rlegend.cxx

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/// \file
/// \ingroup tutorial_rcanvas
///
/// This macro generates two TH1D objects and build RLegend
/// In addition use of auto colors are shown
///
/// \macro_image (rcanvas_js)
/// \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/RPaletteDrawable.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 rlegend()
{
   // 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("RLegend example");
 
   // add palette to canvas, it will not be seen on the canvas but used for colors
   canvas->Draw<RPaletteDrawable>(RPalette({{0., RColor::kWhite}, {.3, RColor::kRed}, {.7, RColor::kBlue}, {1., RColor::kBlack}}), false);
 
   // draw first histogram
   auto draw1 = canvas->Draw(pHist);
   draw1->line.width = 2.f;
   draw1->line.color = .3f; // should be red color
 
   // draw second histogram
   auto draw2 = canvas->Draw(pHist2);
   draw2->line.width = 4.f;
   draw2->line.color = .7f; // should be blue color
 
   auto legend = canvas->Draw<RLegend>("Legend title");
   legend->fill.color = RColor(0, 0, 120, 25);
   legend->fill.style = RAttrFill::k3019;
   legend->border.color = RColor::kRed;
   legend->border.width = 2;
   legend->AddEntry(draw1, "histo1", "l");
   legend->AddEntry(draw2, "histo2", "l");
 
   // add custom entry, showing line, fill and marker attributes
   auto custom = legend->AddEntry("test", "lfm");
   custom->line.color = RColor::kGreen;
   custom->line.width = 5.;
   custom->line.style = RAttrLine::kSolid;
   custom->fill.color = RColor::kBlue;
   custom->fill.style = RAttrFill::k3004;
   custom->marker.color = RColor::kRed;
   custom->marker.size = 0.03;
   custom->marker.style = RAttrMarker::kOpenCross;
 
   canvas->SetSize(1000, 700);
   canvas->Show();
}