#include <vector>
#include <utility>

#include "TGraph.h"
#include "TAxis.h"
#include "TCanvas.h"
#include "TRandom3.h"

using std::vector;
using Pdd=std::pair<double,double>;

void copyTGraphRange(TGraph& in, TGraph& out)
{
  //out.GetXaxis()->SetRangeUser(in.GetXaxis()->GetXmin(),in.GetXaxis()->GetXmax()); //no effect
  *(out.GetXaxis())=*(in.GetXaxis());

  out.GetYaxis()->SetRangeUser(in.GetYaxis()->GetXmin(),in.GetYaxis()->GetXmax());
  //*(out.GetYaxis())=*(in.GetYaxis()); //no effect
}

Pdd randomUnitDisk()
{
  double x=1.0;
  double y=1.0;

  while(x*x+y*y>1.0){
    x=gRandom->Uniform(-1.0,1.0);
    y=gRandom->Uniform(-1.0,1.0);
  }

  return Pdd(x,y);
}

void axisRange()
{
  vector<double> xVec1,yVec1,xVec2,yVec2;
  for(int i=0;i<1000;i++){
    auto p1=randomUnitDisk();
    auto p2=randomUnitDisk();
    xVec1.push_back(2.0*p1.first);
    yVec1.push_back(p1.second);
    xVec2.push_back(p2.first);
    yVec2.push_back(2.0*p2.second);
  }
  TGraph g1(1000,&xVec1[0],&yVec1[0]);
  TGraph g2(1000,&xVec2[0],&yVec2[0]);

  TCanvas canvas;
  g1.Draw("A*");
  canvas.SaveAs("g1.png");
  g2.Draw("A*");
  canvas.SaveAs("g2.png"); 

  copyTGraphRange(g1,g2);
  g2.Draw("A*");
  canvas.SaveAs("g22.png");
}