標籤：
1 <!DOCTYPE html> 2 <html lang=‘zh-cn‘> 3 <head> 4 <title>Insert you title</title> 5 <meta name=‘description‘ content=‘this is my page‘> 6 <meta name=‘keywords‘ content=‘keyword1,keyword2,keyword3‘> 7 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 8 <link rel=‘stylesheet‘ type=‘text/css‘ href=‘./css/index.css‘ /> 9 <script type=‘text/javascript‘ src=‘./js/jquery-1.12.1.min.js‘></script>10 <style type=‘text/css‘>11 html,body,canvas {12 margin: 0; padding: 0;13 }14 15 html {16 height: 100%;17 }18 19 body {20 background: #000;21 }22 23 #can {24 background: #FFF /* url(‘./images/index.jpg‘) no-repeat center; backgrond-size: cover */;25 display: block; margin: 25px auto; border-radius: 2px; cursor: pointer;26 }27 </style>28 <script type=‘text/javascript‘>29 $( function(){30 var can = $( ‘#can‘ ).get( 0 );31 var oCan = can.getContext( ‘2d‘ );32 var oImg = new Image();33 oImg.src = ‘./images/index.jpg‘;34 var gImg = oCan.getImageData( 50 , 30 , 100 , 150 ); /* 之所以進行擷取,是為了迴圈中讀取個數 */35 oImg.onload = function(){36 var num = 0;37 var length = gImg.data.length;38 var img = oCan.createImageData( 100 , 100 );39 for( var i = 0 ; i < length ; i++ ){40 num = i % 4; /* 0 1 2 3 */41 switch( num ){42 case 0 :43 num = 0;44 img.data[ i ] = getRandomNum();45 break;46 case 1 :47 num = 255;48 img.data[ i ] = getRandomNum();49 break;50 case 2 :51 num = 0;52 img.data[ i ] = getRandomNum();53 break;54 case 3 :55 num = getRandomNum();56 img.data[ i ] = num;57 break;58 }59 }60 oCan.putImageData( img , 10 , 20 );61 };62 function getRandomNum(){63 return Math.ceil( Math.random() * 255 ); /* 0-- 255 */64 }65 //alert(getRandomNum());66 } );67 </script>68 </head>69 <body>70 <canvas id=‘can‘ width=‘300‘ height=‘168‘>檢測到您的瀏覽器版本過低請升級您的瀏覽器版本以擷取更好的使用者體驗...</canvas>71 </body>72 </html>
[ html canvas createImageData 建立萬花筒效果 ] canvas繪圖屬性 createImageData 屬性講解 及建立萬花筒效果
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