Zoom Facilities

Several standard zoom modes are provided for mouse interaction with 2D and 3D graphical displays. These are selectable via a call to

int     tv_set_zoomlevel(Tv * tv, int zoomlevel)

where the zoomlevel takes the following defined integer variables

IMZOOM   == standard 2D image zoom 
ZOOMAF   == constrained x and y zoom
ZOOM2    == 2D image zoom including rotation
ZOOM3    == 3D data zoom
ZOOMGR   == 3D surface viewer

Selection of these alternatives determines how the 2D and 3D co-ordinate frames associated with each Tv are manipulated by mouse interactions. The best way to understand the capabilities of these options is to try them.