Refactor rendering framework to allow hover/select points to be drawn in a separate layer

[GoogleCodeExporter]

Currently, the the hover and select points are drawn onto the plot layer along 
with the dataset 
points and connecting segments, etc.  In order to improve rendering 
performance, it would be 
desirable to only have to redraw the datasets when the plot is zoomed or 
scrolled (since other than 
a gss style change, these are the only two events that cause the datasets to 
change their 
appearance).  But since the hover point and select point needs to move based on 
the current mouse 
position, the entire plot, including datasets, need to be redrawn.

It is hoped that this change will significantly speed up rendering in IE and on 
mobile devices.

Original issue reported on code.google.com by chadtaka...@gmail.com on 6 Nov 2008 at 10:49

[GoogleCodeExporter]

Simple optimization in DefaultXYPlot resulted in 15% increase in Safari (see 
r712 for details).

Original comment by chadtaka...@gmail.com on 7 Nov 2008 at 2:17

[GoogleCodeExporter]

Resolved in r715.  Dramatic performance increase when hovering points, since 
redraw() now only re-renders the 
datasets if the plot domain state has changed.

Original comment by chadtaka...@gmail.com on 10 Nov 2008 at 7:12

• Changed state: Fixed