利用OpenLayer绘制扇形的示例代码

// 实例化Map
map = new Map({  // 创建一个地图
  layers: [new TileLayer({
     source: new OSM(),
  }),],
  target: 'map',
  view: new View({
     center: fromLonLat([116.400819, 39.916263]),
     zoom: 15,
     constrainResolution: true,  // 设置缩放级别为整数 
     smoothResolutionConstraint: false,  // 关闭无级缩放地图
  }),
});

	  // 绘制扇形
      addCurve() {
        let origi_point = fromLonLat([116.410819, 39.916263]);  // 绘制扇形的顶点
        let circle = this.createRegularPolyGonCurve(origi_point, 500, 100, 30, 90) // 调用绘制扇形的方法得到扇形
        let feature = new Feature(circle);  // 把扇形加入 feature
        feature.setStyle(  // 设置一下这个扇形的样式
          new Style({
            fill: new Fill({
              color: 'rgba(32, 157, 230, 0.3)'
            }),
            stroke: new Stroke({
              color: 'rgba(255, 205, 67, 0.3)',
              width: 2
            }),
          })
        )
        feature.set('type', 'Curve')  // 这是给这个扇形添加额外的参数 ， 如果是设置id 用 setId方法
        feature.set('curve', {   // 这是给这个扇形添加额外的参数，这里的id和 setId的id没关系
          id: 1,
          title: '测试001',
          msg: '测试001-1',
          msg2: '测试001-2',
        })

		// 创建第二个扇形，和第一个一样
        let circle1 = this.createRegularPolygonCurve(origi_point, 500, 100, 30, 45)
        let feature1 = new Feature(circle1);
        feature1.setStyle(
          new Style({
            fill: new Fill({
              color: 'rgba(32, 157, 230, 0.3)'
            }),
            stroke: new Stroke({
              color: 'rgba(255, 205, 67, 0.3)',
              width: 2
            }),
          })
        )
        feature1.set('type', 'Curve')
        feature1.set('curve', {
          id: 2,
          title: '超级无敌炫酷爆龙战神',
          msg: '超级无敌炫酷爆龙战神 描述001',
          msg2: '超级无敌炫酷爆龙战神 描述002',
        })

        let vectorSource = new VectorSource();  // 创建一个数据源
        vectorSource.addFeatures([feature, feature1]);   // 把两个扇形加进数据源
        let vectorLayer = new VectorLayer({     // 创建一个图层，把数据源加进图层
          source: vectorSource 
        });
        map.addLayer(vectorLayer);   // 把图层加进地图
      },

	 
      createRegularPolygonCurve(origin, radius, sides, r, angel) {
        let rotation = 360 - r;
        let angle = Math.PI * ((1 / sides) - (1 / 2));
        if (rotation) {
          angle += (rotation / 180) * Math.PI;
        }
        let rotatedAngle, x, y;
        let points = [];
        for (let i = 0; i < sides; ++i) {
          let an = i * ((360 - rotation) / 360);
          rotatedAngle = angle + (an * 2 * Math.PI / sides);
          x = origin[0] + (radius * Math.cos(rotatedAngle));
          y = origin[1] + (radius * Math.sin(rotatedAngle));
          points.push([x, y]);
        }
        if (rotation != 0) {
          points.push(origin);
        }
        var ring = new LinearRing(points);
        ring.rotate(angel / 57.3, origin);
        let list = ring.getCoordinates()

        return new Polygon([list]);
      },