七巧板的问题

来源:2-2 绘制直线、多边形和七巧板

飞飞赫赫

2016-03-31 20:53

<!DOCTYPE html>

<html>

<head>

<meta charset="UTF-8">

<title>七巧板的实现</title>

</head>

<body>

<script type="text/javascript">

var tangram = [

{p:[{x:0,y:0},{x:800,y:0},{x:400,y:400}],color:"#caff67"},

{p:[{x:0,y:0},{x:400,y:400},{x:0,y:800}],color:"#67becf"},

{p:[{x:800,y:0},{x:800,y:400},{x:600,y:600},{x:600,y:200}],color:"#ef3d61"},

{p:[{x:600,y:200},{x:600,y:600},{x:400,y:400}],color:"#f9f51a"},

{p:[{x:400,y:400},{x:600,y:600},{x:400,y:800},{x:200,y:600}],color:"#a594c0"},

{p:[{x:200,y:600},{x:400,y:800},{x:0,y:800}],color:"#fa8ecc"},

{p:[{x:800,y:400},{x:800,y:800},{x:400,y:800}],color:"#f6ca29"}

];


window.onload = function(){

var canvas = document.getElementById('canvas');

canvas.width = 800;

canvas.height = 800;

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

for (var i=0;i<tangram.length;i++) {

draw(tangram[i],context);

}

}

function draw(piece,cxt) {

cxt.beginPath();

cxt.moveTo(piece.p[0].x,piece.p[0].y);

for (var i=1;i<piece.length;i++) {

cxt.lineTo(piece.p[i].x,piece.p[i].y);

}

cxt.closePath();

cxt.fillStyle = piece.color;

cxt.fill();

}

</script>

<canvas id="canvas"></canvas>

</body>

</html>

自己到底哪里错了?

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2回答

  • dennyzhou
    2016-03-31 23:19:57
    已采纳

    for (var i=1;i<piece.p.length;i++) {

    cxt.lineTo(piece.p[i].x,piece.p[i].y);

    应该是piece对象的p属性的长度


    飞飞赫赫

    非常感谢!

    2016-04-04 10:39:34

    共 1 条回复 >

  • 慕斯4708754
    2016-03-31 23:17:47

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

       }
       cxt.closePath();
       cxt.fillStyle = piece.color;
       cxt.fill();

       cxt.strokeStyle = "black";
       cxt.stroke();
    }


    第2个for循环里,索引应该是var i = 0;

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