TPad.cxx

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// @(#)root/gpad:$Id$
// Author: Rene Brun   12/12/94
 
/*************************************************************************
 * Copyright (C) 1995-2000, 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 <cstring>
#include <cstdlib>
#include <iostream>
#include <locale>
#include <memory>
 
#include "TROOT.h"
#include "TBuffer.h"
#include "TError.h"
#include "TMath.h"
#include "TSystem.h"
#include "TStyle.h"
#include "TFile.h"
#include "TH1.h"
#include "TH2.h"
#include "TH3.h"
#include "TClass.h"
#include "TBaseClass.h"
#include "TClassTable.h"
#include "TVirtualPS.h"
#include "TVirtualX.h"
#include "TVirtualViewer3D.h"
#include "TView.h"
#include "TPoint.h"
#include "TGraph.h"
#include "TMultiGraph.h"
#include "THStack.h"
#include "TPaveText.h"
#include "TPaveStats.h"
#include "TGroupButton.h"
#include "TBrowser.h"
#include "TVirtualGL.h"
#include "TString.h"
#include "TDataMember.h"
#include "TMethod.h"
#include "TDataType.h"
#include "TFrame.h"
#include "TExec.h"
#include "TDatime.h"
#include "TColor.h"
#include "TCanvas.h"
#include "TPluginManager.h"
#include "TEnv.h"
#include "TImage.h"
#include "TViewer3DPad.h"
#include "TCreatePrimitives.h"
#include "TLegend.h"
#include "TAtt3D.h"
#include "TVirtualPadPainter.h"
#include "strlcpy.h"
#include "snprintf.h"
 
#include "TVirtualMutex.h"
 
static Int_t gReadLevel = 0;
 
Int_t TPad::fgMaxPickDistance = 5;
 
ClassImpQ(TPad)
 
/** \class TPad
\ingroup gpad
 
The most important graphics class in the ROOT system.
 
A Pad is contained in a Canvas.
 
A Pad may contain other pads (unlimited pad hierarchy).
 
A pad is a linked list of primitives of any type (graphics objects,
histograms, detectors, tracks, etc.).
 
Adding a new element into a pad is in general performed by the Draw
member function of the object classes.
 
It is important to realize that the pad is a linked list of references
to the original object.
For example, in case of a histogram, the histogram.Draw() operation
only stores a reference to the histogram object and not a graphical
representation of this histogram.
When the mouse is used to change (say the bin content), the bin content
of the original histogram is changed.
 
The convention used in ROOT is that a Draw operation only adds
a reference to the object. The effective drawing is performed
when the canvas receives a signal to be painted.
 
\image html gpad_pad1.png
 
This signal is generally sent when typing carriage return in the
command input or when a graphical operation has been performed on one
of the pads of this canvas.
When a Canvas/Pad is repainted, the member function Paint for all
objects in the Pad linked list is invoked.
 
\image html gpad_pad2.png
 
When the mouse is moved on the Pad, The member function DistancetoPrimitive
is called for all the elements in the pad. DistancetoPrimitive returns
the distance in pixels to this object.
 
When the object is within the distance window, the member function
ExecuteEvent is called for this object.
 
In ExecuteEvent, move, changes can be performed on the object.
 
For examples of DistancetoPrimitive and ExecuteEvent functions,
see classes
~~~ {.cpp}
      TLine::DistancetoPrimitive, TLine::ExecuteEvent
      TBox::DistancetoPrimitive,  TBox::ExecuteEvent
      TH1::DistancetoPrimitive,   TH1::ExecuteEvent
~~~
A Pad supports linear and log scales coordinate systems.
The transformation coefficients are explained in TPad::ResizePad.
*/
 
////////////////////////////////////////////////////////////////////////////////
/// Pad default constructor.
 
TPad::TPad()
{
   fModified   = kTRUE;
   fTip        = nullptr;
   fPadPointer = nullptr;
   fPrimitives = nullptr;
   fExecs      = nullptr;
   fCanvas     = nullptr;
   fPadPaint   = 0;
   fPixmapID   = -1;
   fGLDevice   = -1;
   fCopyGLDevice = kFALSE;
   fEmbeddedGL = kFALSE;
   fTheta      = 30;
   fPhi        = 30;
   fNumber     = 0;
   fAbsCoord   = kFALSE;
   fEditable   = kTRUE;
   fCrosshair  = 0;
   fCrosshairPos = 0;
   fPadView3D  = nullptr;
   fMother     = (TPad*)gPad;
 
   fAbsHNDC      = 0.;
   fAbsPixeltoXk = 0.;
   fAbsPixeltoYk = 0.;
   fAbsWNDC      = 0.;
   fAbsXlowNDC   = 0.;
   fAbsYlowNDC   = 0.;
   fBorderMode   = 0;
   fBorderSize   = 0;
   fPixeltoX     = 0;
   fPixeltoXk    = 0.;
   fPixeltoY     = 0.;
   fPixeltoYk    = 0.;
   fUtoAbsPixelk = 0.;
   fUtoPixel     = 0.;
   fUtoPixelk    = 0.;
   fVtoAbsPixelk = 0.;
   fVtoPixel     = 0.;
   fVtoPixelk    = 0.;
   fXtoAbsPixelk = 0.;
   fXtoPixel     = 0.;
   fXtoPixelk    = 0.;
   fYtoAbsPixelk = 0.;
   fYtoPixel     = 0.;
   fYtoPixelk    = 0.;
   fXUpNDC       = 0.;
   fYUpNDC       = 0.;
 
   fFixedAspectRatio = kFALSE;
   fAspectRatio      = 0.;
 
   fNumPaletteColor = 0;
   fNextPaletteColor = 0;
   fCGnx = 0;
   fCGny = 0;
 
   fLogx  = 0;
   fLogy  = 0;
   fLogz  = 0;
   fGridx = false;
   fGridy = false;
   fTickx = 0;
   fTicky = 0;
   fFrame = nullptr;
   fView  = nullptr;
 
   fUxmin = fUymin = fUxmax = fUymax = 0;
 
   // Set default world coordinates to NDC [0,1]
   fX1 = 0;
   fX2 = 1;
   fY1 = 0;
   fY2 = 1;
 
   // Set default pad range
   fXlowNDC = 0;
   fYlowNDC = 0;
   fWNDC    = 1;
   fHNDC    = 1;
 
   fViewer3D = nullptr;
   SetBit(kMustCleanup);
 
   // the following line is temporarily disabled. It has side effects
   // when the pad is a TDrawPanelHist or a TFitPanel.
   // the line was supposed to fix a problem with DrawClonePad
   //   gROOT->SetSelectedPad(this);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Pad constructor.
///
///  A pad is a linked list of primitives.
///  A pad is contained in a canvas. It may contain other pads.
///  A pad has attributes. When a pad is created, the attributes
///  defined in the current style are copied to the pad attributes.
///
/// \param[in] name        pad name
/// \param[in] title       pad title
/// \param[in] xlow [0,1]  is the position of the bottom left point of the pad
///             expressed  in the mother pad reference system
/// \param[in] ylow [0,1]  is the Y position of this point.
/// \param[in] xup  [0,1]  is the x position of the top right point of the pad
///                        expressed in the mother pad reference system
/// \param[in] yup  [0,1]  is the Y position of this point.
/// \param[in] color       pad color
/// \param[in] bordersize  border size in pixels
/// \param[in] bordermode  border mode
///                        - bordermode = -1 box looks as it is behind the screen
///                        - bordermode = 0  no special effects
///                        - bordermode = 1  box looks as it is in front of the screen
 
TPad::TPad(const char *name, const char *title, Double_t xlow,
           Double_t ylow, Double_t xup, Double_t yup,
           Color_t color, Short_t bordersize, Short_t bordermode)
          : TVirtualPad(name,title,xlow,ylow,xup,yup,color,bordersize,bordermode)
{
   fModified   = kTRUE;
   fTip        = nullptr;
   fBorderSize = bordersize;
   fBorderMode = bordermode;
   if (gPad)   fCanvas = gPad->GetCanvas();
   else        fCanvas = (TCanvas*)this;
   fMother     = (TPad*)gPad;
   fPrimitives = new TList;
   fExecs      = new TList;
   fPadPointer = nullptr;
   fTheta      = 30;
   fPhi        = 30;
   fGridx      = gStyle->GetPadGridX();
   fGridy      = gStyle->GetPadGridY();
   fTickx      = gStyle->GetPadTickX();
   fTicky      = gStyle->GetPadTickY();
   fFrame      = nullptr;
   fView       = nullptr;
   fPadPaint   = 0;
   fPadView3D  = nullptr;
   fPixmapID   = -1;      // -1 means pixmap will be created by ResizePad()
   fCopyGLDevice = kFALSE;
   fEmbeddedGL = kFALSE;
   fNumber     = 0;
   fAbsCoord   = kFALSE;
   fEditable   = kTRUE;
   fCrosshair  = 0;
   fCrosshairPos = 0;
 
   fVtoAbsPixelk = 0.;
   fVtoPixelk    = 0.;
   fVtoPixel     = 0.;
   fAbsPixeltoXk = 0.;
   fPixeltoXk    = 0.;
   fPixeltoX     = 0;
   fAbsPixeltoYk = 0.;
   fPixeltoYk    = 0.;
   fPixeltoY     = 0.;
   fXlowNDC      = 0;
   fYlowNDC      = 0;
   fWNDC         = 1;
   fHNDC         = 1;
   fXUpNDC       = 0.;
   fYUpNDC       = 0.;
   fAbsXlowNDC   = 0.;
   fAbsYlowNDC   = 0.;
   fAbsWNDC      = 0.;
   fAbsHNDC      = 0.;
   fXtoAbsPixelk = 0.;
   fXtoPixelk    = 0.;
   fXtoPixel     = 0.;
   fYtoAbsPixelk = 0.;
   fYtoPixelk    = 0.;
   fYtoPixel     = 0.;
   fUtoAbsPixelk = 0.;
   fUtoPixelk    = 0.;
   fUtoPixel     = 0.;
 
   fUxmin = fUymin = fUxmax = fUymax = 0;
   fLogx = gStyle->GetOptLogx();
   fLogy = gStyle->GetOptLogy();
   fLogz = gStyle->GetOptLogz();
 
   fFixedAspectRatio = kFALSE;
   fAspectRatio      = 0.;
 
   fNumPaletteColor = 0;
   fNextPaletteColor = 0;
   fCGnx = 0;
   fCGny = 0;
 
   fViewer3D = nullptr;
 
   if (fCanvas) fGLDevice = fCanvas->GetGLDevice();
   // Set default world coordinates to NDC [0,1]
   fX1 = 0;
   fX2 = 1;
   fY1 = 0;
   fY2 = 1;
 
   if (!gPad) {
      Error("TPad", "You must create a TCanvas before creating a TPad");
      MakeZombie();
      return;
   }
 
   TContext ctxt(kTRUE);
 
   Bool_t zombie = kFALSE;
 
   if ((xlow < 0) || (xlow > 1) || (ylow < 0) || (ylow > 1)) {
      Error("TPad", "illegal bottom left position: x=%f, y=%f", xlow, ylow);
      zombie = kTRUE;
   } else if ((xup < 0) || (xup > 1) || (yup < 0) || (yup > 1)) {
      Error("TPad", "illegal top right position: x=%f, y=%f", xup, yup);
      zombie = kTRUE;
   } else if (xup-xlow <= 0) {
      Error("TPad", "illegal width: %f", xup-xlow);
      zombie = kTRUE;
   } else if (yup-ylow <= 0) {
      Error("TPad", "illegal height: %f", yup-ylow);
      zombie = kTRUE;
   }
 
   if (zombie) {
      // error in creating pad occurred, make this pad a zombie
      MakeZombie();
      return;
   }
 
 
   fLogx = gStyle->GetOptLogx();
   fLogy = gStyle->GetOptLogy();
   fLogz = gStyle->GetOptLogz();
 
   fUxmin = fUymin = fUxmax = fUymax = 0;
 
   // Set pad parameters and Compute conversion coefficients
   SetPad(name, title, xlow, ylow, xup, yup, color, bordersize, bordermode);
   Range(0, 0, 1, 1);
   SetBit(kMustCleanup);
   SetBit(kCanDelete);
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Pad destructor.
 
TPad::~TPad()
{
   if (ROOT::Detail::HasBeenDeleted(this)) return;
   Close();
   CloseToolTip(fTip);
   DeleteToolTip(fTip);
   auto primitives = fPrimitives;
   // In some cases, fPrimitives has the kMustCleanup bit set which will lead
   // its destructor to call RecursiveRemove and since this pad is still
   // likely to be (indirectly) in the list of cleanups, we must set
   // fPrimitives to nullptr to avoid TPad::RecursiveRemove from calling
   // a member function of a partially destructed object.
   fPrimitives = nullptr;
   delete primitives;
   SafeDelete(fExecs);
   delete fViewer3D;
 
   // Required since we overload TObject::Hash.
   ROOT::CallRecursiveRemoveIfNeeded(*this);
   if (this == gPad)
      gPad = nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Add an object to list of primitives with speicified draw option
/// When \par modified set to kTRUE (default) pad will be marked as modified
/// Let avoid usage of gPad when drawing object(s) in canvas or in subpads.
///
/// ~~~{.cpp}
/// auto c1 = new TCanvas("c1","Canvas with subpoads", 600, 600);
/// c1->Divide(2,2);
///
/// for (Int_t n = 1; n <= 4; ++n) {
///    auto h1 = new TH1I(TString::Format("hist_%d",n), "Random hist", 100, -5, 5);
///    h1->FillRandom("gaus", 2000 + n*1000);
///    c1->GetPad(n)->Add(h1);
/// }
/// ~~~
 
void TPad::Add(TObject *obj, Option_t *opt, Bool_t modified)
{
   if (!obj)
      return;
 
   if (!fPrimitives)
      fPrimitives = new TList;
 
   obj->SetBit(kMustCleanup);
 
   fPrimitives->Add(obj, opt);
 
   if (modified)
      Modified();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Add an object as first in list of primitives with speicified draw option
/// When \par modified set to kTRUE (default) pad will be marked as modified
/// Let avoid usage of gPad when drawing object(s) in canvas or in subpads.
 
void TPad::AddFirst(TObject *obj, Option_t *opt, Bool_t modified)
{
   if (!obj)
      return;
 
   if (!fPrimitives)
      fPrimitives = new TList;
 
   obj->SetBit(kMustCleanup);
 
   fPrimitives->AddFirst(obj, opt);
 
   if (modified)
      Modified();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Add a new TExec object to the list of Execs.
///
/// When an event occurs in the pad (mouse click, etc) the list of C++ commands
/// in the list of Execs are executed via TPad::AutoExec.
///
/// When a pad event occurs (mouse move, click, etc) all the commands
/// contained in the fExecs list are executed in the order found in the list.
///
/// This facility is activated by default. It can be deactivated by using
/// the canvas "Option" menu.
///
///  The following examples of TExec commands are provided in the tutorials:
///  macros exec1.C and exec2.C.
///
/// ### Example1 of use of exec1.C
///
/// ~~~ {.cpp}
///  Root > TFile f("hsimple.root")
///  Root > hpx.Draw()
///  Root > c1.AddExec("ex1",".x exec1.C")
/// ~~~
///
/// At this point you can use the mouse to click on the contour of
/// the histogram hpx. When the mouse is clicked, the bin number and its
/// contents are printed.
///
/// ### Example2 of use of exec1.C
///
/// ~~~ {.cpp}
///  Root > TFile f("hsimple.root")
///  Root > hpxpy.Draw()
///  Root > c1.AddExec("ex2",".x exec2.C")
/// ~~~
///
/// When moving the mouse in the canvas, a second canvas shows the
/// projection along X of the bin corresponding to the Y position
/// of the mouse. The resulting histogram is fitted with a gaussian.
/// A "dynamic" line shows the current bin position in Y.
/// This more elaborated example can be used as a starting point
/// to develop more powerful interactive applications exploiting the C++
/// interpreter as a development engine.
 
void TPad::AddExec(const char *name, const char *command)
{
   if (!fExecs) fExecs = new TList;
   TExec *ex = new TExec(name,command);
   fExecs->Add(ex);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Execute the list of Execs when a pad event occurs.
 
void TPad::AutoExec()
{
   if (GetCrosshair())
      DrawCrosshair();
 
   if (!fExecs)
      return;
   TIter next(fExecs);
   while (auto exec = (TExec*)next())
      exec->Exec();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Browse pad.
 
void TPad::Browse(TBrowser *b)
{
   cd();
   if (fPrimitives) fPrimitives->Browse(b);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Build a legend from the graphical objects in the pad.
///
/// A simple method to build automatically a TLegend from the primitives in a TPad.
///
/// Only those deriving from TAttLine, TAttMarker and TAttFill are added, excluding
/// TPave and TFrame derived classes.
///
/// \return    The built TLegend
///
/// \param[in] x1, y1, x2, y2       The TLegend coordinates
/// \param[in] title                The legend title. By default it is " "
/// \param[in] option               The TLegend option
///
/// The caller program owns the returned TLegend.
///
/// If the pad contains some TMultiGraph or THStack the individual
/// graphs or histograms in them are added to the TLegend.
///
/// ### Automatic placement of the legend
/// If `x1` is equal to `x2` and `y1` is equal to `y2` the legend will be automatically
/// placed to avoid overlapping with the existing primitives already displayed.
/// `x1` is considered as the width of the legend and `y1` the height. By default
/// the legend is automatically placed with width = `x1`= `x2` = 0.3 and
/// height = `y1`= `y2` = 0.21.
 
