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>
<script src="[email protected]/konva.min.js"></script>
<meta charset="utf-8" />
<title>Konva Line Blob Demo</title>
body {
margin: 0;
padding: 0;
overflow: hidden;
background-color: #f0f0f0;
<div id="container"></div>
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

// add the layer to the stage
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