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>