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>