TPie.cxx

Go to the documentation of this file.

// @(#)root/graf:$Id$
// Author: Guido Volpi, Olivier Couet 03/11/2006

/*************************************************************************
 * 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 "TPie.h"
#include "TPieSlice.h"

#include <Riostream.h>
#include <TROOT.h>
#include <TVirtualPad.h>
#include <TArc.h>
#include <TLegend.h>
#include <TMath.h>
#include <TStyle.h>
#include <TLatex.h>
#include <TPaveText.h>
#include <TH1.h>
#include <TColor.h>

ClassImp(TPie)

/** \class TPie
\ingroup BasicGraphics

Draw a Pie Chart,

Example:

Begin_Macro(source)
../../../tutorials/graphics/piechart.C
End_Macro
*/

Double_t gX             = 0; // Temporary pie X position.
Double_t gY             = 0; // Temporary pie Y position.
Double_t gRadius        = 0; // Temporary pie Radius of the TPie.
Double_t gRadiusOffset  = 0; // Temporary slice's radial offset.
Double_t gAngularOffset = 0; // Temporary slice's angular offset.
Bool_t   gIsUptSlice    = kFALSE; // True if a slice in the TPie should
                                  // be updated.
Int_t    gCurrent_slice = -1;// Current slice under mouse.
Double_t gCurrent_phi1  = 0; // Phimin of the current slice.
Double_t gCurrent_phi2  = 0; // Phimax of the current slice.
Double_t gCurrent_rad   = 0; // Current distance from the vertex of the
                             // current slice.
Double_t gCurrent_x     = 0; // Current x in the pad metric.
Double_t gCurrent_y     = 0; // Current y in the pad metric.
Double_t gCurrent_ang   = 0; // Current angular, within current_phi1
                                    // and current_phi2.

////////////////////////////////////////////////////////////////////////////////
/// Default constructor.

TPie::TPie() : TNamed()
{
   Init(1, 0, 0.5, 0.5, 0.4);
}

////////////////////////////////////////////////////////////////////////////////
/// This constructor creates a pie chart when only the number of
/// the slices is known. The number of slices is fixed.

TPie::TPie(const char *name, const char *title, Int_t npoints) :
           TNamed(name,title)
{
   Init(npoints, 0, 0.5, 0.5, 0.4);
}

////////////////////////////////////////////////////////////////////////////////
/// Normal constructor. The 1st and 2nd parameters are the name of the object
/// and its title.
///
/// The number of points passed at this point is used to allocate the memory.
///
/// Slices values are given as Double_t.
///
/// The 4th elements is an array containing, in double precision format,
/// the value of each slice. It is also possible to specify the filled color
/// of each slice. If the color array is not specified the slices are colored
/// using a color sequence in the standard palette.

TPie::TPie(const char *name, const char *title,
           Int_t npoints, Double_t *vals,
           Int_t *colors, const char *lbls[]) : TNamed(name,title)
{
   Init(npoints, 0, 0.5, 0.5, 0.4);
   for (Int_t i=0; i<fNvals; ++i) fPieSlices[i]->SetValue(vals[i]);

   SetFillColors(colors);
   SetLabels(lbls);
}

////////////////////////////////////////////////////////////////////////////////
/// Normal constructor (Float_t).

TPie::TPie(const char *name,
           const char *title,
           Int_t npoints, Float_t *vals,
           Int_t *colors, const char *lbls[]) : TNamed(name,title)
{
   Init(npoints, 0, 0.5, 0.5, 0.4);
   for (Int_t i=0; i<fNvals; ++i) fPieSlices[i]->SetValue(vals[i]);

   SetFillColors(colors);
   SetLabels(lbls);
}

////////////////////////////////////////////////////////////////////////////////
/// Constructor from a TH1

TPie::TPie(const TH1 *h) : TNamed(h->GetName(),h->GetTitle())
{
   Int_t i;

   const TAxis *axis = h->GetXaxis();
   Int_t first = axis->GetFirst();
   Int_t last  = axis->GetLast();
   Int_t np    = last-first+1;
   Init(np, 0, 0.5, 0.5, 0.4);

   for (i=first; i<=last; ++i) fPieSlices[i-first]->SetValue(h->GetBinContent(i));
   if (axis->GetLabels()) {
      for (i=first; i<=last; ++i) fPieSlices[i-first]->SetTitle(axis->GetBinLabel(i));
   } else {
      SetLabelFormat("%val");
   }
   SetTextSize(axis->GetLabelSize());
   SetTextColor(axis->GetLabelColor());
   SetTextFont(axis->GetLabelFont());
}

////////////////////////////////////////////////////////////////////////////////
/// Copy constructor.

TPie::TPie(const TPie &cpy) : TNamed(cpy), TAttText(cpy)
{
   Init(cpy.fNvals, cpy.fAngularOffset, cpy.fX, cpy.fY, cpy.fRadius);

   for (Int_t i=0;i<fNvals;++i) {
      fPieSlices[i] = cpy.fPieSlices[i];
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Destructor.

TPie::~TPie()
{
   if (fNvals>0) {
      for (int i=0; i<fNvals; ++i) delete fPieSlices[i];
      delete [] fPieSlices;
   }

   if (fSlices) delete [] fSlices;
   if (fLegend) delete fLegend;
}

////////////////////////////////////////////////////////////////////////////////
/// Evaluate the distance to the chart in gPad.

Int_t TPie::DistancetoPrimitive(Int_t px, Int_t py)
{
   Int_t dist = 9999;

   gCurrent_slice = DistancetoSlice(px,py);
   if ( gCurrent_slice>=0 ) {
      if (gCurrent_rad<=fRadius) {
         dist = 0;
      }
   }

   return dist;
}

////////////////////////////////////////////////////////////////////////////////
/// Returns the slice number at the pixel position (px,py).
/// Returns -1 if no slice is picked.
///
/// Used by DistancetoPrimitive.

Int_t TPie::DistancetoSlice(Int_t px, Int_t py)
{
   MakeSlices();

   Int_t result(-1);

   // coordinates
   Double_t xx = gPad->AbsPixeltoX(px); //gPad->PadtoX(gPad->AbsPixeltoX(px));
   Double_t yy = gPad->AbsPixeltoY(py); //gPad->PadtoY(gPad->AbsPixeltoY(py));

   // XY metric
   Double_t radX  = fRadius;
   Double_t radY  = fRadius;
   Double_t radXY = 1.;
   if (fIs3D==kTRUE) {
      radXY = TMath::Sin(fAngle3D/180.*TMath::Pi());
      radY  = radXY*radX;
   }

   Double_t phimin;
   Double_t cphi;
   Double_t phimax;

   Float_t dPxl = (gPad->PixeltoY(0)-gPad->PixeltoY(1))/radY;
   for (Int_t i=0;i<fNvals;++i) {
      fPieSlices[i]->SetIsActive(kFALSE);

      if (gIsUptSlice && gCurrent_slice!=i) continue;

