TScatter.cxx

Go to the documentation of this file.

// @(#)root/hist:$Id$
// Author: Olivier Couet   18/05/2022
 
/*************************************************************************
 * 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 "TROOT.h"
#include "TBuffer.h"
#include "TScatter.h"
#include "TStyle.h"
#include "TMath.h"
#include "TVirtualPad.h"
#include "TH2.h"
#include "TVirtualGraphPainter.h"
#include "strtok.h"
 
#include <iostream>
#include <fstream>
#include <cstring>
#include <string>
 
ClassImp(TScatter);
 
 
////////////////////////////////////////////////////////////////////////////////
 
/** \class TScatter
    \ingroup Graphs
A TScatter is able to draw four variables scatter plot on a single plot. The two first
variables are the x and y position of the markers, the third is mapped on the current
color map and the fourth on the marker size.
 
The following example demonstrates how it works:
 
Begin_Macro(source)
../../../tutorials/visualisation/graphs/gr006_scatter.C
End_Macro
 
### TScatter's plotting options
TScatter can be drawn with the following options:
 
| Option   | Description                                                       |
|----------|-------------------------------------------------------------------|
| "A"      | Produce a new plot with Axis around the graph |
 
*/
 
////////////////////////////////////////////////////////////////////////////////
/// TScatter default constructor.
 
TScatter::TScatter()
{
}
 
////////////////////////////////////////////////////////////////////////////////
/// TScatter normal constructor.
///
///  the arrays are preset to zero
 
TScatter::TScatter(Int_t n)
{
   fGraph     = new TGraph(n);
   fNpoints   = fGraph->GetN();
   fMaxSize   = fGraph->GetMaxSize();
 
   fColor = new Double_t[fMaxSize];
   fSize  = new Double_t[fMaxSize];
 
   memset(fColor, 0, fNpoints * sizeof(Double_t));
   memset(fSize, 0, fNpoints * sizeof(Double_t));
   fMaxMarkerSize = 5.;
   fMinMarkerSize = 1.;
   fMargin = 0.1;
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// TScatter normal constructor.
///
///  if ex or ey are null, the corresponding arrays are preset to zero
 
TScatter::TScatter(Int_t n, const Double_t *x, const Double_t *y, const Double_t *col, const Double_t *size)
{
   fGraph     = new TGraph(n, x, y);
   fNpoints   = fGraph->GetN();
   fMaxSize   = fGraph->GetMaxSize();
 
   Int_t bufsize = sizeof(Double_t) * fNpoints;
   if (col) {
      fColor = new Double_t[fMaxSize];
      memcpy(fColor, col, bufsize);
   }
   if (size) {
      fSize  = new Double_t[fMaxSize];
      memcpy(fSize, size, bufsize);
   }
 
   fMaxMarkerSize = 5.;
   fMinMarkerSize = 1.;
   fMargin = 0.1;
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// TScatter default destructor.
 
TScatter::~TScatter()
{
   delete fGraph;
   delete fHistogram;
   delete [] fColor;
   delete [] fSize;
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Compute distance from point px,py to a scatter plot.
///
///  Compute the closest distance of approach from point px,py to this scatter plot.
///  The distance is computed in pixels units.
 
Int_t TScatter::DistancetoPrimitive(Int_t px, Int_t py)
{
   // Are we on the axis?
   Int_t distance;
   if (this->GetHistogram()) {
      distance = this->GetHistogram()->DistancetoPrimitive(px,py);
      if (distance <= 5) return distance;
   }
 
   TVirtualGraphPainter *painter = TVirtualGraphPainter::GetPainter();
   if (painter)
      return painter->DistancetoPrimitiveHelper(this->GetGraph(), px, py);
   return 0;
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Execute action corresponding to one event.
///
///  This member function is called when a graph is clicked with the locator
///
///  If Left button clicked on one of the line end points, this point
///     follows the cursor until button is released.
///
///  if Middle button clicked, the line is moved parallel to itself
///     until the button is released.
 
void TScatter::ExecuteEvent(Int_t event, Int_t px, Int_t py)
{
   TVirtualGraphPainter *painter = TVirtualGraphPainter::GetPainter();
   if (painter) painter->ExecuteEventHelper(this->GetGraph(), event, px, py);
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Returns a pointer to the histogram used to draw the axis
 
