polytest2.C: This macro is testing new "compacting" algorithm in TPadPainter

//Author: Timur Pocheptsov, 20.01.2014.
//
//This macro is testing new "compacting" algorithm in TPadPainter
//(it reduces the number of polygon's vertices using actual pixel coordinates).
//In principle, this test case is what our histograms (fringe cases) are:
//"saw-like" polygon (bins == teeth).
//

//Includes for ACLiC.
#include <cassert>
#include <vector>

#include "TRandom.h"
#include "TCanvas.h"
#include "Rtypes.h"
#include "TNamed.h"

class PolyTest2 : public TNamed, public TAttLine, public TAttFill {
public:
   PolyTest2();

   void Paint(const Option_t *notUsed);

private:
   enum TestSize {
      kNSawPoints = 10000
   };

   //Part 1.
   std::vector<Double_t> fXs1;
   std::vector<Double_t> fYs1;
   //Part 2.

   std::vector<Double_t> fXs2;
   std::vector<Double_t> fYs2;
};

//_____________________________________________________________
PolyTest2::PolyTest2()
               : TNamed("polygon_compression_test2", "polygon_compression_test2")
{
   //Polygon 1, n of points is 10003, after 'compression' : 1897
   //Polygon 2, n of points is 10003, after 'compression' : 2093

   //Some canvas must already exist by this point.
   assert(gPad != 0 && "PolyTest2, gPad is null");
   //We need a gRandom to exist.
   assert(gRandom != 0 && "PolyTest2, gRandom is null");

   Double_t xMin = 0., xMax = 0., yMin = 0., yMax = 0.;
   gPad->GetRange(xMin, yMin, xMax, yMax);
   assert(xMax - xMin > 0 && yMax - yMin > 0 && "PolyTest2, invalid canvas' ranges");


   // .(0/the last)--------.(1)
   // |                      /
   // |                      \
   // |                      /
   // .(kNSawPoints + 1)--.(kNSawPoints)

   const unsigned nVertices = 3 + kNSawPoints;

   {
   //Polygon 1, "vertical saw":
   fXs1.resize(nVertices);
   fYs1.resize(nVertices);

   fXs1[0] = 0.;
   fYs1[0] = 0.;

   const Double_t w1 = 0.2 * (xMax - xMin);
   const Double_t saw1ToothSize = 0.1 * w1;
   const Double_t yStep = (yMax - yMin) / (kNSawPoints - 1);

   for (unsigned i = 1; i <= kNSawPoints; ++i) {
      fXs1[i] = w1 + gRandom->Rndm() * saw1ToothSize;
      fYs1[i] = yMin + yStep * (i - 1);
   }

   fXs1[nVertices - 2] = 0.;
   fYs1[nVertices - 2] = yMax;
   //Let's close it.
   fXs1[nVertices - 1] = fXs1[0];
   fYs1[nVertices - 1] = fYs1[0];

   }

   //Polygon 2, "horizontal saw":

   {
   const Double_t x2Min = xMin + 0.25 * (xMax - xMin);
   const Double_t h2 = 0.1 * (yMax - yMin);
   const Double_t saw2ToothSize = 0.1 * h2;
   const Double_t xStep = (xMax - x2Min) / (kNSawPoints - 1);

   fXs2.resize(nVertices);
   fYs2.resize(nVertices);

   fXs2[0] = x2Min;
   fYs2[0] = 0.;

   for (unsigned i = 1; i <= kNSawPoints; ++i) {
      fXs2[i] = x2Min + xStep * i;
      fYs2[i] = h2 + gRandom->Rndm() * saw2ToothSize;
   }

   fXs2[nVertices - 2] = xMax;
   fYs2[nVertices - 2] = 0.;
   fXs2[nVertices - 1] = fXs2[0];
   fYs2[nVertices - 1] = fYs2[0];
   }
}

//_____________________________________________________________
void PolyTest2::Paint(const Option_t * /*notUsed*/)
{
   assert(gPad != 0 && "Paint, gPad is null");

   SetFillColor(kGreen);
   TAttFill::Modify();
   gPad->PaintFillArea((Int_t)fXs1.size(), &fXs1[0], &fYs1[0]);

   SetLineColor(kBlue);
   TAttLine::Modify();
   gPad->PaintPolyLine((Int_t)fXs1.size(), &fXs1[0], &fYs1[0]);

   SetFillColor(kOrange);
   TAttFill::Modify();
   gPad->PaintFillArea((Int_t)fXs2.size(), &fXs2[0], &fYs2[0]);

   SetLineColor(kMagenta);
   TAttLine::Modify();
   gPad->PaintPolyLine((Int_t)fXs2.size(), &fXs2[0], &fYs2[0]);
}

void polytest2()
{
   TCanvas * const cnv = new TCanvas;
   cnv->cd();

   PolyTest2 * polygon = new PolyTest2;
   polygon->Draw();//Attach a polygon to a canvas.
}