html5畫布旋轉效果示例

字號:


    本文介紹了JS和html5實現(xiàn)畫布旋轉效果示例,大家參考使用吧
    keleyi.htm的代碼如下:
    代碼如下:
    <!DOCTYPE HTML> 
    <html>
    <head>
    <title>html旋轉畫布</title>
    <script type="text/javascript" src="/jquery-1.10.2.min.js"></script>
    <script type="text/javascript" src="jb51.js"></script>
    </head>
    <body>
    <canvas id="jb51"></canvas>
    </body>
    </html>
    jb51.js的代碼如下:
    代碼如下:
    /*
    * 功能:畫布旋轉
    */
    (function(){
    var canvas=null,
    context=null,
    angle=0;
    function resetCanvas(){
    canvas=document.getElementById("jb51");
    canvas.width=window.innerWidth;
    canvas.height=window.innerHeight;
    context=canvas.getContext("2d");
    }
    function animate(){
    context.save();
    try{
    //清除畫布
    context.clearRect(0, 0, canvas.width, canvas.height);
    //設置原點
    context.translate(canvas.width * 0.5, canvas.height * 0.5);
    //旋轉角度
    context.rotate(angle);
    //設置填充顏色
    context.fillStyle = "#FF0000";
    //繪制矩形
    context.fillRect(-30, -30, 60, 60);
    angle += 0.05 * Math.PI;
    }
    finally{
    context.restore();
    }
    }
    $(window).bind("resize",resetCanvas).bind("reorient",resetCanvas);
    $(document).ready(function(){
    window.scrollTo(0,1);
    resetCanvas();
    setInterval(animate,40);
    });
    })();