jpeglib for Palm OS

jpeglib is a shared library for Palm OS handheld computers. It permits other applications to support easily JPEG encoding and decoding. JPEG is a standard compression method for photographic images. It's lossy, which means that the decoded image is very close to, but not exactly the same as the original image; this permits much larger compression ratios. The trade-off between quality and compression ratio can be chosen. JPEG is often used by digital cameras, such as the built-in camera of the Zire 71.

For the user of the application, jpeglib is just a PRC file which is installed on the Palm OS handheld like any other application file. It weights slightly less than 64 KB, and is shared by all the applications which rely on it. For the C or C++ developer, jpeglib comes with a single .h include file. Port to other languages should be straighforward.

Technical description

jpeglib is based on the work of the Independent JPEG Group. To fit their comprehensive library into the severe constraints of Palm OS (especially the code size and the processing power), only the fast integer implementation of the Discrete Cosine Tranform is included; note that this doesn't limit at all the kind of JPEG files which can be decoded. Support for JPEG data in memory, in file streams (a way to store data in Palm OS databases with an API similar to file systems) and in VFS (the virtual file system used by Palm OS for memory expansion modules) has been added to make the use of the library as easy as possible for Palm OS developers.

Download

Download it now! Last update: 12 September 2003.

The ZIP archive weights 50 KBytes. It contains the PRC file, the include file you can use to develop your applications, sample code, and the source file we wrote. To rebuild the library yourself, you will also need the source code of the Independant JPEG Group's library, version 6b.

License

The license below is known as the modified BSD license, with an additional reference to the Independent JPEG Group to comply with its terms. It applies to the source code written specifically for the Palm, not to the work of the Independent JPEG Group (see the remark below).

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
Neither the name of Yves Piguet nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Remarks

Sorry for shouting; we keep the modified BSD license disclaimer verbatim.

For a discussion on different open-source and "free" ("copyleft") licenses, please visit http://www.opensource.org and http://www.gnu.org.

To build a working JPEG library, you should link the source code specific to the Palm with the JPEG library of the Independent JPEG Group. We used version 6b. Our source code contains all the details.

If you modify this library, please don't distribute incompatible versions under the same name! This would cause a lot of troubles for users who install applications with different versions of JpegLibPalm. Either rename the library, or if you think your modifications are useful, send them to me so that they can be included in a new version.

If you bundle JpegLib for Palm with your product, a book, a magazine, etc., you might consider sending me a copy. Thank you!

Release notes

12 September 2003

BmpGetDimensions replaced with BmpGlueGetDimensions to support pre-Palm OS 4 devices

28 August 2003

Opensourced
The end of VFS files wasn't read when the file size wasn't a multiple of 4096 bytes; fixed

14 July 2003

First release