      // Angles' values for this slice
      phimin = fSlices[2*i  ]*TMath::Pi()/180.;
      cphi   = fSlices[2*i+1]*TMath::Pi()/180.;
      phimax = fSlices[2*i+2]*TMath::Pi()/180.;

      Double_t radOffset = fPieSlices[i]->GetRadiusOffset();

      Double_t dx  = (xx-fX-radOffset*TMath::Cos(cphi))/radX;
      Double_t dy  = (yy-fY-radOffset*TMath::Sin(cphi)*radXY)/radY;

      if (TMath::Abs(dy)<dPxl) dy = dPxl;

      Double_t ang = TMath::ATan2(dy,dx);
      if (ang<0) ang += TMath::TwoPi();

      Double_t dist = TMath::Sqrt(dx*dx+dy*dy);

      if ( ((ang>=phimin && ang <= phimax) || (phimax>TMath::TwoPi() &&
            ang+TMath::TwoPi()>=phimin && ang+TMath::TwoPi()<phimax)) &&
            dist<=1.) { // if true the pointer is in the slice region

         gCurrent_x    = dx;
         gCurrent_y    = dy;
         gCurrent_ang  = ang;
         gCurrent_phi1 = phimin;
         gCurrent_phi2 = phimax;
         gCurrent_rad  = dist*fRadius;

         if (dist<.95 && dist>.65) {
            Double_t range = phimax-phimin;
            Double_t lang = ang-phimin;
            Double_t rang = phimax-ang;
            if (lang<0) lang += TMath::TwoPi();
            else if (lang>=TMath::TwoPi()) lang -= TMath::TwoPi();
            if (rang<0) rang += TMath::TwoPi();
            else if (rang>=TMath::TwoPi()) rang -= TMath::TwoPi();

            if (lang/range<.25 || rang/range<.25) {
               fPieSlices[i]->SetIsActive(kTRUE);
               result = -1;
            }
            else result  = i;
         } else {
            result = i;
         }

         break;
      }
   }
   return result;
}

////////////////////////////////////////////////////////////////////////////////
/// Draw the pie chart.
///
/// The possible options are listed in the TPie::Paint() method.

void TPie::Draw(Option_t *option)
{
   TString soption(option);
   soption.ToLower();

   if (soption.Length()==0) soption = "l";

   if (gPad) {
      if (!gPad->IsEditable()) gROOT->MakeDefCanvas();
      if (!soption.Contains("same")) {
         gPad->Clear();
         gPad->Range(0.,0.,1.,1.);
      }
   }

   for (Int_t i=0;i<fNvals;++i) fPieSlices[i]->AppendPad();
   AppendPad(soption.Data());
}

////////////////////////////////////////////////////////////////////////////////
/// This method is for internal use. It is used by Execute event to draw the
/// outline of "this" TPie. Used when the opaque movements are not permitted.

void TPie::DrawGhost()
{
   MakeSlices();

   // XY metric
   Double_t radXY = 1.;
   if (fIs3D) {
      radXY = TMath::Sin(fAngle3D/180.*TMath::Pi());
   }

   for (Int_t i=0;i<fNvals&&fIs3D==kTRUE;++i) {
      Float_t minphi = (fSlices[i*2]+gAngularOffset+.5)*TMath::Pi()/180.;
      Float_t avgphi = (fSlices[i*2+1]+gAngularOffset)*TMath::Pi()/180.;
      Float_t maxphi = (fSlices[i*2+2]+gAngularOffset-.5)*TMath::Pi()/180.;

      Double_t radOffset = (i == gCurrent_slice ? gRadiusOffset : fPieSlices[i]->GetRadiusOffset());
      Double_t x0 = gX+radOffset*TMath::Cos(avgphi);
      Double_t y0 = gY+radOffset*TMath::Sin(avgphi)*radXY-fHeight;

      gVirtualX->DrawLine( gPad->XtoAbsPixel(x0), gPad->YtoAbsPixel(y0),
                           gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(minphi)),
                           gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(minphi)*radXY) );

      Int_t ndiv = 10;
      Double_t dphi = (maxphi-minphi)/ndiv;

      if (dphi>.15) ndiv = (Int_t) ((maxphi-minphi)/.15);
      dphi = (maxphi-minphi)/ndiv;

      // Loop to draw the arc
      for (Int_t j=0;j<ndiv;++j) {
         Double_t phi = minphi+dphi*j;
         gVirtualX->DrawLine( gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(phi)),
                              gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(phi)*radXY),
                              gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(phi+dphi)),
                              gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(phi+dphi)*radXY));
      }

      gVirtualX->DrawLine( gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(maxphi)),
                           gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(maxphi)*radXY),
                           gPad->XtoAbsPixel(x0), gPad->YtoAbsPixel(y0) );

      gVirtualX->DrawLine(gPad->XtoAbsPixel(x0),
                          gPad->YtoAbsPixel(y0),
                          gPad->XtoAbsPixel(x0),
                          gPad->YtoAbsPixel(y0+fHeight));
      gVirtualX->DrawLine(gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(minphi)),
                          gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(minphi)*radXY),
                          gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(minphi)),
                          gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(minphi)*radXY+fHeight));
      gVirtualX->DrawLine(gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(maxphi)),
                          gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(maxphi)*radXY),
                          gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(maxphi)),
                          gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(maxphi)*radXY+fHeight));
   }


   // Loop over slices
   for (Int_t i=0;i<fNvals;++i) {
      Float_t minphi = (fSlices[i*2]+gAngularOffset+.5)*TMath::Pi()/180.;
      Float_t avgphi = (fSlices[i*2+1]+gAngularOffset)*TMath::Pi()/180.;
      Float_t maxphi = (fSlices[i*2+2]+gAngularOffset-.5)*TMath::Pi()/180.;

      Double_t radOffset = (i == gCurrent_slice ? gRadiusOffset : fPieSlices[i]->GetRadiusOffset());
      Double_t x0 = gX+radOffset*TMath::Cos(avgphi);
      Double_t y0 = gY+radOffset*TMath::Sin(avgphi)*radXY;

      gVirtualX->DrawLine( gPad->XtoAbsPixel(x0), gPad->YtoAbsPixel(y0),
                           gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(minphi)),
                           gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(minphi)*radXY) );


      Int_t ndiv = 10;
      Double_t dphi = (maxphi-minphi)/ndiv;

      if (dphi>.15) ndiv = (Int_t) ((maxphi-minphi)/.15);
      dphi = (maxphi-minphi)/ndiv;

      // Loop to draw the arc
      for (Int_t j=0;j<ndiv;++j) {
         Double_t phi = minphi+dphi*j;
         gVirtualX->DrawLine( gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(phi)),
                              gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(phi)*radXY),
                              gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(phi+dphi)),
                              gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(phi+dphi)*radXY));
      }

      gVirtualX->DrawLine( gPad->XtoAbsPixel(x0+gRadius*TMath::Cos(maxphi)),
                           gPad->YtoAbsPixel(y0+gRadius*TMath::Sin(maxphi)*radXY),
                           gPad->XtoAbsPixel(x0), gPad->YtoAbsPixel(y0) );
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Execute the mouse events.

