Canvas: найти точки пересечения двух эллипсов

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
 
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
 
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
int X1,Y1,R1;
Canvas->Pen->Color=clGreen;
Canvas->Brush->Color=clWhite;
X1=StrToFloat(Edit2->Text);
Y1=StrToFloat(Edit1->Text);
R1=StrToFloat(Edit5->Text);
   Canvas->Ellipse(X1, Y1, X1 + R1, Y1 + R1);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button2Click(TObject *Sender)
{
int X2,Y2,R2;
X2=StrToFloat(Edit4->Text);
Y2=StrToFloat(Edit3->Text);
R2=StrToFloat(Edit6->Text);
   Canvas->Ellipse(X2, Y2, X2 + R2, Y2 + R2);
}
//---------------------------------------------------------------------------
 
 
void __fastcall TForm1::Button3Click(TObject *Sender)
{
Form1->Repaint();
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::Button4Click(TObject *Sender)
{
int y,x;
 
}
//---------------------------------------------------------------------------