是不是这样子的:
procedure TForm1.Button1Click(Sender: TObject);
var
r:thandle;
i:integer;
c:Trect;
begin
for i:=1 to 90 do
begin
r:=CreateEllipticRgn(trunc(width/2)-i,trunc(height/2)-i,trunc(width/2)+i,trunc(height/2)+i);
SetWindowRgn(handle,r,true);
c:=ListBox1.ClientRect;
if not AdjustWindowRect(c,2,false)then exit;
sleep(10);
end;
end;