> Any idea whether this is more efficient than mulitple D_R_M's?
It is. Curtis's solution could of course be cast as a custom
direct manipulation DataRenderer, but it occured to me that
you could do the same thing using the existing
DirectManipulationRendererJ3D (or J2D), by setting a large
value into DisplayRenderer.setPickThreshhold(). Specifically,
you'd have just a single DirectManipulationRendererJ3D and a
single RealTuple with MathType (x, y) and ScalatMaps
x -> XAxis, y-> YAxis. BY setting a large enough value into
setPickThreshhold(), and only a single RealTuple displayed
via direct manipulation, that RealTuple would jump to whatever
location the user clicked the right mouse button on. This would
trigger a CellImpl, which would use the (x, y) values of the
RealTuple to compute the line direction, as in Curtis's code.
And you wouldn't need his code for converting screen x and y
coordinates into data x and y.