an alpha mask automatically as you convert
to PNG format with
<B><A HREF="/cgi-bin/man/man2html?1+pnmtopng">pnmtopng</A></B>(1).
Use its
<B>-transparent</B>
option.
<P>
<I>ppmfile</I>
is the input file. If you don't specify
<I>ppmfile</I>,
the input is from Standard Input.
<P>
The output goes to Standard Output.
<P>
You can specify
<I>color</I>
five ways:
<A NAME="ixAAC"></A>
<DL COMPACT>
<DT id="1">o<DD>
An X11-style color name (e.g.
<B>black</B>).
<DT id="2">o <DD>
An X11-style hexadecimal specifier: rgb:r/g/b, where r g and b are
each 1- to 4-digit hexadecimal numbers.
<DT id="3">o<DD>
An X11-style decimal specifier: rgbi:r/g/b, where r g and b are
floating point numbers between 0 and 1.
<DT id="4">o <DD>
For backwards compatibility, an old-X11-style hexadecimal number:
#rgb, #rrggbb, #rrrgggbbb, or #rrrrggggbbbb.
<DT id="5">o <DD>
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.)
<P>
</DL>
<A NAME="lbAE">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?1+pgmtoppm">pgmtoppm</A></B>(1),
<B><A HREF="/cgi-bin/man/man2html?1+pnmcomp">pnmcomp</A></B>(1),
<B><A HREF="/cgi-bin/man/man2html?1+pbmmask">pbmmask</A></B>(1),
<B><A HREF="/cgi-bin/man/man2html?5+ppm">ppm</A>(5)</B>
<P>
<A NAME="lbAF">&nbsp;</A>
<H2>AUTHOR</H2>
Bryan Henderson (<A HREF="mailto:bryanh@giraffe-data.com">bryanh@giraffe-data.com</A>)
<P>
<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT id="6"><A HREF="#lbAB">NAME</A><DD>
<DT id="7"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="8"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="9"><A HREF="#lbAE">SEE ALSO</A><DD>
<DT id="10"><A HREF="#lbAF">AUTHOR</A><DD>
</DL>
<HR>
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