HTML5 Canvas Set Opacity with KineticJS

To set a shape opacity with KineticJS, we can set the opacity property when we instantiate the shape, or we can use the setOpacity() method. Shapes can have an opacity value between 0 and 1, where 0 is fully transparent, and 1 is fully opaque. Unless otherwise specified, all shapes are defaulted with an opacity value of 1.

Instructions: Mouseover the pentagon to change its opacity.

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Code Editor

<!DOCTYPE HTML>
<html>
  <head>
    <style>
      body {
        margin: 0px;
        padding: 0px;
      }
    </style>
  </head>
  <body>
    <div id="container"></div>
    <script src="http://d3lp1msu2r81bx.cloudfront.net/kjs/js/lib/kinetic-v4.5.2.min.js"></script>
    <script defer="defer">
      var stage = new Kinetic.Stage({
        container: 'container',
        width: 578,
        height: 200
      });
      var layer = new Kinetic.Layer();

var pentagon = new Kinetic.RegularPolygon({
        x: stage.getWidth() / 2,
        y: stage.getHeight() / 2,
        sides: 5,
        radius: 70,
        fill: 'red',
        stroke: 'black',
        strokeWidth: 4,
        opacity: 0.5
      });

pentagon.on('mouseover', function() {
        this.setOpacity(1);
        layer.draw();
      });

pentagon.on('mouseout', function() {
        this.setOpacity(0.5);
        layer.draw();
      });
      // add the shape to the layer
      layer.add(pentagon);

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

< Stroke Shadow >

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Modified on April 9th, 2013 by Eric Rowell