In Version 0.0.1e, bitmapping is included in the YZiForm library & spec. Bitmapping essentially allows an undefined color to be stored in the format. This is very handy for colors which are used rarely for example in a picture file. It prevents the size of the hash table from expanding and thus slowing access, speeds up the load time of the file originally and may save space in the file.
How it works
Inside the format, treat as a normal string but begin with the tag, #. This is followed by 12 hexadecimal characters (1 thru F). The first group of four is for the red channel, the second group of four is for green and the third group for blue. Then the string is closed. The hexes are in big endian and the char values must be upper case.
In Version 0.0.1e, a gzip compressed version of the YZiForm format is also supported. In using compression, an entire image is compressed with Gzip with only a beginning tag <Begin GZIP Compressed YZiForm Image Size=#>. The # is the length of the gzipped portion of the file (or string) not including the header. The Gzipped image should follow. Note that this should be independent of other changes to the YZiForm format as they will simply be compressed within the gziped the image. The standard <Begin YZiForm Image Version w.x.yz> should be compressed as well. (Gzip acts as a wrapper around the YZiForm format.)