arcgis js 4.x实现图层掩膜并且显示掩膜边界样式

  let clipPolygon = new Polygon(graphicson.geometry);
  let bufferPolygon = geometryEngine.buffer(clipPolygon, 50, "meters")
 
   console.log(clipPolygon)
   let graphic = new Graphic({
   geometry: bufferPolygon,
   symbol: {
      type: "simple-fill",  // autocasts as new SimpleFillSymbol()
      color: [255, 255, 255, 1],
      style: "solid",
      outline: {  // autocasts as new SimpleLineSymbol()
          color: "red",
          width: 2
         }
        }
      })
    console.log(graphic)
 
 
 
    let layer = new GraphicsLayer({
        blendMode: "destination-atop",
        title: "layer"
      });
    layer.add(graphic);

实现掩膜边界样式主要是设置blenmode为"destination-atop"，并且设置graphic样式；注意图层加到最上层;