img-jpeg(3tk)															     img-jpeg(3tk)

NAME

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

SYNOPSIS

       package require Tk

       package require img::jpeg  ?1.3?

       image create photo ?name? ?options?

DESCRIPTION

       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

       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 for the option is treated as list and  may  contain
	      any of the special options listed in section JPEG OPTIONS.

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.

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

       -grayscale
	      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.

       -quality n
	      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.

       -smooth n
	      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.

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

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

SEE ALSO

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

KEYWORDS

       image handling, jpeg, tk

COPYRIGHT

       Copyright (c) 1995-2003 Jan Nijtmans <nijtmans@users.sourceforge.com>

Img									1.3							     img-jpeg(3tk)