TLegend *TPad::BuildLegend(Double_t x1, Double_t y1, Double_t x2, Double_t y2,
                           const char* title, Option_t *option)
{
   TList *lop = GetListOfPrimitives();
   if (!lop) return nullptr;
   TList *lof = nullptr;
   TLegend *leg = nullptr;
   TObject *obj = nullptr;
   TIter next(lop);
   TString mes;
   TString opt;
 
   auto AddEntryFromListOfFunctions = [&]() {
      TIter nextobj(lof);
      while ((obj = nextobj())) {
         if (obj->InheritsFrom(TNamed::Class())) {
            if (strlen(obj->GetTitle()))
               mes = obj->GetTitle();
            else
               mes = obj->GetName();
         } else {
            mes = obj->ClassName();
         }
         leg->AddEntry(obj, mes.Data(), "lpf");
      }
   };
 
   while(auto o = next()) {
      if ((o->InheritsFrom(TAttLine::Class()) || o->InheritsFrom(TAttMarker::Class()) ||
          o->InheritsFrom(TAttFill::Class())) &&
         ( !(o->InheritsFrom(TFrame::Class())) && !(o->InheritsFrom(TPave::Class())) )) {
         if (!leg)
            leg = new TLegend(x1, y1, x2, y2, title);
         if (o->InheritsFrom(TNamed::Class()) && strlen(o->GetTitle()))
            mes = o->GetTitle();
         else if (strlen(o->GetName()))
            mes = o->GetName();
         else
            mes = o->ClassName();
         if (option && strlen(option)) {
            opt = option;
         } else {
            if (o->InheritsFrom(TAttLine::Class()))
               opt += "l";
            if (o->InheritsFrom(TAttMarker::Class()))
               opt += "p";
            if (o->InheritsFrom(TAttFill::Class()))
               opt += "f";
         }
         leg->AddEntry(o,mes.Data(), opt.Data());
         if (o->InheritsFrom(TH1::Class())) {
            lof = ((TH1 *)o)->GetListOfFunctions();
            AddEntryFromListOfFunctions();
         }
         if (o->InheritsFrom(TGraph::Class())) {
            lof = ((TGraph *)o)->GetListOfFunctions();
            AddEntryFromListOfFunctions();
         }
      } else if (o->InheritsFrom(TMultiGraph::Class())) {
         if (!leg)
            leg = new TLegend(x1, y1, x2, y2, title);
         TList * grlist = ((TMultiGraph *)o)->GetListOfGraphs();
         TIter nextgraph(grlist);
         TGraph *gr = nullptr;
         while ((obj = nextgraph())) {
            gr = (TGraph*) obj;
            if (strlen(gr->GetTitle()))
               mes = gr->GetTitle();
            else if (strlen(gr->GetName()))
               mes = gr->GetName();
            else
               mes = gr->ClassName();
            if (option && strlen(option))
               opt = option;
            else
               opt = "lpf";
            leg->AddEntry(obj, mes.Data(), opt);
         }
         lof = ((TMultiGraph *)o)->GetListOfFunctions();
         AddEntryFromListOfFunctions();
      } else if (o->InheritsFrom(THStack::Class())) {
         if (!leg)
            leg = new TLegend(x1, y1, x2, y2, title);
         TList * hlist = ((THStack *)o)->GetHists();
         TIter nexthist(hlist);
         while ((obj = nexthist())) {
            TH1 *hist = (TH1*) obj;
            if (strlen(hist->GetTitle()))
               mes = hist->GetTitle();
            else if (strlen(hist->GetName()))
               mes = hist->GetName();
            else
               mes = hist->ClassName();
            if (option && strlen(option))
               opt = option;
            else
               opt = "lpf";
            leg->AddEntry( obj, mes.Data(), opt );
         }
      }
      opt = "";
   }
   if (leg) {
      TContext ctxt(this, kTRUE);
      leg->Draw();
   } else {
      Info("BuildLegend", "No object(s) to build a TLegend.");
   }
   return leg;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Set Current pad.
///
/// When a canvas/pad is divided via TPad::Divide, one can directly
/// set the current path to one of the subdivisions.
/// See TPad::Divide for the convention to number sub-pads.
///
/// Returns the new current pad, or 0 in case of failure.
///
/// For example:
/// ~~~ {.cpp}
///    c1.Divide(2,3); // create 6 pads (2 divisions along x, 3 along y).
/// ~~~
/// To set the current pad to the bottom right pad, do
/// ~~~ {.cpp}
///    c1.cd(6);
/// ~~~
///  Note1:  c1.cd() is equivalent to c1.cd(0) and sets the current pad
///          to c1 itself.
///
///  Note2:  after a statement like c1.cd(6), the global variable gPad
///          points to the current pad. One can use gPad to set attributes
///          of the current pad.
///
///  Note3:  One can get a pointer to one of the sub-pads of pad with:
///          TPad *subpad = (TPad*)pad->GetPad(subpadnumber);
 
TVirtualPad *TPad::cd(Int_t subpadnumber)
{
   if (!subpadnumber) {
      gPad = this;
      if (!gPad->IsBatch() && GetPainter()) GetPainter()->SelectDrawable(fPixmapID);
      if (!fPrimitives) fPrimitives = new TList;
      return gPad;
   }
 
   if (!fPrimitives) fPrimitives = new TList;
   TIter    next(fPrimitives);
   while (auto obj = next()) {
      if (obj->InheritsFrom(TPad::Class())) {
         Int_t n = ((TPad*)obj)->GetNumber();
         if (n == subpadnumber) {
            return ((TPad*)obj)->cd();
         }
      }
   }
   return nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Delete all pad primitives.
///
/// If the bit kClearAfterCR has been set for this pad, the Clear function
/// will execute only after having pressed a CarriageReturn
/// Set the bit with `mypad->SetBit(TPad::kClearAfterCR)`
 
void TPad::Clear(Option_t *option)
{
   if (!IsEditable()) return;
 
   R__LOCKGUARD(gROOTMutex);
 
   if (!fPadPaint) {
      SafeDelete(fView);
      if (fPrimitives) fPrimitives->Clear(option);
      if (fFrame) {
         if (! ROOT::Detail::HasBeenDeleted(fFrame)) delete fFrame;
         fFrame = nullptr;
      }
   }
   if (fCanvas) fCanvas->Cleared(this);
 
   cd();
 
   if (TestBit(kClearAfterCR)) {
      // Intentional do not use the return value of getchar,
      // we just want to get it and forget it
      getchar();
   }
 
   if (!gPad->IsBatch() && GetPainter()) GetPainter()->ClearDrawable();
   if (gVirtualPS && gPad == gPad->GetCanvas()) gVirtualPS->NewPage();
 
   PaintBorder(GetFillColor(), kTRUE);
   fCrosshairPos = 0;
   fNumPaletteColor = 0;
   fCollideGrid.clear();
   fCGnx = 0;
   fCGny = 0;
   ResetBit(TGraph::kClipFrame);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Clipping routine: Cohen Sutherland algorithm.
///
///  - If Clip ==2 the segment is outside the boundary.
///  - If Clip ==1 the segment has one point outside the boundary.
///  - If Clip ==0 the segment is inside the boundary.
///
/// \param[inout]  x[],y[]                       Segment coordinates (2 points)
/// \param[in]     xclipl,yclipb,xclipr,yclipt   Clipping boundary
 
Int_t TPad::Clip(Float_t *x, Float_t *y, Float_t xclipl, Float_t yclipb, Float_t xclipr, Float_t yclipt)
{
   const Float_t kP=10000;
   Int_t clip = 0;
 
   for (Int_t i=0;i<2;i++) {
      if (TMath::Abs(xclipl-x[i]) <= TMath::Abs(xclipr-xclipl)/kP) x[i] = xclipl;
      if (TMath::Abs(xclipr-x[i]) <= TMath::Abs(xclipr-xclipl)/kP) x[i] = xclipr;
      if (TMath::Abs(yclipb-y[i]) <= TMath::Abs(yclipt-yclipb)/kP) y[i] = yclipb;
      if (TMath::Abs(yclipt-y[i]) <= TMath::Abs(yclipt-yclipb)/kP) y[i] = yclipt;
   }
 
   // Compute the first endpoint codes.
   Int_t code1 = ClippingCode(x[0],y[0],xclipl,yclipb,xclipr,yclipt);
   Int_t code2 = ClippingCode(x[1],y[1],xclipl,yclipb,xclipr,yclipt);
 
   Double_t xt=0, yt=0;
   Int_t clipped = 0; //this variable could be used in a future version
   while(code1 + code2) {
      clipped = 1;
 
      // The line lies entirely outside the clipping boundary
      if (code1&code2) {
         clip = 2;
         return clip;
      }
 
      // The line is subdivided into several parts
      Int_t ic = code1;
      if (ic == 0) ic = code2;
      if (ic & 0x1) {
         yt = y[0] + (y[1]-y[0])*(xclipl-x[0])/(x[1]-x[0]);
         xt = xclipl;
      }
      if (ic & 0x2) {
         yt = y[0] + (y[1]-y[0])*(xclipr-x[0])/(x[1]-x[0]);
         xt = xclipr;
      }
      if (ic & 0x4) {
         xt = x[0] + (x[1]-x[0])*(yclipb-y[0])/(y[1]-y[0]);
         yt = yclipb;
      }
      if (ic & 0x8) {
         xt = x[0] + (x[1]-x[0])*(yclipt-y[0])/(y[1]-y[0]);
         yt = yclipt;
      }
      if (ic == code1) {
         x[0]  = xt;
         y[0]  = yt;
         code1 = ClippingCode(xt,yt,xclipl,yclipb,xclipr,yclipt);
      } else {
         x[1]  = xt;
         y[1]  = yt;
         code2 = ClippingCode(xt,yt,xclipl,yclipb,xclipr,yclipt);
      }
   }
   clip = clipped;
   return clip;
}
 
/// @copydoc TPad::Clip(Float_t*,Float_t*,Float_t,Float_t,Float_t,Float_t)
 
Int_t TPad::Clip(Double_t *x, Double_t *y, Double_t xclipl, Double_t yclipb, Double_t xclipr, Double_t yclipt)
{
   const Double_t kP = 10000;
   Int_t clip = 0;
 
   for (Int_t i=0;i<2;i++) {
      if (TMath::Abs(xclipl-x[i]) <= TMath::Abs(xclipr-xclipl)/kP) x[i] = xclipl;
      if (TMath::Abs(xclipr-x[i]) <= TMath::Abs(xclipr-xclipl)/kP) x[i] = xclipr;
      if (TMath::Abs(yclipb-y[i]) <= TMath::Abs(yclipt-yclipb)/kP) y[i] = yclipb;
      if (TMath::Abs(yclipt-y[i]) <= TMath::Abs(yclipt-yclipb)/kP) y[i] = yclipt;
   }
 
   // Compute the first endpoint codes.
   Int_t code1 = 0;
   if (x[0] < xclipl) code1 = code1 | 0x1;
   if (x[0] > xclipr) code1 = code1 | 0x2;
   if (y[0] < yclipb) code1 = code1 | 0x4;
   if (y[0] > yclipt) code1 = code1 | 0x8;
   Int_t code2 = 0;
   if (x[1] < xclipl) code2 = code2 | 0x1;
   if (x[1] > xclipr) code2 = code2 | 0x2;
   if (y[1] < yclipb) code2 = code2 | 0x4;
   if (y[1] > yclipt) code2 = code2 | 0x8;
 
   Double_t xt=0, yt=0;
   Int_t clipped = 0; //this variable could be used in a future version
   while(code1 + code2) {
      clipped = 1;
 
      // The line lies entirely outside the clipping boundary
      if (code1&code2) {
         clip = 2;
         return clip;
      }
 
      // The line is subdivided into several parts
      Int_t ic = code1;
      if (ic == 0) ic = code2;
      if (ic & 0x1) {
         yt = y[0] + (y[1]-y[0])*(xclipl-x[0])/(x[1]-x[0]);
         xt = xclipl;
      }
      if (ic & 0x2) {
         yt = y[0] + (y[1]-y[0])*(xclipr-x[0])/(x[1]-x[0]);
         xt = xclipr;
      }
      if (ic & 0x4) {
         xt = x[0] + (x[1]-x[0])*(yclipb-y[0])/(y[1]-y[0]);
         yt = yclipb;
      }
      if (ic & 0x8) {
         xt = x[0] + (x[1]-x[0])*(yclipt-y[0])/(y[1]-y[0]);
         yt = yclipt;
      }
      if (ic == code1) {
         x[0]  = xt;
         y[0]  = yt;
         code1 = ClippingCode(xt,yt,xclipl,yclipb,xclipr,yclipt);
      } else {
         x[1]  = xt;
         y[1]  = yt;
         code2 = ClippingCode(xt,yt,xclipl,yclipb,xclipr,yclipt);
      }
   }
   clip = clipped;
   return clip;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Compute the endpoint codes for TPad::Clip.
 
Int_t TPad::ClippingCode(Double_t x, Double_t y, Double_t xcl1, Double_t ycl1, Double_t xcl2, Double_t ycl2)
{
   Int_t code = 0;
   if (x < xcl1) code = code | 0x1;
   if (x > xcl2) code = code | 0x2;
   if (y < ycl1) code = code | 0x4;
   if (y > ycl2) code = code | 0x8;
   return code;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Clip polygon using the Sutherland-Hodgman algorithm.
///
/// \param[in]  n                            Number of points in the polygon to
///                                          be clipped
/// \param[in]  x,y                          Polygon x[n], y[n] do be clipped vertices
/// \param[in]  xclipl,yclipb,xclipr,yclipt  Clipping boundary
/// \param[out] nn                           Number of points in xc and yc
/// \param[out] xc,yc                        Clipped polygon vertices. The Int_t
///                                          returned by this function is
///                                          the number of points in the clipped
///                                          polygon. These vectors must
///                                          be allocated by the calling function.
///                                          A size of 2*n for each is
///                                          enough.
///
/// Sutherland and Hodgman's polygon-clipping algorithm uses a divide-and-conquer
/// strategy: It solves a series of simple and identical problems that, when
/// combined, solve the overall problem. The simple problem is to clip a polygon
/// against a single infinite clip edge. Four clip edges, each defining one boundary
/// of the clip rectangle, successively clip a polygon against a clip rectangle.
///
/// Steps of Sutherland-Hodgman's polygon-clipping algorithm:
///
/// * Polygons can be clipped against each edge of the window one at a time.
///   Windows/edge intersections, if any, are easy to find since the X or Y coordinates
///   are already known.
/// * Vertices which are kept after clipping against one window edge are saved for
///   clipping against the remaining edges.
/// * Note that the number of vertices usually changes and will often increases.
///
/// The clip boundary determines a visible and invisible region. The edges from
/// vertex i to vertex i+1 can be one of four types:
///
/// * Case 1 : Wholly inside visible region - save endpoint
/// * Case 2 : Exit visible region - save the intersection
/// * Case 3 : Wholly outside visible region - save nothing
/// * Case 4 : Enter visible region - save intersection and endpoint
 
Int_t TPad::ClipPolygon(Int_t n, Double_t *x, Double_t *y, Int_t nn, Double_t *xc, Double_t *yc, Double_t xclipl, Double_t yclipb, Double_t xclipr, Double_t yclipt)
{
   Int_t nc, nc2;
   Double_t x1, y1, x2, y2, slope; // Segment to be clipped
 
   std::vector<Double_t> xc2(nn), yc2(nn);
 
   // Clip against the left boundary
   x1 = x[n-1]; y1 = y[n-1];
   nc2 = 0;
   Int_t i;
   for (i=0; i<n; i++) {
      x2 = x[i]; y2 = y[i];
      if (x1 == x2) {
         slope = 0;
      } else {
         slope = (y2-y1)/(x2-x1);
      }
      if (x1 >= xclipl) {
         if (x2 < xclipl) {
            xc2[nc2] = xclipl; yc2[nc2++] = slope*(xclipl-x1)+y1;
         } else {
            xc2[nc2] = x2; yc2[nc2++] = y2;
         }
      } else {
         if (x2 >= xclipl) {
            xc2[nc2] = xclipl; yc2[nc2++] = slope*(xclipl-x1)+y1;
            xc2[nc2] = x2; yc2[nc2++] = y2;
         }
      }
      x1 = x2; y1 = y2;
   }
 
   // Clip against the top boundary
   x1 = xc2[nc2-1]; y1 = yc2[nc2-1];
   nc = 0;
   for (i=0; i<nc2; i++) {
      x2 = xc2[i]; y2 = yc2[i];
      if (y1 == y2) {
         slope = 0;
      } else {
         slope = (x2-x1)/(y2-y1);
      }
      if (y1 <= yclipt) {
         if (y2 > yclipt) {
            xc[nc] = x1+(yclipt-y1)*slope; yc[nc++] = yclipt;
         } else {
            xc[nc] = x2; yc[nc++] = y2;
         }
      } else {
         if (y2 <= yclipt) {
            xc[nc] = x1+(yclipt-y1)*slope; yc[nc++] = yclipt;
            xc[nc] = x2; yc[nc++] = y2;
         }
      }
      x1 = x2; y1 = y2;
   }
 
   if (nc>0) {
 
      // Clip against the right boundary
      x1 = xc[nc-1]; y1 = yc[nc-1];
      nc2 = 0;
      for (i=0; i<nc; i++) {
         x2 = xc[i]; y2 = yc[i];
         if (x1 == x2) {
            slope = 0;
         } else {
            slope = (y2-y1)/(x2-x1);
         }
         if (x1 <= xclipr) {
            if (x2 > xclipr) {
               xc2[nc2] = xclipr; yc2[nc2++] = slope*(xclipr-x1)+y1;
            } else {
               xc2[nc2] = x2; yc2[nc2++] = y2;
            }
         } else {
            if (x2 <= xclipr) {
               xc2[nc2] = xclipr; yc2[nc2++] = slope*(xclipr-x1)+y1;
               xc2[nc2] = x2; yc2[nc2++] = y2;
            }
         }
         x1 = x2; y1 = y2;
      }
 
