[Visualpython-users] Graphing is finally fast

[Bruce S. <Bru...@nc...>]

At http://sourceforge.net/projects/visualpython there is finally a beta 
version (4.beta10) for Windows and Linux which makes graphs as fast as 
was the case in Visual 3.

There were two issues. One was that Visual 4 does scaling of user 
coordinates to OpenGL coordinates in a different way than in Visual 3 
(part of Jonathan Brandmeyer's work to give us transparency etc.), and 
it took a while to understand how in this new environment to deal with 
nonuniform axes as are found in graphs. The version 4.beta9 fixed that 
underlying problem.

The second issue turned out to be that in graph.py (visual.graph module) 
an important scrap of code was lost in moving from Visual 3 to Visual 4. 
When a new point on a graph makes it necessary to extend the graph and 
redo the axes (labels and tick marks), that scrap extended the graph a 
bit more than was needed, in the hope that the next few additions to the 
graph would fit on the larger axes. Without that scrap, the heavyweight 
work of readjusting the axes was done way too often.

Bruce Sherwood