void TPie::ExecuteEvent(Int_t event, Int_t px, Int_t py)
{
   if (!gPad) return;
   if (!gPad->IsEditable() && event != kMouseEnter) return;

   if (gCurrent_slice<=-10) {
      gPad->SetCursor(kCross);
      return;
   }

   MakeSlices();

   static bool isMovingPie(kFALSE);
   static bool isMovingSlice(kFALSE);
   static bool isResizing(kFALSE);
   static bool isRotating(kFALSE);
   static bool onBorder(kFALSE);
   bool isRedrawing(kFALSE);
   static Int_t prev_event(-1);
   static Int_t oldpx, oldpy;

   // Portion of pie considered as "border"
   const Double_t dr     = gPad->PixeltoX(3);
   const Double_t minRad = gPad->PixeltoX(10);

   // Angular divisions in radial direction
   const Double_t angstep1 = 0.5*TMath::PiOver4();
   const Double_t angstep2 = 1.5*TMath::PiOver4();
   const Double_t angstep3 = 2.5*TMath::PiOver4();
   const Double_t angstep4 = 3.5*TMath::PiOver4();
   const Double_t angstep5 = 4.5*TMath::PiOver4();
   const Double_t angstep6 = 5.5*TMath::PiOver4();
   const Double_t angstep7 = 6.5*TMath::PiOver4();
   const Double_t angstep8 = 7.5*TMath::PiOver4();

   // XY metric
   Double_t radXY = 1.;
   if (fIs3D==kTRUE) {
      radXY = TMath::Sin(fAngle3D/180.*TMath::Pi());
   }

   Int_t dx, dy;
   Double_t mdx, mdy;

   switch(event) {
      case kArrowKeyPress:
      case kButton1Down:
         // Change cursor to show pie's movement.
         gVirtualX->SetLineColor(1);
         gVirtualX->SetLineWidth(2);

         // Current center and radius.
         gX             = fX;
         gY             = fY;
         gRadius        = fRadius;
         gRadiusOffset  = fPieSlices[gCurrent_slice]->GetRadiusOffset();
         gAngularOffset = 0;
         gIsUptSlice    = kTRUE;

         prev_event = kButton1Down;

      case kMouseMotion:
         if (gCurrent_rad>=fRadius-2.*dr && gCurrent_rad<=fRadius+dr
               && !isMovingPie && !isMovingSlice && !isResizing) {
            if (gCurrent_ang>=angstep8 || gCurrent_ang<angstep1)
               gPad->SetCursor(kRightSide);
            else if (gCurrent_ang>=angstep1 && gCurrent_ang<angstep2)
               gPad->SetCursor(kTopRight);
            else if (gCurrent_ang>=angstep2 && gCurrent_ang<angstep3)
               gPad->SetCursor(kTopSide);
            else if (gCurrent_ang>=angstep3 && gCurrent_ang<angstep4)
               gPad->SetCursor(kTopLeft);
            else if (gCurrent_ang>=angstep4 && gCurrent_ang<=angstep5)
               gPad->SetCursor(kLeftSide);
            else if (gCurrent_ang>=angstep5 && gCurrent_ang<angstep6)
               gPad->SetCursor(kBottomLeft);
            else if (gCurrent_ang>=angstep6 && gCurrent_ang<angstep7)
               gPad->SetCursor(kBottomSide);
            else if (gCurrent_ang>=angstep7 && gCurrent_ang<angstep8)
               gPad->SetCursor(kBottomRight);
            onBorder = kTRUE;
         } else {
            onBorder = kFALSE;
            if (gCurrent_rad>fRadius*.6) {
               gPad->SetCursor(kPointer);
            } else if (gCurrent_rad<=fRadius*.3) {
               gPad->SetCursor(kHand);
            } else if (gCurrent_rad<=fRadius*.6 && gCurrent_rad>=fRadius*.3) {
               gPad->SetCursor(kRotate);
            }
         }
         oldpx = px;
         oldpy = py;
         if (isMovingPie || isMovingSlice) gPad->SetCursor(kMove);
         break;

      case kArrowKeyRelease:
      case kButton1Motion:
         if (!isMovingSlice || !isMovingPie || !isResizing || !isRotating) {
            if (prev_event==kButton1Down) {
               if (onBorder) {
                  isResizing = kTRUE;
               } else if (gCurrent_rad>=fRadius*.6 && gCurrent_slice>=0) {
                  isMovingSlice = kTRUE;
               } else if (gCurrent_rad<=fRadius*.3) {
                  isMovingPie = kTRUE;
               } else if (gCurrent_rad<fRadius*.6 && gCurrent_rad>fRadius*.3) {
                  isRotating = kTRUE;
               }
            }
         }

         dx = px-oldpx;
         dy = py-oldpy;

         mdx = gPad->PixeltoX(dx);
         mdy = gPad->PixeltoY(dy);

         if (isMovingPie || isMovingSlice) {
            gPad->SetCursor(kMove);
            if (isMovingSlice) {
               Float_t avgphi = fSlices[gCurrent_slice*2+1]*TMath::Pi()/180.;

               if (!gPad->OpaqueMoving()) DrawGhost();

               gRadiusOffset += TMath::Cos(avgphi)*mdx +TMath::Sin(avgphi)*mdy/radXY;
               if (gRadiusOffset<0) gRadiusOffset = .0;
               gIsUptSlice         = kTRUE;

               if (!gPad->OpaqueMoving()) DrawGhost();
            } else {
               if (!gPad->OpaqueMoving()) DrawGhost();

               gX += mdx;
               gY += mdy;

               if (!gPad->OpaqueMoving()) DrawGhost();
            }
         } else if (isResizing) {
            if (!gPad->OpaqueResizing()) DrawGhost();

            Float_t dr1 = mdx*TMath::Cos(gCurrent_ang)+mdy*TMath::Sin(gCurrent_ang)/radXY;
            if (gRadius+dr1>=minRad) {
               gRadius += dr1;
            } else {
               gRadius = minRad;
            }

            if (!gPad->OpaqueResizing()) DrawGhost();
         } else if (isRotating) {
            if (!gPad->OpaqueMoving()) DrawGhost();

            Double_t xx = gPad->AbsPixeltoX(px);
            Double_t yy = gPad->AbsPixeltoY(py);

            Double_t dx1  = xx-gX;
            Double_t dy1  = yy-gY;