      // Clip against the bottom boundary
      x1 = xc2[nc2-1]; y1 = yc2[nc2-1];
      nc = 0;
      for (i=0; i<nc2; i++) {
         x2 = xc2[i]; y2 = yc2[i];
         if (y1 == y2) {
            slope = 0;
         } else {
            slope = (x2-x1)/(y2-y1);
         }
         if (y1 >= yclipb) {
            if (y2 < yclipb) {
               xc[nc] = x1+(yclipb-y1)*slope; yc[nc++] = yclipb;
            } else {
               xc[nc] = x2; yc[nc++] = y2;
            }
         } else {
            if (y2 >= yclipb) {
               xc[nc] = x1+(yclipb-y1)*slope; yc[nc++] = yclipb;
               xc[nc] = x2; yc[nc++] = y2;
            }
         }
         x1 = x2; y1 = y2;
      }
   }
 
   if (nc < 3) nc =0;
   return nc;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Delete all primitives in pad and pad itself.
/// Pad cannot be used anymore after this call.
/// Emits signal "Closed()".
 
void TPad::Close(Option_t *)
{
   if (ROOT::Detail::HasBeenDeleted(this)) return;
   if (!fMother) return;
   if (ROOT::Detail::HasBeenDeleted(fMother)) return;
 
   if (fPrimitives)
      fPrimitives->Clear();
   if (fView) {
      if (!ROOT::Detail::HasBeenDeleted(fView)) delete fView;
      fView = nullptr;
   }
   if (fFrame) {
      if (!ROOT::Detail::HasBeenDeleted(fFrame)) delete fFrame;
      fFrame = nullptr;
   }
 
   // emit signal
   if (IsA() != TCanvas::Class())
      Closed();
 
   if (fPixmapID != -1) {
      if (gPad) {
         if (!gPad->IsBatch() && GetPainter())
            GetPainter()->DestroyDrawable(fPixmapID);
      }
      fPixmapID = -1;
 
      if (!gROOT->GetListOfCanvases()) return;
      if (fMother == this) {
         gROOT->GetListOfCanvases()->Remove(this);
         return;   // in case of TCanvas
      }
 
      // remove from the mother's list of primitives
      if (fMother) {
         fMother->Remove(this, kFALSE); // do not produce modified
 
         if (gPad == this)
            fMother->cd();
      }
      if (fCanvas) {
         if (fCanvas->GetPadSave() == this)
            fCanvas->ClearPadSave();
         if (fCanvas->GetSelectedPad() == this)
            fCanvas->SetSelectedPad(nullptr);
         if (fCanvas->GetClickSelectedPad() == this)
            fCanvas->SetClickSelectedPad(nullptr);
      }
   }
 
   fMother = nullptr;
   if (gROOT->GetSelectedPad() == this)
      gROOT->SetSelectedPad(nullptr);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Copy the pixmap of the pad to the canvas.
 
void TPad::CopyPixmap()
{
   int px, py;
   XYtoAbsPixel(fX1, fY2, px, py);
 
   if (fPixmapID != -1 && GetPainter())
      GetPainter()->CopyDrawable(fPixmapID, px, py);
 
   if (this == gPad) HighLight(gPad->GetHighLightColor());
}
 
////////////////////////////////////////////////////////////////////////////////
/// Copy the sub-pixmaps of the pad to the canvas.
 
void TPad::CopyPixmaps()
{
   if (!fPrimitives) fPrimitives = new TList;
   TIter    next(GetListOfPrimitives());
   while (auto obj = next()) {
      if (obj->InheritsFrom(TPad::Class())) {
         ((TPad*)obj)->CopyPixmap();
         ((TPad*)obj)->CopyPixmaps();
      }
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Remove TExec name from the list of Execs.
 
void TPad::DeleteExec(const char *name)
{
   if (!fExecs) fExecs = new TList;
   TExec *ex = (TExec*)fExecs->FindObject(name);
   if (!ex) return;
   fExecs->Remove(ex);
   delete ex;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Compute distance from point px,py to a box.
///
///  Compute the closest distance of approach from point px,py to the
///  edges of this pad.
///  The distance is computed in pixels units.
 
Int_t TPad::DistancetoPrimitive(Int_t px, Int_t py)
{
   Int_t pxl, pyl, pxt, pyt;
   Int_t px1 = gPad->XtoAbsPixel(fX1);
   Int_t py1 = gPad->YtoAbsPixel(fY1);
   Int_t px2 = gPad->XtoAbsPixel(fX2);
   Int_t py2 = gPad->YtoAbsPixel(fY2);
   if (px1 < px2) {pxl = px1; pxt = px2;}
   else           {pxl = px2; pxt = px1;}
   if (py1 < py2) {pyl = py1; pyt = py2;}
   else           {pyl = py2; pyt = py1;}
 
   // Are we inside the box?
   // ======================
   if ( (px > pxl && px < pxt) && (py > pyl && py < pyt) ) {
      if (GetFillStyle()) return 0;  //*-* if pad is filled
   }
 
   // Are we on the edges?
   // ====================
   Int_t dxl = TMath::Abs(px - pxl);
   if (py < pyl) dxl += pyl - py;
   if (py > pyt) dxl += py - pyt;
   Int_t dxt = TMath::Abs(px - pxt);
   if (py < pyl) dxt += pyl - py;
   if (py > pyt) dxt += py - pyt;
   Int_t dyl = TMath::Abs(py - pyl);
   if (px < pxl) dyl += pxl - px;
   if (px > pxt) dyl += px - pxt;
   Int_t dyt = TMath::Abs(py - pyt);
   if (px < pxl) dyt += pxl - px;
   if (px > pxt) dyt += px - pxt;
 
   Int_t distance = dxl;
   if (dxt < distance) distance = dxt;
   if (dyl < distance) distance = dyl;
   if (dyt < distance) distance = dyt;
 
   return distance - Int_t(0.5*fLineWidth);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Automatic pad generation by division.
///
///  - The current canvas is divided in nx by ny equal divisions (pads).
///  - xmargin is the space along x between pads in percent of canvas.
///  - ymargin is the space along y between pads in percent of canvas.
///  - color is the color of the new pads. If 0, color is the canvas color.
///
/// Pads are automatically named `canvasname_n` where `n` is the division number
/// starting from top left pad.
///
/// Example if canvasname=c1 , nx=2, ny=3:
///
/// \image html gpad_pad3.png
///
/// Once a pad is divided into sub-pads, one can set the current pad
/// to a subpad with a given division number as illustrated above
/// with TPad::cd(subpad_number).
///
/// For example, to set the current pad to c1_4, one can do:
/// ~~~ {.cpp}
///    c1->cd(4)
/// ~~~
/// __Note1:__  c1.cd() is equivalent to c1.cd(0) and sets the current pad
///             to c1 itself.
///
/// __Note2:__  after a statement like c1.cd(6), the global variable gPad
///             points to the current pad. One can use gPad to set attributes
///             of the current pad.
///
/// __Note3:__  in case xmargin <=0 and ymargin <= 0, there is no space
///             between pads. The current pad margins are recomputed to
///             optimize the layout.
 
void TPad::Divide(Int_t nx, Int_t ny, Float_t xmargin, Float_t ymargin, Int_t color)
{
   if (!IsEditable()) return;
 
   if (gThreadXAR) {
      void *arr[7];
      arr[1] = this; arr[2] = (void*)&nx;arr[3] = (void*)& ny;
      arr[4] = (void*)&xmargin; arr[5] = (void *)& ymargin; arr[6] = (void *)&color;
      if ((*gThreadXAR)("PDCD", 7, arr, nullptr)) return;
   }
 
   TContext ctxt(kTRUE);
 
   cd();
   if (nx <= 0) nx = 1;
   if (ny <= 0) ny = 1;
   Int_t ix, iy;
   Double_t x1, y1, x2, y2, dx, dy;
   TPad *pad;
   TString name, title;
   Int_t n = 0;
   if (color == 0) color = GetFillColor();
   if (xmargin > 0 && ymargin > 0) {
      //general case
      dy = 1/Double_t(ny);
      dx = 1/Double_t(nx);
      for (iy=0;iy<ny;iy++) {
         y2 = 1 - iy*dy - ymargin;
         y1 = y2 - dy + 2*ymargin;
         if (y1 < 0) y1 = 0;
         if (y1 > y2) continue;
         for (ix=0;ix<nx;ix++) {
            x1 = ix*dx + xmargin;
            x2 = x1 +dx -2*xmargin;
            if (x1 > x2) continue;
            n++;
            name.Form("%s_%d", GetName(), n);
            pad = new TPad(name.Data(), name.Data(), x1, y1, x2, y2, color);
            pad->SetNumber(n);
            pad->Draw();
         }
      }
   } else {
      // special case when xmargin <= 0 && ymargin <= 0
      Double_t xl = GetLeftMargin();
      Double_t xr = GetRightMargin();
      Double_t yb = GetBottomMargin();
      Double_t yt = GetTopMargin();
      xl /= (1-xl+xr)*nx;
      xr /= (1-xl+xr)*nx;
      yb /= (1-yb+yt)*ny;
      yt /= (1-yb+yt)*ny;
      SetLeftMargin(xl);
      SetRightMargin(xr);
      SetBottomMargin(yb);
      SetTopMargin(yt);
      dx = (1-xl-xr)/nx;
      dy = (1-yb-yt)/ny;
      Int_t number = 0;
      for (Int_t i=0;i<nx;i++) {
         x1 = i*dx+xl;
         x2 = x1 + dx;
         if (i == 0) x1 = 0;
         if (i == nx-1) x2 = 1-xr;
         for (Int_t j=0;j<ny;j++) {
            number = j*nx + i +1;
            y2 = 1 -j*dy -yt;
            y1 = y2 - dy;
            if (j == 0)    y2 = 1-yt;
            if (j == ny-1) y1 = 0;
            name.Form("%s_%d", GetName(), number);
            title.Form("%s_%d", GetTitle(), number);
            pad = new TPad(name.Data(), title.Data(), x1, y1, x2, y2);
            pad->SetNumber(number);
            pad->SetBorderMode(0);
            if (i == 0)    pad->SetLeftMargin(xl*nx);
            else           pad->SetLeftMargin(0);
            pad->SetRightMargin(0);
            pad->SetTopMargin(0);
            if (j == ny-1) pad->SetBottomMargin(yb*ny);
            else           pad->SetBottomMargin(0);
            pad->Draw();
         }
      }
   }
   Modified();
}
 
////////////////////////////////////////////////////////////////////////////////
/// "n" is the total number of sub-pads. The number of sub-pads along the X
/// and Y axis are computed according to the square root of n.
 
void TPad::DivideSquare(Int_t n, Float_t xmargin, Float_t ymargin, Int_t color)
{
   Int_t w = 1, h = 1;
   if (!fCanvas) {
      Error("DivideSquare", "No canvas associated with this pad.");
      return;
   }
   if (fCanvas->GetWindowWidth() > fCanvas->GetWindowHeight()) {
      w = TMath::Ceil(TMath::Sqrt(n));
      h = TMath::Floor(TMath::Sqrt(n));
      if (w*h < n) w++;
   } else {
      h = TMath::Ceil(TMath::Sqrt(n));
      w = TMath::Floor(TMath::Sqrt(n));
      if (w*h < n) h++;
   }
 
   Divide( w, h, xmargin, ymargin, color);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Draw Pad in Current pad (re-parent pad if necessary).
 
void TPad::Draw(Option_t *option)
{
   // if no canvas opened yet create a default canvas
   if (!gPad) {
      gROOT->MakeDefCanvas();
   }
 
   // pad cannot be in itself and it can only be in one other pad at a time
   if (!fPrimitives) fPrimitives = new TList;
   if (gPad != this) {
      if (fMother && !ROOT::Detail::HasBeenDeleted(fMother))
            fMother->Remove(this, kFALSE);
      TPad *oldMother = fMother;
      fCanvas = gPad->GetCanvas();
      //
      fMother = (TPad*)gPad;
      if (oldMother != fMother || fPixmapID == -1) ResizePad();
   }
 
   if (fCanvas && fCanvas->IsWeb()) {
      Modified();
      fCanvas->UpdateAsync();
   } else {
      Paint();
   }
 
   if (gPad->IsRetained() && gPad != this && fMother)
      fMother->Add(this, option);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Draw class inheritance tree of the class to which obj belongs.
///
/// If a class B inherits from a class A, description of B is drawn
/// on the right side of description of A.
///
/// Member functions overridden by B are shown in class A with a blue line
/// crossing-out the corresponding member function.
 
void TPad::DrawClassObject(const TObject *classobj, Option_t *option)
{
   if (!classobj) return;
   char dname[256];
   const Int_t kMAXLEVELS = 10;
   TClass *clevel[kMAXLEVELS], *cl, *cll;
   TBaseClass *base, *cinherit;
   TText *ptext = nullptr;
   TString opt=option;
   Double_t x,y,dy,y1,v1,v2,dv;
   Int_t nd,nf,nc,nkd,nkf,i,j;
   TPaveText *pt;
   Int_t maxlev = 4;
   if (opt.Contains("2")) maxlev = 2;
   if (opt.Contains("3")) maxlev = 3;
   if (opt.Contains("5")) maxlev = 5;
   if (opt.Contains("6")) maxlev = 6;
   if (opt.Contains("7")) maxlev = 7;
 
      // Clear and Set Pad range
   Double_t xpad = 20.5;
   Double_t ypad = 27.5;
   Clear();
   Range(0,0,xpad,ypad);
 
   // Find number of levels
   Int_t nlevel = 0;
   TClass *obj = (TClass*)classobj;
   clevel[nlevel] = obj;
   TList *lbase = obj->GetListOfBases();
   while(lbase) {
      base = (TBaseClass*)lbase->First();
      if (!base) break;
      if (!base->GetClassPointer()) break;
      nlevel++;
      clevel[nlevel] = base->GetClassPointer();
      lbase = clevel[nlevel]->GetListOfBases();
      if (nlevel >= maxlev-1) break;
   }
   Int_t maxelem = 0;
   Int_t ncdraw  = 0;
   Int_t ilevel, nelem;
   for (ilevel=nlevel;ilevel>=0;ilevel--) {
      cl = clevel[ilevel];
      nelem = cl->GetNdata() + cl->GetNmethods();
      if (nelem > maxelem) maxelem = nelem;
      nc = (nelem/50) + 1;
      ncdraw += nc;
   }
 
   Double_t tsizcm = 0.40;
   Double_t x1 = 0.25;
   Double_t x2 = 0;
   Double_t dx = 3.5;
   if (ncdraw > 4) {
      dx = dx - 0.42*Double_t(ncdraw-5);
      if (dx < 1.3) dx = 1.3;
      tsizcm = tsizcm - 0.03*Double_t(ncdraw-5);
      if (tsizcm < 0.27) tsizcm = 0.27;
   }
   Double_t tsiz = 1.2*tsizcm/ypad;
 
   // Now loop on levels
   for (ilevel=nlevel;ilevel>=0;ilevel--) {
      cl    = clevel[ilevel];
      nelem = cl->GetNdata() + cl->GetNmethods();
      if (nelem > maxelem) maxelem = nelem;
      nc    = (nelem/50) + 1;
      dy    = 0.45;
      if (ilevel < nlevel) x1 = x2 + 0.5;
      x2    = x1 + nc*dx;
      v2    = ypad - 0.5;
      lbase = cl->GetListOfBases();
      cinherit = nullptr;
      if (lbase) cinherit = (TBaseClass*)lbase->First();
 
      do {
         nd = cl->GetNdata();
         nf = cl->GetNmethods() - 2; //do not show default constructor and destructor
         if (cl->GetListOfMethods()->FindObject("Dictionary")) {
            nf -= 6;  // do not count the Dictionary/ClassDef functions
         }
         nkf= nf/nc +1;
         nkd= nd/nc +1;
         if (nd == 0) nkd=0;
         if (nf == 0) nkf=0;
         y1 = v2 - 0.7;
         v1 = y1 - Double_t(nkf+nkd+nc-1)*dy;
         dv = v2 - v1;
 
         // Create a new PaveText
         pt = new TPaveText(x1,v1,x2,v2);
         pt->SetBit(kCanDelete);
         pt->SetFillColor(19);
         pt->Draw();
         pt->SetTextColor(4);
         pt->SetTextFont(61);
         pt->SetTextAlign(12);
         pt->SetTextSize(tsiz);
         TBox *box = pt->AddBox(0,(y1+0.01-v1)/dv,0,(v2-0.01-v1)/dv);
         if (box) box->SetFillColor(17);
         pt->AddLine(0,(y1-v1)/dv,0,(y1-v1)/dv);
         TText *title = pt->AddText(0.5,(0.5*(y1+v2)-v1)/dv,(char*)cl->GetName());
         title->SetTextAlign(22);
         title->SetTextSize(0.6*(v2-y1)/ypad);
 
