标签：
<!DOCTYPE html>
<html>
<head>
<title>太阳系</title>
</head>
<body>
<canvas id="canvas" width="1000" height="1000" style="background: #000">您的浏览器不支持</canvas>
<script>
var cxt = document.getElementById('canvas').getContext('2d');//设置2d环境
//轨道
function drawTrack() {
for (var i = 0; i < 8; i++) {
cxt.beginPath();
cxt.arc(500, 500, 50 * (i + 1), 0, 360, false);
cxt.closePath();
cxt.strokeStyle = "#fff";
cxt.stroke();
}
}
//drawTrack();
//星球
function drawStar(x, y, radius, startColor, endColor, cycle) {
//星球的坐标点、半径、颜色（开始、结束）、公转周期
this.x = x;
this.y = y;
this.radius = radius;
this.startColor = startColor;
this.endColor = endColor;
this.cycle = cycle;
//渐变颜色空对象
this.color = null;
this.time = 0;//设置一个计时器
this.draw = function () {
cxt.save();
cxt.translate(500, 500);
cxt.rotate(this.time * (360 / this.cycle) * Math.PI / 180);
cxt.beginPath();
cxt.arc(this.x, this.y, this.radius, 0, 360, false);
cxt.closePath();
this.color = cxt.createRadialGradient(this.x, this.y, 0, this.x,
this.y, this.radius);//径向渐变
this.color.addColorStop(0, this.startColor);
this.color.addColorStop(1, this.endColor);
cxt.fillStyle = this.color;
cxt.fill();
cxt.restore();
this.time += 1;
}
}
//创建一个太阳对象的构造函数
function Sun() {
//第一个参数是this,从第二个参数开始才是drawStar方法的参数
drawStar.call(this, 0, 0, 20, "#f60", "#f90", 0);
}
//水星
function Mercury() {
drawStar.call(this, 0, -50, 10, "#a69697", "#5c3e40", 87.7);
}
//金星
function Venus() {
drawStar.call(this, 0, -100, 10, "#c4bbac", "#1f1315", 224.701);
}
//地球
function Earth() {
drawStar.call(this, 0, -150, 10, "#78B1E8", "#050C12", 365.2422);
}
//火星
function Mars() {
drawStar.call(this, 0, -200, 10, "#CEC9B6", "#76422D", 686.98);
}
//木星
function Jupiter() {
drawStar.call(this, 0, -250, 10, "#C0A48E", "#322222", 4332.589);
}
//土星
function Saturn() {
drawStar.call(this, 0, -300, 10, "#F7F9E3", "#5C4533", 10759.5);
}
//天王星
function Uranus() {
drawStar.call(this, 0, -350, 10, "#A7E1E5", "#19243A", 30799.095);
}
//海王星
function Neptune() {
drawStar.call(this, 0, -400, 10, "#0661B2", "#1E3B73", 164.8 * 365);
}
var sun = new Sun();
var mercury = new Mercury();
var venus = new Venus();
var earth = new Earth();
var mars = new Mars();
var jupiter = new Jupiter();
var saturn = new Saturn();
var uranus = new Uranus();
var neptune = new Neptune();
function drawAll() {
cxt.clearRect(0, 0, 1000, 1000);
//先画轨道
drawTrack();
//画行星
sun.draw();
mercury.draw();
venus.draw();
earth.draw();
mars.draw();
jupiter.draw();
saturn.draw();
uranus.draw();
neptune.draw();
}
setInterval(drawAll, 10);
</script>
</body>
</html>
标签：
原文地址：http://blog.csdn.net/lindonglian/article/details/44996293
