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<A NAME="PAGENUM-412"><P>Page 412</P></A>
<H3><A NAME="ch01_ 307">
ppmquantall
</A></H3>
<P>ppmquantall—Run ppmquant on a bunch of files all at once, so they share a common colormap
</P>
<P><B>
SYNOPSIS
</B>
</P>
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<PRE>
ppmquantall ncolors ppmfile ...
</PRE>
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<P><B>
DESCRIPTION
</B>
</P>
<P>ppmquantall takes a bunch of portable pixmap as input. It chooses
ncolors colors to best represent all of the images, maps
the existing colors to the new ones, and overwrites the input files with the new quantized versions.
</P>
<P>Verbose explanation: Say you have a dozen pixmaps that you want to display on the screen all at the same time. Your
screen can only display 256 different colors, but the pixmaps have a total of a thousand or so different colors. For a single
pixmap, you solve this problem with ppmquant; this script solves it for multiple pixmaps. All it does is concatenate them together
into one big pixmap, run ppmquant on that, and then split it up into little pixmaps again.
</P>
<P>(Note that another way to solve this problem is to preselect a set of colors and then use
ppmquant's -map option to separately quantize each pixmap to that set.)
</P>
<P><B>
SEE ALSO
</B>
</P>
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<PRE>
ppmquant(1), ppm(5)
</PRE>
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<P><B>
BUGS
</B>
</P>
<P>It's a csh script. csh scripts are not portable to System V. Scripts in general are not portable to non-UNIX environments.
</P>
<P><B>
AUTHOR
</B>
</P>
<P>Copyright" 1991 by Jef Poskanzer.
</P>
<P>27 July 1990
</P>
<H3><A NAME="ch01_ 308">
ppmqvga
</A></H3>
<P>ppmqvga—8-plane quantization
</P>
<P><B>
SYNOPSIS
</B>
</P>
<!-- CODE SNIP //-->
<PRE>
ppmqvga [ options ] [ input file ]
</PRE>
<!-- END CODE SNIP //-->
<P><B>
DESCRIPTION
</B>
</P>
<P>ppmqvga quantizes PPM files to eight planes, with optional Floyd-Steinberg dithering. Input is a PPM file from the
file named, or standard input if no file is provided.
</P>
<P><B>
OPTIONS
</B>
</P>
<TABLE>
<TR><TD>
-d
</TD><TD>
dither
</TD><TD>
Apply Floyd-Steinberg dithering to the data
</TD></TR><TR><TD>
-q
</TD><TD>
quiet
</TD><TD>
Produces no progress reporting, and no terminal output unless an error occurs.
</TD></TR><TR><TD>
-v
</TD><TD>
verbose
</TD><TD>
Produces additional output describing the number of colors found, and some information on the
resulting mapping. May be repeated to generate loads of internal table output, but generally only useful once.
</TD></TR></TABLE>
<P><B>
EXAMPLES
</B></P>
<!-- CODE SNIP //-->
<PRE>
ppmqvga -d my_image.ppm | ppmtogif >my_image.gif
tgatoppm zombie.tga | ppmqvga | ppmtotif > zombie.tif
</PRE>
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<A NAME="PAGENUM-413"><P>Page 413</P></A>
<P><B>
SEE ALSO
</B>
</P>
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<PRE>
ppmquant
</PRE>
<!-- END CODE SNIP //-->
<P>Diagnostics
<P>Error messages if problems; various levels of optional progress reporting.
</P>
<P><B>
AUTHORS
</B>
</P>
<P>Original by Lyle Rains (lrains@netcom.com) as
ppmq256 and ppmq256fs combined; documented and enhanced by Bill
Davidsen (davidsen@crd.ge.com).
</P>
<P><B>
COPYRIGHT
</B></P>
<P>Copyright" 1991, 1992 by Bill Davidsen, all rights reserved. The program and documentation may be freely distributed
by anyone in source or binary format. Please clearly note any changes.
</P>
<P>Local
</P>
<H3><A NAME="ch01_ 309">
ppmrelief
</A></H3>
<P>ppmrelief—Run a Laplacian relief filter on a portable pixmap
</P>
<P><B>
SYNOPSIS
</B>
</P>
<!-- CODE SNIP //-->
<PRE>
ppmrelief [ppmfile]
</PRE>
<!-- END CODE SNIP //-->
<P><B>
DESCRIPTION
</B>
</P>
<P>ppmrelief reads a portable pixmap as input, does a Laplacian relief filter, and writes a portable pixmap as output.
