DOKK / manpages / debian 13 / libtk-img-doc / img-jpeg.3tk.en
img-jpeg(3tk) Img img-jpeg(3tk) 







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








package require img::jpeg ?2.0?












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 [https://www.tcl.tk/man/tcl9.0/TkCmd/photo.html] image
  type.


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


All of the above means that in a call like image create
    photo ?name? ?options?



  
[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 of option -format is treated as a
    list and may contain any of the special options listed in section
    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.









  
[1]

  
Chapter Image Metadata of the Img manual page describes the
      parameters of the resolution related options.










The handler provides the following options:



  

  
This option is supported for reading and writing. Available since version
      2.0.
    
If set to true, additional information about the read
        or written image is printed to stdout. Default is false.

  

  

  
This option is supported for reading only. Available since version 1.2.4.
    
If specified, it activates a processing mode which is fast,
        but provides only low-quality information.

  

  

  
This option is supported for reading and writing. Available since version
      1.2.4.
    
Usage of this option forces incoming images to grayscale and
        written images will be monochrome.

  

  

  
This option is supported for writing only. Available since version 1.2.4.
    
If specified, it causes the writer to optimize the Huffman
        table used to encode the JPEG coefficients.

  

  

  
This option is supported for writing only. Available since version 1.2.4.
    
If specified, it causes the creation of a progressive
        JPEG file.

  

  

  
This option is supported for writing only. Available since version 1.2.4.
    
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 supported for writing only. Available since version 1.2.4.
    
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 supported for writing only. Available since version 2.0.
    
Set the resolution values of the written image file. If
        yres is not specified, it is set to the value of xres.

    
If option is not specified, the DPI and aspect
        values of the metadata dictionary are written. If no metadata values are
        available, no resolution values are written.

  

  

  
This option is supported for writing only. Available since version 2.0.
    
Set the horizontal resolution value of the written image
      file.

  

  

  
This option is supported for writing only. Available since version 2.0.
    
Set the vertical resolution value of the written image
      file.

  










img, img-bmp, img-dted, img-flir, img-gif, img-ico, 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








Copyright (c) 1995-2024 Jan Nijtmans <nijtmans@users.sourceforge.net>
Copyright (c) 2002-2024 Andreas Kupries <andreas_kupries@users.sourceforge.net>
Copyright (c) 2003-2024 Paul Obermeier <obermeier@users.sourceforge.net>








  

    2.0
    img-jpeg