Re: ST XZIP, Color and Mouse, addendum to spec
Date: 5/26/87

    The color function in the XZIP spec lists eight colors.  The Atari
ST, in 80-column mode, can display at most four of them at any one time.
They are identified internally by color index numbers 0-3.

    There are two additional restrictions:

    () Only one background color is allowed, which is always index 0.
(This is a limitation of the software support, not the hardware.)
This effectively leaves three foreground colors.

    () The mouse pointer uses index 1.  Index 1 should always be
different from index 0 for this reason, or the pointer will be visible
only as an odd silhouette.

    The current ST XZIP implementation will recycle indices to satisfy
requests for new colors, using a cheap LRU method.  Index 1 will always
be used to satisfy the first request.