From: Dmitri Semenov <hatter@chollian.net>
  To  : ggi-develop@eskimo.com
  Date: Sun, 7 Nov 1999 13:19:25 +0900

RE: problems over matrox fb

>But why? I'm very curious about how any application can benefit so
>much from being able to pass negative coordinates that it warrants
>this >10x slowdown? If there's a valid reason to why negative
>coordinates should be supported allthough it will slow down _all_
>applications (not very much, but still a slow down) I'd like to
>hear it.

Many applications have 2d or 3d transformation before access to any draw
functions. That transformation usually does not care about negative values.
I can give a some navigational system with map inside as sample

There are two way:
1. clip before transformation
2. clip after
Sometimes 1 is better and only I can do in case of performance suppositions
(sample big filled polygons). We just have to be sure that our result for
the clipped area will be inside of our screen after transformation. What is
wrong. We lack hardware clipping.
Second item is good in case of we have hardware clipper (sample we have to
draw a lot of lines). I need clipping from GGI library only to access to
hardware. If I have to clip by myself there is no place to assumption that
GGI has clipping and I lose acces to hardware clipper.

Best regards, Dmitry Semenov