canvas-tangram.html 

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <canvas id="canvas" style="border: 1px #ddd solid;display: block;margin:0 auto"></canvas>
    <script>
        var tangram = [
            {p:[{x:0,y:0},{x:800,y:0},{x:400,y:400}],color:"red"},
            {p:[{x:0,y:0},{x:400,y:400},{x:0,y:800}],color:"blue"},
            {p:[{x:800,y:0},{x:800,y:400},{x:600,y:600},{x:600,y:200}],color:"yellow"},
            {p:[{x:600,y:200},{x:600,y:600},{x:400,y:400}],color:"green"},
            {p:[{x:400,y:400},{x:600,y:600},{x:400,y:800},{x:200,y:600}],color:"pink"},
            {p:[{x:200,y:600},{x:0,y:800},{x:400,y:800}],color:"orange"},
            {p:[{x:800,y:400},{x:800,y:800},{x:400,y:800}],color:"purple"}
        ];

        function draw(piece,cxt){
            cxt.beginPath();
            cxt.moveTo(piece.p[0].x , piece.p[0].y);
            for(var i=1;i<piece.p.length;i++){
                cxt.lineTo(piece.p[i].x , piece.p[i].y);
            }
            cxt.closePath();
            cxt.fillStyle = piece.color;
            cxt.fill();
        }

        window.onload = function(){
            var canvas = document.getElementById('canvas');

            canvas.width = 800;
            canvas.height = 800;

            if(canvas.getContext('2d')){
                var context = canvas.getContext('2d');

                for(var i=0;i<tangram.length;i++){
                    draw(tangram[i],context)
                }
                

            }else{
                alert('当前游览器不支持Canvas，请更换游览器后再试！');
            }
        }
    </script>
</body>
<script>
/*
  总结 绘制七巧板

  主要运用的js的for循环的巧妙

  1.定义路径 trangram

  2.第一层for，循环trangram[i]

  3.函数draw,第二层for，循环取出绘制路径 trangram.p[i].x 
*/
</script>
</html>

 

posted @ 2015-11-19 17:25  Cynthia娆墨旧染  阅读(360)  评论(0)    收藏  举报