I display a graph of numbers, normalized so the full range of values just fits my height. I support a movable cursor that can be dragged with the mouse.
Implementation notes: Some operations on me may be done at sound sampling rates (e.g. 11-44 thousand times/second). To allow such high bandwidth application, certain operations that change my appearance do not immediately report a damage rectangle. Instead, a flag is set indicating that my display needs to refreshed and a step method reports the damage rectangle if that flag is set. Also, I cache a bitmap of my graph to allow the cursor to be moved without redrawing the graph.
