Страницы справочника OS X

Эта страница руководства для  версии 10.9 Mac OS X

Читать страницы руководства

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



____________________________________________________________________________________________________________

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?

____________________________________________________________________________________________________________

DESCRIPTION
       The  package  img::jpeg  is a sub-package of Img. It can be loaded as a part of the complete Img sup-port, support,
       port, 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 percent-age. percentage.
              age.  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  per-forming performing
              forming  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, imgps,
       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                                                  1.4                                         img-jpeg(n)