            Double_t ang = TMath::ATan2(dy1,dx1);
            if (ang<0) ang += TMath::TwoPi();

            gAngularOffset = (ang-gCurrent_ang)*180/TMath::Pi();

            if (!gPad->OpaqueMoving()) DrawGhost();
         }

         oldpx = px;
         oldpy = py;

         if ( ((isMovingPie || isMovingSlice || isRotating) && gPad->OpaqueMoving()) ||
               (isResizing && gPad->OpaqueResizing()) ) {
            isRedrawing = kTRUE;
            event = kButton1Up;
         }
         else break;

      case kButton1Up:
         if (!isRedrawing) {
            prev_event = kButton1Up;
            gIsUptSlice = kFALSE;
         }

         if (gROOT->IsEscaped()) {
            gROOT->SetEscape(kFALSE);
            gIsUptSlice = kFALSE;
            isRedrawing = kFALSE;
            break;
         }

         fX      = gX;
         fY      = gY;
         fRadius = gRadius;
         fPieSlices[gCurrent_slice]->SetRadiusOffset(gRadiusOffset);
         SetAngularOffset(fAngularOffset+gAngularOffset);

         if (isRedrawing && (isMovingPie || isMovingSlice)) gPad->SetCursor(kMove);

         if (isMovingPie)   isMovingPie   = kFALSE;
         if (isMovingSlice) isMovingSlice = kFALSE;
         if (isResizing)    isResizing    = kFALSE;
         if (isRotating)    {
            isRotating = kFALSE;
            // this is important mainly when OpaqueMoving==kTRUE
            gCurrent_ang += gAngularOffset/180.*TMath::Pi();
         }

         gPad->Modified(kTRUE);


         isRedrawing = kFALSE;
         gIsUptSlice = kFALSE;

         gVirtualX->SetLineColor(-1);
         gVirtualX->SetLineWidth(-1);

         break;
      case kButton1Locate:

         ExecuteEvent(kButton1Down, px, py);

         while (1) {
            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;
            }
         }
         break;

      case kMouseEnter:
         break;

      default:
         // unknown event
         break;
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Returns the label of the entry number "i".

const char* TPie::GetEntryLabel(Int_t i)
{
   return GetSlice(i)->GetTitle();
}

////////////////////////////////////////////////////////////////////////////////
/// Return the color of the slice number "i".

Int_t TPie::GetEntryFillColor(Int_t i)
{
   return GetSlice(i)->GetFillColor();
}

////////////////////////////////////////////////////////////////////////////////
/// Return the style use to fill the slice number "i".

Int_t TPie::GetEntryFillStyle(Int_t i)
{
   return GetSlice(i)->GetFillStyle();
}

////////////////////////////////////////////////////////////////////////////////
/// Return the line color used to outline thi "i" slice

Int_t TPie::GetEntryLineColor(Int_t i)
{
   return GetSlice(i)->GetLineColor();
}

////////////////////////////////////////////////////////////////////////////////
/// Return the style used to outline thi "i" slice

Int_t TPie::GetEntryLineStyle(Int_t i)
{
   return GetSlice(i)->GetLineStyle();
}

////////////////////////////////////////////////////////////////////////////////
/// Return the line width used to outline thi "i" slice

Int_t TPie::GetEntryLineWidth(Int_t i)
{
   return GetSlice(i)->GetLineWidth();
}

////////////////////////////////////////////////////////////////////////////////
/// Return the radial offset's value for the slice number "i".

Double_t TPie::GetEntryRadiusOffset(Int_t i)
{
   return GetSlice(i)->GetRadiusOffset();
}

////////////////////////////////////////////////////////////////////////////////
/// Return the value associated with the slice number "i".

Double_t TPie::GetEntryVal(Int_t i)
{
   return GetSlice(i)->GetValue();
}

////////////////////////////////////////////////////////////////////////////////
/// If created before by Paint option or by MakeLegend method return
/// the pointer to the legend, otherwise return 0;

TLegend* TPie::GetLegend()
{
   return fLegend;
}

////////////////////////////////////////////////////////////////////////////////
/// Return the reference to the slice of index 'id'. There are no controls
/// of memory corruption, be carefull.

TPieSlice* TPie::GetSlice(Int_t id)
{
   return fPieSlices[id];
}

////////////////////////////////////////////////////////////////////////////////
/// Common initialization for all constructors.
/// This is a private function called to allocate the memory.

void TPie::Init(Int_t np, Double_t ao, Double_t x, Double_t y, Double_t r)
{
   gIsUptSlice = kFALSE;

   fAngularOffset = ao;
   fX             = x;
   fY             = y;
   fRadius        = r;
   fNvals         = np;
   fSum           = 0.;
   fSlices        = 0;
   fLegend        = 0;
   fHeight        = 0.08;
   fAngle3D       = 30;
   fIs3D          = kFALSE;

   fLabelsOffset = gStyle->GetLabelOffset();

   fPieSlices = new TPieSlice*[fNvals];

   for (Int_t i=0;i<fNvals;++i) {
      TString tmplbl = "Slice";
      tmplbl += i;
      fPieSlices[i] = new TPieSlice(tmplbl.Data(), tmplbl.Data(), this);
      fPieSlices[i]->SetRadiusOffset(0.);
      fPieSlices[i]->SetLineColor(1);
      fPieSlices[i]->SetLineStyle(1);
      fPieSlices[i]->SetLineWidth(1);
      fPieSlices[i]->SetFillColor(gStyle->GetColorPalette(i));
      fPieSlices[i]->SetFillStyle(1001);
   }

   fLabelFormat    = "%txt";
   fFractionFormat = "%3.2f";
   fValueFormat    = "%4.2f";
   fPercentFormat  = "%3.1f";
}

////////////////////////////////////////////////////////////////////////////////
/// This method create a legend that explains the contents
/// of the slice for this pie-chart.
///
/// The parameter passed reppresents the option passed to shown the slices,
/// see TLegend::AddEntry() for further details.
///
/// The pointer of the TLegend is returned.

TLegend* TPie::MakeLegend(Double_t x1, Double_t y1, Double_t x2, Double_t y2, const char *leg_header)
{
   if (!fLegend) fLegend = new TLegend(x1,y1,x2,y2,leg_header);
   else fLegend->Clear();

   for (Int_t i=0;i<fNvals;++i) {
      fLegend->AddEntry(*(fPieSlices+i),fPieSlices[i]->GetTitle(),"f");
   }

   if (gPad) fLegend->Draw();

   return fLegend;
}

////////////////////////////////////////////////////////////////////////////////
/// Paint a Pie chart in a canvas.
/// The possible option are:
///
///  - "R"   Print the labels along the central "R"adius of slices.
///  - "T"   Print the label in a direction "T"angent to circle that describes
///          the TPie.
///  - "SC"  Paint the the labels with the "S"ame "C"olor as the slices.
///  - "3D"  Draw the pie-chart with a pseudo 3D effect.
///  - "NOL" No OutLine: Don't draw the slices' outlines, any property over the
///          slices' line is ignored.
///  - ">"   Sort the slices in increasing order.
///  - "<"   Sort the slices in decreasing order.
///
/// After the use of > or < options the internal order of the TPieSlices
/// is changed.
///
/// Other options changing the labels' format are described in
/// TPie::SetLabelFormat().

