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







img-jpeg - Img, Joint Picture Expert Group format (jpeg)








package require Tk 


package require img::jpeg ?1.4?


image create photo ?name?
  ?options?












The package img::jpeg 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::jpeg.


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 Joint Picture Expert Group
    format (jpeg). More specifically img::jpeg extends Tk's
    photo image type.


The name of the new format handler is jpeg. This handler
    provides new additional configuration options. See section JPEG
    OPTIONS for more detailed explanations.


All of the above means that in a call like



  

  





  
[1]

  
Image data in jpeg format (options -data and -file) is
      detected automatically.

  
[2]

  
The format name jpeg 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 JPEG OPTIONS.










The handler provides six options, two effective when reading from
    a JPEG image, and five influencing the writing of such. One option is usable
    for both reading an writing.



  

  
This option is for reading from JPEG data. It usage activates a processing
      mode which is fast, but also provides only low-quality information.

  

  
This option can be used for both reading and writing of JPEG data. Usage
      of this option forces incoming images to grayscale, and written images
      will be monochrome.

  

  
This option is for writing JPEG data. It specifies the compression level
      as a quality percentage. The higher the quality, the less the compression.
      The nominal range for n is 0...100. Useful values are
      in the range 5...95. The default value is 75.

  

  
This option is for writing JPEG data. When used the writer will smooth the
      image before performing the compression. Values in the
      10...30 are usually enough. The default is 0, i.e no
      smoothing.

  

  
This option is for writing JPEG data. It usage causes the writer to
      optimize the huffman table used to encode the jpeg coefficients.

  

  
This option is for writing JPEG data. It usage causes the creation of a
      progressive JPEG file.










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








image handling, jpeg, tk








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








  

    1.4
    img-jpeg