向一个 canvas 上的矩形应用透明度
<!DOCTYPE html>
<html>
<head>
<title>HTML5 Canvas Demo</title>
<!--[if IE]>
<script type="text/javascript" src="excanvas.js"></script>
<![endif]-->
<script>
window.onload=function() {
var mycanvas=document.getElementById("myCanvasTag");
var mycontext=mycanvas.getContext('2d');
mycontext.fillStyle='rgb(0,0,255)';
mycontext.fillRect(30,30,300,300);
mycontext.fillStyle='rgba(0,255,0,0.5)';
mycontext.fillRect(60,60,300,300);
mycontext.fillStyle='rgba(255,0,0,0.25)';
mycontext.fillRect(90,90,300,300);
}
</script>
</head>
<body>
<div style="margin-left:30px;">
<canvas id="myCanvasTag" width="400" height="400" style="border: 10px yellow solid">
</canvas>
<br /><br />
<a href="index.html">back</a>
</div>
</body>
</html>
开心洋葱 , 版权所有丨如未注明 , 均为原创丨未经授权请勿修改 , 转载请注明向一个 canvas 上的矩形应用透明度！
