Beyond Linux® From Scratch - Version svn-20070421

Chapter 9. Graphics and Font Libraries

libjpeg-6b

Introduction to libjpeg

The libjpeg package contains libraries that allow compression of image files based on the Joint Photographic Experts Group standard. It is a "lossy" compression algorithm.

Package Information

User Notes: http://wiki.linuxfromscratch.org/blfs/wiki/libjpeg

Installation of libjpeg

Install libjpeg by running the following commands: 

./configure --prefix=/usr --enable-static --enable-shared &&
make

To test the results, issue: make test.

Now, as the root user: 

make install

Command Explanations

--enable-static --enable-shared: These switches tell libjpeg to build both shared and static libraries.

Configuring libjpeg

Configuration Information

As with most libraries, there is no configuration to do, save that the library directory, i.e., /opt/lib or /usr/local/lib should appear in /etc/ld.so.conf so that ldd can find the shared libraries. After checking that this is the case, /sbin/ldconfig should be run while logged in as root.

Contents

Installed Programs: cjpeg, djpeg, jpegtran, rdjpgcom, and wrjpgcom
Installed Library: libjpeg.{so,a}
Installed Directories: None

Short Descriptions

cjpeg

compresses image files to produce a JPEG/JFIF file on the standard output. Currently supported input file formats are: PPM (PBMPLUS color format), PGM (PBMPLUS gray-scale format), BMP, and Targa.

djpeg

decompresses image files from JPEG/JFIF format to either PPM (PBMPLUS color format), PGM (PBMPLUS gray-scale format), BMP, or Targa format.

jpegtran

is used for lossless transformation of JPEG files.

rdjpgcom

displays text comments from within a JPEG file.

wrjpgcom

inserts text comments into a JPEG file.

libjpeg.{so,a}

library is used by many programs for reading and writing JPEG format files.

Last updated on 2007-04-04 21:42:53 +0200