Hi Damir, several remarks: - don't use TT fonts for high performance. - don't use scaled fonts for performance. - use fixed size fonts (e.g. precision 0 or 3 with a pixel size equal to a natural pixel size) - root graphics is always double buffered (this cannot be turned off, and provides nice smooth updates) - the bigger the window the more has to be rendered the more time it takes Most can be gained by optimized font usage. Cheers, Fons. - Damir Buskulic wrote: > > Hi, > > There was a thread a few months ago about drawing speed of ROOT. I'm > trying to replace PAW routines by ROOT ones in an online data display > program. The main observed difference is the drawing speed in the case > of ROOT, which is much slower than PAW. While I can understand this (a > factor of two in the best case) it is difficult to understand the > variation of drawing speed with the canvas size. Try the following macro > : > > { > gBenchmark->Start("toto"); > c1 = new TCanvas("c1","test",10,10,700,700); > h = new TH1F("h","h",1000,0,10); > for (int i=1;i<100;i++) { > h->Fill(gRandom->Gaus(5,1.5),1); > if (i == 1) h->Draw(); <-- change gPad->Modified(); <-- add > gPad->Update(); > } > gBenchmark->Show("toto"); > } > > on my machine this needs around 14 s real time to be completed (Alpha > XP1000). > change the size of the canvas to 50x50 (not usable, it's just for > demonstrating the effect), the real time goes down to 2.8s ! > > Though fons explained the speed difference between PAW and ROOT, he > stated that the drawing speed should not depend much on the canvas size. > This is true for CPU time but not for real time. > > I also tested on a distant display, and the results are the same (14s > and 3s). > > In our context, and if this figure cannot be changed, I don't see yet > how to use root to display in real time a set of 10 histograms or plots. > > Anyone has a suggestion ? it will be welcome ! > > Cheers > > Damir > -- > ===================================================================== > | Damir Buskulic | Universite de Savoie/LAPP | > | | Chemin de Bellevue, B.P. 110 | > | Tel : +33 (0)450091600 | F-74941 Annecy-le-Vieux Cedex | > | e-mail: buskulic@lapp.in2p3.fr | FRANCE | > ===================================================================== > mailto:buskulic@lapp.in2p3.fr -- Org: CERN, European Laboratory for Particle Physics. Mail: 1211 Geneve 23, Switzerland E-Mail: Fons.Rademakers@cern.ch Phone: +41 22 7679248 WWW: http://root.cern.ch/~rdm/ Fax: +41 22 7677910
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