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img-jpeg(n) 1.3 "Img"
img-jpeg - Img, Joint Picture Expert Group format (jpeg)
TABLE OF CONTENTS
SYNOPSIS
DESCRIPTION
JPEG OPTIONS
SEE ALSO
KEYWORDS
COPYRIGHT
package require Tk
package require img::jpeg ?1.3?
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?
-
-
Image data in jpeg format (options -data and -file) is
detected automatically.
-
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.
- -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.
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
image handling , jpeg , tk
Copyright © 1995-2003 Jan Nijtmans <nijtmans@users.sourceforge.com>