%%cpp -d
#include <RooDataSet.h>
#include <RooExponential.h>
#include <RooPlot.h>
#include <RooRealVar.h>
#include <TCanvas.h>

using namespace RooFit;

RooRealVar x("x", "The observable", 1, 30);
RooRealVar tau("tau", "The exponent", -0.1337, -10., -0.1);
RooExponential expo("expo", "A falling exponential function", x, tau);

x.setRange("full", 1, 30);
x.setRange("left", 1, 10);
x.setRange("right", 20, 30);

std::unique_ptr<RooDataSet> data{expo.generate(x, 1000)};
std::unique_ptr<RooAbsData> blindedData{data->reduce(CutRange("left,right"))};

tau.setVal(-2.);
expo.fitTo(*blindedData, Range("left,right"), PrintLevel(-1));

expo.removeStringAttribute("fitrange");

TCanvas *canvas=new TCanvas("canvas","canvas",800,600);
canvas->Divide(2,1);

std::cout << "Now plotting with unique normalisation for each slice." << std::endl;
canvas->cd(1);
RooPlot* plotFrame = x.frame(RooFit::Title("Wrong: Each slice normalised over its plotting range"));

blindedData->plotOn(plotFrame);
expo.plotOn(plotFrame, LineColor(kRed),   Range("full"));
expo.plotOn(plotFrame, LineColor(kBlue),  Range("left"));
expo.plotOn(plotFrame, LineColor(kGreen), Range("right"));

plotFrame->Draw();

std::cout << "\n\nNow plotting with correct norm ranges:" << std::endl;
canvas->cd(2);
RooPlot* plotFrameWithNormRange = x.frame(RooFit::Title("Right: All slices have common normalisation"));

blindedData->plotOn(plotFrameWithNormRange);
expo.plotOn(plotFrameWithNormRange, LineColor(kBlue),  Range("left"),  RooFit::NormRange("left,right"));
expo.plotOn(plotFrameWithNormRange, LineColor(kGreen), Range("right"), RooFit::NormRange("left,right"));
expo.plotOn(plotFrameWithNormRange, LineColor(kRed),   Range("full"),  RooFit::NormRange("left,right"), LineStyle(10));

plotFrameWithNormRange->Draw();

canvas->Draw();

%jsroot on
gROOT->GetListOfCanvases()->Draw()