HTML5 Canvas Hue, Saturation and Value filter Image Tutorial

To apply filter to an Konva.Node, we have to cache it first with cache() function. Then apply filter with filter() function.

To change hue, saturation and value components of an image with Konva, we can use the Konva.Filters.HSV.

Instructions: Slide the controls to change hsv values.

For all available filters go to Filters Documentation.

Konva Hue, Saturation and Value Image Demoview raw
<!DOCTYPE html>
<html>

<head>
<script src="https://unpkg.com/konva@2.4.2/konva.min.js"></script>
<meta charset="utf-8">
<title>Konva HSV Image Demo</title>
<style>
body {
margin: 0;
padding: 0;
overflow: hidden;
background-color: #F0F0F0;
}

#controls {
position: absolute;
top: 20px;
left: 20px;
}
</style>
</head>

<body>
<div id="container"></div>
<div id="controls">
hue:
<input id="hue" type="range" min="0" max="259" step="1" value="150"> saturation:
<input id="saturation" type="range" min="-2" max="10" step="0.5" value="0"> value:
<input id="value" type="range" min="-2" max="2" step="0.1" value="0">
</div>
<script>
Konva.Image.fromURL('../../../assets/lion.png', function (lion) {
var stage = new Konva.Stage({
container: 'container',
width: window.innerWidth,
height: window.innerHeight
});

var layer = new Konva.Layer();

lion.position({
x: 50,
y: 50
});
lion.cache();
lion.filters([Konva.Filters.HSV]);
layer.add(lion);
stage.add(layer);

var sliders = ['hue', 'saturation', 'value'];
sliders.forEach(function (attr) {
var slider = document.getElementById(attr);
function update() {
lion[attr](parseFloat(slider.value));
layer.batchDraw();
}
slider.oninput = update;
update();
});
});
</script>

</body>

</html>