如何在画布动画下在画布上播放视频？
例如this剪辑。
所以这个动画沿着视频的底部移动。
码：
<html>
<head>
<script type='text/javascript' src='http://code.jquery.com/jquery-1.8.3.js'></script>
<script type="text/javascript">
var context;
var text = "";
var textDirection ="";
$(function()
{
context = document.getElementById("cvs").getContext("2d");
setInterval("animate()", 360);
textDirection ="right";
textXpos = 5;
text = "This is my video..";
});
function animate() {
// Clear screen
context.clearRect(0, 0, 500, 500);
context.globalAlpha = 1;
context.fillStyle = '#fff';
context.fillRect(0, 0, 500, 500);
var metrics = context.measureText(text);
var textWidth = metrics.width;
if (textDirection == "right") {
textXpos += 10;
if (textXpos > 500 - textWidth) {
textDirection = "left";
}
}
else {
textXpos -= 10;
if (textXpos < 10) {
textDirection = "right";
}
}
context.font = '20px _sans';
context.fillStyle = 'black';
context.textBaseline = 'top';
context.fillText ( text, textXpos, 180);
}
</script>
</head>
<body>
<div id="page">
<canvas id="cvs" width="500" height="500">
Your browser does not support the HTML 5 Canvas.
</canvas>
</div>
</body>
</html>
我不认为你需要在画布上播放视频。只需在HTML中创建一个视频元素，然后使用CSS将canvas元素放在其上。
HTML：
<div id="page">
<video id="video" autoplay loop>
<source id='mp4'
src="http://media.w3.org/2010/05/sintel/trailer.mp4"
type='video/mp4'>
<source id='webm'
src="http://media.w3.org/2010/05/sintel/trailer.webm"
type='video/webm'>
<source id='ogv'
src="http://media.w3.org/2010/05/sintel/trailer.ogv"
type='video/ogg'>
<p>Your user agent does not support the HTML5 Video element.</p>
</video>
<canvas id="cvs" width="500" height="500">
Your browser does not support the HTML 5 Canvas.
</canvas>
</div>
CSS：
#cvs {
position: absolute;
top: 0px;
left: 0px;
}