img-jpeg - Img, Joint Picture Expert Group format (jpeg)
package require Tk
package require img::jpeg ?1.4?
image create photo
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
so that it supports files
containing raster images in the Joint Picture Expert Group format (jpeg). More
The name of the new format handler is jpeg
. This handler provides new
additional configuration options. See section JPEG OPTIONS
All of the above means that in a call like
- image create photo ?name? ?options?
- Image data in jpeg format (options -data and -file) is
- 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.
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.
- This option is for reading from JPEG data. It usage activates a processing
mode which is fast, but also provides only low-quality information.
- 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
- This option is for writing JPEG data. It usage causes the writer to
optimize the huffman table used to encode the jpeg coefficients.
- This option is for writing JPEG data. It usage causes the creation of a
progressive JPEG file.
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
image handling, jpeg, tk
Copyright (c) 1995-2009 Jan Nijtmans <email@example.com>