void TPie::Paint(Option_t *option)
{
   MakeSlices();

   TString soption(option);

   bool optionSame(kFALSE);

   // if true the lines around the slices are drawn, if false not
   Bool_t optionLine(kTRUE);

   // if true the labels' colors are the same as the slices' colors
   Bool_t optionSameColor(kFALSE);

   // For the label orientation there are 3 possibilities:
   //   0: horizontal
   //   1: radial
   //   2: tangent
   Int_t lblor(0);

   // Parse the options
   Int_t idx;
   // Paint the TPie in an existing canvas
   if ( (idx=soption.Index("same"))>=0 ) {
      optionSame = kTRUE;
      soption.Remove(idx,4);
   }

   if ( (idx=soption.Index("nol"))>=0 ) {
      optionLine = kFALSE;
      soption.Remove(idx,3);
   }

   if ( (idx=soption.Index("sc"))>=0 ) {
      optionSameColor = kTRUE;
      soption.Remove(idx,2);
   }

   // check if is active the pseudo-3d
   if ( (idx=soption.Index("3d"))>=0 ) {
      fIs3D = kTRUE;
      soption.Remove(idx,2);
   } else {
      fIs3D = kFALSE;
   }

   // seek if have to draw the labels around the pie chart
   if ( (idx=soption.Index("t"))>=0 ) {
      lblor = 2;
      soption.Remove(idx,1);
   }

   // Seek if have to paint the labels along the radii
   if ( (idx=soption.Index("r"))>=0 ) {
      lblor = 1;
      soption.Remove(idx,1);
   }

   // Seeks if has to paint sort the slices in increasing mode
   if ( (idx=soption.Index(">"))>=0 ) {
      SortSlices(kTRUE);
      soption.Remove(idx,1);
   }

   // Seeks if has to paint sort the slices in decreasing mode
   if ( (idx=soption.Index("<"))>=0 ) {
      SortSlices(kFALSE);
      soption.Remove(idx,1);
   }

   if (fNvals<=0) {
      Warning("Paint","No vals");
      return;
   }

   if (!fPieSlices) {
      Warning("Paint","No valid arrays of values");
      return;
   }

   // Check if gPad exists and define the drawing range.
   if (!gPad) return;

   // Objects useful to draw labels and slices
   TLatex *textlabel = new TLatex();
   TArc *arc = new TArc();
   TLine *line = new TLine();

   // XY metric
   Double_t radX  = fRadius;
   Double_t radY  = fRadius;
   Double_t radXY = 1.;

   if (fIs3D) {
      radXY = TMath::Sin(fAngle3D/180.*TMath::Pi());
      radY = fRadius*radXY;
   }

   // Draw the slices.
   Int_t pixelHeight = gPad->YtoPixel(0)-gPad->YtoPixel(fHeight);
   for (Int_t pi=0;pi<pixelHeight&&fIs3D==kTRUE; ++pi) { // loop for pseudo-3d effect
      for (Int_t i=0;i<fNvals;++i) {
         // draw the arc
         // set the color of the next slice
         if (pi>0) {
            arc->SetFillStyle(0);
            arc->SetLineColor(TColor::GetColorDark((fPieSlices[i]->GetFillColor())));
         } else {
            arc->SetFillStyle(0);
            if (optionLine==kTRUE) {
               arc->SetLineColor(fPieSlices[i]->GetLineColor());
               arc->SetLineStyle(fPieSlices[i]->GetLineStyle());
               arc->SetLineWidth(fPieSlices[i]->GetLineWidth());
            } else {
               arc->SetLineWidth(1);
               arc->SetLineColor(TColor::GetColorDark((fPieSlices[i]->GetFillColor())));
            }
         }
         // Paint the slice
         Float_t aphi = fSlices[2*i+1]*TMath::Pi()/180.;

         Double_t ax = fX+TMath::Cos(aphi)*fPieSlices[i]->GetRadiusOffset();
         Double_t ay = fY+TMath::Sin(aphi)*fPieSlices[i]->GetRadiusOffset()*radXY+gPad->PixeltoY(pixelHeight-pi);

         arc->PaintEllipse(ax, ay, radX, radY, fSlices[2*i],
                                               fSlices[2*i+2], 0.);

         if (optionLine==kTRUE) {
            line->SetLineColor(fPieSlices[i]->GetLineColor());
            line->SetLineStyle(fPieSlices[i]->GetLineStyle());
            line->SetLineWidth(fPieSlices[i]->GetLineWidth());
            line->PaintLine(ax,ay,ax,ay);

            Double_t x0, y0;
            x0 = ax+radX*TMath::Cos(fSlices[2*i]/180.*TMath::Pi());
            y0 = ay+radY*TMath::Sin(fSlices[2*i]/180.*TMath::Pi());
            line->PaintLine(x0,y0,x0,y0);

            x0 = ax+radX*TMath::Cos(fSlices[2*i+2]/180.*TMath::Pi());
            y0 = ay+radY*TMath::Sin(fSlices[2*i+2]/180.*TMath::Pi());
            line->PaintLine(x0,y0,x0,y0);
         }
      }
   } // end loop for pseudo-3d effect

   for (Int_t i=0;i<fNvals;++i) { // loop for the piechart
      // Set the color of the next slice
      arc->SetFillColor(fPieSlices[i]->GetFillColor());
      arc->SetFillStyle(fPieSlices[i]->GetFillStyle());
      if (optionLine==kTRUE) {
         arc->SetLineColor(fPieSlices[i]->GetLineColor());
         arc->SetLineStyle(fPieSlices[i]->GetLineStyle());
         arc->SetLineWidth(fPieSlices[i]->GetLineWidth());
      } else {
         arc->SetLineWidth(1);
         arc->SetLineColor(fPieSlices[i]->GetFillColor());
      }

      // Paint the slice
      Float_t aphi = fSlices[2*i+1]*TMath::Pi()/180.;

      Double_t ax = fX+TMath::Cos(aphi)*fPieSlices[i]->GetRadiusOffset();
      Double_t ay = fY+TMath::Sin(aphi)*fPieSlices[i]->GetRadiusOffset()*radXY;
      arc->PaintEllipse(ax, ay, radX, radY, fSlices[2*i],
                                            fSlices[2*i+2], 0.);

   } // end loop to draw the slices


   // Set the font
   textlabel->SetTextFont(GetTextFont());
   textlabel->SetTextSize(GetTextSize());
   textlabel->SetTextColor(GetTextColor());

   // Loop to place the labels.
   for (Int_t i=0;i<fNvals;++i) {
      Float_t aphi = fSlices[2*i+1]*TMath::Pi()/180.;
      //aphi = TMath::ATan2(TMath::Sin(aphi)*radXY,TMath::Cos(aphi));

      Float_t label_off = fLabelsOffset;


