Is there a way to add a label to the Zoom Slider?


I need to add a label that says ‘100%’ just above the ‘+’ button on a vertical Zoom Slider we use in our diagram. I can edit the HTML manually in DevTools to make this happen locally, but I don’t know how to do this in a .tsx file.


Just add your HTML separate from the Zoom Slider, and have it overlap your Diagram.

<!DOCTYPE html>
  <meta charset="UTF-8">
  <title>Zoom Slider</title>
  <meta name="description" content="HTML controls for panning and zooming that are shown in front of a Diagram." />
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <!-- Copyright 1998-2020 by Northwoods Software Corporation. -->

  <script src="go.js"></script>
  <script src="../assets/js/goSamples.js"></script>  <!-- this is only for the GoJS Samples framework -->

  <link rel='stylesheet' href='ZoomSlider.css' />
  <script src="ZoomSlider.js"></script>

  <script id="code">
    function init() {
      if (window.goSamples) goSamples();  // init for these samples -- you don't need to call this

      var $ = go.GraphObject.make;  // for conciseness in defining templates

      myDiagram = $(go.Diagram, "myDiagramDiv",  // create a Diagram for the DIV HTML element
          "undoManager.isEnabled": true,  // enable undo & redo
          "ViewportBoundsChanged": function(e) {
            if (e.diagram.scale !== e.subject.scale) {
              var extra = document.getElementById("myExtra");
              extra.textContent = (e.diagram.scale*100).toFixed(0) + "%";

      // define a simple Node template
      myDiagram.nodeTemplate =
        $(go.Node, "Auto",  // the Shape will go around the TextBlock
          $(go.Shape, "RoundedRectangle", { strokeWidth: 0, fill: "white" },
            // Shape.fill is bound to
            new go.Binding("fill", "color")),
            { margin: 8 },  // some room around the text
            // TextBlock.text is bound to
            new go.Binding("text", "key"))

      // but use the default Link template, by not setting Diagram.linkTemplate

      // create the model data that will be represented by Nodes and Links
      myDiagram.model = new go.GraphLinksModel(
          { key: "Alpha", color: "lightblue" },
          { key: "Beta", color: "orange" },
          { key: "Gamma", color: "lightgreen" },
          { key: "Delta", color: "pink" }
          { from: "Alpha", to: "Beta" },
          { from: "Alpha", to: "Gamma" },
          { from: "Beta", to: "Beta" },
          { from: "Gamma", to: "Delta" },
          { from: "Delta", to: "Alpha" }

      zoomSlider = new ZoomSlider(myDiagram);

      var extra = document.getElementById("myExtra");
<body onload="init()">
  <div id="sample" style="position: relative;">
    <div id="myDiagramDiv" style="border: solid 1px black; width:400px; height:400px"></div>
    <span id="myExtra" style="position: absolute; bottom: 125px; right: 0px;">100%</span>
      This sample demostrates the use of the ZoomSlider extension.
      When using the ZoomSlider extension, the diagram Div must always be a direct child
      of a Div using <code>position: relative</code> or <code>position: absolute</code>,
      so that the ZoomSlider HTML DOM can be positioned correctly relative to the Diagram Div.