DragonFly On-Line Manual Pages

img-jpeg(n)                           Img                          img-jpeg(n)

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

SYNOPSIS
       package require Tk

       package require img::jpeg  ?1.4?

       image create photo ?name? ?options?

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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-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

KEYWORDS
       image handling, jpeg, tk

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

img-jpeg                              1.4                          img-jpeg(n)