Как сделать круг при большом количестве пикселей

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
 
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
 
void PaintPlanet()
  {
  }
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Edit1Change(TObject *Sender)
{
       int x,y;
int p = 0;
 p = StrToInt(Form1->Edit1->Text);
 for (int i = 0; i < p; i++)
  {
    x = random(Form1->PaintBox1->Width)+1;
    y = random(Form1->PaintBox1->Height)+1;
   Form1->PaintBox1->Canvas->Pixels[x][y] = clYellow;
 }
 
}
//---------------------------------------------------------------------------

if (X < Width/2 && Y < Height/2)
Part1++;

int x,y;
int p = 0;
 p = StrToInt(Form1->Edit1->Text);
 for (int i = 0; i < p; i++)
  {
    x = random(Form1->PaintBox1->Width)+1;
    y = random(Form1->PaintBox1->Height)+1;
   Form1->PaintBox1->Canvas->Pixels[x][y] = clYellow;

TPaintBox * pb = Form1->PaintBox1;
int x, y, p = StrToInt(Form1->Edit1->Text), w = pb->Width, h = pb->Height, w2 = w/2, h2 = h/2,
        count_lefttop = 0, count_righttop = 0, count_rightbottom = 0, count_leftbottom = 0;
 
for ( int i = 0; i < p; ++i ) {
    x = random( w ) + 1;
    y = random( h ) + 1;
    pb->Canvas->Pixels[x][y] = clYellow;
    ( x <= w2 && y <= h2 ) ? ++count_lefttop:
        ( ( x > w2 && y <= h2 ) ? ++count_righttop: 
        ( ( x <= w2 && y > h2 ) ? ++count_leftbottom: 
        ( ( x > w2 && y > h2 ) ? ++count_rightbottom: 0 ) ) );
}
pb->Canvas->Brush->Color = clRed;
if( count_lefttop >= 500 ) pb->Canvas->Ellipse( 10, 10, w2 - 10, h2 - 10 );
if( count_righttop >= 500 ) pb->Canvas->Ellipse( w2 + 10, 10, w - 10, h2 - 10 );
if( count_rightbottom >= 500 ) pb->Canvas->Ellipse( w2 + 10, h2 + 10, w - 10, h - 10 );
if( count_leftbottom >= 500 ) pb->Canvas->Ellipse( 10, h2 + 10, w2 - 10, h - 10 );

    ( x <= w2 && y <= h2 ) ? ++count_lefttop:
        ( ( x > w2 && y <= h2 ) ? ++count_righttop: 
        ( ( x <= w2 && y > h2 ) ? ++count_leftbottom: 
        ( ( x > w2 && y > h2 ) ? ++count_rightbottom: 0 ) ) );

void __fastcall TForm1::Button1Click(TObject *Sender) // то что ниже - вставить в обработчик нажатия кнопки
{
        TPaintBox * pb = PaintBox1;
        pb->Repaint();
        TCanvas *canva = pb->Canvas;
 
        enum { LEFT_TOP, RIGHT_TOP, LEFT_BOTTOM, RIGHT_BOTTOM }; // ïåðå÷èñëåíèå
        int max_place = -1;
 
        // â Edit1 çàäàåòñÿ âñåãî òî÷åê
        int x, y, p = Edit1->Text.ToInt(), w = pb->Width, h = pb->Height, w2 = w/2, h2 = h/2;
        int count[4] = {0}, max_count = 0;
 
 
        // ðèñóåì òî÷êè
        for ( int i = 0; i < p; i++ )
        {
                x = random(w);
                y = random(h);
                canva->Pixels[x][y] = clBlue;
                if ( x < w2 && y < h2 ) count[LEFT_TOP]++;
                else if ( x >= w2 && y < h2 ) count[RIGHT_TOP]++;
                else if ( x < w2 && y >= h2 ) count[LEFT_BOTTOM]++;
                else if ( x >= w2 && y >= h2 ) count[RIGHT_BOTTOM]++;
        }
 
        // îïðåäåëÿåì ÷àñòü ñ áîëüøèì ñêîïëåíèåì òî÷åê
        for ( int i = 0; i < 4; i++ )
        {
                if ( count[i] > max_count )
                {
                        max_count = count[i];
                        max_place = i;
                }
        }
 
        // âûâîä êðóãà
        canva->Brush->Color = clRed;
        if ( max_place == LEFT_TOP )
        {
                canva->Ellipse( 10, 10, w2 - 10, h2 - 10 );
        }
        else if ( max_place == RIGHT_TOP )
        {
                canva->Ellipse( w2 + 10, 10, w - 10, h2 - 10 );
        }
        else if ( max_place == LEFT_BOTTOM )
        {
                pb->Canvas->Ellipse( 10, h2 + 10, w2 - 10, h - 10 );
        }
        else if ( max_place == RIGHT_BOTTOM )
        {
                pb->Canvas->Ellipse( w2 + 10, h2 + 10, w - 10, h - 10 );
        }
 
        // вывод текста (количество точек) по середине каждой части
        canva->Brush->Style = bsClear;
        canva->TextOut( (w2 - canva->TextExtent(count[LEFT_TOP]).cx) / 2,
                        (h2 - canva->TextExtent(count[LEFT_TOP]).cy) / 2, count[LEFT_TOP] );
        canva->TextOut( (w2 - canva->TextExtent(count[RIGHT_TOP]).cx) / 2 + w2,
                        (h2 - canva->TextExtent(count[RIGHT_TOP]).cy) / 2, count[RIGHT_TOP] );
        canva->TextOut( (w2 - canva->TextExtent(count[LEFT_BOTTOM]).cx) / 2,
                        (h2 - canva->TextExtent(count[LEFT_BOTTOM]).cy) / 2 + h2, count[LEFT_BOTTOM] );
        canva->TextOut( (w2 - canva->TextExtent(count[RIGHT_BOTTOM]).cx) / 2 + w2,
                        (h2 - canva->TextExtent(count[RIGHT_BOTTOM]).cy) / 2 + h2, count[RIGHT_BOTTOM] );
}