Direct2D (27) : 获取几何图形的轮廓 - ID2D1Geometry.Outline()

uses Direct2D, D2D1;



procedure TForm1.FormPaint(Sender: TObject);

var

  cvs: TDirect2DCanvas;

  iEllipseGeometry: ID2D1EllipseGeometry;

  iTransformedGeometrys: array[0..7] of ID2D1TransformedGeometry;

  iGeometryGroup: ID2D1GeometryGroup;

  iGeometrySink: ID2D1GeometrySink;

  iPathGeometry: ID2D1PathGeometry;

  ptCenter: TD2DPoint2f;

  i: Integer;

begin

  {建立几何对象}

  ptCenter := D2D1PointF(ClientWidth/2, ClientHeight/2);

  for i := 0 to 7 do

  begin

    D2DFactory.CreateEllipseGeometry(D2D1Ellipse(ptCenter, 100, 25), iEllipseGeometry);

    D2DFactory.CreateTransformedGeometry(iEllipseGeometry, TD2DMatrix3x2F.Rotation(360/8*i, ptCenter), iTransformedGeometrys[i]);

  end;

  D2DFactory.CreateGeometryGroup(D2D1_FILL_MODE_WINDING, @iTransformedGeometrys[0], 8, iGeometryGroup);



  {获取轮廓到 iPathGeometry}

  D2DFactory.CreatePathGeometry(iPathGeometry);

  iPathGeometry.Open(iGeometrySink);

  iGeometryGroup.Outline(TD2DMatrix3x2F.Identity, 0, iGeometrySink);

  iGeometrySink.Close;



  {绘制图形与轮廓}

  cvs := TDirect2DCanvas.Create(Canvas, ClientRect);

  cvs.BeginDraw;

  cvs.RenderTarget.Clear(D2D1ColorF(clWhite));



  cvs.Brush.Color := clYellow;

  cvs.Pen.Color := clRed;

  cvs.FillGeometry(iGeometryGroup);

  cvs.DrawGeometry(iGeometryGroup);



  cvs.Pen.Brush.Handle.SetOpacity(0.5);

  cvs.Pen.Width := 11;

  cvs.DrawGeometry(iPathGeometry);



  cvs.EndDraw;

  cvs.Free;

end;



procedure TForm1.FormResize(Sender: TObject);

begin

  Repaint;

end;

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效果图：

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