先看看最简单的效果图：
代码如下：
JavaScript Code复制内容到剪贴板
- var canvas = document.getElementById('my'), ctx = canvas.getContext('2d');
-
setInterval(function(){
- ctx.clearRect(0,0,400,400);
- ctx.save();
- ctx.translate(200,200);
-
var ci =90, pi = Math.PI / ci, x1 = 100, y1 =0, x2 =0, y2 =0, x3 =0, y3 =0;
- ctx.beginPath();
-
for(var i = ci *2; i >0; i--){
- ctx.rotate(pi);
- ctx.moveTo(x1,y1);
- y2 = x1 * Math.sin(pi);
- x2 = x1 * Math.cos(pi);
- x3 = (x1 - x2) /2+ x2 +10+ Math.random() *20;
- y3 = y2 /2;
- ctx.lineTo(x3,y3);
- ctx.lineTo(x2,y2);
- }
- ctx.stroke();
- ctx.restore();
- },100);
在上面多角形的基础上进一步之后为：
代码如下：
JavaScript Code复制内容到剪贴板
- var canvas = document.getElementById('my'), ctx = canvas.getContext('2d'), r =10;
-
setInterval(function(){
- ctx.clearRect(0,0,400,400);
- ctx.save();
- ctx.translate(200,200);
-
var grad = ctx.createRadialGradient(0,0,0,0,0,r+20);
-
grad.addColorStop(0.2,'white');
-
grad.addColorStop(0.7,'yellow');
-
grad.addColorStop(0.8,'orange');
- ctx.beginPath();
- ctx.fillStyle = grad;
-
ctx.arc(0,0,r,0,Math.PI*2,true);
- ctx.fill();
-
var ci =90, pi = Math.PI / ci, x2 =0, y2 =0, x3 =0, y3 =0;
- x1 =100;
- y1 =0;
- ctx.beginPath();
-
for(var i = ci *2; i >0; i--){
- ctx.rotate(pi);
- ctx.moveTo(r,0);
- y2 = r * Math.sin(pi);
- x2 = r * Math.cos(pi);
-
- x3 = (r - x2) /2+ x2 +10+ Math.random() *20;
- y3 = y2 /2;
-
- ctx.lineTo(x3,y3);
- ctx.lineTo(x2,y2);
- }
- ctx.fill();
- ctx.restore();
- r
- },100);
-
以上就是本文的全部内容，希望对大家的学习有所帮助。
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
