HTML5 canvas Blob Tutorial

To create a blob with Konva, we can instantiate a Konva.Line() object with closed = true and tension attributes.

To define the path of the line you should use points property. If you have three points with x and y coordinates you should define points property as: [x1, y1, x2, y2, x3, y3].

Flat array of numbers should work faster and use less memory than array of objects.

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

Konva Blob Demoview raw

<!DOCTYPE html>
<html>
  <head>
    <script src="https://unpkg.com/[email protected]/konva.min.js"></script>
    <meta charset="utf-8" />
    <title>Konva Line Blob 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 blob = new Konva.Line({
        points: [23, 20, 23, 160, 70, 93, 150, 109, 290, 139, 270, 93],
        fill: '#00D2FF',
        stroke: 'black',
        strokeWidth: 5,
        closed: true,
        tension: 0.3,
      });

      // add the shape to the layer
      layer.add(blob);

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

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