         // Draw data Members
         i = 0;
         x = 0.03;
         y = y1 + 0.5*dy;
         TDataMember *d;
         TIter        nextd(cl->GetListOfDataMembers());
         while ((d = (TDataMember *) nextd())) {
            if (i >= nkd) { i = 1; y = y1 - 0.5*dy; x += 1/Double_t(nc); }
            else { i++; y -= dy; }
 
            // Take in account the room the array index will occupy
 
            Int_t dim = d->GetArrayDim();
            Int_t indx = 0;
            snprintf(dname,256,"%s",d->GetName());
            Int_t ldname = 0;
            while (indx < dim ){
               ldname = strlen(dname);
               snprintf(&dname[ldname],256-ldname,"[%d]",d->GetMaxIndex(indx));
               indx++;
            }
            pt->AddText(x,(y-v1)/dv,dname);
         }
 
         // Draw a separator line
         Double_t ysep;
         if (nd) {
            ysep = y1 - Double_t(nkd)*dy;
            pt->AddLine(0,(ysep-v1)/dv,0,(ysep-v1)/dv);
            ysep -= 0.5*dy;
         } else  ysep = y1;
 
         // Draw Member Functions
         Int_t fcount = 0;
         i = 0;
         x = 0.03;
         y = ysep + 0.5*dy;
         TMethod *m;
         TIter        nextm(cl->GetListOfMethods());
         while ((m = (TMethod *) nextm())) {
            if (
               !strcmp( m->GetName(), "Dictionary"    ) ||
               !strcmp( m->GetName(), "Class_Version" ) ||
               !strcmp( m->GetName(), "DeclFileName"  ) ||
               !strcmp( m->GetName(), "DeclFileLine"  ) ||
               !strcmp( m->GetName(), "ImplFileName"  ) ||
               !strcmp( m->GetName(), "ImplFileLine"  )
            ) continue;
            fcount++;
            if (fcount > nf) break;
            if (i >= nkf) { i = 1; y = ysep - 0.5*dy; x += 1/Double_t(nc); }
            else { i++; y -= dy; }
 
            ptext = pt->AddText(x,(y-v1)/dv,m->GetName());
            // Check if method is overloaded in a derived class
            // If yes, Change the color of the text to blue
            for (j=ilevel-1;j>=0;j--) {
               if (cl == clevel[ilevel]) {
                  if (clevel[j]->GetMethodAny((char*)m->GetName())) {
                     ptext->SetTextColor(15);
                     break;
                  }
               }
            }
         }
 
         // Draw second inheritance classes for this class
         cll = nullptr;
         if (cinherit) {
            cinherit = (TBaseClass*)lbase->After(cinherit);
            if (cinherit) {
               cl  = cinherit->GetClassPointer();
               cll = cl;
               v2  = v1 -0.4;
               dy  = 0.35;
            }
         }
      } while (cll);
   }
   Update();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Function called to draw a crosshair in the canvas
///
/// Example:
/// ~~~ {.cpp}
/// Root > TFile f("hsimple.root");
/// Root > hpxpy.Draw();
/// Root > c1.SetCrosshair();
/// ~~~
/// When moving the mouse in the canvas, a crosshair is drawn
///
///  - if the canvas fCrosshair = 1 , the crosshair spans the full canvas
///  - if the canvas fCrosshair > 1 , the crosshair spans only the pad
 
void TPad::DrawCrosshair()
{
   if (!gPad || (gPad->GetEvent() == kMouseEnter)) return;
 
   TPad *cpad = (TPad*)gPad;
   TCanvas *canvas = cpad->GetCanvas();
   canvas->FeedbackMode(kTRUE);
 
   //erase old position and draw a line at current position
   Int_t pxmin,pxmax,pymin,pymax,px,py;
#ifndef R__HAS_COCOA
   Int_t pxold = fCrosshairPos%10000;
   Int_t pyold = fCrosshairPos/10000;
#endif // R__HAS_COCOA
   px    = cpad->GetEventX();
   py    = cpad->GetEventY()+1;
   if (canvas->GetCrosshair() > 1) {  //crosshair only in the current pad
      pxmin = cpad->XtoAbsPixel(fX1);
      pxmax = cpad->XtoAbsPixel(fX2);
      pymin = cpad->YtoAbsPixel(fY1);
      pymax = cpad->YtoAbsPixel(fY2);
   } else { //default; crosshair spans the full canvas
      pxmin = 0;
      pxmax = canvas->GetWw();
      pymin = 0;
      pymax = cpad->GetWh();
   }
#ifndef R__HAS_COCOA
   // Not needed, no XOR with Cocoa.
   if(pxold) gVirtualX->DrawLine(pxold,pymin,pxold,pymax);
   if(pyold) gVirtualX->DrawLine(pxmin,pyold,pxmax,pyold);
#endif // R__HAS_COCOA
   if (cpad->GetEvent() == kButton1Down ||
       cpad->GetEvent() == kButton1Up   ||
       cpad->GetEvent() == kMouseLeave) {
      fCrosshairPos = 0;
      return;
   }
   gVirtualX->DrawLine(px,pymin,px,pymax);
   gVirtualX->DrawLine(pxmin,py,pxmax,py);
   fCrosshairPos = px + 10000*py;
}
 
////////////////////////////////////////////////////////////////////////////////
///  Draw an empty pad frame with X and Y axis.
///
///   \return   The pointer to the histogram used to draw the frame.
///
///   \param[in] xmin      X axis lower limit
///   \param[in] xmax      X axis upper limit
///   \param[in] ymin      Y axis lower limit
///   \param[in] ymax      Y axis upper limit
///   \param[in] title     Pad title.If title is of the form "stringt;stringx;stringy"
///                        the pad title is set to stringt, the x axis title to
///                        stringx, the y axis title to stringy.
///
/// #### Example:
///
/// Begin_Macro(source)
/// {
///    auto c = new TCanvas("c","c",200,10,500,300);
///
///    const Int_t n = 50;
///    auto g = new TGraph();
///    for (Int_t i=0;i<n;i++) g->SetPoint(i,i*0.1,100*sin(i*0.1+0.2));
///
///    auto frame = c->DrawFrame(0, -110, 2, 110);
///    frame->GetXaxis()->SetTitle("X axis");
///
///    g->Draw("L*");
/// }
/// End_Macro
 
TH1F *TPad::DrawFrame(Double_t xmin, Double_t ymin, Double_t xmax, Double_t ymax, const char *title)
{
   if (!IsEditable())
      return nullptr;
 
   if (this != gPad) {
      Warning("DrawFrame", "Must be called for the current pad only");
      if (gPad) return gPad->DrawFrame(xmin,ymin,xmax,ymax,title);
   }
 
   cd();
 
   TH1F *hframe = (TH1F*)FindObject("hframe");
   if (hframe) delete hframe;
   Int_t nbins = 1000;
   //if log scale in X, use variable bin size linear with log(x)
   //this gives a better precision when zooming on the axis
   if (fLogx && xmin > 0 && xmax > xmin) {
      Double_t xminl = TMath::Log(xmin);
      Double_t xmaxl = TMath::Log(xmax);
      Double_t dx = (xmaxl-xminl)/nbins;
      std::vector<Double_t> xbins(nbins+1);
      xbins[0] = xmin;
      for (Int_t i=1;i<=nbins;i++) {
         xbins[i] = TMath::Exp(xminl+i*dx);
      }
      hframe = new TH1F("hframe",title,nbins,xbins.data());
   } else {
      hframe = new TH1F("hframe",title,nbins,xmin,xmax);
   }
   hframe->SetBit(TH1::kNoStats);
   hframe->SetBit(kCanDelete);
   hframe->SetMinimum(ymin);
   hframe->SetMaximum(ymax);
   hframe->GetYaxis()->SetLimits(ymin,ymax);
   hframe->SetDirectory(nullptr);
   hframe->Draw(" ");
   Update();
   cd();
   return hframe;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Static function to Display Color Table in a pad.
 
void TPad::DrawColorTable()
{
   Int_t i, j;
   Int_t color;
   Double_t xlow, ylow, xup, yup, hs, ws;
   Double_t x1, y1, x2, y2;
   x1 = y1 = 0;
   x2 = y2 = 20;
 
   gPad->SetFillColor(0);
   gPad->Clear();
   gPad->Range(x1,y1,x2,y2);
 
   TText text(0,0,"");
   text.SetTextFont(61);
   text.SetTextSize(0.07);
   text.SetTextAlign(22);
 
   TBox box;
 
   // Draw color table boxes.
   hs = (y2-y1)/Double_t(5);
   ws = (x2-x1)/Double_t(10);
   for (i=0;i<10;i++) {
      xlow = x1 + ws*(Double_t(i)+0.1);
      xup  = x1 + ws*(Double_t(i)+0.9);
      for (j=0;j<5;j++) {
         ylow = y1 + hs*(Double_t(j)+0.1);
         yup  = y1 + hs*(Double_t(j)+0.9);
         color = 10*j + i;
         box.SetFillStyle(1001);
         box.SetFillColor(color);
         box.DrawBox(xlow, ylow, xup, yup);
         box.SetFillStyle(0);
         box.SetLineColor(1);
         box.DrawBox(xlow, ylow, xup, yup);
         if (color == 1) text.SetTextColor(0);
         else            text.SetTextColor(1);
         text.DrawText(0.5*(xlow+xup), 0.5*(ylow+yup), TString::Format("%d",color).Data());
      }
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Execute action corresponding to one event.
///
/// This member function is called when a TPad object is clicked.
///
/// If the mouse is clicked in one of the 4 corners of the pad (pA,pB,pC,pD)
/// the pad is resized with the rubber rectangle.
///
/// If the mouse is clicked inside the pad, the pad is moved.
///
/// If the mouse is clicked on the 4 edges (pL,pR,pTop,pBot), the pad is scaled
/// parallel to this edge.
///
/// \image html gpad_pad4.png
///
/// Note that this function duplicates on purpose the functionality
/// already implemented in TBox::ExecuteEvent.
/// If somebody modifies this function, may be similar changes should also
/// be applied to TBox::ExecuteEvent.
 
void TPad::ExecuteEvent(Int_t event, Int_t px, Int_t py)
{
   const Int_t kMaxDiff = 5;
   const Int_t kMinSize = 20;
   static Int_t pxorg, pyorg;
   static Int_t px1, px2, py1, py2, pxl, pyl, pxt, pyt, pxold, pyold;
   static Int_t px1p, px2p, py1p, py2p, pxlp, pylp, pxtp, pytp;
   static Bool_t pA, pB, pC, pD, pTop, pL, pR, pBot, pINSIDE;
   Int_t  wx, wy;
   Bool_t opaque  = OpaqueMoving();
   Bool_t ropaque = OpaqueResizing();
   Bool_t fixedr  = HasFixedAspectRatio();
 
   if (!IsEditable() && event != kMouseEnter) return;
   TVirtualPad  *parent = GetMother();
   if (!parent->IsEditable()) return;
 
   HideToolTip(event);
 
   if (fXlowNDC < 0 && event != kButton1Down) return;
   if (fYlowNDC < 0 && event != kButton1Down) return;
 
   // keep old mouse position
   if (event == kButton1Down) {
      pxorg = px;
      pyorg = py;
   }
 
   Int_t newcode = gROOT->GetEditorMode();
   if (newcode)
      pA = pB = pC = pD = pTop = pL = pR = pBot = pINSIDE = kFALSE;
   switch (newcode) {
      case kPad:
         TCreatePrimitives::Pad(event,px,py,0);
         break;
      case kMarker:
      case kText:
         TCreatePrimitives::Text(event,px,py,newcode);
         break;
      case kLine:
         TCreatePrimitives::Line(event,px,py,kLine);
         break;
      case kArrow:
         TCreatePrimitives::Line(event,px,py,kArrow);
         break;
      case kCurlyLine:
         TCreatePrimitives::Line(event,px,py,kCurlyLine);
         break;
      case kCurlyArc:
         TCreatePrimitives::Line(event,px,py,kCurlyArc);
         break;
      case kPolyLine:
         TCreatePrimitives::PolyLine(event,px,py,kPolyLine);
         break;
      case kCutG:
         TCreatePrimitives::PolyLine(event,px,py,kCutG);
         break;
      case kArc:
         TCreatePrimitives::Ellipse(event,px,py,kArc);
         break;
      case kEllipse:
         TCreatePrimitives::Ellipse(event,px,py,kEllipse);
         break;
      case kButton:
      case kPave:
      case kPaveLabel:
      case kPaveText:
      case kPavesText:
      case kDiamond:
         TCreatePrimitives::Pave(event,px,py,newcode);
         return;
      default:
         break;
      }
      if (newcode) return;
 
   switch (event) {
 
   case kMouseEnter:
      if (fTip)
         ResetToolTip(fTip);
      break;
 
   case kArrowKeyPress:
   case kButton1Down:
 
      fXUpNDC = fXlowNDC + fWNDC;
      fYUpNDC = fYlowNDC + fHNDC;
 
      GetPainter()->SetLineColor(-1);
      TAttLine::Modify();  //Change line attributes only if necessary
      if (GetFillColor())
         GetPainter()->SetLineColor(GetFillColor());
      else
         GetPainter()->SetLineColor(1);
      GetPainter()->SetLineWidth(2);
 
      // No break !!!
 
   case kMouseMotion:
 
      px1 = XtoAbsPixel(fX1);
      py1 = YtoAbsPixel(fY1);
      px2 = XtoAbsPixel(fX2);
      py2 = YtoAbsPixel(fY2);
 
      if (px1 < px2) {
         pxl = px1;
         pxt = px2;
      } else {
         pxl = px2;
         pxt = px1;
      }
      if (py1 < py2) {
         pyl = py1;
         pyt = py2;
      } else {
         pyl = py2;
         pyt = py1;
      }
 
      px1p = parent->XtoAbsPixel(parent->GetX1()) + parent->GetBorderSize();
      py1p = parent->YtoAbsPixel(parent->GetY1()) - parent->GetBorderSize();
      px2p = parent->XtoAbsPixel(parent->GetX2()) - parent->GetBorderSize();
      py2p = parent->YtoAbsPixel(parent->GetY2()) + parent->GetBorderSize();
 
      if (px1p < px2p) {
         pxlp = px1p;
         pxtp = px2p;
      } else {
         pxlp = px2p;
         pxtp = px1p;
      }
      if (py1p < py2p) {
         pylp = py1p;
         pytp = py2p;
      } else {
         pylp = py2p;
         pytp = py1p;
      }
 
      pA = pB = pC = pD = pTop = pL = pR = pBot = pINSIDE = kFALSE;
 
                                                         // case pA
      if (TMath::Abs(px - pxl) <= kMaxDiff && TMath::Abs(py - pyl) <= kMaxDiff) {
         pxold = pxl; pyold = pyl; pA = kTRUE;
         SetCursor(kTopLeft);
      }
                                                         // case pB
      if (TMath::Abs(px - pxt) <= kMaxDiff && TMath::Abs(py - pyl) <= kMaxDiff) {
         pxold = pxt; pyold = pyl; pB = kTRUE;
         SetCursor(kTopRight);
      }
                                                         // case pC
      if (TMath::Abs(px - pxt) <= kMaxDiff && TMath::Abs(py - pyt) <= kMaxDiff) {
         pxold = pxt; pyold = pyt; pC = kTRUE;
         SetCursor(kBottomRight);
      }
                                                         // case pD
      if (TMath::Abs(px - pxl) <= kMaxDiff && TMath::Abs(py - pyt) <= kMaxDiff) {
         pxold = pxl; pyold = pyt; pD = kTRUE;
         SetCursor(kBottomLeft);
      }
 
      if ((px > pxl+kMaxDiff && px < pxt-kMaxDiff) &&
          TMath::Abs(py - pyl) < kMaxDiff) {             // top edge
         pxold = pxl; pyold = pyl; pTop = kTRUE;
         SetCursor(kTopSide);
      }
 
      if ((px > pxl+kMaxDiff && px < pxt-kMaxDiff) &&
          TMath::Abs(py - pyt) < kMaxDiff) {             // bottom edge
         pxold = pxt; pyold = pyt; pBot = kTRUE;
         SetCursor(kBottomSide);
      }
 
      if ((py > pyl+kMaxDiff && py < pyt-kMaxDiff) &&
          TMath::Abs(px - pxl) < kMaxDiff) {             // left edge
         pxold = pxl; pyold = pyl; pL = kTRUE;
         SetCursor(kLeftSide);
      }
 
      if ((py > pyl+kMaxDiff && py < pyt-kMaxDiff) &&
         TMath::Abs(px - pxt) < kMaxDiff) {             // right edge
         pxold = pxt; pyold = pyt; pR = kTRUE;
         SetCursor(kRightSide);
      }
 
      if ((px > pxl+kMaxDiff && px < pxt-kMaxDiff) &&
          (py > pyl+kMaxDiff && py < pyt-kMaxDiff)) {    // inside box
         pxold = px; pyold = py; pINSIDE = kTRUE;
         if (event == kButton1Down)
            SetCursor(kMove);
         else
            SetCursor(kCross);
      }
 
      fResizing = kFALSE;
      if (pA || pB || pC || pD || pTop || pL || pR || pBot)
         fResizing = kTRUE;
 
      if (!pA && !pB && !pC && !pD && !pTop && !pL && !pR && !pBot && !pINSIDE)
         SetCursor(kCross);
 
      break;
 
   case kArrowKeyRelease:
   case kButton1Motion:
 
      if (TestBit(kCannotMove)) break;
      wx = wy = 0;
 
