var
  g: TGPGraphics;
  p: TGPPen;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  p := TGPPen.Create(MakeColor(255,0,0),2);
  g.Clear(aclWhite);

  g.DrawArc(p,11,32,300,200,0,90);    {假设有一条从左端到右边的直线，右端为0度，中间为圆心，左端为180度，我让它从0度到90度画一条弧线}

  p.SetColor(aclCrimson);
  g.DrawLine(p,11,133,161,133);

  p.SetColor(MakeColor(0,255,0));
  g.DrawArc(p,11,32,300,200,90,90);   {我让它从90度开始，再画多90度的一段弧线}

  p.SetColor(aclDeepPink);
  g.DrawLine(p,161,133,311,133);

  p.SetColor(MakeColor(0,0,255));
  g.DrawArc(p,11,32,300,200,180,90);  {我让它从180度开始，再画多90度的一段弧线}

  p.SetColor(MakeColor(255,255,0));
  g.DrawArc(p,11,32,300,200,270,90);  {我让它从270度开始，再画多90度的一段弧线，至此，刚刚一个圆}

  p.SetColor(MakeColor(0,0,0));
  g.DrawArc(p,88,88,200,100,0,360);   {如果直接从 0 度开始不间断地延伸 360 度, 就是画椭圆线了}

  p.Free;
  g.Free;
end;