TH2F *TScatter::GetHistogram() const
{
   if (!fHistogram) {
      // do not add the histogram to gDirectory
      // use local TDirectory::TContect that will set temporarly gDirectory to a nullptr and
      // will avoid that histogram is added in the global directory
      TDirectory::TContext ctx(nullptr);
      double rwxmin, rwymin, rwxmax, rwymax;
      int npt = 50;
      fGraph->ComputeRange(rwxmin, rwymin, rwxmax, rwymax);
      double dx = (rwxmax-rwxmin)*fMargin;
      double dy = (rwymax-rwymin)*fMargin;
      auto h = new TH2F(TString::Format("%s_h",GetName()),GetTitle(),npt,rwxmin-dx,rwxmax+dx,npt,rwymin-dy,rwymax+dy);
      h->SetBit(TH1::kNoStats);
      h->SetDirectory(nullptr);
      h->Sumw2(kFALSE);
      const_cast<TScatter *>(this)->fHistogram = h;
   }
   return fHistogram;
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Get the scatter's x axis.
 
TAxis *TScatter::GetXaxis() const
{
   auto h = GetHistogram();
   return h ? h->GetXaxis() : nullptr;
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Get the scatter's y axis.
 
TAxis *TScatter::GetYaxis() const
{
   auto h = GetHistogram();
   return h ? h->GetYaxis() : nullptr;
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Get the scatter's z axis.
 
TAxis *TScatter::GetZaxis() const
{
   auto h = GetHistogram();
   return h ? h->GetZaxis() : nullptr;
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Paint this scatter plot with its current attributes.
 
void TScatter::Paint(Option_t *option)
{
   TVirtualGraphPainter *painter = TVirtualGraphPainter::GetPainter();
   if (painter) painter->PaintScatter(this, option);
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Print graph and errors values.
 
void TScatter::Print(Option_t *) const
{
   Double_t *X = fGraph->GetX();
   Double_t *Y = fGraph->GetY();
   for (Int_t i = 0; i < fNpoints; i++) {
      printf("x[%d]=%g, y[%d]=%g", i, X[i], i, Y[i]);
      if (fColor) printf(", color[%d]=%g", i, fColor[i]);
      if (fSize) printf(", size[%d]=%g", i, fSize[i]);
      printf("\n");
   }
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Set the margin around the plot in %
 
void TScatter::SetMargin(Double_t margin)
{
   if (fMargin != margin) {
      delete fHistogram;
      fHistogram = nullptr;
      fMargin = margin;
   }
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Save primitive as a C++ statement(s) on output stream out
 
void TScatter::SavePrimitive(std::ostream &out, Option_t *option /*= ""*/)
{
   TString arr_x = SavePrimitiveArray(out, "scat_x", fNpoints, fGraph->GetX(), kTRUE);
   TString arr_y = SavePrimitiveArray(out, "scat_y", fNpoints, fGraph->GetY());
   TString arr_col = SavePrimitiveArray(out, "scat_col", fNpoints, fColor);
   TString arr_size = SavePrimitiveArray(out, "scat_size", fNpoints, fSize);
 
   SavePrimitiveConstructor(
      out, Class(), "scat",
      TString::Format("%d, %s, %s, %s, %s", fNpoints, arr_x.Data(), arr_y.Data(), arr_col.Data(), arr_size.Data()),
      kFALSE);
 
   SavePrimitiveNameTitle(out, "scat");
   SaveFillAttributes(out, "scat", 0, 1001);
   SaveLineAttributes(out, "scat", 1, 1, 1);
   SaveMarkerAttributes(out, "scat", 1, 1, 1);
 
   out << "   scat->SetMargin(" << GetMargin() << ");\n";
   out << "   scat->SetMinMarkerSize(" << GetMinMarkerSize() << ");\n";
   out << "   scat->SetMaxMarkerSize(" << GetMaxMarkerSize() << ");\n";
 
   if (fHistogram) {
      static int histcnt = 0;
      TString hname = fHistogram->GetName();
      fHistogram->SetName(TString::Format("scat_stack_hist%d", histcnt++));
      fHistogram->SavePrimitive(out, "nodraw");
      out << "   scat->SetHistogram(" << fHistogram->GetName() << ");\n";
      out << "   \n";
      fHistogram->SetName(hname);
   }
 
   out << "   scat->Draw(\"" << TString(option).ReplaceSpecialCppChars() << "\");\n";
}