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giftopnm !!!giftopnm NAME SYNOPSIS DESCRIPTION OPTIONS BUGS SEE ALSO AUTHOR LICENSE ---- !!NAME giftopnm - convert a GIF file into a portable anymap !!SYNOPSIS __giftopnm__ [[__--alphaout=__{''alpha-filename'',__-__}] [[__-verbose__] [[__-comments__] [[__-image__ ''N''] [[''GIFfile''] !!DESCRIPTION Reads a GIF file for input, and outputs portable anymap. If you have an animated GIF file, you can extract individual frames from it with __gifsicle__ and then convert those using __giftopnm__. A GIF image contains rectangular pixels. They all have the same aspect ratio, but may not be square (it's actually quite unusual for them not to be square, but it could happen). The pixels of a Netpbm image are always square. Because of the computational complexity to do otherwise, __giftopnm__ converts a GIF image to a Netpbm image pixel-for-pixel. This means if the GIF pixels are not square, the Netpbm output image has the wrong aspect ratio. In this case, __giftopnm__ issues an informational message telling you to run __pnmscale__ to correct the output. !!OPTIONS __--alphaout=__''alpha-filename'' __giftopnm__ creates a PGM (portable graymap) file containing the alpha channel values in the input image. If the input image doesn't contain an alpha channel, the ''alpha-filename'' file contains all zero (transparent) alpha values. If you don't specify __--alphaout__, __giftopnm__ does not generate an alpha file, and if the input image has an alpha channel, __giftopnm__ simply discards it. If you specify __-__ as the filename, __giftopnm__ writes the alpha output to Standard Output and discards the image. See pnmcomp(1) for one way to use the alpha output file. __-verbose__ Produce verbose output about the GIF file input. __-comments__ Only output GIF89 comment fields. __-image__ Output the specified gif image from the input GIF archive (where ''N'' is '1', '2', '20'...). Normally there is only one image per file, so this option is not needed. All flags can be abbreviated to their shortest unique prefix. !!BUGS This does not correctly handle the Plain Text Extension of the GIF89 standard, since I did not have any example input files containing them. !!SEE ALSO ppmtogif(1), ppmcolormask(1), pnmcomp(1), gifsicle(1) ppm(5). !!AUTHOR Copyright (c) 1993 by David Koblas (koblas@netcom.com) !!LICENSE If you use __giftopnm__, 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 __giftopnm__. A replacement for the GIF format that does not require any patents to use is the PNG format. ----
4 pages link to
giftopnm(1)
:
webcollage(1)
pbmfilters(1)
Man1g
ppm(5)
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