Draw a Gradient Circle

procedure TForm1.FormCreate(Sender: TObject);
Var
  Max, Xo, Yo, Radius, C, R, H, W, L : Integer;
  Angle, Step : Real;
begin
   { Get form size }
   H:=Image1.Height;
   W:=Image1.Width;

   { Fill area with form color }
   Image1.Canvas.Pen.Color:=Form1.Color;
   Image1.Canvas.Brush.Color:=Form1.Color;
   Image1.Canvas.Rectangle(0,0,W,H);

   Max:=360;
   Image1.Canvas.Pen.Width:=5;

   { Set fill size }
   L:=Max Div 4;

   { Set fill step size }
   Step:=255/L;

   { Set circle coodinates }
   Xo:=W Div 2;
   Yo:=H Div 2;
   Radius:=(H Div 2)-30;


   C:=0;
   Angle:=0;
   For R:=0 To Max Do
   Begin
     { Select color for gradient starting from RED
     to YELLOW }

     { Change fill color }
     If R<=L Then
     Begin
        C:=Round(R*Step);
        { Red - Green }
        Image1.Canvas.Pen.Color:=RGB(255-C,C,0)
     End
     Else If R<=2*L Then
     Begin
        C:=Round((R-L)*Step);
        { Green - Blue }
        Image1.Canvas.Pen.Color:=RGB(0,255-C,C)
     End
     Else If R<=3*L Then
     Begin
        C:=Round((R-2*L)*Step);
        { Blue - Yellow }
        Image1.Canvas.Pen.Color:=RGB(C,C,255-C);
     End
     Else If R<=4*L Then
     Begin
        C:=Round((R-3*L)*Step);
        { Yellow - Red }
        Image1.Canvas.Pen.Color:=RGB(255,255-C,0);
     End;

     { Fill area by drawing lines }
     Image1.Canvas.MoveTo(Xo,Yo);
     Image1.Canvas.LineTo(Xo+Round(Radius*Sin(R*(Pi/180))),
     Yo-Round(Radius*Cos(R*(Pi/180))));
   End;
end;