HTML5 Canvas Shadows Tutorial

To apply shadows with Konva, we can set the shadowColor, shadowOffset, shadowBlur, and shadowOpacity properties when we instantiate a shape.

We can adjust the shadow properties after instantiation by using the shadowColor(), shadowOffset(), shadowBlur(), and shadowOpacity() methods.

Konva Shadows Demoview raw

<!DOCTYPE html>
<html>
  <head>
    <script src="https://unpkg.com/[email protected]/konva.min.js"></script>
    <meta charset="utf-8" />
    <title>Konva Shadow 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();

      var text = new Konva.Text({
        text: 'Text Shadow!',
        fontFamily: 'Calibri',
        fontSize: 40,
        x: 20,
        y: 20,
        stroke: 'red',
        strokeWidth: 2,
        shadowColor: 'black',
        shadowBlur: 0,
        shadowOffset: { x: 10, y: 10 },
        shadowOpacity: 0.5,
      });

      var line = new Konva.Line({
        stroke: 'green',
        strokeWidth: 10,
        lineJoin: 'round',
        lineCap: 'round',
        points: [50, 140, 250, 160],
        shadowColor: 'black',
        shadowBlur: 10,
        shadowOffset: { x: 10, y: 10 },
        shadowOpacity: 0.5,
      });

      var rect = new Konva.Rect({
        x: 100,
        y: 120,
        width: 100,
        height: 50,
        fill: '#00D2FF',
        stroke: 'black',
        strokeWidth: 4,
        shadowColor: 'black',
        shadowBlur: 10,
        shadowOffset: { x: 10, y: 10 },
        shadowOpacity: 0.5,
      });

      layer.add(text);
      layer.add(line);
      layer.add(rect);

      // add the layer to the stage
      stage.add(layer);
    </script>
  </body>
</html>

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