This manual documents the sg lossless image compression library, Version 0.52 released September 8,2000. It's intended for continuous-tone optical images which, for example, are what a digital camera typically produces but not what a computer drawing program produces. Otherwise, pict points to preallocated space which will hold the decompressed image. Prints a help message.
Limitations sg is intended only for experimental use.
This could be fixed by adding a special mode, which most predictive lossless image compressors have, for such images. Please see the paper mentioned in the Reference and Credits Section for more details. This makes for a simpler implementation, but the algorithm only requires three rows of the image at any given time. David Neuhoff helped design the algorithm.