[新增] 多边形中心点

src/app/working-area/working-area.component.ts

@@ -1078,8 +1078,8 @@ export class PolygonIcon extends PIXI.Container {
     this.addChild(this.polygonLineGraphics);
 
     this.text.anchor.set(0.5);
-    // this.text.position = this.getCenterOfGravityPoint(this.pointsData);
-    console.log(this.polygonLineGraphics._bounds);
+    this.text.position = this.calculatePolygonGravityCenter(this.pointsData);
+    // console.log(this.calculatePolygonGravityCenter(this.pointsData));
     this.polygonLineGraphics.addChild(this.text);
     // 添加圆点事件
     this.pointsGraphics.forEach((item, index, array) => {
@@ -1123,6 +1123,8 @@ export class PolygonIcon extends PIXI.Container {
             this.polygonLineGraphics.lineStyle(1, 0xFFBD01, 1);
             this.polygonLineGraphics.drawPolygon(this.getPoints());
             this.polygonLineGraphics.closePath();
+
+            this.text.position = this.calculatePolygonGravityCenter(this.pointsData);
           }
         })
         .on('rightclick', event => {
@@ -1176,31 +1178,30 @@ export class PolygonIcon extends PIXI.Container {
     });
   }
 
-  public getCenterOfGravityPoint(points) {
-    let sumX = 0;
-    let sumY = 0;
-    let sumArea = 0;
-    let area = 0;
-    let p1 = points[1];
-    for (let i = 2; i < points.length; i++) {
-      const p2 = points[i];
-      area = this.Area(points[0], p1, p2);
-      sumArea += area;
-      sumX += (points[0][0] + p1[0] + p2[0]) * area;
-      sumY += (points[0][1] + p1[1] + p2[1]) * area;
-      p1 = p2;
-    }
-    const pointX = sumX / sumArea / 3;
-    const pointY = sumY / sumArea / 3;
-    console.log(pointX);
-    console.log(pointY);
-    return new PIXI.Point(pointX, pointY);
-  }
-  Area(p0, p1, p2) {
-    let area = 0.0;
-    area = p0[0] * p1[1] + p1[0] * p2[1] + p2[0] * p0[1] - p1[0] * p0[1] - p2[0] * p1[1] - p0[0] * p2[1];
-    return area / 2;
-  }
+  public calculatePolygonGravityCenter(points: PIXI.Point[]) {
+  let area = 0.0; // 多边形面积
+  let gravityLat = 0.0; // 重心点 latitude
+  let gravityLng = 0.0; // 重心点 longitude
+  points.forEach((item, index) => {
+    // 1
+    const lat = item.x;
+    const lng = item.y;
+    const nextLat = points[(index + 1) % points.length].x;
+    const nextLng = points[(index + 1) % points.length].y;
+    // 2
+    const tempArea = (nextLat * lng - nextLng * lat) / 2.0;
+    // 3
+    area += tempArea;
+    // 4
+    gravityLat += tempArea * (lat + nextLat) / 3;
+    gravityLng += tempArea * (lng + nextLng) / 3;
+    });
+  // 5
+  gravityLat = gravityLat / area;
+  gravityLng = gravityLng / area;
+
+  return new PIXI.Point(gravityLat, gravityLng);
+}
   /**
    * 获取点集合
    */