TScatter.cxx

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// @(#)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 "TScatter.h"
#include "TH2.h"
#include "TVirtualGraphPainter.h"
 
 #include <iostream>
 
 
////////////////////////////////////////////////////////////////////////////////
 
/** \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 |
| "SKIPCOL" | Do not draw the points outside the color range. By default, such points' color is clipped to the minimum or maximum color, depending on whether the color is smaller or bigger than the color range |
 
*/
 
////////////////////////////////////////////////////////////////////////////////
/// 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 = SavePrimitiveVector(out, "scat_x", fNpoints, fGraph->GetX(), kTRUE);
   TString arr_y = SavePrimitiveVector(out, "scat_y", fNpoints, fGraph->GetY());
   TString arr_col = SavePrimitiveVector(out, "scat_col", fNpoints, fColor);
   TString arr_size = SavePrimitiveVector(out, "scat_size", fNpoints, fSize);
 
   SavePrimitiveConstructor(out, Class(), "scat",
                            TString::Format("%d, %s.data(), %s.data(), %s.data(), %s.data()", 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);
   }
 
   SavePrimitiveDraw(out, "scat", option);
}