      if (pA) {
         if (!ropaque) gVirtualX->DrawBox(pxold, pyt, pxt, pyold, TVirtualX::kHollow);
         if (px > pxt-kMinSize) { px = pxt-kMinSize; wx = px; }
         if (py > pyt-kMinSize) { py = pyt-kMinSize; wy = py; }
         if (px < pxlp) { px = pxlp; wx = px; }
         if (py < pylp) { py = pylp; wy = py; }
         if (fixedr) {
            Double_t dy = Double_t(TMath::Abs(pxt-px))/parent->UtoPixel(1.) /
                          fAspectRatio;
            Int_t npy2 = pyt - TMath::Abs(parent->VtoAbsPixel(dy) -
                                          parent->VtoAbsPixel(0));
            if (npy2 < pylp) {
               px = pxold;
               py = pyold;
            } else
               py = npy2;
 
            wx = wy = 0;
         }
         if (!ropaque) gVirtualX->DrawBox(px, pyt, pxt, py, TVirtualX::kHollow);
      }
      if (pB) {
         if (!ropaque) gVirtualX->DrawBox(pxl  , pyt, pxold, pyold, TVirtualX::kHollow);
         if (px < pxl+kMinSize) { px = pxl+kMinSize; wx = px; }
         if (py > pyt-kMinSize) { py = pyt-kMinSize; wy = py; }
         if (px > pxtp) { px = pxtp; wx = px; }
         if (py < pylp) { py = pylp; wy = py; }
         if (fixedr) {
            Double_t dy = Double_t(TMath::Abs(pxl-px))/parent->UtoPixel(1.) /
                          fAspectRatio;
            Int_t npy2 = pyt - TMath::Abs(parent->VtoAbsPixel(dy) -
                                          parent->VtoAbsPixel(0));
            if (npy2 < pylp) {
               px = pxold;
               py = pyold;
            } else
               py = npy2;
 
            wx = wy = 0;
         }
         if (!ropaque) gVirtualX->DrawBox(pxl  , pyt, px ,  py,    TVirtualX::kHollow);
      }
      if (pC) {
         if (!ropaque) gVirtualX->DrawBox(pxl  , pyl, pxold, pyold, TVirtualX::kHollow);
         if (px < pxl+kMinSize) { px = pxl+kMinSize; wx = px; }
         if (py < pyl+kMinSize) { py = pyl+kMinSize; wy = py; }
         if (px > pxtp) { px = pxtp; wx = px; }
         if (py > pytp) { py = pytp; wy = py; }
         if (fixedr) {
            Double_t dy = Double_t(TMath::Abs(pxl-px))/parent->UtoPixel(1.) /
                          fAspectRatio;
            Int_t npy2 = pyl + TMath::Abs(parent->VtoAbsPixel(dy) -
                                          parent->VtoAbsPixel(0));
            if (npy2 > pytp) {
               px = pxold;
               py = pyold;
            } else
               py = npy2;
 
            wx = wy = 0;
         }
         if (!ropaque) gVirtualX->DrawBox(pxl, pyl, px, py, TVirtualX::kHollow);
      }
      if (pD) {
         if (!ropaque) gVirtualX->DrawBox(pxold, pyold, pxt, pyl, TVirtualX::kHollow);
         if (px > pxt-kMinSize) { px = pxt-kMinSize; wx = px; }
         if (py < pyl+kMinSize) { py = pyl+kMinSize; wy = py; }
         if (px < pxlp) { px = pxlp; wx = px; }
         if (py > pytp) { py = pytp; wy = py; }
         if (fixedr) {
            Double_t dy = Double_t(TMath::Abs(pxt-px))/parent->UtoPixel(1.) /
                          fAspectRatio;
            Int_t npy2 = pyl + TMath::Abs(parent->VtoAbsPixel(dy) -
                                          parent->VtoAbsPixel(0));
            if (npy2 > pytp) {
               px = pxold;
               py = pyold;
            } else
               py = npy2;
 
            wx = wy = 0;
         }
         if (!ropaque) gVirtualX->DrawBox(px, py, pxt, pyl, TVirtualX::kHollow);
      }
      if (pTop) {
         if (!ropaque) gVirtualX->DrawBox(px1, py1, px2, py2, TVirtualX::kHollow);
         py2 += py - pyold;
         if (py2 > py1-kMinSize) { py2 = py1-kMinSize; wy = py2; }
         if (py2 < py2p) { py2 = py2p; wy = py2; }
         if (fixedr) {
            Double_t dx = Double_t(TMath::Abs(py2-py1))/parent->VtoPixel(0) *
                          fAspectRatio;
            Int_t npx2 = px1 + parent->UtoPixel(dx);
            if (npx2 > px2p)
               py2 -= py - pyold;
            else
               px2 = npx2;
         }
         if (!ropaque) gVirtualX->DrawBox(px1, py1, px2, py2, TVirtualX::kHollow);
      }
      if (pBot) {
         if (!ropaque) gVirtualX->DrawBox(px1, py1, px2, py2, TVirtualX::kHollow);
         py1 += py - pyold;
         if (py1 < py2+kMinSize) { py1 = py2+kMinSize; wy = py1; }
         if (py1 > py1p) { py1 = py1p; wy = py1; }
         if (fixedr) {
            Double_t dx = Double_t(TMath::Abs(py2-py1))/parent->VtoPixel(0) *
                          fAspectRatio;
            Int_t npx2 = px1 + parent->UtoPixel(dx);
            if (npx2 > px2p)
               py1 -= py - pyold;
            else
               px2 = npx2;
         }
         if (!ropaque) gVirtualX->DrawBox(px1, py1, px2, py2, TVirtualX::kHollow);
      }
      if (pL) {
         if (!ropaque) gVirtualX->DrawBox(px1, py1, px2, py2, TVirtualX::kHollow);
         px1 += px - pxold;
         if (px1 > px2-kMinSize) { px1 = px2-kMinSize; wx = px1; }
         if (px1 < px1p) { px1 = px1p; wx = px1; }
         if (fixedr) {
            Double_t dy = Double_t(TMath::Abs(px2-px1))/parent->UtoPixel(1.) /
                          fAspectRatio;
            Int_t npy2 = py1 - TMath::Abs(parent->VtoAbsPixel(dy) -
                                          parent->VtoAbsPixel(0));
            if (npy2 < py2p)
               px1 -= px - pxold;
            else
               py2 = npy2;
         }
         if (!ropaque) gVirtualX->DrawBox(px1, py1, px2, py2, TVirtualX::kHollow);
      }
      if (pR) {
         if (!ropaque) gVirtualX->DrawBox(px1, py1, px2, py2, TVirtualX::kHollow);
         px2 += px - pxold;
         if (px2 < px1+kMinSize) { px2 = px1+kMinSize; wx = px2; }
         if (px2 > px2p) { px2 = px2p; wx = px2; }
         if (fixedr) {
            Double_t dy = Double_t(TMath::Abs(px2-px1))/parent->UtoPixel(1.) /
                          fAspectRatio;
            Int_t npy2 = py1 - TMath::Abs(parent->VtoAbsPixel(dy) -
                                          parent->VtoAbsPixel(0));
            if (npy2 < py2p)
               px2 -= px - pxold;
            else
               py2 = npy2;
         }
         if (!ropaque) gVirtualX->DrawBox(px1, py1, px2, py2, TVirtualX::kHollow);
      }
      if (pINSIDE) {
         if (!opaque) gVirtualX->DrawBox(px1, py1, px2, py2, TVirtualX::kHollow);  // draw the old box
         Int_t dx = px - pxold;
         Int_t dy = py - pyold;
         px1 += dx; py1 += dy; px2 += dx; py2 += dy;
         if (px1 < px1p) { dx = px1p - px1; px1 += dx; px2 += dx; wx = px+dx; }
         if (px2 > px2p) { dx = px2 - px2p; px1 -= dx; px2 -= dx; wx = px-dx; }
         if (py1 > py1p) { dy = py1 - py1p; py1 -= dy; py2 -= dy; wy = py-dy; }
         if (py2 < py2p) { dy = py2p - py2; py1 += dy; py2 += dy; wy = py+dy; }
         if (!opaque) gVirtualX->DrawBox(px1, py1, px2, py2, TVirtualX::kHollow);  // draw the new box
      }
 
      if (wx || wy) {
         if (wx) px = wx;
         if (wy) py = wy;
         gVirtualX->Warp(px, py);
      }
 
      pxold = px;
      pyold = py;
 
      Double_t x1, y1, x2, y2;
      x1 = x2 = y1 = y2 = 0;
 
      if ((!fResizing && opaque) || (fResizing && ropaque)) {
         if (pA) {
            x1 = AbsPixeltoX(pxold);
            y1 = AbsPixeltoY(pyt);
            x2 = AbsPixeltoX(pxt);
            y2 = AbsPixeltoY(pyold);
         }
         if (pB) {
            x1 = AbsPixeltoX(pxl);
            y1 = AbsPixeltoY(pyt);
            x2 = AbsPixeltoX(pxold);
            y2 = AbsPixeltoY(pyold);
         }
         if (pC) {
            x1 = AbsPixeltoX(pxl);
            y1 = AbsPixeltoY(pyold);
            x2 = AbsPixeltoX(pxold);
            y2 = AbsPixeltoY(pyl);
         }
         if (pD) {
            x1 = AbsPixeltoX(pxold);
            y1 = AbsPixeltoY(pyold);
            x2 = AbsPixeltoX(pxt);
            y2 = AbsPixeltoY(pyl);
         }
         if (pTop || pBot || pL || pR || pINSIDE) {
            x1 = AbsPixeltoX(px1);
            y1 = AbsPixeltoY(py1);
            x2 = AbsPixeltoX(px2);
            y2 = AbsPixeltoY(py2);
         }
 
         if (px != pxorg || py != pyorg) {
 
            // Get parent corners pixels coordinates
            Int_t parentpx1 = fMother->XtoAbsPixel(parent->GetX1());
            Int_t parentpx2 = fMother->XtoAbsPixel(parent->GetX2());
            Int_t parentpy1 = fMother->YtoAbsPixel(parent->GetY1());
            Int_t parentpy2 = fMother->YtoAbsPixel(parent->GetY2());
 
            // Get pad new corners pixels coordinates
            Int_t apx1 = XtoAbsPixel(x1); if (apx1 < parentpx1) {apx1 = parentpx1; }
            Int_t apx2 = XtoAbsPixel(x2); if (apx2 > parentpx2) {apx2 = parentpx2; }
            Int_t apy1 = YtoAbsPixel(y1); if (apy1 > parentpy1) {apy1 = parentpy1; }
            Int_t apy2 = YtoAbsPixel(y2); if (apy2 < parentpy2) {apy2 = parentpy2; }
 
            // Compute new pad positions in the NDC space of parent
            fXlowNDC = Double_t(apx1 - parentpx1)/Double_t(parentpx2 - parentpx1);
            fYlowNDC = Double_t(apy1 - parentpy1)/Double_t(parentpy2 - parentpy1);
            fWNDC    = Double_t(apx2 - apx1)/Double_t(parentpx2 - parentpx1);
            fHNDC    = Double_t(apy2 - apy1)/Double_t(parentpy2 - parentpy1);
         }
 
         // Reset pad parameters and recompute conversion coefficients
         ResizePad();
 
         if (pINSIDE) gPad->ShowGuidelines(this, event);
         if (pTop) gPad->ShowGuidelines(this, event, 't', true);
         if (pBot) gPad->ShowGuidelines(this, event, 'b', true);
         if (pL) gPad->ShowGuidelines(this, event, 'l', true);
         if (pR) gPad->ShowGuidelines(this, event, 'r', true);
         if (pA) gPad->ShowGuidelines(this, event, '1', true);
         if (pB) gPad->ShowGuidelines(this, event, '2', true);
         if (pC) gPad->ShowGuidelines(this, event, '3', true);
         if (pD) gPad->ShowGuidelines(this, event, '4', true);
 
         Modified(kTRUE);
      }
 
      break;
 
   case kButton1Up:
 
      if (gROOT->IsEscaped()) {
         gROOT->SetEscape(kFALSE);
         break;
      }
 
      if (opaque||ropaque) {
         ShowGuidelines(this, event);
      } else {
         x1 = x2 = y1 = y2 = 0;
 
         if (pA) {
            x1 = AbsPixeltoX(pxold);
            y1 = AbsPixeltoY(pyt);
            x2 = AbsPixeltoX(pxt);
            y2 = AbsPixeltoY(pyold);
         }
         if (pB) {
            x1 = AbsPixeltoX(pxl);
            y1 = AbsPixeltoY(pyt);
            x2 = AbsPixeltoX(pxold);
            y2 = AbsPixeltoY(pyold);
         }
         if (pC) {
            x1 = AbsPixeltoX(pxl);
            y1 = AbsPixeltoY(pyold);
            x2 = AbsPixeltoX(pxold);
            y2 = AbsPixeltoY(pyl);
         }
         if (pD) {
            x1 = AbsPixeltoX(pxold);
            y1 = AbsPixeltoY(pyold);
            x2 = AbsPixeltoX(pxt);
            y2 = AbsPixeltoY(pyl);
         }
         if (pTop || pBot || pL || pR || pINSIDE) {
            x1 = AbsPixeltoX(px1);
            y1 = AbsPixeltoY(py1);
            x2 = AbsPixeltoX(px2);
            y2 = AbsPixeltoY(py2);
         }
 
         if (pA || pB || pC || pD || pTop || pL || pR || pBot)
            Modified(kTRUE);
 
         gVirtualX->SetLineColor(-1);
         gVirtualX->SetLineWidth(-1);
 
         if (px != pxorg || py != pyorg) {
 
            // Get parent corners pixels coordinates
            Int_t parentpx1 = fMother->XtoAbsPixel(parent->GetX1());
            Int_t parentpx2 = fMother->XtoAbsPixel(parent->GetX2());
            Int_t parentpy1 = fMother->YtoAbsPixel(parent->GetY1());
            Int_t parentpy2 = fMother->YtoAbsPixel(parent->GetY2());
 
            // Get pad new corners pixels coordinates
            Int_t apx1 = XtoAbsPixel(x1); if (apx1 < parentpx1) {apx1 = parentpx1; }
            Int_t apx2 = XtoAbsPixel(x2); if (apx2 > parentpx2) {apx2 = parentpx2; }
            Int_t apy1 = YtoAbsPixel(y1); if (apy1 > parentpy1) {apy1 = parentpy1; }
            Int_t apy2 = YtoAbsPixel(y2); if (apy2 < parentpy2) {apy2 = parentpy2; }
 
            // Compute new pad positions in the NDC space of parent
            fXlowNDC = Double_t(apx1 - parentpx1)/Double_t(parentpx2 - parentpx1);
            fYlowNDC = Double_t(apy1 - parentpy1)/Double_t(parentpy2 - parentpy1);
            fWNDC    = Double_t(apx2 - apx1)/Double_t(parentpx2 - parentpx1);
            fHNDC    = Double_t(apy2 - apy1)/Double_t(parentpy2 - parentpy1);
         }
 
         // Reset pad parameters and recompute conversion coefficients
         ResizePad();
 
 
         // emit signal
         RangeChanged();
      }
 
      break;
 
   case kButton1Locate:
 
      ExecuteEvent(kButton1Down, px, py);
 
      while (true) {
         px = py = 0;
         event = gVirtualX->RequestLocator(1, 1, px, py);
 
         ExecuteEvent(kButton1Motion, px, py);
 
         if (event != -1) {                     // button is released
            ExecuteEvent(kButton1Up, px, py);
            return;
         }
      }
 
   case kButton2Down:
 
      Pop();
      break;
 
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Execute action corresponding to one event for a TAxis object
/// (called by TAxis::ExecuteEvent.)
///  This member function is called when an axis is clicked with the locator
///
/// The axis range is set between the position where the mouse is pressed
/// and the position where it is released.
///
/// If the mouse position is outside the current axis range when it is released
/// the axis is unzoomed with the corresponding proportions.
///
/// Note that the mouse does not need to be in the pad or even canvas
/// when it is released.
 
void TPad::ExecuteEventAxis(Int_t event, Int_t px, Int_t py, TAxis *axis)
{
   if (!IsEditable()) return;
   if (!axis) return;
   SetCursor(kHand);
 
   TView *view = GetView();
   static Int_t axisNumber;
   static Double_t ratio1, ratio2;
   static Int_t px1old, py1old, px2old, py2old;
   Int_t nbd, inc, bin1, bin2, first, last;
   Double_t temp, xmin,xmax;
   Bool_t opaque  = gPad->OpaqueMoving();
   static std::unique_ptr<TBox> zoombox;
   Double_t zbx1=0,zbx2=0,zby1=0,zby2=0;
 
