JPEG library

Included is version 6a by the IJG (Independant JPEG group). The distribution is downloaded from: ftp://ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz

Several options can be provided in the format string, for example:


Supported options for reading:

-fast:
Fast, low-quality processing
-grayscale:
Force incoming image to grayscale

Supported options for writing:

-quality N:
Compression quality (0..100; 5-95 is useful range)
Default value: 75
-smooth N:
Perform smoothing (10-30 is enough for most GIF's)
Default value: 0.
Remark: This option doesn't work reliable with earlier versions (than 6a) of the IJG JPEG library.
-grayscale:
Create monochrome JPEG file
-optimize:
Optimize Huffman table
-progressive:
Create progressive JPEG file

Thanks to Tom Lane for his support. The JPEG format handler (imgJPEG.c) is mainly written by him, although I (Jan Nijtmans) added the support for dynamical loading.

Although imgJPEG.c should work unchanged with v5, v6 and v6a of the JPEG library, is it advised that you upgrade to v6b if you can. There is a known bug in the "-smooth" option of earlier versions.


Jan Nijtmans, CMG (Computer Management Group) Arnhem B.V.
email: Jan.Nijtmans@wxs.nl (private)
Jan.Nijtmans@cmg.nl (work)
url: http://home.wxs.nl/~nijtmans/