比例尺item修改

package.json

@@ -1,6 +1,6 @@
 {
     "name": "@saga-web/cad-engine",
-    "version": "2.0.571",
+    "version": "2.0.572",
     "description": "上格云 CAD图形引擎。",
     "main": "lib/index.js",
     "types": "lib/index.d.js",

src/items/EditLineItem.ts

@@ -211,6 +211,8 @@ export class EditLineItem extends SGraphItem {
             ];
             this.textPos = new SPoint(dis / 2, 0);
             this.calculate();
+        } else {
+            this.lineList = [];
         }
     }