如何让背景图随 cancas 的移动而移动
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
*{
margin: 0;
padding: 0;
}
</style>
</head>
<body>
<canvas id="myCanvas" height="" width="">
此浏览器不支持canvas,请更换浏览器
</canvas>
<script type="text/javascript">
var canvas = document.getElementById('myCanvas');
var context = canvas.getContext('2d');
canvas.width = document.documentElement.clientWidth;
canvas.height = document.documentElement.clientHeight;
var imgs = new Image();
imgs.src = 'img/background.png';
var bgY = 0;
function bgmove(){
context.clearRect(0,0,canvas.width,canvas.height);
bgY++;
var pattarn = context.createPattern(imgs,'repeat');
console.log(bgY);
context.fillRect(0,bgY,canvas.width,canvas.height/2);
context.fillStyle = pattarn;
context.fill();
}
setInterval(bgmove,30)
</script>
</body>
</html>想让背景图随 cancas 的移动而移动,该如何改进,求大神指导.
