NAME
    giftopnm - convert a GIF file into a portable anymap

SYNOPSIS
    giftopnm [--alphaout={alpha-filename,-}] [-verbose] [-comments] [-image
    N] [GIFfile]

DESCRIPTION
    This is a graphics format converter from the GIF format to the PNM
    (i.e. PBM, PGM, or PPM) format.

    If the image contains only black and maximally bright white, the output
    is PBM. If the image contains more than those two colors, but only
    grays, the output is PGM. If the image contains other colors, the out-
    put is PPM.

    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 engineering 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 con-
    tains 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 out-
    put 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 N
    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.

RESTRICTIONS
    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)
    <http://www.lcdf.org/gifsicle>, 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, and has made statements that it is much
    less concerned about people using the patent for  decompression (which
    is what  giftopnm does  than for compression.  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.