/// \file
/// \ingroup tutorial_graphics
/// \notebook -js
/// \preview Show some basic primitives.
///
/// \macro_image
/// \macro_code
///
/// \author Rene Brun

void first()
{

   TCanvas *nut = new TCanvas("nut", "FirstSession", 100, 10, 700, 900);
   nut->Range(0, 0, 20, 24);
   nut->SetFillColor(10);
   nut->SetBorderSize(2);

   TPaveLabel *pl = new TPaveLabel(3, 22, 17, 23.7, "My first ROOT interactive session", "br");
   pl->SetFillColor(18);
   pl->Draw();

   TText t(0, 0, "a");
   t.SetTextFont(62);
   t.SetTextSize(0.025);
   t.SetTextAlign(12);
   t.DrawText(2, 20.3, "ROOT is based on CLING, a powerful C/C++ interpreter.");
   t.DrawText(2, 19.3, "Blocks of lines can be entered within {...}.");
   t.DrawText(2, 18.3, "Previous typed lines can be recalled.");

   t.SetTextFont(72);
   t.SetTextSize(0.026);
   t.DrawText(3, 17, "Root >  float x=5; float y=7;");
   t.DrawText(3, 16, "Root >  x*sqrt(y)");
   t.DrawText(3, 14, "Root >  for (int i=2;i<7;i++) printf(\"sqrt(%d) = %f\\n\",i,sqrt(i));");
   t.DrawText(3, 10, "Root >  TF1 f1(\"f1\",\"sin(x)/x\",0,10)");
   t.DrawText(3, 9, "Root >  f1.Draw()");
   t.SetTextFont(81);
   t.SetTextSize(0.018);
   t.DrawText(4, 15, "(float) 13.2288f");
   t.DrawText(4, 13.3, "sqrt(2) = 1.414214");
   t.DrawText(4, 12.7, "sqrt(3) = 1.732051");
   t.DrawText(4, 12.1, "sqrt(4) = 2.000000");
   t.DrawText(4, 11.5, "sqrt(5) = 2.236068");
   t.DrawText(4, 10.9, "sqrt(6) = 2.449490");

   TPad *pad = new TPad("pad", "pad", .2, .05, .8, .35);
   pad->Draw();
   pad->cd();
   pad->SetGrid();
   TF1 *f1 = new TF1("f1", "sin(x)/x", 0, 10);
   f1->Draw();
}
