The keystone function of the Pandoras Box Server and Player PRO is a powerful feature for planar projection.
It is designed in the way that it can be operated as standard beam shapers. Each output edge can be moved in or out and rotated according to the projection surface. Please note that it is not possible to keystone an image if an object is used as the object already deforms the camera texture.
Once you have set up each edge, you might compensate for the linearity distortion with the X&Y Keystone parameters. To do this, use a raster grid test pattern on a layer and reset the image center with the X&Y channels.