draw_subpads.cxx

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/// \file
/// \ingroup tutorial_v7
//
/// This ROOT 7 example demonstrates how to create a ROOT 7 canvas (RCanvas),
/// divide on subpads and draw histograms there
///
/// \macro_code
///
/// \date 2018-03-13
/// \warning This is part of the ROOT 7 prototype! It will change without notice. It might trigger earthquakes. Feedback is welcome!
/// \author Sergey Linev
 
/*************************************************************************
 * 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/RPad.hxx"
#include "ROOT/RStyle.hxx"
#include "ROOT/RDirectory.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)
 
void draw_subpads()
{
  using namespace ROOT::Experimental;
 
  // Create the histogram.
  RAxisConfig xaxis(25, 0., 10.);
  auto pHist1 = std::make_shared<RH1D>(xaxis);
  auto pHist2 = std::make_shared<RH1D>(xaxis);
  auto pHist3 = std::make_shared<RH1D>(xaxis);
 
 
  for (int n=0;n<1000;n++) {
     pHist1->Fill(gRandom->Gaus(3., 0.8));
     pHist2->Fill(gRandom->Gaus(5., 1.));
     pHist3->Fill(gRandom->Gaus(7., 1.2));
  }
 
  // Create a canvas to be displayed.
  auto canvas = RCanvas::Create("Canvas Title");
 
  // Divide canvas on sub-pads
 
  auto subpads = canvas->Divide(2,2);
 
  subpads[0][0]->Draw(pHist1)->AttrLine().SetColor(RColor::kRed);
  subpads[1][0]->Draw(pHist2)->AttrLine().SetColor(RColor::kBlue);
  subpads[0][1]->Draw(pHist3)->AttrLine().SetColor(RColor::kGreen);
 
  // Divide pad on sub-sub-pads
  auto subsubpads = subpads[1][1]->Divide(2,2);
 
  subsubpads[0][0]->Draw(pHist1)->AttrLine().SetColor(RColor::kBlue);
  subsubpads[1][0]->Draw(pHist2)->AttrLine().SetColor(RColor::kGreen);
  subsubpads[0][1]->Draw(pHist3)->AttrLine().SetColor(RColor::kRed);
 
   auto style = RStyle::Parse(
        "frame {"              // select type frame for RFrame
        "   gridx: true;"      // enable grid drawing
        "   gridy: true;"
        "   ticksx: 2;"        // enable ticks drawing on both sides
        "   ticksy: 2;"
        "   x_labels_size: 0.05;" // below 1 is scaling factor for pad height
        "   y_labels_size: 20;"   // just a font size in pixel
        "   y_labels_color_name: green;"  // and name labels color
        "}");
  canvas->UseStyle(style);
  RDirectory::Heap().Add("style", style); // required to keep style alive
 
  canvas->SetSize(1200, 600);
  canvas->Show();
}