function officialseal(opt) {
opt = opt || {
canvas: $$('#canvas'),
companyName: canvas.getAttribute('data-companyName'),
sealTypeName: canvas.getAttribute('data-sealTypeName')
};
// official seal
var ctx = opt['canvas'].getContext('2d'), color = '#f00', width = opt['canvas'].width/2, height = opt['canvas'].height/2;
ctx.lineWidth = 6;
ctx.strokeStyle = color;
ctx.beginPath();
ctx.arc(width, height, 110, 0, Math.PI*2);
ctx.stroke();
// five pointed star
var radius = 30, rotato = 0;
ctx.save();
ctx.fillStyle = color;
ctx.translate(width, height);
ctx.rotate(Math.PI+rotato);
ctx.beginPath();
var x, y, dig = Math.PI/5*4;
for (var i = 0;i< 5;i++) {
x = Math.sin(i*dig);
y = Math.cos(i*dig);
ctx.lineTo(x*radius, y*radius);
}
ctx.closePath();
ctx.stroke();
ctx.fill();
ctx.restore();
// sealTypeName
ctx.font = '20px Microsoft YaHei';
ctx.textBaseline = 'middle';
ctx.textAlign = 'center';
ctx.lineWidth = 1;
ctx.fillStyle = color;
ctx.fillText(opt['sealTypeName'], width, height+70);
// companyName
ctx.translate(width, height);
ctx.font = '26px Microsoft YaHei';
var chars = opt['companyName'].split('')
, count = chars.length
, angle = 4*Math.PI / (3*(count - 1))
;
for (var i = 0; i < chars.length; i++){ // var character = chars[i];
if (i == 0) {
ctx.rotate(5*Math.PI/6);
} else {
ctx.rotate(angle);
}
ctx.save();
ctx.translate(90, 0);
ctx.rotate(Math.PI/2);
ctx.fillText(chars[i], 0, 5);
ctx.restore();
}
}<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<meta name="renderer" content="webkit" />
<meta name="viewport" content="width=device-width,user-scalable=yes" />
<meta name="renderer" content="webkit|ie-comp|ie-stand" />
<title>official_seal</title>
<script src="/js/u.js?v=1"></script>
</head>
<body onclick="clickHandler(event);" onchange="changeHandler(event);">
<canvas id="canvas" width="250" height="250" data-companyName="郑州快马科技有限公司" data-sealTypeName="测试专用章"></canvas>
<script src="official_seal.js?v=1"></script>
</body>
</html>
文章来源地址https://uudwc.com/A/qRyjp
文章来源：https://uudwc.com/A/qRyjp
