draw_legend.cxx

Go to the documentation of this file.

/// \file
/// \ingroup tutorial_v7
///
/// This macro generates two TH1D objects and build RLegend
/// In addition use of auto colors are shown
///
/// \macro_code
///
/// \date 2019-10-09
/// \warning This is part of the ROOT 7 prototype! It will change without notice. It might trigger earthquakes. Feedback is welcome!
/// \author Sergey Linev <s.linev@gsi.de>
 
/*************************************************************************
 * Copyright (C) 1995-2019, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
#include "ROOT/RHistDrawable.hxx"
#include "ROOT/RCanvas.hxx"
#include "ROOT/RLegend.hxx"
#include "TRandom.h"
 
// macro must be here while cling is not capable to load
// library automatically for outlined function see ROOT-10336
R__LOAD_LIBRARY(libROOTHistDraw)
R__LOAD_LIBRARY(libROOTGraphicsPrimitives)
 
using namespace ROOT::Experimental;
 
void draw_legend()
{
   // Create the histograms.
   RAxisConfig xaxis(25, 0., 10.);
   auto pHist = std::make_shared<RH1D>(xaxis);
   auto pHist2 = std::make_shared<RH1D>(xaxis);
 
   for (int n=0;n<1000;n++) {
      pHist->Fill(gRandom->Gaus(3,0.8));
      pHist2->Fill(gRandom->Gaus(7,1.2));
   }
 
   // Create a canvas to be displayed.
   auto canvas = RCanvas::Create("Canvas Title");
 
   // draw histogram
   auto draw1 = canvas->Draw(pHist);
   draw1->AttrLine().SetWidth(2).AttrColor().SetAuto();
 
   // draw histogram
   auto draw2 = canvas->Draw(pHist2);
   draw2->AttrLine().SetWidth(4).AttrColor().SetAuto();
 
   canvas->AssignAutoColors();
 
   auto legend = canvas->Draw<RLegend>("Legend title");
   legend->AttrFill().SetStyle(5).SetColor(RColor::kWhite);
   legend->AttrBorder().SetWidth(2).SetColor(RColor::kRed);
   legend->AddEntry(draw1, "histo1");
   legend->AddEntry(draw2, "histo2");
 
   legend->AddEntry("test").SetAttrLine(RAttrLine().SetColor(RColor::kGreen).SetWidth(5))
                           .SetAttrFill(RAttrFill().SetColor(RColor::kBlue).SetStyle(3004))
                           .SetAttrMarker(RAttrMarker().SetColor(RColor::kRed).SetSize(3).SetStyle(28));
 
   canvas->SetSize(1000, 700);
   canvas->Show();
}