      // Paint the text in the pad
      TString tmptxt  = fLabelFormat;

      tmptxt.ReplaceAll("%txt",fPieSlices[i]->GetTitle());
      tmptxt.ReplaceAll("%val",Form(fValueFormat.Data(),fPieSlices[i]->GetValue()));
      tmptxt.ReplaceAll("%frac",Form(fFractionFormat.Data(),fPieSlices[i]->GetValue()/fSum));
      tmptxt.ReplaceAll("%perc",Form(Form("%s %s",fPercentFormat.Data(),"%s"),(fPieSlices[i]->GetValue()/fSum)*100,"%"));

      textlabel->SetTitle(tmptxt.Data());
      Double_t h = textlabel->GetYsize();
      Double_t w = textlabel->GetXsize();

      Float_t lx = fX+(fRadius+fPieSlices[i]->GetRadiusOffset()+label_off)*TMath::Cos(aphi);
      Float_t ly = fY+(fRadius+fPieSlices[i]->GetRadiusOffset()+label_off)*TMath::Sin(aphi)*radXY;

      Double_t lblang = 0;

      if (lblor==1) { // radial direction for the label
         aphi = TMath::ATan2(TMath::Sin(aphi)*radXY,TMath::Cos(aphi));
         lblang += aphi;
         if (lblang<=0) lblang += TMath::TwoPi();
         if (lblang>TMath::TwoPi()) lblang-= TMath::TwoPi();

         lx += h/2.*TMath::Sin(lblang);
         ly -= h/2.*TMath::Cos(lblang);

         // This control prevent text up-side
         if (lblang>TMath::PiOver2() && lblang<=3.*TMath::PiOver2()) {
            lx     += w*TMath::Cos(lblang)-h*TMath::Sin(lblang);
            ly     += w*TMath::Sin(lblang)+h*TMath::Cos(lblang);
            lblang -= TMath::Pi();
         }
      } else if (lblor==2) { // tangential direction of the labels
         aphi -=TMath::PiOver2();
         aphi = TMath::ATan2(TMath::Sin(aphi)*radXY,TMath::Cos(aphi));
         lblang += aphi;//-TMath::PiOver2();
         if (lblang<0) lblang+=TMath::TwoPi();

         lx -= w/2.*TMath::Cos(lblang);
         ly -= w/2.*TMath::Sin(lblang);

         if (lblang>TMath::PiOver2() && lblang<3.*TMath::PiOver2()) {
            lx     += w*TMath::Cos(lblang)-h*TMath::Sin(lblang);
            ly     += w*TMath::Sin(lblang)+h*TMath::Cos(lblang);
            lblang -= TMath::Pi();
         }
      } else { // horizontal labels (default direction)
         aphi = TMath::ATan2(TMath::Sin(aphi)*radXY,TMath::Cos(aphi));
         if (aphi>TMath::PiOver2() || aphi<=-TMath::PiOver2()) lx -= w;
         if (aphi<0)                                           ly -= h;
      }

      Float_t rphi = TMath::ATan2((ly-fY)*radXY,lx-fX);
      if (rphi < 0 && fIs3D && label_off>=0.)
         ly -= fHeight;

      if (optionSameColor) textlabel->SetTextColor((fPieSlices[i]->GetFillColor()));
      textlabel->PaintLatex(lx,ly,
                            lblang*180/TMath::Pi()+GetTextAngle(),
                            GetTextSize(), tmptxt.Data());
   }

   delete arc;
   delete line;
   delete textlabel;

   if (optionSame) return;

   // Draw title
   TPaveText *title = 0;
   TObject *obj;
   if ((obj = gPad->GetListOfPrimitives()->FindObject("title"))) {
      title = dynamic_cast<TPaveText*>(obj);
   }

   // Check the OptTitle option
   if (strlen(GetTitle()) == 0 || gStyle->GetOptTitle() <= 0) {
      if (title) delete title;
      return;
   }

   // Height and width of the title
   Double_t ht = gStyle->GetTitleH();
   Double_t wt = gStyle->GetTitleW();
   if (ht<=0) ht = 1.1*gStyle->GetTitleFontSize();
   if (ht<=0) ht = 0.05; // minum height
   if (wt<=0) { // eval the width of the title
      TLatex l;
      l.SetTextSize(ht);
      l.SetTitle(GetTitle());
      // adjustment in case the title has several lines (#splitline)
      ht = TMath::Max(ht, 1.2*l.GetYsize()/(gPad->GetY2() - gPad->GetY1()));
      Double_t wndc = l.GetXsize()/(gPad->GetX2() - gPad->GetX1());
      wt = TMath::Min(0.7, 0.02+wndc);
   }

   if (title) {
      TText *t0 = (TText*)title->GetLine(0);
      if (t0) {
         if (!strcmp(t0->GetTitle(),GetTitle())) return;
         t0->SetTitle(GetTitle());
         if (wt > 0) title->SetX2NDC(title->GetX1NDC()+wt);
      }
      return;
   }

   Int_t talh = gStyle->GetTitleAlign()/10;
   if (talh < 1) talh = 1; else if (talh > 3) talh = 3;
   Int_t talv = gStyle->GetTitleAlign()%10;
   if (talv < 1) talv = 1; else if (talv > 3) talv = 3;
   Double_t xpos, ypos;
   xpos = gStyle->GetTitleX();
   ypos = gStyle->GetTitleY();
   if (talh == 2) xpos = xpos-wt/2.;
   if (talh == 3) xpos = xpos-wt;
   if (talv == 2) ypos = ypos+ht/2.;
   if (talv == 1) ypos = ypos+ht;

   title = new TPaveText(xpos,ypos-ht,xpos+wt,ypos,"blNDC");
   title->SetFillColor(gStyle->GetTitleFillColor());
   title->SetFillStyle(gStyle->GetTitleStyle());
   title->SetName("title");

   title->SetBorderSize(gStyle->GetTitleBorderSize());
   title->SetTextColor(gStyle->GetTitleTextColor());
   title->SetTextFont(gStyle->GetTitleFont(""));
   if (gStyle->GetTitleFont("")%10 > 2)
      title->SetTextSize(gStyle->GetTitleFontSize());
   title->AddText(GetTitle());

   title->SetBit(kCanDelete);

   title->Draw();
   title->Paint();
}

////////////////////////////////////////////////////////////////////////////////
/// Save primitive as a C++ statement(s) on output stream out

void TPie::SavePrimitive(std::ostream &out, Option_t *option)
{
   out << "   " << std::endl;
   if (gROOT->ClassSaved(TPie::Class())) {
      out << "   ";
   } else {
      out << "   TPie *";
   }
   out << GetName() << " = new TPie(\"" << GetName() << "\", \"" << GetTitle()
       << "\", " << fNvals << ");" << std::endl;
   out << "   " << GetName() << "->SetCircle(" << fX << ", " << fY << ", "
       << fRadius << ");" << std::endl;
   out << "   " << GetName() << "->SetValueFormat(\"" << GetValueFormat()
       << "\");" << std::endl;
   out << "   " << GetName() << "->SetLabelFormat(\"" << GetLabelFormat()
       << "\");" << std::endl;
   out << "   " << GetName() << "->SetPercentFormat(\"" << GetPercentFormat()
       << "\");" << std::endl;
   out << "   " << GetName() << "->SetLabelsOffset(" << GetLabelsOffset()
       << ");" << std::endl;
   out << "   " << GetName() << "->SetAngularOffset(" << GetAngularOffset()
       << ");" << std::endl;
   out << "   " << GetName() << "->SetTextAngle(" << GetTextAngle() << ");" << std::endl;
   out << "   " << GetName() << "->SetTextColor(" << GetTextColor() << ");" << std::endl;
   out << "   " << GetName() << "->SetTextFont(" << GetTextFont() << ");" << std::endl;
   out << "   " << GetName() << "->SetTextSize(" << GetTextSize() << ");" << std::endl;


