HTML5 Canvas Custom Filter Tutorial

How apply custom filter for Konva nodes?

This demo demonstrate how to use custom filters with Konva framework.

Filter is a function that have canvas ImageData as input and it should mutate it.

function Filter(imageData) {
// do something with image data[0] = 0;

For all available filters go to Filters Documentation.

Also take a look into Image Border Demo for custom filter example.

In this demo we will remove all transparency from the image..

Konva Custom Filter Image Demoview raw
<!DOCTYPE html>
<script src="[email protected]/konva.min.js"></script>
<meta charset="utf-8" />
<title>Konva Custom Filter Demo</title>
body {
margin: 0;
padding: 0;
overflow: hidden;
background-color: #f0f0f0;

<div id="container"></div>
var stage = new Konva.Stage({
container: 'container',
width: window.innerWidth,
height: window.innerHeight,

var layer = new Konva.Layer();

// lets define a custom filter:
var OpacityFilter = function (imageData) {
// make all pixels opaque 100%
var nPixels =;
for (var i = 3; i < nPixels; i += 4) {[i] = 255;

Konva.Image.fromURL('/assets/lion.png', function (image) {
x: 80,
y: 30,
borderSize: 5,
borderColor: 'red',