NAME

       img-gif - Img, Graphics Interchange Format (gif)

SYNOPSIS

       package require Tk

       package require img::gif  ?1.4?

       image create photo ?name? ?options?

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DESCRIPTION

       package require img::gif.

       Like  all  packages  of  Img it does not provide new commands, but extends the existing Tk
       command image so  that  it  supports  files  containing  raster  images  in  the  Graphics
       Interchange Format (gif). More specifically img::gif extends Tk's photo image type.

       The name of the new format handler is gif.

       The  package  img::gif is a sub-package of Img. It can be loaded as a part of the complete
       Img support, via package require Img, or on its own, via package require img::gif.

       This handler provides new additional configuration options. See section  GIF  OPTIONS  for
       more detailed explanations.

       All of the above means that in a call like

       image create photo ?name? ?options?

       [1]    Image data in gif format (options -data and -file) is detected automatically.

       [2]    The format name gif is recognized by the option -format.  In addition the value for
              the option is treated as list and may contain any of the special options listed  in
              section GIF OPTIONS.

GIF OPTIONS

       The handler provides the following options:

       -index n
              This  option is for reading from GIF files containing more than one image (animated
              GIF's, GIF movies). When specified, it will read the n'th image in  the  data.  The
              first  image is at index 0 and will be read by default, i.e. when the option is not
              specified.

IMAGE COMPRESSION

       Instead of LZW the run-length encoding of Hutchison Avenue Software Corporation  is  used,
       also known as miGIF compression. The miGIF compression routines do not, strictly speaking,
       generate files conforming to the GIF spec, since the  image  data  is  not  LZW-compressed
       (this  is  the  point:  in  order  to  avoid transgression of the Unisys patent on the LZW
       algorithm.)  However,  miGIF  generates  data  streams  that  any  reasonably   sane   LZW
       decompresser will decompress to what we want.

TRANSPARENCY

       If  you  want  to write images to disk which contain transparency information (e.g. GIF89)
       you need at least Tk 8.3.

SEE ALSO

       img-bmp, img-dted, img-flir, img-gif, img-ico, img-intro, img-jpeg,  img-pcx,  img-pixmap,
       img-png,  img-ppm,  img-ps, img-raw, img-sgi, img-sun, img-tga, img-tiff, img-window, img-
       xbm, img-xpm

KEYWORDS

       gif, image handling, tk

COPYRIGHT

       Copyright (c) 1995-2023 Jan Nijtmans <nijtmans@users.sourceforge.net>