Plotting Generalized Curves
We have seen how geodesic curves and grid lines can be drawn. The PlotPlot
class includes another method,
astGenCurveastGenCurve,
which allows curves of any form to be drawn. The caller supplies a
MappingMapping which maps offset along the curve
into the
corresponding position in the current FrameFrame of the Plot.
astGenCurve,
then takes care of Mapping these positions into graphics coordinates. The
choice of exactly which positions along the curve are to be used to
define the curve is also made by
astGenCurve,
using an adaptive algorithm which concentrates points around areas where
the curve is bending sharply or is discontinuous in graphics coordinates.
The IntraMapIntraMap class may be of particular use in this context since it allows
you to code your own Mappings to do any transformation you choose.