made structure to be a public property

src/plugin/depiction.ts

@@ -20,7 +20,7 @@ class Depiction {
     private root: d3.Selection<SVGGElement, unknown, null, undefined>;
     private highlight: d3.Selection<SVGGElement, unknown, null, undefined>;
     public weight: d3.Selection<SVGGElement, unknown, null, undefined>;
-    private structure: d3.Selection<SVGGElement, unknown, null, undefined>;
+    public structure: d3.Selection<SVGGElement, unknown, null, undefined>;
 
     constructor(parent: HTMLElement, root: any, data: any) {
         this.root = root;