修复bug

src/graphic/Coordinate.js

@@ -103,6 +103,7 @@ export default class Coordinate {
       this.width = canvas.width;
       this.height = canvas.height;
     }
+    this.zoom = defaultZoom;
     this.setCenter(canvas);
     Constant.minAdsorbPix = minAdsorbPix * this.ratio;
     console.log(