Zoom the Diagram on Ctrl Keypress Only

Updated on Dec 10, 2025

Environment

Product	Progress® Kendo UI® Diagram for jQuery
Operating System	Windows 10 64bit
Visual Studio Version	Visual Studio 2017
Preferred Language	JavaScript

Description

How can I allow zooming in and out the Kendo UI for jQuery Diagram only through pressing the Ctrl key?

Solution

The following example demonstrates how to set up the Diagram to allow zooming in and out only when the Ctrl key is pressed.

    <div style="overflow:auto; width: 1000px; height: 300px;">
      <div id="diagram"></div>
    </div>

    <script>
      $("#diagram").kendoDiagram({
        dataSource: new kendo.data.HierarchicalDataSource({
          data: diagramNodes()
        }),
        layout: {
          type: "tree",
          horizontalSeparation: 30,
          verticalSeparation: 20
        },
        shapeDefaults: {
          width: 40,
          height: 40
        },
        zoomStart: function(ev) {
          if (!ev.meta.ctrlKey) {
            ev.preventDefault(true);
          }
        }
      });

      function diagramNodes() {
        var root = { name: "0", items: [] };
        addNodes(root, [3, 3, 3, 3]);
        return [root];
      }

      function addNodes(root, levels) {
        if (levels.length > 0) {
          for (var i = 0; i < levels[0]; i++) {
            var node = { name: "0", items: [] };
            root.items.push(node);

            addNodes(node, levels.slice(1));
          }
        }
      }
    </script>

See Also

• Basic Usage of the Diagram (Demo)
• JavaScript API Reference of the Diagram
• Implement Local Data Editing
• Render External Content in Shapes
• Wrap Text