rline.cxx

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/// \file
/// \ingroup tutorial_rcanvas
///
/// This ROOT 7 example demonstrates how to create a ROOT 7 canvas (RCanvas) and
/// draw ROOT 7 lines in it (RLine). It generates a set of lines using the
/// "normal" coordinates' system and changing the line color linearly from black
/// to red.
///
/// \macro_code
///
/// \date 2018-03-18
/// \warning This is part of the ROOT 7 prototype! It will change without notice. It might trigger earthquakes. Feedback
/// is welcome!
/// \authors Olivier Couet, Iliana Betsou
 
#include <ROOT/RCanvas.hxx>
#include <ROOT/RColor.hxx>
#include <ROOT/RLine.hxx>
#include <ROOT/RPadPos.hxx>
#include "TMath.h"
 
void rline()
{
   using namespace ROOT::Experimental;
 
   // Create a canvas to be displayed.
   auto canvas = RCanvas::Create("RLine example");
 
   for (double i = 0; i < 360; i += 1) {
      double angle = i * TMath::Pi() / 180;
      RColor col(50 + (int)i / 360 * 200, 0, 0);
      auto draw = canvas->Draw<RLine>();
      draw->SetP1({0.5_normal, 0.5_normal});
      draw->SetP2({0.5_normal + 0.3_normal * TMath::Cos(angle), 0.5_normal + 0.3_normal * TMath::Sin(angle)});
      draw->line.color = col;
   }
 
   canvas->Draw<RLine>()->SetP1({0.0_normal, 0.0_normal}).SetP2({1.0_normal, 1.0_normal});
   canvas->Draw<RLine>()->SetP1({0.1_normal, 0.1_normal}).SetP2({0.9_normal, 0.1_normal});
   canvas->Draw<RLine>()->SetP1({0.9_normal, 0.1_normal}).SetP2({0.9_normal, 0.9_normal});
   canvas->Draw<RLine>()->SetP1({0.9_normal, 0.9_normal}).SetP2({0.1_normal, 0.9_normal});
   canvas->Draw<RLine>()->SetP1({0.1_normal, 0.1_normal}).SetP2({0.1_normal, 0.9_normal});
   canvas->Draw<RLine>()->SetP1({0.0_normal, 1.0_normal}).SetP2({1.0_normal, 0.0_normal});
 
   canvas->SetSize(900, 700);
 
   if (canvas->SaveAs("line.png"))
      printf("Store RCanvas in line.png\n");
 
   canvas->Show();
}