TGraphPolargram.cxx

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// @(#)root/graf:$Id$
// Author: Sebastian Boser, Mathieu Demaret 02/02/06

/*************************************************************************
 * 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.             *
 *************************************************************************/

/** \class TGraphPolargram
\ingroup BasicGraphics

To draw polar axis

TGraphPolargram draw the polar axis of the TGraphPolar.

Example:

Begin_Macro(source)
{
   TCanvas * CPol = new TCanvas("CPol","TGraphPolar Examples",500,500);

   Double_t rmin=0;
   Double_t rmax=TMath::Pi()*2;
   Double_t r[1000];
   Double_t theta[1000];

   TF1 * fp1 = new TF1("fplot","cos(x)",rmin,rmax);
   for (Int_t ipt = 0; ipt < 1000; ipt++) {
      r[ipt] = ipt*(rmax-rmin)/1000+rmin;
      theta[ipt] = fp1->Eval(r[ipt]);
   }
   TGraphPolar * grP1 = new TGraphPolar(1000,r,theta);
   grP1->SetLineColor(2);
   grP1->Draw("AOL");

   return CPol;
}
End_Macro
*/

#include "TGraphPolar.h"
#include "TGraphPolargram.h"
#include "TGaxis.h"
#include "THLimitsFinder.h"
#include "TVirtualPad.h"
#include "TROOT.h"
#include "TLatex.h"
#include "TEllipse.h"
#include "TMath.h"

ClassImp(TGraphPolargram);

////////////////////////////////////////////////////////////////////////////////
/// TGraphPolargram Constructor.

TGraphPolargram::TGraphPolargram(const char* name, Double_t rmin, Double_t rmax,
                                 Double_t tmin, Double_t tmax):
                                 TNamed(name,"Polargram")
{
   Init();
   fNdivRad          = 508;
   fNdivPol          = 508;
   fPolarLabels      = NULL;
   fRwrmax           = rmax;
   fRwrmin           = rmin;
   fRwtmin           = tmin;
   fRwtmax           = tmax;
}

////////////////////////////////////////////////////////////////////////////////
/// Short constructor used in the case of a spider plot.

TGraphPolargram::TGraphPolargram(const char* name):
                                 TNamed(name,"Polargram")
{
   Init();
   fNdivRad     = 0;
   fNdivPol     = 0;
   fPolarLabels = NULL;
   fRwrmax      = 1;
   fRwrmin      = 0;
   fRwtmax      = 0;
   fRwtmin      = 0;
}

////////////////////////////////////////////////////////////////////////////////
/// TGraphPolargram destructor.

TGraphPolargram::~TGraphPolargram()
{
   if (fPolarLabels != NULL) delete [] fPolarLabels;
}

////////////////////////////////////////////////////////////////////////////////
/// Set the Polar range.
/// \param[in] tmin   the start number.
/// \param[in] tmax   the end number.

void TGraphPolargram::ChangeRangePolar(Double_t tmin, Double_t tmax)
{
   if (tmin < tmax) {
      fRwtmin = tmin;
      fRwtmax = tmax;
   }
   if (gPad) gPad->Modified();
}

////////////////////////////////////////////////////////////////////////////////
/// Everything within the circle belongs to the TGraphPolargram.

Int_t TGraphPolargram::DistancetoPrimitive(Int_t px, Int_t py)
{
   Int_t i;
   Double_t x = gPad->AbsPixeltoX(px);
   Double_t y = gPad->AbsPixeltoY(py);

   // Check if close to a (major) radial line.
   Double_t rad = TMath::Sqrt(x*x+y*y);
   Int_t div    = (Int_t)rad*(fNdivRad%100);
   Double_t dr  = TMath::Min(TMath::Abs(rad-div*1./(fNdivRad%100)),
                             TMath::Abs(rad-(div+1)*1./(fNdivRad%100)));
   Int_t drad   = gPad->XtoPixel(dr)-gPad->XtoPixel(0);

   // Check if close to a (major) Polar line.
   // This is not a proper calculation, but rather fast.
   Int_t dt = kMaxPixel;
   for (i=0; i<(fNdivPol%100); i++) {
      Double_t theta = i*2*TMath::Pi()/(fNdivPol%100);

      // Attention: px,py in pixel units, line given in user coordinates.
      Int_t dthis = DistancetoLine(px,py,0.,0.,TMath::Cos(theta),
                                               TMath::Sin(theta));

      // Fails if we are outside box described by the line.
      // (i.e for all hor/vert lines)
      if (dthis==9999) {

         // Outside -> Get distance to endpoint of line.
         if (rad>1) {
            dthis = (Int_t)TMath::Sqrt(
                    TMath::Power(px-gPad->XtoPixel(