changed autoResize to only draw when change is detected.

lib/network/modules/Canvas.js

@@ -57,7 +57,12 @@ class Canvas {
     if (this.options.autoResize === true) {
       // automatically adapt to a changing size of the browser.
       this._cleanUp();
-      this.resizeTimer = setInterval(() => {this.setSize(); this.body.emitter.emit("_requestRedraw");}, 1000);
+      this.resizeTimer = setInterval(() => {
+        let changed = this.setSize();
+        if (changed === true) {
+          this.body.emitter.emit("_requestRedraw");
+        }
+      }, 1000);
       this.resizeFunction = this._onResize.bind(this);
       util.addEventListener(window,'resize',this.resizeFunction);
     }
@@ -228,6 +233,8 @@ class Canvas {
     if (emitEvent === true) {
       this.body.emitter.emit('resize', {width:this.frame.canvas.width / this.pixelRatio, height:this.frame.canvas.height / this.pixelRatio, oldWidth: oldWidth / this.pixelRatio, oldHeight: oldHeight / this.pixelRatio});
     }
+
+    return emitEvent;
   };