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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Pointer event test</title>
</head>
<body>
<p>
<canvas id="listener" width="500" height="500" style="border: silver 1px dotted;"></canvas>
</p>
<p>
Touch this circle with a stylus. Its size indicates your pressure; its position is the angle between your stylus and your tablet device; and the radius is the rotation - if your tablet supports it.
</p>
</body>
<script>
var canvas = document.getElementById("listener");
var context = canvas.getContext('2d');
var eventName = [
"pointerover",
"pointerenter",
"pointerdown",
"pointermove",
"pointerup",
"pointercancel",
"pointerout",
"pointerleave",
"gotpointercapture",
"lostpointercapture"
];
for (var i = 0; i < eventName.length; i++) {
canvas.addEventListener(eventName[i], function(ev) {
drawCircle(ev.pressure, ev.tiltX, ev.tiltY, ev.twist);
}, false);
}
drawCircle(0, 0, 0, 0);
function drawCircle(pressure, tiltX, tiltY, twist) {
var centerX = canvas.width / 2 + tiltX;
var centerY = canvas.height / 2 + tiltY;
var radius = 100 + 100 * pressure;
context.clearRect(0, 0, canvas.width, canvas.height);
context.beginPath();
context.arc(centerX,
centerY,
radius,
0,
2 * Math.PI,
false);
context.fillStyle = 'lightblue';
context.fill();
context.lineWidth = 3;
context.strokeStyle = '#008B8B';
context.stroke();
context.beginPath();
context.moveTo(centerX, centerY);
context.lineTo(centerX + radius * Math.cos(twist), centerY + radius * Math.sin(twist));
context.stroke();
}
</script>
</html>
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