{
   //
   // This macro displays the ROOT Directory data structure
   //Author: Rene Brun
   
   gROOT->Reset();
   c1 = new TCanvas("c1","ROOT FilDir description",700,900);
   c1->Range(1,1,19,24.5);
   TPaveLabel title(4,23,16,24.2,"ROOT File/Directory/Key description");
   title.SetFillColor(16);
   title.Draw();

   Int_t keycolor = 42;
   Int_t dircolor = 21;
   Int_t objcolor = 46;
   TPaveText file(2,19,6,22);
   file.SetFillColor(39);
   file.Draw();
   file.SetTextSize(0.04);
   file.AddText("TFile");
   file.AddText("Header");
   TArrow arrow(6,20.5,17,20.5,0.02,"|>");
   arrow.SetFillStyle(1001);
   arrow.SetLineWidth(2);
   arrow.Draw();
   TPaveText free(8,20,11,21);
   free.SetFillColor(18);
   free.Draw();
   free.AddText("First:Last");
   TPaveText free2(12,20,15,21);
   free2.SetFillColor(18);
   free2.Draw();
   free2.AddText("First:Last");
   TText tfree(6.2,21.2,"fFree = TList of free blocks");
   tfree.SetTextSize(0.02);
   tfree.Draw();
   TText tkeys(5.2,18.2,"fKeys = TList of Keys");
   tkeys.SetTextSize(0.02);
   tkeys.Draw();
   TText tmemory(3.2,15.2,"fListHead = TList of Objects in memory");
   tmemory.SetTextSize(0.02);
   tmemory.Draw();

   arrow.DrawArrow(5,17,17,17,0.02,"|>");
   TLine line(5,19,5,17);
   line.SetLineWidth(2);
   line.Draw();
   TPaveText key0(7,16,10,18);
   key0.SetTextSize(0.04);
   key0.SetFillColor(keycolor);
   key0.AddText("Key 0");
   key0.Draw();
   TPaveText key1(12,16,15,18);
   key1.SetTextSize(0.04);
   key1.SetFillColor(keycolor);
   key1.AddText("Key 1");
   key1.Draw();
   line.DrawLine(3,19,3,14);
   line.DrawLine(3,14,18,14);
   TPaveText obj0(5,13,8,15);
   obj0.SetFillColor(objcolor);
   obj0.AddText("Object");
   obj0.Draw();
   TPaveText dir1(10,13,13,15);
   dir1.SetFillColor(dircolor);
   dir1.AddText("SubDir");
   dir1.Draw();
   TPaveText obj1(15,13,18,15);
   obj1.SetFillColor(objcolor);
   obj1.AddText("Object");
   obj1.Draw();
   arrow.DrawArrow(12,11,17,11,0.015,"|>");
   arrow.DrawArrow(11,9,17,9,0.015,"|>");
   line.DrawLine(12,13,12,11);
   line.DrawLine(11,13,11,9);
   TPaveText key2(14,10.5,16,11.5);
   key2.SetFillColor(keycolor);
   key2.AddText("Key 0");
   key2.Draw();
   TPaveText obj2(14,8.5,16,9.5);
   obj2.SetFillColor(objcolor);
   obj2.AddText("Object");
   obj2.Draw();
   TLine ldot(10,15,2,11);
   ldot.SetLineStyle(2);
   ldot.Draw();
   ldot.DrawLine(13,15,8,11);
   ldot.DrawLine(13,13,8,5);
   TPaveText dirdata(2,5,8,11);
   dirdata.SetTextAlign(12);
   dirdata.SetFillColor(dircolor);
   dirdata.Draw();
   dirdata.SetTextSize(0.015);
   dirdata.AddText("fModified: True if directory is modified");
   dirdata.AddText("fWritable: True if directory is writable");
   dirdata.AddText("fDatimeC: Creation Date/Time");
   dirdata.AddText("fDatimeM: Last mod Date/Time");
   dirdata.AddText("fNbytesKeys: Number of bytes of key");
   dirdata.AddText("fNbytesName : Header length up to title");
   dirdata.AddText("fSeekDir: Start of Directory on file");
   dirdata.AddText("fSeekParent: Start of Parent Directory");
   dirdata.AddText("fSeekKeys: Pointer to Keys record");
   TPaveText keydata(10,2,17,7);
   keydata.SetTextAlign(12);
   keydata.SetFillColor(keycolor);
   keydata.Draw();
   ldot.DrawLine(14,11.5,10,7);
   ldot.DrawLine(16,11.5,17,7);
   keydata.SetTextSize(0.015);
   keydata.AddText("fNbytes: Size of compressed Object");
   keydata.AddText("fObjLen: Size of uncompressed Object");
   keydata.AddText("fDatime: Date/Time when written to store");
   keydata.AddText("fKeylen: Number of bytes for the key");
   keydata.AddText("fCycle : Cycle number");
   keydata.AddText("fSeekKey: Pointer to Object on file");
   keydata.AddText("fSeekPdir: Pointer to directory on file");
   keydata.AddText("fClassName: 'TKey'");
   keydata.AddText("fName: Object name");
   keydata.AddText("fTitle: Object Title");
}