Анимация без мерцания

program atom bora;
uses crt,graphABC;
var
x,y,x0,y0,rvod,xe,ye,rel,re,dy,i,ro1,ro2:integer;
begin
x:=640; 
y:=480;
setwindowsize(x,y); 
x0:= x div 2; 
y0:= y div 2; 
rvod:=30; 
rel:=10; 
dy:=100; 
re:=y0-dy;
i:=360;
repeat
clearwindow;
setpencolor(clblue); 
circle (x0,y0,rvod);
floodfill(x0,y0,clred); 
ro1:=y0-dy;
circle (x0,y0,ro1); 
ro2:=y0-dy-30;
circle (x0,y0,ro2); 
if i=360 then i:=1 else i:=i+1;
xe:=x0+round(re*cos(i*pi/180));
ye:=y0+round(re*sin(i*pi/180));
circle (xe,ye,rel); 
delay(20);
end.

uses GraphWPF;
 
begin
  Window.SetSize(640, 480);
  var Center := Window.Center;
  var rvod := 30; 
  var rel := 10; 
  var dy := 100; 
  var re := Center.Y - dy;
  var i := 360;
  
  BeginFrameBasedAnimation(()->
  begin
    Pen.Color := Colors.Blue;
    Brush.Color := Colors.Red;
    Circle(Center.X, Center.Y, rvod);
    
    Brush.Color := Colors.Transparent;
    Circle(Center.X, Center.Y, Center.Y - dy);
    Circle(Center.X, Center.Y, Center.Y - dy - 30);
    
    i := i mod 360 + 1;
    Circle(
      Center.X + re * Cos(DegToRad(i)),
      Center.Y + re * Sin(DegToRad(i)),
      rel
    );
    
  end);
  
end.