HTML5 Canvas Konva Scale Animation Tutorial

To animate a shape’s scale with Konva, we can create a new animation with
Konva.Animation, and define a function which modifies the shape’s scale with each animation frame.

In this tutorial, we’ll scale the x and y component of a blue hexagon, the y component
of a yellow hexagon, and the x component of a red hexagon about an axis positioned on the right side of the shape.

Instructions: drag and drop the hexagons as they animate

For a full list of attributes and methods, check out the Konva.Animation documentation.

Konva Scale Animation Demoview raw

<!DOCTYPE html>
<html>
  <head>
    <script src="https://unpkg.com/konva@4.0.18/konva.min.js"></script>
    <meta charset="utf-8" />
    <title>Konva Scale Animation 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();

      /*
       * leave center point positioned
       * at the default which is at the center
       * of the hexagon
       */
      var blueHex = new Konva.RegularPolygon({
        x: 50,
        y: stage.height() / 2,
        sides: 6,
        radius: 40,
        fill: '#00D2FF',
        stroke: 'black',
        strokeWidth: 4,
        draggable: true
      });

      var yellowHex = new Konva.RegularPolygon({
        x: 150,
        y: stage.height() / 2,
        sides: 6,
        radius: 50,
        fill: 'yellow',
        stroke: 'black',
        strokeWidth: 4,
        draggable: true
      });

      /*
       * move center point to right side
       * of hexagon
       */
      var redHex = new Konva.RegularPolygon({
        x: 300,
        y: stage.height() / 2,
        sides: 6,
        radius: 50,
        fill: 'red',
        stroke: 'black',
        strokeWidth: 4,
        offset: {
          x: 50,
          y: 0
        },
        draggable: true
      });

      layer.add(blueHex);
      layer.add(yellowHex);
      layer.add(redHex);
      stage.add(layer);

      var period = 2000;

      var anim = new Konva.Animation(function(frame) {
        var scale = Math.sin((frame.time * 2 * Math.PI) / period) + 0.001;
        // scale x and y
        blueHex.scale({ x: scale, y: scale });
        // scale only y
        yellowHex.scaleY(scale);
        // scale only x
        redHex.scaleX(scale);
      }, layer);

      anim.start();
    </script>
  </body>
</html>