ROOT_528-00b_version: tutorials/graphs/graphpolar.C Source File

00001 //Create and draw a polar graph
00002 //Author: Olivier Couet
00003    
00004 void graphpolar()
00005 {
00006    // Illustrates how to use TGraphPolar
00007 
00008    TCanvas * CPol = new TCanvas("CPol","TGraphPolar Examples",1200,600);
00009    CPol->Divide(2,1);
00010    CPol->cd(1);
00011   
00012    Double_t xmin=0;
00013    Double_t xmax=TMath::Pi()*2;
00014 
00015    Double_t x[1000];
00016    Double_t y[1000];
00017    Double_t x1[20];
00018    Double_t y1[20];
00019 
00020    TF1 * fplot = new TF1("fplot","cos(2*x)*cos(20*x)",xmin,xmax);
00021   
00022    for (Int_t ipt = 0; ipt < 1000; ipt++){
00023       x[ipt] = ipt*(xmax-xmin)/1000+xmin;
00024       y[ipt] = fplot->Eval(x[ipt]);
00025    }
00026 
00027    TGraphPolar * grP = new TGraphPolar(1000,x,y);
00028    grP->SetLineColor(2);
00029    grP->SetLineWidth(0.2);
00030    grP->SetFillStyle(3012);
00031    grP->SetFillColor(2);
00032    grP->Draw("AFL");
00033 
00034    for (Int_t ipt = 0; ipt < 20; ipt++){
00035       x1[ipt] = x[1000/20*ipt];
00036       y1[ipt] = y[1000/20*ipt];
00037    }
00038 
00039    TGraphPolar * grP1 = new TGraphPolar(20,x1,y1);
00040    grP1->SetMarkerStyle(29);
00041    grP1->SetMarkerSize(2);
00042    grP1->SetMarkerColor(4);
00043    grP1->SetLineColor(4);
00044    grP1->Draw("CP");
00045 
00046    // Update, otherwise GetPolargram returns 0
00047    CPol->Update();
00048    grP1->GetPolargram()->SetTextColor(8);
00049    grP1->GetPolargram()->SetRangePolar(-TMath::Pi(),TMath::Pi());
00050    grP1->GetPolargram()->SetNdivPolar(703);
00051    grP1->GetPolargram()->SetToRadian();
00052 
00053    CPol->cd(2);
00054    Double_t x2[30];
00055    Double_t y2[30];
00056    Double_t ex[30];
00057    Double_t ey[30];
00058    for (Int_t ipt = 0; ipt < 30; ipt++){
00059       x2[ipt] = x[1000/30*ipt];
00060       y2[ipt] = 1.2 + 0.4*sin(TMath::Pi()*2*ipt/30);
00061       ex[ipt] = 0.2+0.1*cos(2*TMath::Pi()/30*ipt);
00062       ey[ipt] = 0.2;
00063    }
00064 
00065    TGraphPolar * grPE = new TGraphPolar(30,x2,y2,ex,ey);
00066    grPE->SetMarkerStyle(22);
00067    grPE->SetMarkerSize(1.5);
00068    grPE->SetMarkerColor(5);
00069    grPE->SetLineColor(6);
00070    grPE->SetLineWidth(2);
00071    grPE->Draw("EP");
00072    CPol->Update();
00073    grPE->GetPolargram()->SetTextSize(0.03);
00074    grPE->GetPolargram()->SetTwoPi();
00075    grPE->GetPolargram()->SetToRadian();
00076 }