rf106_plotdecoration.C

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/// \file
/// \ingroup tutorial_roofit
/// \notebook -js
///  'BASIC FUNCTIONALITY' RooFit tutorial macro #106
///
///   Adding boxes with parameters, statistics to RooPlots.
///   Decorating RooPlots with arrows, text etc...
/// \macro_image
/// \macro_output
/// \macro_code
/// \author 07/2008 - Wouter Verkerke 



#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
#include "TText.h"
#include "TArrow.h"
#include "TFile.h"
using namespace RooFit ;


void rf106_plotdecoration()
{
   // S e t u p   m o d e l 
   // ---------------------

   // Create observables
   RooRealVar x("x","x",-10,10) ;

   // Create Gaussian
   RooRealVar sigma("sigma","sigma",1,0.1,10) ;
   RooRealVar mean("mean","mean",-3,-10,10) ;
   RooGaussian gauss("gauss","gauss",x,mean,sigma) ;

   // Generate a sample of 1000 events with sigma=3
   RooDataSet* data = gauss.generate(x,1000) ;

   // Fit pdf to data
   gauss.fitTo(*data) ;


   // P l o t   p . d . f   a n d   d a t a 
   // -------------------------------------

   // Overlay projection of gauss on data
   RooPlot* frame = x.frame(Name("xframe"),Title("RooPlot with decorations"),Bins(40)) ;
   data->plotOn(frame) ;
   gauss.plotOn(frame) ;


   // A d d   b o x   w i t h   p d f   p a r a m e t e r s 
   // -----------------------------------------------------

   // Left edge of box starts at 55% of Xaxis)
   gauss.paramOn(frame,Layout(0.55)) ;


   // A d d   b o x   w i t h   d a t a   s t a t i s t i c s
   // -------------------------------------------------------  

   // X size of box is from 55% to 99% of Xaxis range, top of box is at 80% of Yaxis range)
   data->statOn(frame,Layout(0.55,0.99,0.8)) ;


   // A d d   t e x t   a n d   a r r o w 
   // -----------------------------------

   // Add text to frame
   TText* txt = new TText(2,100,"Signal") ;
   txt->SetTextSize(0.04) ;
   txt->SetTextColor(kRed) ;
   frame->addObject(txt) ;

   // Add arrow to frame
   TArrow* arrow = new TArrow(2,100,-1,50,0.01,"|>") ;
   arrow->SetLineColor(kRed) ;
   arrow->SetFillColor(kRed) ;
   arrow->SetLineWidth(3) ;
   frame->addObject(arrow) ;


   // P e r s i s t   f r a m e   w i t h   a l l   d e c o r a t i o n s   i n   R O O T   f i l e
   // ---------------------------------------------------------------------------------------------

   TFile f("rf106_plotdecoration.root","RECREATE") ;
   frame->Write() ;
   f.Close() ;

   // To read back and plot frame with all decorations in clean root session do
   // root> TFile f("rf106_plotdecoration.root") ;
   // root>  xframe->Draw() ;

   new TCanvas("rf106_plotdecoration","rf106_plotdecoration",600,600) ;
   gPad->SetLeftMargin(0.15) ; frame->GetYaxis()->SetTitleOffset(1.6) ; frame->Draw() ;

}