Stock package of jpeg9e
NOTE: This file README.md is my personal addition to the jpeg-9e package. It is intended to be a quick start and pointers to the important information to get started. It is not intendent to replace the README file from the source package (https://github.com/intelxai/jpeg-9e/blob/main/README).
In short, this repository contains the is the original package from the Independent JPEG group as found on the internet (https://www.ijg.org) as the un-tar product of (jpegsrc.v9e.tar.gz).
For background information on libjpeg you may want to see https://en.wikipedia.org/wiki/Libjpeg
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Clone this git repository
% git clone [email protected]:intelxai/EXT_libjpeg-9e
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If it is your first time with jpeg check the following documentation files:
User documentation (From the jpeg-9e/README file):
install.txt How to configure and install the IJG software.
usage.txt Usage instructions for cjpeg, djpeg, jpegtran and more
*.1 Unix-style man pages for programs (same info as usage.txt).
wizard.txt Advanced usage instructions for JPEG wizards only.
cdaltui.txt Description of alternate user interface for cjpeg/djpeg.
change.log Version-to-version change highlights.
Programmer and internal documentation:
libjpeg.txt How to use the JPEG library in your own programs.
example.c Sample code for calling the JPEG library.
structure.txt Overview of the JPEG library's internal structure.
filelist.txt Road map of IJG files.
coderules.txt Coding style rules --- please read if you contribute code.
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Install the jpeg software package - instructions (From jpeg-9e/install.txt):
./configure
make
make test
NOTE: Unlike many libraries, the main api include file "jconfig.h" is not included in the package as a file. Instead, the ./configure script above will produce it. If you run into troubles the first place to look is in config.log. See jconfig.txt from this repository for explanations
If the instructions at step (2.) doesn't produce errors, do
make -n install
- Where did make saved the resulting files?
On my unix systems (MacOS and Linux) the following where produced as executable binairies
/usr/local/bin/cjpeg
/usr/local/bin/djpeg
/usr/local/bin/jpegtran
/usr/local/bin/rdjpgcom
/usr/local/bin/wrjpgcom
And the following where produced as linkable libraries
/usr/local/lib/libjpeg.a
/usr/local/lib/libjpeg.la
/usr/local/lib/libjpeg.so
/usr/local/lib/libjpeg.dylib -> libjpeg.9.dylib
/usr/local/lib/libjpeg.la
/usr/local/lib/pkgconfig (A directory)
NOTE: On my linux systems I needed to run step 2. as superuser for the files to be copied at these locations.
- Use the utilities (From jpeg-9e/usage.txt)
Two most generaly usefull programs are: cjpeg to compress an image file into JPEG format, and djpeg to decompress a JPEG file back into a conventional image format.
On Unix-like systems, you invoke:
cjpeg [switches] [imagefile] >jpegfile
or djpeg [switches] [jpegfile] >imagefile
On most non-Unix systems, you say:
cjpeg [switches] imagefile jpegfile
or djpeg [switches] jpegfile imagefile
For more usage
cjpeg -help
and
djpeg -help
Have fun.
André