   // The CONT4 option, used to paint TH2, is a special case; it uses a 3D
   // drawing technique to paint a 2D plot.
   TString opt = axis->GetParent()->GetDrawOption();
   opt.ToLower();
   Bool_t kCont4 = kFALSE;
   if (strstr(opt,"cont4")) {
      view = nullptr;
      kCont4 = kTRUE;
   }
 
   switch (event) {
 
   case kButton1Down:
      axisNumber = 1;
      if (!strcmp(axis->GetName(),"xaxis")) {
         axisNumber = 1;
         if (!IsVertical()) axisNumber = 2;
      }
      if (!strcmp(axis->GetName(),"yaxis")) {
         axisNumber = 2;
         if (!IsVertical()) axisNumber = 1;
      }
      if (!strcmp(axis->GetName(),"zaxis")) {
         axisNumber = 3;
      }
      if (view) {
         view->GetDistancetoAxis(axisNumber, px, py, ratio1);
      } else {
         if (axisNumber == 1) {
            ratio1 = (AbsPixeltoX(px) - GetUxmin())/(GetUxmax() - GetUxmin());
            px1old = XtoAbsPixel(GetUxmin()+ratio1*(GetUxmax() - GetUxmin()));
            py1old = YtoAbsPixel(GetUymin());
            px2old = px1old;
            py2old = YtoAbsPixel(GetUymax());
         } else if (axisNumber == 2) {
            ratio1 = (AbsPixeltoY(py) - GetUymin())/(GetUymax() - GetUymin());
            py1old = YtoAbsPixel(GetUymin()+ratio1*(GetUymax() - GetUymin()));
            px1old = XtoAbsPixel(GetUxmin());
            px2old = XtoAbsPixel(GetUxmax());
            py2old = py1old;
         } else {
            ratio1 = (AbsPixeltoY(py) - GetUymin())/(GetUymax() - GetUymin());
            py1old = YtoAbsPixel(GetUymin()+ratio1*(GetUymax() - GetUymin()));
            px1old = XtoAbsPixel(GetUxmax());
            px2old = XtoAbsPixel(GetX2());
            py2old = py1old;
         }
         if (!opaque) {
            gVirtualX->DrawBox(px1old, py1old, px2old, py2old, TVirtualX::kHollow);
         } else {
            if (axisNumber == 1) {
               zbx1 = AbsPixeltoX(px1old);
               zbx2 = AbsPixeltoX(px2old);
               zby1 = GetUymin();
               zby2 = GetUymax();
            } else if (axisNumber == 2) {
               zbx1 = GetUxmin();
               zbx2 = GetUxmax();
               zby1 = AbsPixeltoY(py1old);
               zby2 = AbsPixeltoY(py2old);
            }
            if (GetLogx()) {
               zbx1 = TMath::Power(10,zbx1);
               zbx2 = TMath::Power(10,zbx2);
            }
            if (GetLogy()) {
               zby1 = TMath::Power(10,zby1);
               zby2 = TMath::Power(10,zby2);
            }
            zoombox = std::make_unique<TBox>(zbx1, zby1, zbx2, zby2);
            Int_t ci = TColor::GetColor("#7d7dff");
            TColor *zoomcolor = gROOT->GetColor(ci);
            if (!TCanvas::SupportAlpha() || !zoomcolor) zoombox->SetFillStyle(3002);
            else                                        zoomcolor->SetAlpha(0.5);
            zoombox->SetFillColor(ci);
            zoombox->Draw();
            gPad->Modified();
            gPad->Update();
         }
      }
      if (!opaque) gVirtualX->SetLineColor(-1);
      // No break !!!
 
   case kButton1Motion:
      if (view) {
         view->GetDistancetoAxis(axisNumber, px, py, ratio2);
      } else {
         if (!opaque) gVirtualX->DrawBox(px1old, py1old, px2old, py2old, TVirtualX::kHollow);
         if (axisNumber == 1) {
            ratio2 = (AbsPixeltoX(px) - GetUxmin())/(GetUxmax() - GetUxmin());
            px2old = XtoAbsPixel(GetUxmin()+ratio2*(GetUxmax() - GetUxmin()));
         } else {
            ratio2 = (AbsPixeltoY(py) - GetUymin())/(GetUymax() - GetUymin());
            py2old = YtoAbsPixel(GetUymin()+ratio2*(GetUymax() - GetUymin()));
         }
         if (!opaque) {
            gVirtualX->DrawBox(px1old, py1old, px2old, py2old, TVirtualX::kHollow);
         } else {
            if (axisNumber == 1) {
               zbx1 = AbsPixeltoX(px1old);
               zbx2 = AbsPixeltoX(px2old);
               zby1 = GetUymin();
               zby2 = GetUymax();
            } else if (axisNumber == 2) {
               zbx1 = GetUxmin();
               zbx2 = GetUxmax();
               zby1 = AbsPixeltoY(py1old);
               zby2 = AbsPixeltoY(py2old);
            }
            if (GetLogx()) {
               zbx1 = TMath::Power(10,zbx1);
               zbx2 = TMath::Power(10,zbx2);
            }
            if (GetLogy()) {
               zby1 = TMath::Power(10,zby1);
               zby2 = TMath::Power(10,zby2);
            }
            if (zoombox) {
               zoombox->SetX1(zbx1);
               zoombox->SetY1(zby1);
               zoombox->SetX2(zbx2);
               zoombox->SetY2(zby2);
            }
            gPad->Modified();
            gPad->Update();
         }
      }
   break;
 
   case kWheelUp:
      nbd  = (axis->GetLast()-axis->GetFirst());
      inc  = TMath::Max(nbd/100,1);
      bin1 = axis->GetFirst()+inc;
      bin2 = axis->GetLast()-inc;
      bin1 = TMath::Max(bin1, 1);
      bin2 = TMath::Min(bin2, axis->GetNbins());
      if (bin2>bin1) {
         axis->SetRange(bin1,bin2);
         gPad->Modified();
         gPad->Update();
      }
   break;
 
   case kWheelDown:
      nbd  = (axis->GetLast()-axis->GetFirst());
      inc  = TMath::Max(nbd/100,1);
      bin1 = axis->GetFirst()-inc;
      bin2 = axis->GetLast()+inc;
      bin1 = TMath::Max(bin1, 1);
      bin2 = TMath::Min(bin2, axis->GetNbins());
      if (bin2>bin1) {
         axis->SetRange(bin1,bin2);
         gPad->Modified();
         gPad->Update();
      }
   break;
 
   case kButton1Up:
      if (gROOT->IsEscaped()) {
         gROOT->SetEscape(kFALSE);
         if (opaque && zoombox)
            zoombox.reset();
         break;
      }
 
      if (view) {
         view->GetDistancetoAxis(axisNumber, px, py, ratio2);
         if (ratio1 > ratio2) {
            temp   = ratio1;
            ratio1 = ratio2;
            ratio2 = temp;
         }
         if (ratio2 - ratio1 > 0.05) {
            TH1 *hobj = (TH1*)axis->GetParent();
            if (axisNumber == 3 && hobj && hobj->GetDimension() != 3) {
               Float_t zmin = hobj->GetMinimum();
               Float_t zmax = hobj->GetMaximum();
               if(GetLogz()){
                  if (zmin <= 0 && zmax > 0) zmin = TMath::Min((Double_t)1,
                                                               (Double_t)0.001*zmax);
                  zmin = TMath::Log10(zmin);
                  zmax = TMath::Log10(zmax);
               }
               Float_t newmin = zmin + (zmax-zmin)*ratio1;
               Float_t newmax = zmin + (zmax-zmin)*ratio2;
               if (newmin < zmin) newmin = hobj->GetBinContent(hobj->GetMinimumBin());
               if (newmax > zmax) newmax = hobj->GetBinContent(hobj->GetMaximumBin());
               if (GetLogz()){
                  newmin = TMath::Exp(2.302585092994*newmin);
                  newmax = TMath::Exp(2.302585092994*newmax);
               }
               hobj->SetMinimum(newmin);
               hobj->SetMaximum(newmax);
               hobj->SetBit(TH1::kIsZoomed);
            } else {
               first = axis->GetFirst();
               last  = axis->GetLast();
               bin1 = first + Int_t((last-first+1)*ratio1);
               bin2 = first + Int_t((last-first+1)*ratio2);
               bin1 = TMath::Max(bin1, 1);
               bin2 = TMath::Min(bin2, axis->GetNbins());
               axis->SetRange(bin1, bin2);
            }
            delete view;
            SetView(nullptr);
            Modified(kTRUE);
         }
      } else {
         if (axisNumber == 1) {
            ratio2 = (AbsPixeltoX(px) - GetUxmin())/(GetUxmax() - GetUxmin());
            xmin = GetUxmin() +ratio1*(GetUxmax() - GetUxmin());
            xmax = GetUxmin() +ratio2*(GetUxmax() - GetUxmin());
            if (GetLogx() && !kCont4) {
               xmin = PadtoX(xmin);
               xmax = PadtoX(xmax);
            }
         } else if (axisNumber == 2) {
            ratio2 = (AbsPixeltoY(py) - GetUymin())/(GetUymax() - GetUymin());
            xmin = GetUymin() +ratio1*(GetUymax() - GetUymin());
            xmax = GetUymin() +ratio2*(GetUymax() - GetUymin());
            if (GetLogy() && !kCont4) {
               xmin = PadtoY(xmin);
               xmax = PadtoY(xmax);
            }
         } else {
            ratio2 = (AbsPixeltoY(py) - GetUymin())/(GetUymax() - GetUymin());
            xmin = ratio1;
            xmax = ratio2;
         }
         if (xmin > xmax) {
            temp   = xmin;
            xmin   = xmax;
            xmax   = temp;
            temp   = ratio1;
            ratio1 = ratio2;
            ratio2 = temp;
         }
 
         // xmin and xmax need to be adjusted in case of CONT4.
         if (kCont4) {
            Double_t low = axis->GetBinLowEdge(axis->GetFirst());
            Double_t up  = axis->GetBinUpEdge(axis->GetLast());
            Double_t xmi = GetUxmin();
            Double_t xma = GetUxmax();
            xmin = ((xmin-xmi)/(xma-xmi))*(up-low)+low;
            xmax = ((xmax-xmi)/(xma-xmi))*(up-low)+low;
         }
 
         if (!strcmp(axis->GetName(),"xaxis")) axisNumber = 1;
         if (!strcmp(axis->GetName(),"yaxis")) axisNumber = 2;
         if (ratio2 - ratio1 > 0.05) {
            //update object owning this axis
            TH1 *hobj1 = (TH1*)axis->GetParent();
            bin1 = axis->FindFixBin(xmin);
            bin2 = axis->FindFixBin(xmax);
            bin1 = TMath::Max(bin1, 1);
            bin2 = TMath::Min(bin2, axis->GetNbins());
            if (axisNumber == 1) axis->SetRange(bin1,bin2);
            if (axisNumber == 2 && hobj1) {
               if (hobj1->GetDimension() == 1) {
                  if (hobj1->GetNormFactor() != 0) {
                     Double_t norm = hobj1->GetSumOfWeights()/hobj1->GetNormFactor();
                     xmin *= norm;
                     xmax *= norm;
                  }
                  hobj1->SetMinimum(xmin);
                  hobj1->SetMaximum(xmax);
                  hobj1->SetBit(TH1::kIsZoomed);
               } else {
                  axis->SetRange(bin1,bin2);
               }
            }
            //update all histograms in the pad
            TIter next(GetListOfPrimitives());
            TObject *obj;
            while ((obj= next())) {
               if (!obj->InheritsFrom(TH1::Class())) continue;
               TH1 *hobj = (TH1*)obj;
               if (hobj == hobj1) continue;
               bin1 = hobj->GetXaxis()->FindFixBin(xmin);
               bin2 = hobj->GetXaxis()->FindFixBin(xmax);
               if (axisNumber == 1) {
                  hobj->GetXaxis()->SetRange(bin1,bin2);
               } else if (axisNumber == 2) {
                  if (hobj->GetDimension() == 1) {
                     Double_t xxmin = xmin;
                     Double_t xxmax = xmax;
                     if (hobj->GetNormFactor() != 0) {
                        Double_t norm = hobj->GetSumOfWeights()/hobj->GetNormFactor();
                        xxmin *= norm;
                        xxmax *= norm;
                     }
                     hobj->SetMinimum(xxmin);
                     hobj->SetMaximum(xxmax);
                     hobj->SetBit(TH1::kIsZoomed);
                  } else {
                     bin1 = hobj->GetYaxis()->FindFixBin(xmin);
                     bin2 = hobj->GetYaxis()->FindFixBin(xmax);
                     hobj->GetYaxis()->SetRange(bin1,bin2);
                  }
               }
            }
            Modified(kTRUE);
         }
      }
      if (!opaque) {
         gVirtualX->SetLineColor(-1);
      } else {
         if (zoombox) {
            zoombox.reset();
            gPad->Modified();
            gPad->Update();
         }
      }
      break;
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Search if object named name is inside this pad or in pads inside this pad.
///
/// In case name is in several sub-pads the first one is returned.
 
TObject *TPad::FindObject(const char *name) const
{
   if (!fPrimitives) return nullptr;
   TObject *found = fPrimitives->FindObject(name);
   if (found) return found;
   TIter    next(GetListOfPrimitives());
   while (auto cur = next()) {
      if (cur->InheritsFrom(TPad::Class())) {
         found = ((TPad*)cur)->FindObject(name);
         if (found) return found;
      }
   }
   return nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Search if obj is in pad or in pads inside this pad.
///
/// In case obj is in several sub-pads the first one is returned.
 
TObject *TPad::FindObject(const TObject *obj) const
{
   if (!fPrimitives) return nullptr;
   TObject *found = fPrimitives->FindObject(obj);
   if (found) return found;
   TIter    next(GetListOfPrimitives());
   while (auto cur = next()) {
      if (cur->InheritsFrom(TPad::Class())) {
         found = ((TPad*)cur)->FindObject(obj);
         if (found) return found;
      }
   }
   return nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get canvas identifier.
 
Int_t TPad::GetCanvasID() const
{
   return fCanvas ? fCanvas->GetCanvasID() : -1;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get canvas implementation pointer if any
 
TCanvasImp *TPad::GetCanvasImp() const
{
   return fCanvas ? fCanvas->GetCanvasImp() : nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get Event.
 
Int_t TPad::GetEvent() const
{
   return  fCanvas ? fCanvas->GetEvent() : 0;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get X event.
 
Int_t TPad::GetEventX() const
{
   return  fCanvas ? fCanvas->GetEventX() : 0;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get Y event.
 
Int_t TPad::GetEventY() const
{
   return  fCanvas ? fCanvas->GetEventY() : 0;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get virtual canvas.
 
TVirtualPad *TPad::GetVirtCanvas() const
{
   return  fCanvas ? (TVirtualPad*) fCanvas : nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get highlight color.
 
Color_t TPad::GetHighLightColor() const
{
   return  fCanvas ? fCanvas->GetHighLightColor() : 0;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Static function (see also TPad::SetMaxPickDistance)
 
Int_t TPad::GetMaxPickDistance()
{
   return fgMaxPickDistance;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get selected.
 
TObject *TPad::GetSelected() const
{
   if (fCanvas == this) return nullptr;
   return  fCanvas ? fCanvas->GetSelected() : nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get selected pad.
 
TVirtualPad *TPad::GetSelectedPad() const
{
   if (fCanvas == this) return nullptr;
   return  fCanvas ? fCanvas->GetSelectedPad() : nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get save pad.
 
TVirtualPad *TPad::GetPadSave() const
{
   if (fCanvas == this) return nullptr;
   return  fCanvas ? fCanvas->GetPadSave() : nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get Wh.
 
UInt_t TPad::GetWh() const
{
   return  fCanvas ? fCanvas->GetWh() : 0;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get Ww.
 
UInt_t TPad::GetWw() const
{
   return  fCanvas ? fCanvas->GetWw() : 0;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Hide tool tip depending on the event type. Typically tool tips
/// are hidden when event is not a kMouseEnter and not a kMouseMotion
/// event.
 
void TPad::HideToolTip(Int_t event)
{
   if (event != kMouseEnter && event != kMouseMotion && fTip)
      gPad->CloseToolTip(fTip);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Is pad in batch mode ?
 
Bool_t TPad::IsBatch() const
{
   return  fCanvas ? fCanvas->IsBatch() : kFALSE;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Is pad retained ?
 
Bool_t TPad::IsRetained() const
{
   return  fCanvas ? fCanvas->IsRetained() : kFALSE;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Is web ?
Bool_t TPad::IsWeb() const
{
   return fCanvas ? fCanvas->IsWeb() : kFALSE;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Is pad moving in opaque mode ?
 
Bool_t TPad::OpaqueMoving() const
{
   return  fCanvas ? fCanvas->OpaqueMoving() : kFALSE;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Is pad resizing in opaque mode ?
 
Bool_t TPad::OpaqueResizing() const
{
   return  fCanvas ? fCanvas->OpaqueResizing() : kFALSE;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Set pad in batch mode.
 
void TPad::SetBatch(Bool_t batch)
{
   if (fCanvas) fCanvas->SetBatch(batch);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Set canvas size.
 
void TPad::SetCanvasSize(UInt_t ww, UInt_t wh)
{
   if (fCanvas) fCanvas->SetCanvasSize(ww,wh);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Set cursor type.
 
void TPad::SetCursor(ECursor cursor)
{
   if (fCanvas) fCanvas->SetCursor(cursor);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Set double buffer mode ON or OFF.
 
void TPad::SetDoubleBuffer(Int_t mode)
{
   if (fCanvas) fCanvas->SetDoubleBuffer(mode);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Set selected.
 
void TPad::SetSelected(TObject *obj)
{
   if (fCanvas) fCanvas->SetSelected(obj);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Update pad.
 
void TPad::Update()
{
   if (fCanvas) fCanvas->Update();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Asynchronous pad update.
/// In case of web-based canvas triggers update of the canvas on the client side,
/// but does not wait that real update is completed. Avoids blocking of caller thread.
/// Have to be used if called from other web-based widget to avoid logical dead-locks.
/// In case of normal canvas just canvas->Update() is performed.
 
void TPad::UpdateAsync()
{
   if (fCanvas) fCanvas->UpdateAsync();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get frame.
 
