Re: [ROOT] How to setting Y axis on a TGraph picture with slider

From: Rene Brun (Rene.Brun@cern.ch)
Date: Wed Jun 21 2000 - 15:44:14 MEST 

Yongzhao Zhou wrote:
> 
> Dear Prof. Rene Brun,
> Sure, I can change Y scale on a canvas with TGraph by left button of the
> mouse using option "ALP" or "AL" to draw a TGraph but in that case the
> slider will not be worked.
> Is there any function directly to change X scaler of TGraph as action
> of TH1 in the macro grSliderAction.C of my code? Because I did not find a
> function directly to change the X scaler of a TGraph so I have to use a
> TH1 plot and draw a TGraph picture on it to make slider working on TGraph
> picture.
> Best Regards,
> Yongzhao Zhou
> 
> ------

Here is an example with sliders and a TGraph
do
 root > .x gslider.C

//------------macro gslider.C
{
   //Example of macro with two sliders

   TCanvas *c1 = new TCanvas("c1","A Simple Graph Example",200,10,700,500);
   c1->SetFillColor(38);

   TPad *pad = new TPad("pad","lego pad",0.1,0.1,0.98,0.98);
   pad->SetFillColor(33);
   pad->Draw();
   pad->cd();
//   gStyle->SetFrameFillColor(42);
   pad->SetFillColor(42);
   pad->SetGrid();
   pad->DrawFrame(0,0,2,11);

   const Int_t n = 20;
   Double_t x[n], y[n];
   for (Int_t i=0;i<n;i++) {
     x[i] = i*0.1;
     y[i] = 10*sin(x[i]+0.2);
   }
   gr = new TGraph(n,x,y);
   gr->SetLineColor(2);
   gr->SetLineWidth(4);
   gr->SetMarkerColor(4);
   gr->SetMarkerStyle(21);
   gr->SetTitle("a simple graph");
   gr->Draw("CP");

   
   //Create two sliders in main canvas. When button1 will be released
   //the macro xysliderAction.C will be called.
   c1->cd();
   TSlider *xslider = new TSlider("xslider","x",0.1,0.02,0.98,0.08);
   xslider->SetMethod(".x gsliderAction.C");
   TSlider *yslider = new TSlider("yslider","y",0.02,0.1,0.06,0.98);
   yslider->SetMethod(".x gsliderAction.C");
}

//-----------------macro gsliderAction.C
{
   Float_t xrange = 2;
   Float_t yrange = 11;
   Float_t xmin = xrange*xslider->GetMinimum();
   Float_t xmax = xrange*xslider->GetMaximum();
   Float_t ymin = yrange*yslider->GetMinimum();
   Float_t ymax = yrange*yslider->GetMaximum();
   pad->cd();
   pad->DrawFrame(xmin,ymin,xmax,ymax);
   gr->Draw("cp");
   c1->Update();
}

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