class HParticlePairDraw: public TObject

_HADES_CLASS_DESCRIPTION



 HParticlePairDraw

 Helper class to draw pair cases
  (HParticleDraw works for single tracks using eClosePairSelect flags
  for candidate 2 (kxxx2) (hparticledef.h).)

    Example:


    TCanvas* c = new TCanvas("pairCase","pairCase",1500,800);
    c->SetGridx();
    c->SetGridy();
    c->SetBottomMargin(0.25); // 0.15


    Double_t offsetX  =  0.25;
    Double_t offsetY  = -8;
    Double_t scaleX   =  1;
    Double_t scaleY   =  1;

    HParticlePairDraw pairdraw;

    vector<UInt_t> cases;


    cases.push_back(kPairCase1|kIsLepton2|kNoSamePolarity|kNoFittedInnerMDC2|kRK2);
    cases.push_back(kPairCase2|kIsUsed2);
    cases.push_back(kPairCase3|kNoRK2);
    cases.push_back(kPairCase4);
    cases.push_back(kPairCase5);
    cases.push_back(kPairCase6);
    cases.push_back(kPairCase7|kNoFittedInnerMDC2);
    cases.push_back(kPairCase8|kNoFittedOuterMDC2);
    cases.push_back(kPairCase9);
    cases.push_back(kPairCase10);
    cases.push_back(kPairCase11);
    cases.push_back(kPairCase12);

    cases.push_back(kPairCase13);
    cases.push_back(kPairCase14);
    cases.push_back(kPairCase15);
    cases.push_back(kPairCase16);
    cases.push_back(kPairCase17);
    cases.push_back(kPairCase18);
    cases.push_back(kPairCase19);
    cases.push_back(kPairCase20);


    UInt_t bins = cases.size();

    TH1F* h = new TH1F("h","",bins,0,bins);
    h->SetLineColor(kRed);
    h->SetLineWidth(3);
    h->SetYTitle("Fraction of pairs [%]");
    h->GetXaxis()->SetNdivisions(100+bins);
    h->GetXaxis()->SetLabelSize(0);

    h->GetYaxis()->SetRangeUser(0.,50.);

    for(Int_t i=0;i<100;i++){
	h->Fill(gRandom->Rndm()*bins);
    }
    h->Draw();

    for(UInt_t i=0; i < bins; i++){
	pairdraw.drawPair(offsetX+i,offsetY,scaleX,scaleY,cases[i],Form("Case%i",i+1),"RK<100,oA<5,MQA<2,RQA<2,#beta>0.9");
    }