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ppmquantall—Run ppmquant on a bunch of files all at once, so they share a common colormap
SYNOPSIS
ppmquantall ncolors ppmfile ...
DESCRIPTION
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.
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.
(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.)
SEE ALSO
ppmquant(1), ppm(5)
BUGS
It's a csh script. csh scripts are not portable to System V. Scripts in general are not portable to non-UNIX environments.
AUTHOR
Copyright" 1991 by Jef Poskanzer.
27 July 1990
ppmqvga—8-plane quantization
SYNOPSIS
ppmqvga [ options ] [ input file ]
DESCRIPTION
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.
OPTIONS
| -d | dither | Apply Floyd-Steinberg dithering to the data |
| -q | quiet | Produces no progress reporting, and no terminal output unless an error occurs. |
| -v | verbose | 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. |
EXAMPLES
ppmqvga -d my_image.ppm | ppmtogif >my_image.gif tgatoppm zombie.tga | ppmqvga | ppmtotif > zombie.tif
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SEE ALSO
ppmquant
Diagnostics
Error messages if problems; various levels of optional progress reporting.
AUTHORS
Original by Lyle Rains (lrains@netcom.com) as ppmq256 and ppmq256fs combined; documented and enhanced by Bill Davidsen (davidsen@crd.ge.com).
COPYRIGHT
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.
Local
ppmrelief—Run a Laplacian relief filter on a portable pixmap
SYNOPSIS
ppmrelief [ppmfile]
DESCRIPTION
ppmrelief reads a portable pixmap as input, does a Laplacian relief filter, and writes a portable pixmap as output.
The Laplacian relief filter is described in Beyond Photography by Holzmann, equation 3.19. It's a sort of edge-detection.
SEE ALSO
pgmbentley(1), pgmoil(1), ppm(5)
AUTHOR
Copyright" 1990 by Wilson Bent (whb@hoh-2.att.com).
11 January 1991
ppmshift—Shift lines of a portable pixmap left or right by a random amount
SYNOPSIS
ppmshift shift [ppmfile]
DESCRIPTION
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.
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.
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EXAMPLE
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:
The resulting picture looks like the image being reflected on a water surface with slight ripples.
SEE ALSO
ppm(5), pnmcut(1), pnmflip(1), ppmdim(1), pnmcat(1)
AUTHOR
Copyright" 1993 by Frank Neumann.
16 November 1993
ppmspread—Displace a portable pixmap's pixels by a random amount
SYNOPSIS
ppmspread amount [ppmfile]
DESCRIPTION
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.
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).
SEE ALSO
ppm(5), pnmconvol(1)
AUTHOR
Copyright" 1993 by Frank Neumann.
16 November 1993
ppmtoacad—Convert portable pixmap to AutoCAD database or slide
SYNOPSIS
ppmtoacad [-dxb][-poly][-background colour][-white][-aspect ratio][-8][ppmfile]
DESCRIPTION
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.