ppmtogif
Section: User Commands (1)
Updated: 20 May 2000
Index
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NAME
ppmtogif - convert a portable pixmap into a GIF file
SYNOPSIS
ppmtogif
[-interlace]
[-sort]
[-map
mapfile]
[-transparent
color]
[ppmfile]
DESCRIPTION
Reads a portable pixmap as input.
Produces a GIF file as output.
OPTIONS
- -interlace
-
Produce an interlaced GIF file.
- -sort
-
Produces a GIF file with a sorted color map.
- -map
-
mapfile
Uses the colors found in the
mapfile
to create the colormap in the GIF file, instead of the colors from
ppmfile.
The
mapfile
can be any
ppm
file; all that matters is the colors in it. If the colors in
ppmfile
do not match those in
mapfile
, they are matched to a "best match." A (much) better result can be obtained by
using the following filter in advance:
ppmquant
-floyd -map
mapfile
- -transparent color
-
Mark the given color as transparent in the GIF file. The color is specified
as in
ppmmake(1).
Note that this option outputs a GIF89a format file which might not be
understood by your software.
All flags can be abbreviated to their shortest unique prefix.
SEE ALSO
giftopnm(1),
ppmquant(1),
pngtopnm(1),
ppm(5).
AUTHOR
Based on GIFENCOD by David Rowley <mgardi@watdcsu.waterloo.edu>.
Lempel-Ziv compression based on "compress".
Copyright (C) 1989 by Jef Poskanzer.
LICENSE
If you use
ppmtogif,
you are using a patent on the LZW compression method which is owned by
Unisys, and in all probability you do not have a license from Unisys
to do so. Unisys typically asks $5000 for a license for trivial use
of the patent. Unisys has never enforced the patent against trivial
users. The patent expires in 2003.
Rumor has it that IBM also owns a patent covering
ppmtogif.
A replacement for the GIF format that does not require any patents to use
is the PNG format.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- SEE ALSO
-
- AUTHOR
-
- LICENSE
-
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