学步园

uses Direct2D, D2D1;

procedure TForm1.FormPaint(Sender: TObject);
var
  cvs: TDirect2DCanvas;
  R: TRect;
begin
  cvs := TDirect2DCanvas.Create(Canvas, ClientRect);
  cvs.BeginDraw;
  cvs.Pen.Color := Color;

  cvs.Brush.Color := clGreen;
  R := Rect(30, 30, 200, 150);
  cvs.Ellipse(R);

  cvs.Brush.Handle.SetOpacity(0.75);
  OffsetRect(R, 30, 20);
  cvs.Ellipse(R);

  cvs.Brush.Handle.SetOpacity(0.5);
  OffsetRect(R, 30, 20);
  cvs.Ellipse(R);

  cvs.Brush.Handle.SetOpacity(0.25);
  OffsetRect(R, 30, 20);
  cvs.Ellipse(R);

  cvs.EndDraw;
  cvs.Free;
end;

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效果图：

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