TFrame *TPad::GetFrame()
{
   if (!fPrimitives) fPrimitives = new TList;
   TFrame     *frame = (TFrame*)GetListOfPrimitives()->FindObject(fFrame);
   if (!frame) frame = (TFrame*)GetListOfPrimitives()->FindObject("TFrame");
   fFrame = frame;
   if (!fFrame) {
      if (!frame) fFrame = new TFrame(0,0,1,1);
      Int_t framecolor = GetFrameFillColor();
      if (!framecolor) framecolor = GetFillColor();
      fFrame->SetFillColor(framecolor);
      fFrame->SetFillStyle(GetFrameFillStyle());
      fFrame->SetLineColor(GetFrameLineColor());
      fFrame->SetLineStyle(GetFrameLineStyle());
      fFrame->SetLineWidth(GetFrameLineWidth());
      fFrame->SetBorderSize(GetFrameBorderSize());
      fFrame->SetBorderMode(GetFrameBorderMode());
   } else {
      // Preexisting and now assigned to fFrame, let's make sure it is not
      // deleted twice (the bit might have been set in TPad::Streamer)
      fFrame->ResetBit(kCanDelete);
   }
   return fFrame;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get primitive.
 
TObject *TPad::GetPrimitive(const char *name) const
{
   if (!fPrimitives) return nullptr;
   TIter next(fPrimitives);
   TObject *found, *obj;
   while ((obj=next())) {
      if (!strcmp(name, obj->GetName())) return obj;
      if (obj->InheritsFrom(TPad::Class())) continue;
      found = obj->FindObject(name);
      if (found) return found;
   }
   return nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get a pointer to subpadnumber of this pad.
 
TVirtualPad *TPad::GetPad(Int_t subpadnumber) const
{
   if (!subpadnumber) {
      return (TVirtualPad*)this;
   }
 
   TObject *obj;
   if (!fPrimitives) return nullptr;
   TIter    next(GetListOfPrimitives());
   while ((obj = next())) {
      if (obj->InheritsFrom(TVirtualPad::Class())) {
         TVirtualPad *pad = (TVirtualPad*)obj;
         if (pad->GetNumber() == subpadnumber) return pad;
      }
   }
   return nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Return lower and upper bounds of the pad in NDC coordinates.
 
void TPad::GetPadPar(Double_t &xlow, Double_t &ylow, Double_t &xup, Double_t &yup)
{
   xlow = fXlowNDC;
   ylow = fYlowNDC;
   xup  = fXlowNDC+fWNDC;
   yup  = fYlowNDC+fHNDC;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Return pad world coordinates range.
 
void TPad::GetRange(Double_t &x1, Double_t &y1, Double_t &x2, Double_t &y2)
{
   x1 = fX1;
   y1 = fY1;
   x2 = fX2;
   y2 = fY2;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Return pad axis coordinates range.
 
void TPad::GetRangeAxis(Double_t &xmin, Double_t &ymin, Double_t &xmax, Double_t &ymax)
{
   xmin = fUxmin;
   ymin = fUymin;
   xmax = fUxmax;
   ymax = fUymax;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Highlight pad.
/// do not highlight when printing on Postscript
 
void TPad::HighLight(Color_t color, Bool_t set)
{
   if (gVirtualPS && gVirtualPS->TestBit(kPrintingPS)) return;
 
   if (color <= 0) return;
 
   AbsCoordinates(kTRUE);
 
   // We do not want to have active(executable) buttons, etc highlighted
   // in this manner, unless we want to edit'em
   if (GetMother() && GetMother()->IsEditable() && !InheritsFrom(TButton::Class())) {
      //When doing a DrawClone from the GUI you would do
      //  - select an empty pad -
      //  - right click on object -
      //     - select DrawClone on menu -
      //
      // Without the SetSelectedPad(); in the HighLight function, the
      // above instruction lead to the clone to be drawn in the
      // same canvas as the original object.  This is because the
      // 'right clicking' (via TCanvas::HandleInput) changes gPad
      // momentarily such that when DrawClone is called, it is
      // not the right value (for DrawClone). Should be FIXED.
      gROOT->SetSelectedPad(this);
      if (GetBorderMode()>0) {
         if (set) PaintBorder(-color, kFALSE);
         else     PaintBorder(-GetFillColor(), kFALSE);
      }
   }
 
   AbsCoordinates(kFALSE);
}
 
////////////////////////////////////////////////////////////////////////////////
/// List all primitives in pad.
 
void TPad::ls(Option_t *option) const
{
   TROOT::IndentLevel();
   std::cout <<IsA()->GetName()<<" fXlowNDC=" <<fXlowNDC<<" fYlowNDC="<<fYlowNDC<<" fWNDC="<<GetWNDC()<<" fHNDC="<<GetHNDC()
        <<" Name= "<<GetName()<<" Title= "<<GetTitle()<<" Option="<<option<<std::endl;
   TROOT::IncreaseDirLevel();
   if (!fPrimitives) return;
   fPrimitives->ls(option);
   TROOT::DecreaseDirLevel();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Increment (i==1) or set (i>1) the number of autocolor in the pad.
 
Int_t TPad::IncrementPaletteColor(Int_t i, TString opt)
{
   if (opt.Index("pfc")>=0 || opt.Index("plc")>=0 || opt.Index("pmc")>=0) {
       if (i==1) fNumPaletteColor++;
       else      fNumPaletteColor = i;
       return    fNumPaletteColor;
   } else {
      return 0;
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Get the next autocolor in the pad.
 
Int_t TPad::NextPaletteColor()
{
   Int_t i = 0;
   Int_t ncolors = gStyle->GetNumberOfColors();
   if (fNumPaletteColor>1) {
      i = fNextPaletteColor*(ncolors/(fNumPaletteColor-1));
      if (i>=ncolors) i = ncolors-1;
   }
   fNextPaletteColor++;
   if (fNextPaletteColor > fNumPaletteColor-1) fNextPaletteColor = 0;
   return gStyle->GetColorPalette(i);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Initialise the grid used to find empty space when adding a box (Legend) in a pad
 
void TPad::FillCollideGrid(TObject *oi)
{
   Int_t const cellSize = 10; // Size of an individual grid cell in pixels.
 
   fCGnx = GetWw()/cellSize;
   fCGny = GetWh()/cellSize;
 
   // Initialise the collide grid
   fCollideGrid.resize(fCGnx*fCGny);
   for (int i = 0; i < fCGnx; i++)
      for (int j = 0; j < fCGny; j++)
         fCollideGrid[i + j * fCGnx] = kTRUE;
 
   // Fill the collide grid
   TIter iter(GetListOfPrimitives());
 
   while(auto o = iter()) {
      if (o == oi)
         continue;
      if (o->InheritsFrom(TFrame::Class()))
         FillCollideGridTFrame(o);
      else if (o->InheritsFrom(TBox::Class()))
         FillCollideGridTBox(o);
      else if (o->InheritsFrom(TH1::Class()))
         FillCollideGridTH1(o);
      else if (o->InheritsFrom(TGraph::Class()))
         FillCollideGridTGraph(o);
      else if (o->InheritsFrom(TMultiGraph::Class())) {
         TIter nextgraph(((TMultiGraph *)o)->GetListOfGraphs());
         while (auto og = nextgraph())
            FillCollideGridTGraph(og);
      } else if (o->InheritsFrom(THStack::Class())) {
         TIter nexthist(((THStack *)o)->GetHists());
         while (auto oh = nexthist()) {
            if (oh->InheritsFrom(TH1::Class()))
               FillCollideGridTH1(oh);
         }
      }
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Check if a box of size w and h collide some primitives in the pad at
/// position i,j
 
Bool_t TPad::Collide(Int_t i, Int_t j, Int_t w, Int_t h)
{
   for (int r = i; r < w + i; r++) {
      for (int c = j; c < h + j; c++) {
         if (!fCollideGrid[r + c * fCGnx])
            return kTRUE;
      }
   }
   return kFALSE;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Place a box in NDC space
///
/// \return `true` if the box could be placed, `false` if not.
///
/// \param[in]  o               pointer to the box to be placed
/// \param[in]  w               box width to be placed
/// \param[in]  h               box height to be placed
/// \param[out] xl              x position of the bottom left corner of the placed box
/// \param[out] yb              y position of the bottom left corner of the placed box
/// \param[in]  option          l=left, r=right, t=top, b=bottom, w=within margins. Order determines
///                             priority for placement. Default is "lb" (prioritises horizontal over vertical)
 
Bool_t TPad::PlaceBox(TObject *o, Double_t w, Double_t h, Double_t &xl, Double_t &yb, Option_t* option)
{
   FillCollideGrid(o);
 
   Int_t iw = (int)(fCGnx*w);
   Int_t ih = (int)(fCGny*h);
 
   Int_t nxbeg = 0;
   Int_t nybeg = 0;
   Int_t nxend = fCGnx-iw-1;
   Int_t nyend = fCGny-ih-1;
   Int_t dx = 1;
   Int_t dy = 1;
 
   bool isFirstVertical = false;
   bool isFirstHorizontal = false;
 
   for (std::size_t i = 0; option[i] != '\0'; ++i) {
      char letter = std::tolower(option[i]);
      if (letter == 'w') {
         nxbeg += fCGnx*GetLeftMargin();
         nybeg += fCGny*GetBottomMargin();
         nxend -= fCGnx*GetRightMargin();
         nyend -= fCGny*GetTopMargin();
      } else if (letter == 't' || letter == 'b') {
         isFirstVertical = !isFirstHorizontal;
         // go from top to bottom instead of bottom to top
         dy = letter == 't' ? -1 : 1;
      } else if (letter == 'l' || letter == 'r') {
         isFirstHorizontal = !isFirstVertical;
         // go from right to left instead of left to right
         dx = letter == 'r' ? -1 : 1;
      }
   }
 
   if(dx < 0) std::swap(nxbeg, nxend);
   if(dy < 0) std::swap(nybeg, nyend);
 
   auto attemptPlacement = [&](Int_t i, Int_t j) {
      if (Collide(i, j, iw, ih)) {
         return false;
      } else {
         xl = (Double_t)(i) / (Double_t)(fCGnx);
         yb = (Double_t)(j) / (Double_t)(fCGny);
         return true;
      }
   };
 
   if(!isFirstVertical) {
      for (Int_t i = nxbeg; i != nxend; i += dx) {
         for (Int_t j = nybeg; j != nyend; j += dy) {
            if (attemptPlacement(i, j)) return true;
         }
      }
   } else {
      // prioritizing vertical over horizontal
      for (Int_t j = nybeg; j != nyend; j += dy) {
         for (Int_t i = nxbeg; i != nxend; i += dx) {
            if (attemptPlacement(i, j)) return true;
         }
      }
   }
 
   return kFALSE;
}
 
#define NotFree(i, j) fCollideGrid[TMath::Max(TMath::Min(i+j*fCGnx,fCGnx*fCGny),0)] = kFALSE;
 
////////////////////////////////////////////////////////////////////////////////
/// Mark as "not free" the cells along a line.
 
void TPad::LineNotFree(Int_t x1, Int_t x2, Int_t y1, Int_t y2)
{
   NotFree(x1, y1);
   NotFree(x2, y2);
   Int_t i, j, xt, yt;
 
   // horizontal lines
   if (y1==y2) {
      for (i=x1+1; i<x2; i++) NotFree(i,y1);
      return;
   }
 
   // vertical lines
   if (x1==x2) {
      for (i=y1+1; i<y2; i++) NotFree(x1,i);
      return;
   }
 
   // other lines
   if (TMath::Abs(x2-x1)>TMath::Abs(y2-y1)) {
      if (x1>x2) {
         xt = x1; x1 = x2; x2 = xt;
         yt = y1; y1 = y2; y2 = yt;
      }
      for (i=x1+1; i<x2; i++) {
         j = (Int_t)((Double_t)(y2-y1)*(Double_t)((i-x1)/(Double_t)(x2-x1))+y1);
         NotFree(i,j);
         NotFree(i,(j+1));
      }
   } else {
      if (y1>y2) {
         yt = y1; y1 = y2; y2 = yt;
         xt = x1; x1 = x2; x2 = xt;
      }
      for (j=y1+1; j<y2; j++) {
         i = (Int_t)((Double_t)(x2-x1)*(Double_t)((j-y1)/(Double_t)(y2-y1))+x1);
         NotFree(i,j);
         NotFree((i+1),j);
      }
   }
}
 
////////////////////////////////////////////////////////////////////////////////
void TPad::FillCollideGridTBox(TObject *o)
{
   TBox *b = (TBox *)o;
   if (fCGnx==0||fCGny==0) return;
   Double_t xs   = (fX2-fX1)/fCGnx;
   Double_t ys   = (fY2-fY1)/fCGny;
 
   Int_t x1 = (Int_t)((b->GetX1()-fX1)/xs);
   Int_t x2 = (Int_t)((b->GetX2()-fX1)/xs);
   Int_t y1 = (Int_t)((b->GetY1()-fY1)/ys);
   Int_t y2 = (Int_t)((b->GetY2()-fY1)/ys);
   for (int i = x1; i<=x2; i++) {
      for (int j = y1; j<=y2; j++) NotFree(i, j);
   }
}
 
////////////////////////////////////////////////////////////////////////////////
void TPad::FillCollideGridTFrame(TObject *o)
{
   TFrame *f = (TFrame *)o;
   if (fCGnx==0||fCGny==0) return;
   Double_t xs   = (fX2-fX1)/fCGnx;
   Double_t ys   = (fY2-fY1)/fCGny;
 
   Int_t x1 = (Int_t)((f->GetX1()-fX1)/xs);
   Int_t x2 = (Int_t)((f->GetX2()-fX1)/xs);
   Int_t y1 = (Int_t)((f->GetY1()-fY1)/ys);
   Int_t y2 = (Int_t)((f->GetY2()-fY1)/ys);
   Int_t i;
 
   for (i = x1; i<=x2; i++) {
      NotFree(i, y1);
      NotFree(i, (y1-1));
      NotFree(i, (y1-2));
   }
   for (i = y1; i<=y2; i++) {
      NotFree(x1, i);
      NotFree((x1-1), i);
      NotFree((x1-2), i);
   }
}
 
////////////////////////////////////////////////////////////////////////////////
void TPad::FillCollideGridTGraph(TObject *o)
{
   TGraph *g = (TGraph *)o;
   if (fCGnx==0||fCGny==0) return;
   Double_t xs   = (fX2-fX1)/fCGnx;
   Double_t ys   = (fY2-fY1)/fCGny;
 
   Int_t n = g->GetN();
   Int_t s = TMath::Max(n/10,1);
   Double_t x1, x2, y1, y2;
   for (Int_t i=s; i<n; i=i+s) {
      g->GetPoint(TMath::Max(0,i-s),x1,y1);
      g->GetPoint(i  ,x2,y2);
      if (fLogx) {
         if (x1 > 0) x1 = TMath::Log10(x1);
         else        x1 = fUxmin;
         if (x2 > 0) x2 = TMath::Log10(x2);
         else        x2 = fUxmin;
      }
      if (fLogy) {
         if (y1 > 0) y1 = TMath::Log10(y1);
         else        y1 = fUymin;
         if (y2 > 0) y2 = TMath::Log10(y2);
         else        y2 = fUymin;
      }
      LineNotFree((int)((x1-fX1)/xs), (int)((x2-fX1)/xs),
                  (int)((y1-fY1)/ys), (int)((y2-fY1)/ys));
   }
}
 
////////////////////////////////////////////////////////////////////////////////
void TPad::FillCollideGridTH1(TObject *o)
{
   TH1 *h = (TH1 *)o;
   if (fCGnx==0||fCGny==0) return;
   if (o->InheritsFrom(TH2::Class())) return;
   if (o->InheritsFrom(TH3::Class())) return;
 
   TString name = h->GetName();
   if (name.Index("hframe") >= 0) return;
 
   Double_t xs   = (fX2-fX1)/fCGnx;
   Double_t ys   = (fY2-fY1)/fCGny;
 
   bool haserrors = false;
   TString drawOption = h->GetDrawOption();
   drawOption.ToLower();
   drawOption.ReplaceAll("same","");
 
   if (drawOption.Index("hist") < 0) {
      if (drawOption.Index("e") >= 0) haserrors = true;
   }
 
   Int_t nx = h->GetNbinsX();
   Int_t  x1, y1, y2;
   Int_t i, j;
   Double_t x1l, y1l, y2l;
 
   for (i = 1; i<nx; i++) {
      if (haserrors) {
         x1l = h->GetBinCenter(i);
         if (fLogx) {
            if (x1l > 0) x1l = TMath::Log10(x1l);
            else         x1l = fUxmin;
         }
         x1 = (Int_t)((x1l-fX1)/xs);
         y1l = h->GetBinContent(i)-h->GetBinErrorLow(i);
         if (fLogy) {
            if (y1l > 0) y1l = TMath::Log10(y1l);
            else         y1l = fUymin;
         }
         y1 = (Int_t)((y1l-fY1)/ys);
         y2l = h->GetBinContent(i)+h->GetBinErrorUp(i);
         if (fLogy) {
            if (y2l > 0) y2l = TMath::Log10(y2l);
            else         y2l = fUymin;
         }
         y2 = (Int_t)((y2l-fY1)/ys);
         for (j=y1; j<y2; j++) {
            NotFree(x1, j);
         }
      }
      x1l = h->GetBinLowEdge(i);
      if (fLogx) {
         if (x1l > 0) x1l = TMath::Log10(x1l);
         else         x1l = fUxmin;
      }
      x1 = (Int_t)((x1l-fX1)/xs);
      y1l = h->GetBinContent(i);
      if (fLogy) {
         if (y1l > 0) y1l = TMath::Log10(y1l);
         else         y1l = fUymin;
      }
      y1 = (Int_t)((y1l-fY1)/ys);
      NotFree(x1, y1);
      x1l = h->GetBinLowEdge(i)+h->GetBinWidth(i);
      if (fLogx) {
         if (x1l > 0) x1l = TMath::Log10(x1l);
         else         x1l = fUxmin;
      }
      x1 = (int)((x1l-fX1)/xs);
      NotFree(x1, y1);
   }
 