   // Save the values for the slices
   for (Int_t i=0;i<fNvals;++i) {
      out << "   " << GetName() << "->GetSlice(" << i << ")->SetTitle(\""
          << fPieSlices[i]->GetTitle() << "\");" << std::endl;
      out << "   " << GetName() << "->GetSlice(" << i << ")->SetValue("
          << fPieSlices[i]->GetValue() << ");" << std::endl;
      out << "   " << GetName() << "->GetSlice(" << i << ")->SetRadiusOffset("
          << fPieSlices[i]->GetRadiusOffset() << ");" << std::endl;
      out << "   " << GetName() << "->GetSlice(" << i << ")->SetFillColor("
          << fPieSlices[i]->GetFillColor() << ");" << std::endl;
      out << "   " << GetName() << "->GetSlice(" << i << ")->SetFillStyle("
          << fPieSlices[i]->GetFillStyle() << ");" << std::endl;
      out << "   " << GetName() << "->GetSlice(" << i << ")->SetLineColor("
          << fPieSlices[i]->GetLineColor() << ");" << std::endl;
      out << "   " << GetName() << "->GetSlice(" << i << ")->SetLineStyle("
          << fPieSlices[i]->GetLineStyle() << ");" << std::endl;
      out << "   " << GetName() << "->GetSlice(" << i << ")->SetLineWidth("
          << fPieSlices[i]->GetLineWidth() << ");" << std::endl;
   }

   out << "   " << GetName() << "->Draw(\"" << option << "\");" << std::endl;
}

////////////////////////////////////////////////////////////////////////////////
/// Set the value of for the pseudo 3D view angle, in degree.
/// The range of the permitted values is: [0,90]

void TPie::SetAngle3D(Float_t val) {
   // check if val is in the permitted range
   while (val>360.) val -= 360.;
   while (val<0)    val += 360.;
   if      (val>=90 && val<180)   val = 180-val;
   else if (val>=180 && val<=360) val = 360-val;

   fAngle3D = val;
}

////////////////////////////////////////////////////////////////////////////////
/// Set the global angular offset for slices in degree [0,360]

void TPie::SetAngularOffset(Double_t offset)
{
   fAngularOffset = offset;

   while (fAngularOffset>=360.) fAngularOffset -= 360.;
   while (fAngularOffset<0.)    fAngularOffset += 360.;

   MakeSlices(kTRUE);
}

////////////////////////////////////////////////////////////////////////////////
/// Set the coordinates of the circle that describe the pie:
/// - the 1st and the 2nd arguments are the x and y center's coordinates.
/// - the 3rd value is the pie-chart's radius.
///
/// All the coordinates are in NDC space.

void TPie::SetCircle(Double_t x, Double_t y, Double_t rad)
{
   fX      = x;
   fY      = y;
   fRadius = rad;
}

////////////////////////////////////////////////////////////////////////////////
/// Set slice number "i" label. The first parameter is the index of the slice,
/// the other is the label text.

void TPie::SetEntryLabel(Int_t i, const char *text)
{
   // Set the Label of a single slice
   if (i>=0 && i<fNvals) fPieSlices[i]->SetTitle(text);
}

////////////////////////////////////////////////////////////////////////////////
/// Set the color for the slice's outline. "i" is the slice number.

void TPie::SetEntryLineColor(Int_t i, Int_t color)
{
   if (i>=0 && i<fNvals) fPieSlices[i]->SetLineColor(color);
}

////////////////////////////////////////////////////////////////////////////////
/// Set the style for the slice's outline. "i" is the slice number.

void TPie::SetEntryLineStyle(Int_t i, Int_t style)
{
   if (i>=0 && i<fNvals) fPieSlices[i]->SetLineStyle(style);
}

////////////////////////////////////////////////////////////////////////////////
/// Set the width of the slice's outline. "i" is the slice number.

void TPie::SetEntryLineWidth(Int_t i, Int_t width)
{
   if (i>=0 && i<fNvals) fPieSlices[i]->SetLineWidth(width);
}

////////////////////////////////////////////////////////////////////////////////
/// Set the color for the slice "i".

void TPie::SetEntryFillColor(Int_t i, Int_t color)
{
   if (i>=0 && i<fNvals) fPieSlices[i]->SetFillColor(color);
}

////////////////////////////////////////////////////////////////////////////////
/// Set the fill style for the "i" slice

void TPie::SetEntryFillStyle(Int_t i, Int_t style)
{
   if (i>=0 && i<fNvals) fPieSlices[i]->SetFillStyle(style);
}

////////////////////////////////////////////////////////////////////////////////
/// Set the distance, in the direction of the radius of the slice.

void TPie::SetEntryRadiusOffset(Int_t i, Double_t shift)
{
   if (i>=0 && i<fNvals) fPieSlices[i]->SetRadiusOffset(shift);
}

////////////////////////////////////////////////////////////////////////////////
/// Set the value of a slice

void TPie::SetEntryVal(Int_t i, Double_t val)
{
   if (i>=0 && i<fNvals) fPieSlices[i]->SetValue(val);

   MakeSlices(kTRUE);
}

////////////////////////////////////////////////////////////////////////////////
/// Set the fill colors for all the TPie's slices.

void TPie::SetFillColors(Int_t *colors)
{
   if (!colors) return;
   for (Int_t i=0;i<fNvals;++i) fPieSlices[i]->SetFillColor(colors[i]);
}

////////////////////////////////////////////////////////////////////////////////
/// Set the height, in pixel, for the piechart if is drawn using
/// the pseudo-3d mode.
///
/// The default value is 20 pixel.

