Added text that zooms vis font size changes,

lib/pixi/labeledgraphics.html

@@ -23,23 +23,62 @@
     </p>
     <p><a href="../../doc/out/LabeledGraphics.html">JavaScript API</a></p>
     <p>Let's look at an example:</p><br />
-    <canvas id="canvas" class="interactive"></canvas>
+    <canvas id="canvas1" class="interactive"></canvas>
     <p>
         What you should see: A box with a label.
     </p>
     <script class="doctest">
 const app = new PIXIApp({
-    view: canvas,
+    view: canvas1,
     width: 900,
     height: 150
 }).setup().run()
 
 const labeledBox = new LabeledGraphics()
 labeledBox.ensureLabel('key', 'This is a label in a box', { justify: 'top'})
-labeledBox.beginFill(0x0000FF)
+labeledBox.beginFill(0x333333)
 labeledBox.drawRect(0, 0, 300, 100)
 labeledBox.endFill()
 
 app.scene.addChild(labeledBox)
     </script>
+    <h2>Zoomable Labels</h2>
+    <p>Labeled graphics can also be used to represent zoomable text columns in more complex layouts.
+        Use the mousewheel to zoom the following text column:
+    </p>
+
+    <canvas id="canvas2" class="interactive"></canvas>
+    <script class="doctest">
+const app2 = new PIXIApp({
+    view: canvas2,
+    width: 900,
+    height: 150
+}).setup().run()
+
+const loremIpsum = `Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. 
+At vero eos et accusam et justo duo dolores et ea rebum.`
+
+const column = new LabeledGraphics()
+const text = column.ensureLabel('key', loremIpsum, { maxWidth: 250, zoomFonts: true, justify: 'top', align: 'align'})
+column.beginFill(0x333333)
+column.drawRect(0, 0, 900, 150)
+column.endFill()
+
+column.interactive = true
+text.interactive = true
+text.getLocalBounds()
+
+text.on('zoom', (event) => {
+    let factor = 1.0 + event.wheelDelta / 1000
+    text.zoom(factor)
+})
+
+app2.view.addEventListener('mousewheel', (event) => {
+    text.emit('zoom', event)
+    event.preventDefault()
+})
+
+app2.scene.addChild(column)
+    </script>
+
 </body>