   // Extra objects in the list of function
   TPaveStats *ps = (TPaveStats*)h->GetListOfFunctions()->FindObject("stats");
   if (ps) FillCollideGridTBox(ps);
}
 
////////////////////////////////////////////////////////////////////////////////
/// This method draws the collide grid on top of the canvas. This is used for
/// debugging only. At some point it will be removed.
 
void TPad::DrawCollideGrid()
{
   if (fCGnx==0||fCGny==0) return;
 
   TContext ctxt(this, kTRUE);
 
   TBox box;
   box.SetFillColorAlpha(kRed,0.5);
 
   Double_t xs   = (fX2-fX1)/fCGnx;
   Double_t ys   = (fY2-fY1)/fCGny;
 
   Double_t X1L, X2L, Y1L, Y2L;
   Double_t t = 0.15;
   Double_t Y1, Y2;
   Double_t X1 = fX1;
   Double_t X2 = X1+xs;
 
   for (int i = 0; i<fCGnx; i++) {
      Y1 = fY1;
      Y2 = Y1+ys;
      for (int j = 0; j<fCGny; j++) {
         if (GetLogx()) {
            X1L = TMath::Power(10,X1);
            X2L = TMath::Power(10,X2);
         } else {
            X1L = X1;
            X2L = X2;
         }
         if (GetLogy()) {
            Y1L = TMath::Power(10,Y1);
            Y2L = TMath::Power(10,Y2);
         } else {
            Y1L = Y1;
            Y2L = Y2;
         }
         if (!fCollideGrid[i + j*fCGnx]) {
            box.SetFillColorAlpha(kBlack,t);
            box.DrawBox(X1L, Y1L, X2L, Y2L);
         } else {
            box.SetFillColorAlpha(kRed,t);
            box.DrawBox(X1L, Y1L, X2L, Y2L);
         }
         Y1 = Y2;
         Y2 = Y1+ys;
         if (t==0.15) t = 0.1;
         else         t = 0.15;
      }
      X1 = X2;
      X2 = X1+xs;
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Short cut to call Modified() and Update() in a single call.
/// On Mac with Cocoa, it performs an additional ProcessEvents().
 
void TPad::ModifiedUpdate()
{
   Modified();
   Update();
#ifdef R__HAS_COCOA
   gSystem->ProcessEvents();
#endif
}
 
////////////////////////////////////////////////////////////////////////////////
/// Convert x from pad to X.
 
Double_t TPad::PadtoX(Double_t x) const
{
   if (fLogx && x < 50) return Double_t(TMath::Exp(2.302585092994*x));
   return x;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Convert y from pad to Y.
 
Double_t TPad::PadtoY(Double_t y) const
{
   if (fLogy && y < 50) return Double_t(TMath::Exp(2.302585092994*y));
   return y;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Convert x from X to pad.
 
Double_t TPad::XtoPad(Double_t x) const
{
   if (fLogx) {
      if (x > 0) x = TMath::Log10(x);
      else       x = fUxmin;
   }
   return x;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Convert y from Y to pad.
 
Double_t TPad::YtoPad(Double_t y) const
{
   if (fLogy) {
      if (y > 0) y = TMath::Log10(y);
      else       y = fUymin;
   }
   return y;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Paint all primitives in pad.
 
void TPad::Paint(Option_t * /*option*/)
{
   if (!fPrimitives)
      fPrimitives = new TList;
   if (fViewer3D && fViewer3D->CanLoopOnPrimitives()) {
      fViewer3D->PadPaint(this);
      Modified(kFALSE);
      if (GetGLDevice()!=-1 && gVirtualPS) {
         TContext ctxt(this, kFALSE);
         if (gGLManager) gGLManager->PrintViewer(GetViewer3D());
      }
      return;
   }
 
   if (fCanvas) TColor::SetGrayscale(fCanvas->IsGrayscale());
 
   Bool_t began3DScene = kFALSE;
   fPadPaint = 1;
 
   {
      TContext ctxt(this, kTRUE);
 
      PaintBorder(GetFillColor(), kTRUE);
      PaintDate();
 
      auto lnk = GetListOfPrimitives()->FirstLink();
 
      while (lnk) {
         TObject *obj = lnk->GetObject();
 
         // Create a pad 3D viewer if none exists and we encounter a 3D shape
         if (!fViewer3D && obj->InheritsFrom(TAtt3D::Class())) {
            GetViewer3D("pad");
         }
 
         // Open a 3D scene if required
         if (fViewer3D && !fViewer3D->BuildingScene()) {
            fViewer3D->BeginScene();
            began3DScene = kTRUE;
         }
 
         obj->Paint(lnk->GetOption());
         lnk = lnk->Next();
      }
   }
 
   fPadPaint = 0;
   Modified(kFALSE);
 
   // Close the 3D scene if we opened it. This must be done after modified
   // flag is cleared, as some viewers will invoke another paint by marking pad modified again
   if (began3DScene) {
      fViewer3D->EndScene();
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Paint the pad border.
/// Draw first  a box as a normal filled box
 
void TPad::PaintBorder(Color_t color, Bool_t tops)
{
   if (color >= 0) {
      TAttLine::Modify();  //Change line attributes only if necessary
      TAttFill::Modify();  //Change fill area attributes only if necessary
 
      //With Cocoa we have a transparency. But we also have
      //pixmaps, and if you just paint a new content over the old one
      //with alpha < 1., you'll be able to see the old content.
      if (!gROOT->IsBatch() && gVirtualX->InheritsFrom("TGCocoa") && GetPainter())
         GetPainter()->ClearDrawable();
 
      PaintBox(fX1,fY1,fX2,fY2);
   }
   if (color < 0) color = -color;
   // then paint 3d frame (depending on bordermode)
   if (IsTransparent()) return;
   // Paint a 3D frame around the pad.
 
   if (fBorderMode == 0) return;
   Int_t bordersize = fBorderSize;
   if (bordersize <= 0) bordersize = 2;
 
   const Double_t realBsX = bordersize / (GetAbsWNDC() * GetWw()) * (fX2 - fX1);
   const Double_t realBsY = bordersize / (GetAbsHNDC() * GetWh()) * (fY2 - fY1);
 
   Short_t px1,py1,px2,py2;
   Double_t xl, xt, yl, yt;
 
   // GetColorDark() and GetColorBright() use GetFillColor()
   Color_t oldcolor = GetFillColor();
   SetFillColor(color);
   TAttFill::Modify();
   Color_t light = 0, dark = 0;
   if (color != 0) {
      light = TColor::GetColorBright(color);
      dark  = TColor::GetColorDark(color);
   }
 
   // Compute real left bottom & top right of the box in pixels
   px1 = XtoPixel(fX1);   py1 = YtoPixel(fY1);
   px2 = XtoPixel(fX2);   py2 = YtoPixel(fY2);
   if (px1 < px2) {xl = fX1; xt = fX2; }
   else           {xl = fX2; xt = fX1;}
   if (py1 > py2) {yl = fY1; yt = fY2;}
   else           {yl = fY2; yt = fY1;}
 
   Double_t frameXs[7] = {}, frameYs[7] = {};
 
   if (!IsBatch() && GetPainter()) {
      // Draw top&left part of the box
      frameXs[0] = xl;           frameYs[0] = yl;
      frameXs[1] = xl + realBsX; frameYs[1] = yl + realBsY;
      frameXs[2] = frameXs[1];   frameYs[2] = yt - realBsY;
      frameXs[3] = xt - realBsX; frameYs[3] = frameYs[2];
      frameXs[4] = xt;           frameYs[4] = yt;
      frameXs[5] = xl;           frameYs[5] = yt;
      frameXs[6] = xl;           frameYs[6] = yl;
 
      if (fBorderMode == -1) GetPainter()->SetFillColor(dark);
      else                   GetPainter()->SetFillColor(light);
      GetPainter()->DrawFillArea(7, frameXs, frameYs);
 
      // Draw bottom&right part of the box
      frameXs[0] = xl;              frameYs[0] = yl;
      frameXs[1] = xl + realBsX;    frameYs[1] = yl + realBsY;
      frameXs[2] = xt - realBsX;    frameYs[2] = frameYs[1];
      frameXs[3] = frameXs[2];      frameYs[3] = yt - realBsY;
      frameXs[4] = xt;              frameYs[4] = yt;
      frameXs[5] = xt;              frameYs[5] = yl;
      frameXs[6] = xl;              frameYs[6] = yl;
 
      if (fBorderMode == -1) GetPainter()->SetFillColor(light);
      else                   GetPainter()->SetFillColor(dark);
      GetPainter()->DrawFillArea(7, frameXs, frameYs);
 
      // If this pad is a button, highlight it
      if (InheritsFrom(TButton::Class()) && fBorderMode == -1) {
         if (TestBit(kFraming)) {  // bit set in TButton::SetFraming
            if (GetFillColor() != 2) GetPainter()->SetLineColor(2);
            else                     GetPainter()->SetLineColor(4);
            GetPainter()->DrawBox(xl + realBsX, yl + realBsY, xt - realBsX, yt - realBsY, TVirtualPadPainter::kHollow);
         }
      }
      GetPainter()->SetFillColor(-1);
      SetFillColor(oldcolor);
   }
 
   if (!tops) return;
 
   PaintBorderPS(xl, yl, xt, yt, fBorderMode, bordersize, dark, light);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Paint a frame border with Postscript.
 
void TPad::PaintBorderPS(Double_t xl,Double_t yl,Double_t xt,Double_t yt,Int_t bmode,Int_t bsize,Int_t dark,Int_t light)
{
   if (!gVirtualPS) return;
   gVirtualPS->DrawFrame(xl, yl, xt, yt, bmode,bsize,dark,light);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Paint the current date and time if the option `Date` is set on via `gStyle->SetOptDate()`
/// Paint the current file name if the option `File` is set on via `gStyle->SetOptFile()`
 
void TPad::PaintDate()
{
   if (fCanvas == this) {
      if (gStyle->GetOptDate()) {
         TDatime dt;
         const char *dates;
         char iso[16];
         if (gStyle->GetOptDate() < 10) {
            //by default use format like "Wed Sep 25 17:10:35 2002"
            dates = dt.AsString();
         } else if (gStyle->GetOptDate() < 20) {
            //use ISO format like 2002-09-25
            strlcpy(iso,dt.AsSQLString(),16);
            dates = iso;
         } else {
            //use ISO format like 2002-09-25 17:10:35
            dates = dt.AsSQLString();
         }
         TText tdate(gStyle->GetDateX(),gStyle->GetDateY(),dates);
         tdate.SetTextSize( gStyle->GetAttDate()->GetTextSize());
         tdate.SetTextFont( gStyle->GetAttDate()->GetTextFont());
         tdate.SetTextColor(gStyle->GetAttDate()->GetTextColor());
         tdate.SetTextAlign(gStyle->GetAttDate()->GetTextAlign());
         tdate.SetTextAngle(gStyle->GetAttDate()->GetTextAngle());
         tdate.SetNDC();
         tdate.Paint();
      }
      if (gStyle->GetOptFile() && gFile) {
         TText tfile(1. - gStyle->GetDateX(),gStyle->GetDateY(),gFile->GetName());
         tfile.SetTextSize( gStyle->GetAttDate()->GetTextSize());
         tfile.SetTextFont( gStyle->GetAttDate()->GetTextFont());
         tfile.SetTextColor(gStyle->GetAttDate()->GetTextColor());
         tfile.SetTextAlign(31);
         tfile.SetTextAngle(gStyle->GetAttDate()->GetTextAngle());
         tfile.SetNDC();
         tfile.Paint();
      }
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Paint histogram/graph frame.
 
void TPad::PaintPadFrame(Double_t xmin, Double_t ymin, Double_t xmax, Double_t ymax)
{
   if (!fPrimitives) fPrimitives = new TList;
   TList *glist  = GetListOfPrimitives();
   TFrame *frame = GetFrame();
   frame->SetX1(xmin);
   frame->SetX2(xmax);
   frame->SetY1(ymin);
   frame->SetY2(ymax);
   if (!glist->FindObject(fFrame)) {
      glist->AddFirst(frame);
      fFrame->SetBit(kMustCleanup);
   }
   frame->Paint();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Traverse pad hierarchy and (re)paint only modified pads.
 
void TPad::PaintModified()
{
   if (fViewer3D && fViewer3D->CanLoopOnPrimitives()) {
      if (IsModified()) {
         fViewer3D->PadPaint(this);
         Modified(kFALSE);
      }
      TList *pList = GetListOfPrimitives();
      auto lnk = pList ? pList->FirstLink() : nullptr;
      while (lnk) {
         auto obj = lnk->GetObject();
         if (obj->InheritsFrom(TPad::Class()))
            ((TPad*)obj)->PaintModified();
         lnk = lnk->Next();
      }
      return;
   }
 
   if (fCanvas) TColor::SetGrayscale(fCanvas->IsGrayscale());
 
   TVirtualPS *saveps = gVirtualPS;
   if (gVirtualPS) {
      if (gVirtualPS->TestBit(kPrintingPS))
         gVirtualPS = nullptr;
   }
 
   Bool_t began3DScene = kFALSE;
   fPadPaint = 1;
   {
      TContext ctxt(this, kTRUE);
      if (IsModified() || IsTransparent()) {
         if ((fFillStyle < 3026) && (fFillStyle > 3000)) {
            if (!gPad->IsBatch() && GetPainter()) GetPainter()->ClearDrawable();
         }
         PaintBorder(GetFillColor(), kTRUE);
      }
 
      PaintDate();
 
      TList *pList = GetListOfPrimitives();
      auto lnk = pList ? pList->FirstLink() : nullptr;
 
      while (lnk) {
         TObject *obj = lnk->GetObject();
         if (obj->InheritsFrom(TPad::Class())) {
            ((TPad*)obj)->PaintModified();
         } else if (IsModified() || IsTransparent()) {
 
            // Create a pad 3D viewer if none exists and we encounter a
            // 3D shape
            if (!fViewer3D && obj->InheritsFrom(TAtt3D::Class())) {
               GetViewer3D("pad");
            }
 
            // Open a 3D scene if required
            if (fViewer3D && !fViewer3D->BuildingScene()) {
               fViewer3D->BeginScene();
               began3DScene = kTRUE;
            }
 
            obj->Paint(lnk->GetOption());
         }
         lnk = lnk->Next();
      }
   }
 
   fPadPaint = 0;
   Modified(kFALSE);
 
   // This must be done after modified flag is cleared, as some
   // viewers will invoke another paint by marking pad modified again
   if (began3DScene) {
      if (fViewer3D) fViewer3D->EndScene();
   }
 
   gVirtualPS = saveps;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Paint box in CurrentPad World coordinates.
///
///  - if option[0] = 's' the box is forced to be paint with style=0
///  - if option[0] = 'l' the box contour is drawn
 
void TPad::PaintBox(Double_t x1, Double_t y1, Double_t x2, Double_t y2, Option_t *option)
{
   if (!gPad->IsBatch() && GetPainter()) {
      Int_t style0 = GetPainter()->GetFillStyle();
      Int_t style  = style0;
      if (option[0] == 's') {
         GetPainter()->SetFillStyle(0);
         style = 0;
      }
      if (style) {
         if (style > 3000 && style < 4000) {
            if (style < 3026) {
               // draw stipples with fFillColor foreground
               GetPainter()->DrawBox(x1, y1, x2, y2, TVirtualPadPainter::kFilled);
            }
 
            if (style >= 3100 && style < 4000) {
               Double_t xb[4], yb[4];
               xb[0] = x1; xb[1] = x1; xb[2] = x2; xb[3] = x2;
               yb[0] = y1; yb[1] = y2; yb[2] = y2; yb[3] = y1;
               PaintFillAreaHatches(4, xb, yb, style);
               return;
            }
            //special case for TAttFillCanvas
            if (GetPainter()->GetFillColor() == 10) {
               GetPainter()->SetFillColor(1);
               GetPainter()->DrawBox(x1, y1, x2, y2, TVirtualPadPainter::kFilled);
               GetPainter()->SetFillColor(10);
            }
         } else if (style >= 4000 && style <= 4100) {
            // For style >=4000 we make the window transparent.
            // From 4000 to 4100 the window is 100% transparent to 100% opaque
 
            //ignore this style option when this is the canvas itself
            if (this == fMother) {
               //It's clear, that virtual X checks a style (4000) and will render a hollow rect!
               const Style_t oldFillStyle = GetPainter()->GetFillStyle();
               if (gVirtualX->InheritsFrom("TGCocoa"))
                  GetPainter()->SetFillStyle(1000);
               GetPainter()->DrawBox(x1, y1, x2, y2, TVirtualPadPainter::kFilled);
               if (gVirtualX->InheritsFrom("TGCocoa"))
                  GetPainter()->SetFillStyle(oldFillStyle);
            } else {
               //draw background by blitting all bottom pads
               int px, py;
               XYtoAbsPixel(