</P>
<P>The Laplacian relief filter is described in Beyond
Photography by Holzmann, equation 3.19. It's a sort of edge-detection.
</P>
<P><B>
SEE ALSO
</B>
</P>
<!-- CODE SNIP //-->
<PRE>
pgmbentley(1), pgmoil(1), ppm(5)
</PRE>
<!-- END CODE SNIP //-->
<P><B>
AUTHOR
</B>
</P>
<P>Copyright" 1990 by Wilson Bent
(whb@hoh-2.att.com).
</P>
<P>11 January 1991
</P>
<H3><A NAME="ch01_ 310">
ppmshift
</A></H3>
<P>ppmshift—Shift lines of a portable pixmap left or right by a random amount
</P>
<P><B>
SYNOPSIS
</B>
</P>
<!-- CODE SNIP //-->
<PRE>
ppmshift shift [ppmfile]
</PRE>
<!-- END CODE SNIP //-->
<P><B>
DESCRIPTION
</B>
</P>
<P>ppmshift reads a portable pixmap as input and shifts every row of image data to the left or right by a certain amount.
The shift parameter determines by how many pixels a row is to be shifted at most.
</P>
<P>Another one of those effects I intended to use for MPEG tests. Unfortunately, this program will not help me here—it
creates patterns that are too random to be used for animations. Still, it might give interesting results on still images.
</P>
<A NAME="PAGENUM-414"><P>Page 414</P></A>
<P><B>
EXAMPLE
</B></P>
<P>Check this out: Save your favorite model's picture from something like
alt.binaries.pictures.supermodels (okay, or from any other picture source), convert it to
ppm, and process it like this, assuming the picture is
800¥600 pixels:
</P>
<OL>
<LI> Take the upper half and leave it like it is:
pnmcut 0 0 800 300 cs.ppm >upper.ppm.
<LI> Take the lower half, flip it upside down, dim it, and distort it a little:
pnmcut 0 300 800 300 cs.ppm | pnmflip -tb | ppmdim 0.7 | ppmshift 10
>lower.ppm.
<LI> Concatenate the two pieces: pnmcat -tb upper.ppm lower.ppm
>newpic.ppm.
</OL>
<P>The resulting picture looks like the image being reflected on a water surface with slight ripples.
</P>
<P><B>
SEE ALSO
</B>
</P>
<!-- CODE SNIP //-->
<PRE>
ppm(5), pnmcut(1), pnmflip(1), ppmdim(1),
pnmcat(1)
</PRE>
<!-- END CODE SNIP //-->
<P><B>
AUTHOR
</B>
</P>
<P>Copyright" 1993 by Frank Neumann.
</P>
<P>16 November 1993
</P>
<H3><A NAME="ch01_ 311">
ppmspread
</A></H3>
<P>ppmspread—Displace a portable pixmap's pixels by a random amount
</P>
<P><B>
SYNOPSIS
</B>
</P>
<!-- CODE SNIP //-->
<PRE>
ppmspread amount [ppmfile]
</PRE>
<!-- END CODE SNIP //-->
<P><B>
DESCRIPTION
</B>
</P>
<P>ppmspread reads a portable pixmap as input and moves every pixel around a bit relative to its original position.
amount determines by how many pixels a pixel is to be moved around at most.
</P>
<P>Pictures processed with this filter will seem to be somewhat dissolved or unfocussed (although they appear more coarse
than images processed by something like pnmconvol).
</P>
<P><B>
SEE ALSO
</B>
</P>
<!-- CODE SNIP //-->
<PRE>
ppm(5), pnmconvol(1)
</PRE>
<!-- END CODE SNIP //-->
<P><B>
AUTHOR
</B>
</P>
<P>Copyright" 1993 by Frank Neumann.
</P>
<P>16 November 1993
</P>
<H3><A NAME="ch01_ 312">
ppmtoacad
</A></H3>
<P>ppmtoacad—Convert portable pixmap to AutoCAD database or slide
</P>
<P><B>
SYNOPSIS
</B>
</P>
<!-- CODE SNIP //-->
<PRE>
ppmtoacad [-dxb][-poly][-background colour][-white][-aspect ratio][-8][ppmfile]
</PRE>
<!-- END CODE SNIP //-->
<P><B>
DESCRIPTION
</B>
</P>
<P>ppmtoacad reads a portable pixmap as input. Produces an AutoCAD slide file or binary database import (DXB) file as
output. If no ppmfile is specified, input is read from standard input.
</P>
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