Re: [ROOT] Drawing Markers in log scale

From: Olivier Couet (Olivier.Couet@cern.ch)
Date: Mon Aug 05 2002 - 17:23:20 MEST


 Hi Giacomo,

 TMarker doesn't know about log scale in pad. You should compute the Log10
yourself. Here is an example:

{
        gROOT->Reset();
        TCanvas *c1 = new TCanvas("c1","Test",0,0,600,600);
        c1->SetLogy();
        fun1 = new TF1("fun1","10^x",1,3);     
        fun1->SetFillColor(1);
        fun1->Draw("C"); 
        TMarker *marker = new TMarker(2.,TMath::Log10(100.),21);
        marker->SetMarkerSize(4.); 
        marker->Draw();         
}

 Cheers,        Olivier

--
Org:    CERN - European Laboratory for Particle Physics.
Mail:   1211 Geneve 23 - Switzerland                                    
E-Mail: Olivier.Couet@cern.ch                      Phone: +41 22 7676522
WWW:    http://cern.ch/Olivier.Couet/              Fax:   +41 22 7677155

On Mon, 5 Aug 2002, Giacomo Bruno wrote:

> Hi,
>  I would like to draw markers in a canvas where histos
>  in y-logarithmic scale are already drawn.
>  I tried with both the Draw and the DrawMarker method, but the
>  markers are  drawn at wrong y-positions. I also tried to use NDC
>  coordinates without success.
>  Has anyone ever faced and solved this problem?
> 
> Cheers
> 
>  Giacomo
> 
> 
> 
>   -----------------------------------------
>  |            Giacomo BRUNO                |
>  |                                         |
>  |            CERN			   |
>  |	      EP Division		   |
>  |					   |
>  | mail:      40-2-B20                     |
>  |            C.E.R.N.                     |
>  |            CH - 1211 Geneva 23          |
>  |            Switzerland                  |
>  | e-mail:    Giacomo.Bruno@cern.ch        |
>  | phone:     +41 22 76 71624		   |
>   -----------------------------------------
> 
> 
> 
> 



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