void TPie::SetHeight(Double_t val/*=20*/)
{
   fHeight = val;
}

////////////////////////////////////////////////////////////////////////////////
/// This method is used to customize the label format. The format string
/// must contain one of these modifiers:
///
/// - %txt  : to print the text label associated with the slice
/// - %val  : to print the numeric value of the slice
/// - %frac : to print the relative fraction of this slice
/// - %perc : to print the % of this slice
///
/// ex. : mypie->SetLabelFormat("%txt (%frac)");

void TPie::SetLabelFormat(const char *fmt)
{
   fLabelFormat = fmt;
}

////////////////////////////////////////////////////////////////////////////////
/// Set numeric format in the label, is used if the label format
/// there is the modifier %frac, in this case the value is printed
/// using this format.
///
/// The numeric format use the standard C modifier used in stdio library:
/// %f, %2.1$, %e... for further documentation you can use the printf
/// man page ("man 3 printf" on linux)
///
/// Example:
/// ~~~ {.cpp}
///       mypie->SetLabelFormat("%txt (%frac)");
///       mypie->SetFractionFormat("2.1f");
/// ~~~

void TPie::SetFractionFormat(const char *fmt)
{
   fFractionFormat = fmt;
}

////////////////////////////////////////////////////////////////////////////////
/// Set the labels for all the slices.

void TPie::SetLabels(const char *lbls[])
{
   if (!lbls) return;
   for (Int_t i=0;i<fNvals;++i) fPieSlices[i]->SetTitle(lbls[i]);
}

////////////////////////////////////////////////////////////////////////////////
/// Set the distance between the label end the external line of the TPie.

void TPie::SetLabelsOffset(Float_t labelsoffset)
{
   fLabelsOffset = labelsoffset;
}

////////////////////////////////////////////////////////////////////////////////
/// Set the numeric format for the percent value of a slice, default: %3.1f

void TPie::SetPercentFormat(const char *fmt)
{
   fPercentFormat = fmt;
}

////////////////////////////////////////////////////////////////////////////////
/// Set the pie chart's radius' value.

void TPie::SetRadius(Double_t rad)
{
   if (rad>0) {
      fRadius = rad;
   } else {
      Warning("SetRadius",
              "It's not possible set the radius to a negative value");
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Set the numeric format the slices' values.
/// Used by %val (see SetLabelFormat()).

void TPie::SetValueFormat(const char *fmt)
{
   fValueFormat = fmt;
}

////////////////////////////////////////////////////////////////////////////////
/// Set X value.

void TPie::SetX(Double_t x)
{
   fX = x;
}

////////////////////////////////////////////////////////////////////////////////
/// Set Y value.

void TPie::SetY(Double_t y)
{
   fY = y;
}

////////////////////////////////////////////////////////////////////////////////
/// Make the slices.
/// If they already exist it does nothing unless force=kTRUE.

void TPie::MakeSlices(Bool_t force)
{
   if (fSlices && !force) return;

   fSum = .0;

   for (Int_t i=0;i<fNvals;++i) {
      if (fPieSlices[i]->GetValue()<0) {
         Warning("MakeSlices",
                 "Negative values in TPie, absolute value will be used");
         fPieSlices[i]->SetValue(-1.*fPieSlices[i]->GetValue());
      }
      fSum += fPieSlices[i]->GetValue();
   }

   if (fSum<=.0) return;

   if (!fSlices) fSlices = new Float_t[2*fNvals+1];

   // Compute the slices size and position (2 angles for each slice)
   fSlices[0] = fAngularOffset;
   for (Int_t i=0;i<fNvals;++i) {
      Float_t dphi   = fPieSlices[i]->GetValue()/fSum*360.;
      fSlices[2*i+1] = fSlices[2*i]+dphi/2.;
      fSlices[2*i+2] = fSlices[2*i]+dphi;
   }
}

////////////////////////////////////////////////////////////////////////////////
/// This method, mainly intended for internal use, ordered the  slices according their values.
/// The default (amode=kTRUE) is increasing order, but is also possible in decreasing order (amode=kFALSE).
///
/// If the merge_threshold>0 the slice that contains a quantity smaller than merge_threshold are merged
/// together

void TPie::SortSlices(Bool_t amode, Float_t merge_threshold)
{

   // main loop to order, bubble sort, the array
   Bool_t isDone = kFALSE;

   while (isDone==kFALSE) {
      isDone = kTRUE;

      for (Int_t i=0;i<fNvals-1;++i) { // loop over the values
         if ( (amode && (fPieSlices[i]->GetValue()>fPieSlices[i+1]->GetValue())) ||
              (!amode && (fPieSlices[i]->GetValue()<fPieSlices[i+1]->GetValue()))
            )
         {
            // exchange the order
            TPieSlice *tmpcpy = fPieSlices[i];
            fPieSlices[i] = fPieSlices[i+1];
            fPieSlices[i+1] = tmpcpy;

            isDone = kFALSE;
         }
      }  // end loop the values
   } // end main ordering loop

   if (merge_threshold>0) {
      // merge smallest slices
      TPieSlice *merged_slice = new TPieSlice("merged","other",this);
      merged_slice->SetRadiusOffset(0.);
      merged_slice->SetLineColor(1);
      merged_slice->SetLineStyle(1);
      merged_slice->SetLineWidth(1);
      merged_slice->SetFillColor(gStyle->GetColorPalette( (amode ? 0 : fNvals-1) ));
      merged_slice->SetFillStyle(1001);

      if (amode) {
         // search slices under the threshold
         Int_t iMerged = 0;
         for (;iMerged<fNvals&&fPieSlices[iMerged]->GetValue()<merge_threshold;++iMerged) {
            merged_slice->SetValue( merged_slice->GetValue()+fPieSlices[iMerged]->GetValue() );
         }

         // evaluate number of valid slices
         if (iMerged<=1) { // no slices to merge
            delete merged_slice;
         }
         else { // write a new array with the right dimension
            Int_t old_fNvals = fNvals;
            fNvals = fNvals-iMerged+1;
            TPieSlice **new_array = new TPieSlice*[fNvals];
            new_array[0] = merged_slice;
            for (Int_t i=0;i<old_fNvals;++i) {
               if (i<iMerged) delete fPieSlices[i];
               else new_array[i-iMerged+1] = fPieSlices[i];
            }
            delete [] fPieSlices;
            fPieSlices = new_array;
         }
      }
      else {
         Int_t iMerged = fNvals-1;
         for (;iMerged>=0&&fPieSlices[iMerged]->GetValue()<merge_threshold;--iMerged) {
            merged_slice->SetValue( merged_slice->GetValue()+fPieSlices[iMerged]->GetValue() );
         }

         // evaluate number of valid slices
         Int_t nMerged = fNvals-1-iMerged;
         if (nMerged<=1) { // no slices to merge
            delete merged_slice;
         }
         else { // write a new array with the right dimension
            Int_t old_fNvals = fNvals;
            fNvals = fNvals-nMerged+1;
            TPieSlice **new_array = new TPieSlice*[fNvals];
            new_array[fNvals-1] = merged_slice;
            for (Int_t i=old_fNvals-1;i>=0;--i) {
               if (i>iMerged) delete fPieSlices[i];
               else new_array[i-nMerged-1] = fPieSlices[i];
            }
            delete [] fPieSlices;
            fPieSlices = new_array;
         }

      }
   }

   MakeSlices(kTRUE);
}