Added text that zooms vis font size changes,

lib/pixi/labeledgraphics.js

@@ -130,6 +130,47 @@ export class Hypenate {
     }
 }
 
+class TextLabel extends PIXI.Text {
+
+    /**
+     *Creates an instance of TextLabel.
+     * @param {string} text - The string that you would like the text to display
+     * @param {object PIXI.TextStyle optional} style - The style parameters 
+     * @param {canvas} 
+     * @memberof TextLabel
+     */
+    constructor(text, style=null, canvas=null, { minZoom = 0.1, maxZoom = 10} = {}) {
+        super(text, style, canvas )
+        this.normFontSize = this.style.fontSize 
+        this.minZoom = minZoom
+        this.maxZoom = maxZoom
+    }
+
+    zoom(factor) {
+        let oldValue = parseFloat(this.style.fontSize) / this.normFontSize
+        let value = oldValue * factor
+        this.setZoom(value)
+    }
+
+    setZoom(value) {
+        let oldValue = parseFloat(this.style.fontSize) / this.normFontSize
+        if (value > this.maxZoom) {
+            value = this.maxZoom
+        }
+        if (value < this.minZoom) {
+            value = this.minZoom
+        }
+        if (value != oldValue) {
+            this.style.fontSize = Math.max(value * this.normFontSize, 1)
+        }
+    }
+
+    setZoomAndScale(scale) {
+        this.scale.set(1 / scale)
+        this.setZoom(scale)
+    }
+}
+
 /**
  * A specialization of the PIXI.Graphics class that allows to
  * resuse and place labels across different layout variants
@@ -151,7 +192,7 @@ export class LabeledGraphics extends PIXI.Graphics {
     }
 
     _createText(label, fontInfo) {
-        return new PIXI.Text(label, fontInfo)
+        return new TextLabel(label, fontInfo)
     }