• 从一个QQ群友那儿偷来的js图形 ^_^


    <script type="text/javascript">
    var head=document.createElement("HEAD");
    document.documentElement.appendChild(head);
    var title=document.createElement("TITLE");
    head.appendChild(title);
    var text=document.createTextNode("HTML5 Canvas Demo");
    title.appendChild(text);
    var b = document.createElement("BODY");
    document.documentElement.appendChild(b);
    var c=document.createElement("CANVAS");
    var node=document.createTextNode("your browser does not support the canvas tag");
    var img=document.createElement("IMG");
    c.appendChild(node);
    b.appendChild(c);
    c.id="myCanvas";
    c.width="600";
    c.height="600";
    c.style.border="3px solid #FF0000";
     var FPS = 1000;
     var FRAME_MSEC = 1000 / FPS >> 0;
     var center_X = 300;
     var center_Y = 300;
     var max = 300;
     
     var $ = c.getContext("2d");
     
    c.onmousedown = function(e){
                            b.appendChild(img);
    var url = c.toDataURL();
    img.src=url;
    }
     var n = 0;
     setInterval(intervalHandler, FRAME_MSEC);
     function intervalHandler() {
        $.clearRect(0, 0, 600, 600);
        var prevX = center_X;
        var prevY = center_Y;
        for (var i = 0; i < max; i++) {
            $.beginPath();
            $.lineWidth = 1;
            $.strokeStyle = getColorHSV(i / max * 360 + n * 4000);
            $.moveTo(prevX, prevY);
            $.lineTo(
                prevX = center_X + (i * Math.cos(i + (i * n))), //prevX, prevY values will change structures
                prevY = center_Y + (i * Math.sin(i + (i * n))));
            $.stroke();
        }
        n += .00025; //spin & transform speed control
    
    
    
     }
     function getColorHSV(h) { //color scheme.
        var ht = (((h %= 360) < 0) ? h + 360 : h) / 60;
        var hi = Math.floor(ht);
        var r, g, b;
        var m = Math.round;
        
        switch (hi) {
            case 0:
                r = 0xff;
                g = m(0xff * (ht - hi));
                b = 0;
                break;
            case 1:
                g = 0xff;
                r = m(0xff * (1 - (ht - hi)));
                b = 0;
                break;
            case 2:
                g = 0xff;
                b = m(0xff * (ht - hi));
                r = 0;
                break;
            case 3:
                b = 0xff;
                g = m(0xff * (1 - (ht - hi)));
                r = 0;
                break;
            case 4:
                b = 0xff;
                r = m(0xff * (ht - hi));
                g = 0;
                break;
            case 5:
                r = 0xff;
                b = m(0xff * (1 - (ht - hi)));
                g = 0;
                break;
        }
        return "rgb(" + r + ", " + g + ", " + b + ")";
        
     }  
    </script>                  

    直接保存为xx.html文件,双击用浏览器打开,结果为一个不断旋转的动态图,示例请点开链接

    http://fb.xin3e.com/jsgraph/canvans.html

    结果截图如下

    已经过作者同意……

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  • 原文地址:https://www.cnblogs.com/fengbohello/p/4341594.html
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