<!DOCTYPE html>
<html>
<body>
<canvas id ="canvas" width="540" height="550"></canvas>
<script>
var canvas = document.getElementById('canvas');
// In the test page, the paint worklet canvas has a size of width of 270 CSS
// pixels, and height of 275. To divided by 2 is to match the canvas size.
canvas.style.width = (canvas.width / 2) + 'px';
canvas.style.height = (canvas.height / 2) + 'px';
var ctx = canvas.getContext("2d");
var fillW = 250;
var fillH = 50;
ctx.setTransform(2 * devicePixelRatio, 0, 0, 2 * devicePixelRatio, 0, 200);
ctx.beginPath();
ctx.rect(0, 0, fillW, fillH);
ctx.closePath();
ctx.clip();
ctx.fillStyle = 'green';
ctx.fillRect(0, 0, fillW, fillH);
</script>
</body>
</html>
