I have a TGraph2D with roughtly 5000 Points. To draw it with “pcol” or “p” or “p0” is quick, but all the other Options are incredibly slow, why?
When drawin the TGraph2D as contour-plot I would like toc change the contour-level. How? There is no SetContourLevel()
Drawing options which need Delaunay triangulation are time consuming.
You can change the number of contour levels using:
gStyle->SetNumberContours(number); // see TStyle::SetNumberContours
or you can define the number and values of contour levels using:
YourTGraph2D->GetHistogram()->SetContour(nlevels, levels); // see TH1::SetContour
and you can modify the value for one contour level using:
YourTGraph2D->GetHistogram()->SetContourLevel(level, value); // see TH1::SetContourLevel
Which ROOT version are you using ? the Delaunay triangulation algorithm has been changed recently and the speed has been unproved a lot.