HTML5 Canvas Shape Resize Relative to Center

How to resize shape in both sides simultaneously?

To resize a node into both sides at the same time you can set centeredScaling to true or hold ALT key while moving an anchor (even if centeredScaling is false).

Instructions: Try to resize texts.

Konva Shape transform and selection Demoview raw

<!DOCTYPE html>
<html>
  <head>
    <!-- USE DEVELOPMENT VERSION -->
    <script src="https://unpkg.com/konva@4.0.18/konva.min.js"></script>
    <meta charset="utf-8" />
    <title>Konva Centered Scaling Demo</title>
    <style>
      body {
        margin: 0;
        padding: 0;
        overflow: hidden;
        background-color: #f0f0f0;
      }
    </style>
  </head>

  <body>
    <div id="container"></div>
    <script>
      var width = window.innerWidth;
      var height = window.innerHeight;

      var stage = new Konva.Stage({
        container: 'container',
        width: width,
        height: height
      });

      var layer = new Konva.Layer();
      stage.add(layer);

      var text1 = new Konva.Text({
        x: 50,
        y: 70,
        fontSize: 30,
        text: 'centeredScaling = true',
        draggable: true
      });
      layer.add(text1);

      var tr1 = new Konva.Transformer({
        node: text1,
        centeredScaling: true
      });
      layer.add(tr1);

      var text2 = new Konva.Text({
        x: 50,
        y: 200,
        fontSize: 30,
        text: 'centeredScaling = false',
        draggable: true
      });
      layer.add(text2);

      var tr2 = new Konva.Transformer({
        node: text2,
        centeredScaling: false
      });
      layer.add(tr2);

      layer.draw();
    </script>
  </body>
</html>