效果圖
html結構
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>canvas15</title>
<link rel="stylesheet" href="">
</head>
<body>
<canvas id="canvas" style ="border:1px solid #aaa;diplay:block;margin:50px auto;">
當前瀏覽器不支持canvas,請更換瀏覽器後再試
</canvas>
</body>
</html>
js腳本
<script>
window.onload = function(){
var canvas = document.getElementById("canvas");
canvas.width = 800;
canvas.height = 800;
var context = canvas.getContext("2d");
drawStar(context,80,200,400,400,50,10,"#058");
}
function drawStar(context,r,R,x,y,rot,lineWidth,strokeStyle){
context.beginPath();
for(var i = 0;i<5;i++){
context.lineTo(Math.cos((18+i*72 - rot)/180 * Math.PI) * R + x,-Math.sin((18+i*72 - rot)/180*Math.PI)*R + y);
context.lineTo(Math.cos((54+i*72 - rot)/180 * Math.PI) * r + x,-Math.sin((54+i*72 - rot)/180*Math.PI)*r + y);
}
context.closePath();
context.lineWidth = lineWidth;
context.strokeStyle = strokeStyle;
context.stroke();
}
</script>