[ html canvas createLinearGradient createRadialGradient ] canvas绘制渐变 createLinearGradient createRadialGradient方式实例演示

<!DOCTYPE html>
<html lang='zh-cn'>
<head>
<title>Insert you title</title>
<meta name='description' content='this is my page'>
<meta name='keywords' content='keyword1,keyword2,keyword3'>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel='stylesheet' type='text/css' href='./css/index.css' />
<script type='text/javascript' src='./js/jquery-1.12.1.min.js'></script>
<style type='text/css'>
html,body {
    margin: 0; padding: 0;
}

html {
    background: #999; height: 100%;
}

#can {
    background: #FFF; display: block; margin: 75px auto; border-radius: 2px;
}
</style>
<script type='text/javascript'>
    $( function(){
        var canvas = $( '#can' ).get( 0 );
        var oCan = canvas.getContext( '2d' );
        var img = new Image(); /* 新建图片对象 */
        img.src = './images/bg.jpg';
        createLinearGradient();
        function createLinearGradient(){
            //var color = oCan.createLinearGradient( 0 , 0 , 500 , 500 ); /* 线性渐变 :渐变的起止位置 */
            var color = oCan.createRadialGradient( 250 , 250 , 100 , 250 , 250 , 300 ) /* 内圆坐标及半径 , 外圆坐标及半径 */
            color.addColorStop( 0 , '#333255' ); /* 添加起止颜色 , 参数 1 :位置(0,1),参数2:颜色  如果位置要有多个就不断的添加就可以了*/
            //color.addColorStop( 0.2 , '#CDE6BA' );
            //color.addColorStop( 0.5 , '#D33E59' );
            //color.addColorStop( 0.9 , '#985365' );
            color.addColorStop( 1 , '#6C9AE3' );
            oCan.fillStyle = color; /* 请注意 : fillStyle 填充样式这个属性不仅可以设置颜色还可以设置背景图片 */
            oCan.fillRect( 0 , 0 , canvas.width , canvas.height );
        }
    } );
</script>
</head>
<body>
    <canvas id='can' width='500' height='500'>您的浏览器版本过低,请升级您的浏览器以获取更好的用户体验...</canvas>
</body>
</html>
原文地址:https://www.cnblogs.com/mysearchblog/p/5762542.html