twoscales.py

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## \file
## \ingroup tutorial_hist
## \notebook
## Example of macro illustrating how to superimpose two histograms
## with different scales in the "same" pad.
## Inspired by work of Rene Brun.
##
## \macro_image
## \macro_code
##
## \author Alberto Ferro

#include "TCanvas.h"
#include "TStyle.h"
#include "TH1.h"
#include "TGaxis.h"
#include "TRandom.h"

import ROOT

c1 = ROOT.TCanvas("c1","hists with different scales",600,400)

ROOT.gStyle.SetOptStat(False)

h1 = ROOT.TH1F("h1","my histogram",100,-3,3)

for i in range(10000) :
    h1.Fill(ROOT.gRandom.Gaus(0,1))

h1.Draw()

hint1 = ROOT.TH1F("hint1","h1 bins integral",100,-3,3)

sum = 0
for i in range(1,101) :
   sum += h1.GetBinContent(i)
   hint1.SetBinContent(i,sum)

rightmax = 1.1*hint1.GetMaximum();
scale = ROOT.gPad.GetUymax()/rightmax;
hint1.SetLineColor(ROOT.kRed)
hint1.Scale(scale)
hint1.Draw("same")

axis = ROOT.TGaxis(ROOT.gPad.GetUxmax(),ROOT.gPad.GetUymin(),
      ROOT.gPad.GetUxmax(), ROOT.gPad.GetUymax(),0,rightmax,510,"+L")
axis.SetLineColor(ROOT.kRed)
axis.SetLabelColor(ROOT.kRed)
axis.Draw()