DOKK / manpages / debian 11 / libtk-img-doc / img-gif.3tk.en
img-gif(3tk) Img img-gif(3tk) 







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








package require Tk 


package require img::gif ?1.4?


image create photo ?name?
  ?options?












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.


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. 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



  

  





  
[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.










The handler provides two options, one for reading from a GIF
    image, the other influencing the writing of such.



  

  
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.

  

  
If the value of this option is set to true the image will be written using
      the interlaced sub-format of GIF. The default is to write non-interlaced
      files. This option is not implemented yet.










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.








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








img-bmp, img-dted, 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








gif, image handling, tk








Copyright (c) 1995-2009 Jan Nijtmans <nijtmans@users.sourceforge.net>








  

    1.4
    img-gif