Circular Buffering - Removing Points

[Joe_B]

Hi All -

I'm working with a "scatter" type plot (QwtPlotCurve without the curve) to display data contained in a large circular buffer (200k points updating at around 2k-5k points per second). Adding points to the plot at this rate is no problem - I'm using the DirectPainter and everything is running fine. What I would like to do is remove the points from the plot as they get overwritten in the circular buffer. Is there a trick to this that I haven't found, or does this imply re-plotting the whole buffer? What about something simple like overwriting the next block of points with white-colored points?

Thanks much,

Joe.

[Uwe]

In earlier Qt versions ( Qt 3 ) you had the possibility to paint in XOR mode, but today I'm not aware of any technique to erase something - beside replotting. Maybe there are some optimizations possible using of the characteristics of your samples ( f.e. when they are ordered ).

Uwe

[Joe_B]

Thanks for the reply, Uwe. Optimizing the data somehow was what I was thinking I was going to have to do. We'll see if I can come up with something witty. :)

Thanks,

Joe.