QwtPlotDirectPainter usage with simple plots

[Momergil]

Hello Uwe and Co!

I'ld like to know if it's actually meaningful to use QwtPlotDirectPainter to improve efficiency in drawing QwtPlots in a embedded device (real time pretended), but when graphs are quite simple (lets say a 800 x 600 QwtPlot with max 8 simple QwtPlotCurves). Is there so much significance in using this class, or should I stay in KISS and just use replot() anyway?


Thanks,

Momergil

[Uwe]

QwtPlotDirectPainter renders something on top without repainting the rest of the scene. Using it makes sense when the rest of the scene doesn't change and of course it would take a significant amount of time to replot it.
Another use case might be in situations, where your graphic system is slow f.e. when running an unaccelerated frame buffer device. Here QwtPlotDirectPainter might have an effect because only the region behind the incremental painting is blitted.

Uwe