#include "StandardLabels.C"

void pion_theta(void)
{
	TColor::CreateColorWheel();
	
	TCanvas *c1 = new TCanvas("c1", "", 800, 600);
	c1->SetTicks();
	c1->SetGridy();
	
	TFile *f = new TFile("generated_b.root");
	TTree *thrown_tree = (TTree*)gROOT->FindObject("pip_pim");
	
	TH1D *pip = new TH1D("pip","#pi^{+} #theta", 200, 0.0, 3.5);
	TH1D *pim = (TH1D*)pip->Clone("pim");
	
	thrown_tree->Project("pip","57.3*acos(pip_pz/sqrt(pip_px*pip_px + pip_py*pip_py + pip_pz*pip_pz))");
	thrown_tree->Project("pim","57.3*acos(pim_pz/sqrt(pim_px*pim_px + pim_py*pim_py + pim_pz*pim_pz))");

	double max = pip->GetMaximum()*1.05;

	TH2D *axes = new TH2D("axes", "#pi^{#pm} polar angle distribution in lab frame", 100, 0.0, 3.5, 100, 0.0, max);
	axes->SetStats(0);
	axes->SetXTitle("#theta (degrees)");
	axes->Draw();
	
	pip->SetLineColor(kRed);
	pim->SetLineColor(kBlue);
	pip->SetLineWidth(3);
	pim->SetLineWidth(3);
	
	pip->Draw("same");
	pim->Draw("same");
	
	TLine *lin = new TLine(1.0, 0.0, 1.0, max);
	lin->SetLineColor(kGray+2);
	lin->SetLineStyle(2);
	lin->SetLineWidth(3.0);
	lin->Draw();
	
	TLatex *lab = new TLatex(1.02, 500.0, "Acceptance at nominal GlueX target center");
	lab->SetTextSize(0.028);
	lab->SetTextAngle(270.0);
	lab->SetTextAlign(21);
	lab->Draw();
	
	TLegend *leg = new TLegend(0.636, 0.621, 0.841, 0.854);
	leg->SetFillColor(kWhite);
	leg->AddEntry(pip, "#pi^{+}");
	leg->AddEntry(pim, "#pi^{-}");
	leg->Draw();
	
	//StandardLabels(axes, "", "", "Generated values for threshold #leq W_{#pi#pi} #leq 400 MeV/c^{2}");
	
	c1->SaveAs("pion_theta.png");
	c1->SaveAs("pion_theta.pdf");
}