<!DOCTYPE html>
<html>
<meta charset="utf-8">
<head>
<title>canvas</title>
</head>
<body>
<canvas id="canvas" style="width: 1550px; height: 750px; border:1px solid red"></canvas>
</body>
<script>
var c = document.getElementById('canvas');
var ctx = c.getContext('2d');
ctx.moveTo(0,0);
ctx.lineTo(1550, 750);
ctx.stroke();
</script>
</html>
