I am cheating
Its a windowedscreen, with added scroll bars at the bottom and right sides...
The map is drawn to the screen with the map start x,y dependent on the position of the scroll bars.
The zoom mode, the map is drawn to a 256x256 sprite that has a link to a 3d sprite.
The 3d sprite is zoomed to the size of the windowed screen.
AntiA is just smooth zoom on/off
Looks okay though, ehh?
-Anthony