Direct2D (23) : 复合几何对象之 ID2D1GeometryGroup

uses Direct2D, D2D1;



procedure TForm1.FormPaint(Sender: TObject);

var

  cvs: TDirect2DCanvas;

  iGeometryGroup: ID2D1GeometryGroup;

  arrGeometry: array[0..3] of ID2D1EllipseGeometry;

  ptCenter: TD2D1Point2F;

  i: Integer;

  rh,rv: Single;

  iFactory: ID2D1Factory;

begin

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



  {建立几何对象数组}

  iFactory := D2DFactory();

  rh := ClientWidth / 12;

  rv := ClientHeight / 12;

  for i := 0 to Length(arrGeometry)-1 do

  begin

    iFactory.CreateEllipseGeometry(D2D1Ellipse(ptCenter, rh*(i+1), rv*(i+1)), arrGeometry[i]);

  end;



  {建立 ID2D1GeometryGroup 对象}

  D2DFactory.CreateGeometryGroup(

    D2D1_FILL_MODE_ALTERNATE, //另可选 D2D1_FILL_MODE_WINDING，测试效果图演示了两种填充模式的区别

    @arrGeometry[0],

    Length(arrGeometry),

    iGeometryGroup

  );



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

  cvs.BeginDraw;

  cvs.Brush.Color := clWebCornFlowerBlue;

  cvs.FillGeometry(iGeometryGroup);

  cvs.DrawGeometry(iGeometryGroup);

  cvs.EndDraw;

  cvs.Free;

end;



procedure TForm1.FormResize(Sender: TObject);

begin

  Repaint;

end;

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效果图：

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