.LP
Clicking on the "Perspective" button on the left side of the main Xprism
form will bring up the "Perspective" pane, which controls the changing of
viewing perspective.  
The plot(s) in the graphics workspace will be replaced with a set of axes 
(if on a color display, X is in green, Y is in yellow, and Z is in blue). 
Moving the scrollbars will cause the axes to move to the 
perspective orientation specified.  In addition, the values of the camera 
distance, view distance, alpha and theta will be printed at the bottom of the
window. Specific actions dictated by clicking on these boxes is described
as follows (explanations of alpha, theta, camera distance and view distance
follow):
.IP \(bx
Eye distance: moves the camera (eye) either closer to or farther away from
the plot. By setting the eye distance to 0, would be as if one were
standing right on top on the plot.
.IP \(bx
View distance: allows the camera to zoom in on the plot from a stationary
point.
.IP \(bx
Rotate about X: rotates all plots about the X axis.
.IP \(bx
Rotate about Z: rotates all plots about the Z axis.
.IP \(bx
Reset last:  resets eye distance, view distance, alpha and theta to the
last setting.
.IP \(bx
Reset defaults:  resets eye distance, view distance, alpha and theta to what
they were when "Change Perspective" was first selected
.IP \(bx
Use:  Indicates that the current orientation is satisfactory, and that the
user wishes to use this perspective with the plot
.IP \(bx
Exit: Exit the "Change Perspective Interactively" routines, and re-display
the plot(s) from the new perspective.  In addition, the perspective parameters
listed under "Direct Parameters" will be changed according to the new values.
Note:  if "Use" was not selected before "Exit", the perspective will revert to
the last active orientation.
