html 绘图阴影和透明度 

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        #mycanvas{
            border: 1px solid #9c9898;
            background: blue;
        }

    </style>
    <script language="JavaScript">
        window.onload=function(){
            var canvas = document.getElementById("mycanvas");
            var contex = canvas.getContext("2d");
            //绘制矩形
            contex.beginPath();
            contex.rect(50,50,100,50);
            contex.lineWidth=5;
            contex.strokeStyle="blue";
            contex.stroke();
            contex.fillStyle="red";
            //设置阴影在fill方法之前
            contex.shadowColor="black";//阴影颜色
            contex.shadowBlur=0;//模糊度，越大越模糊
            contex.shadowOffsetX=50;//偏移量;
            contex.shadowOffsetY=10;
            contex.globalAlpha=1;//透明度 介于0-1 0 完全透明
            contex.fill();


            //绘制圆
            contex.beginPath();
            var centx=320;
            var centy=400;
            var r=100;
            contex.arc(centx,centy,r,0,2*Math.PI);
            contex.lineWidth=10;
            contex.strokeStyle="black";
            contex.stroke();
            contex.fillStyle="green";
            contex.fill();
        }
    </script>
</head>
<body>
    <canvas id="mycanvas" width="800" height="800"></canvas>
</body>
</html>

 

posted @ 2016-07-28 15:08  超级学渣渣  阅读(748)  评论(0)    收藏  举报