HTML5 Canvas Canvas Multi-Event Binding Tutorial

To bind multiple events to a single handler with Konva, we can use the on() method and pass in a space delimited string containing multiple event types.

Instructions: Mouseover, mousedown, and mouseup over the circle to observe that the function bound to the circle is executed for each event.

Konva Multi_Event Demoview raw
<!DOCTYPE html>
<html>
<head>
<script src="https://unpkg.com/[email protected]/konva.min.js"></script>
<meta charset="utf-8" />
<title>Konva Multi-Event Binding Demo</title>
<style>
body {
margin: 0;
padding: 0;
overflow: hidden;
background-color: #f0f0f0;
}
</style>
</head>

<body>
<div id="container"></div>
<script>
function writeMessage(message) {
text.text(message);
layer.draw();
}

var stage = new Konva.Stage({
container: 'container',
width: window.innerWidth,
height: window.innerHeight
});

var layer = new Konva.Layer();

var text = new Konva.Text({
x: 10,
y: 10,
fontFamily: 'Calibri',
fontSize: 20,
text: '',
fill: 'black'
});

var numEvents = 0;

var circle = new Konva.Circle({
x: stage.width() / 2,
y: stage.height() / 2 + 10,
radius: 70,
fill: 'red',
stroke: 'black',
strokeWidth: 4
});

circle.on('mouseover mousedown mouseup', function() {
writeMessage('Multi-event binding! Events: ' + ++numEvents);
});
circle.on('mouseout', function() {
writeMessage('');
});

layer.add(circle);
layer.add(text);

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