Direct2D (19) : 图层之 TD2D1LayerParameters.geometricMask (使用几何图形剪裁图层)

uses Direct2D, D2D1;



procedure TForm1.FormPaint(Sender: TObject);

var

  cvs: TDirect2DCanvas;

  iLayer: ID2D1Layer;

  rLayerParameters: TD2D1LayerParameters;

  wic: TWICImage;

  R: TRect;

  iEllipse: ID2D1EllipseGeometry;

begin

  wic := TWICImage.Create;

  wic.LoadFromFile('C:\Temp\Test.png');

  R := Rect(0, 0, wic.Width, wic.Height);



  {几何图形}

  D2DFactory.CreateEllipseGeometry(D2D1Ellipse(D2D1PointF(wic.Width/2, wic.Height/2), wic.Width/2, wic.Height/2), iEllipse);



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

  cvs.RenderTarget.SetTransform(TD2DMatrix3x2F.Translation((ClientWidth-wic.width)/2, (ClientHeight-wic.height)/2));



  cvs.BeginDraw;

  cvs.RenderTarget.CreateLayer(nil, iLayer);

  rLayerParameters.contentBounds := R;

  rLayerParameters.geometricMask := iEllipse; //!

  rLayerParameters.maskAntialiasMode := D2D1_ANTIALIAS_MODE_PER_PRIMITIVE;

  rLayerParameters.maskTransform := TD2DMatrix3x2F.Identity;

  rLayerParameters.opacity := 1.0;

//  rLayerParameters.opacityBrush := nil;

  rLayerParameters.layerOptions := D2D1_LAYER_OPTIONS_NONE;



  cvs.RenderTarget.PushLayer(rLayerParameters, iLayer);

  cvs.StretchDraw(R, wic);

  cvs.RenderTarget.PopLayer;



  cvs.EndDraw;

  cvs.Free;

  wic.Free;

end;



procedure TForm1.FormResize(Sender: TObject);

begin

  Repaint;

end;

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效果图：

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