这份不是我自己写的 是转载别人的 但是我找不到 我在哪里找到的了
非常抱歉 但是学习的目的都是统一的 这个的写法比较高大上 可以看看
html 代码
- <!DOCTYPE html>
- <html>
- <head>
- <meta charset="UTF-8">
- <title>canvas</title>
- <style type="text/CSS">
- body{
- text-align: center;
- background: #F7FAFC;
- overflow: hidden;
- background: #fff;
- }
- </style>
- </head>
- <body>
- <canvas id="Mycanvas"></canvas>
- <script>
- // 定义画布宽高和生成点的个数
- var WIDTH = window.innerWidth, HEIGHT = window.innerHeight, POINT = 35;
- var canvas = document.getElementById('Mycanvas');
- canvas.width = WIDTH,
- canvas.height = HEIGHT;
- var context = canvas.getContext('2d');
- context.strokeStyle = 'rgba(0,0,0,0.02)',
- context.strokeWidth = 1,
- context.fillStyle = 'rgba(0,0,0,0.05)';
- var circleArr = [];
- // 线条: 开始 xy 坐标, 结束 xy 坐标, 线条透明度
- function Line (x, y, _x, _y, o) {
- this.beginX = x,
- this.beginY = y,
- this.closeX = _x,
- this.closeY = _y,
- this.o = o;
- }
- // 点: 圆心 xy 坐标, 半径, 每帧移动 xy 的距离
- function Circle (x, y, r, moveX, moveY) {
- this.x = x,
- this.y = y,
- this.r = r,
- this.moveX = moveX,
- this.moveY = moveY;
- }
- // 生成 max 和 min 之间的随机数
- function num (max, _min) {
- var min = arguments[1] || 0;
- return Math.floor(Math.random()*(max-min+1)+min);
- }
- // 绘制原点
- function drawCricle (cxt, x, y, r, moveX, moveY) {
- var circle = new Circle(x, y, r, moveX, moveY)
- cxt.beginPath()
- cxt.arc(circle.x, circle.y, circle.r, 0, 2*Math.PI)
- cxt.closePath()
- cxt.fill();
- return circle;
- }
- // 绘制线条
- function drawLine (cxt, x, y, _x, _y, o) {
- var line = new Line(x, y, _x, _y, o)
- cxt.beginPath()
- cxt.strokeStyle = 'rgba(0,0,0,'+ o +')'
- cxt.moveTo(line.beginX, line.beginY)
- cxt.lineTo(line.closeX, line.closeY)
- cxt.closePath()
- cxt.stroke();
- }
- // 初始化生成原点
- function init () {
- circleArr = [];
- for (var i = 0; i <POINT; i++) {
- circleArr.push(drawCricle(context, num(WIDTH), num(HEIGHT), num(15, 2), num(10, -10)/40, num(10, -10)/40));
- }
- draw();
- }
- // 每帧绘制
- function draw () {
- context.clearRect(0,0,canvas.width, canvas.height);
- for (var i = 0; i < POINT; i++) {
- drawCricle(context, circleArr[i].x, circleArr[i].y, circleArr[i].r);
- }
- for (var i = 0; i < POINT; i++) {
- for (var j = 0; j < POINT; j++) {
- if (i + j < POINT) {
- var A = Math.abs(circleArr[i+j].x - circleArr[i].x),
- B = Math.abs(circleArr[i+j].y - circleArr[i].y);
- var lineLength = Math.sqrt(A*A + B*B);
- var C = 1/lineLength*7-0.009;
- var lineOpacity = C> 0.03 ? 0.03 : C;
- if (lineOpacity> 0) {
- drawLine(context, circleArr[i].x, circleArr[i].y, circleArr[i+j].x, circleArr[i+j].y, lineOpacity);
- }
- }
- }
- }
- }
- // 调用执行
- window.onload = function () {
- init();
- setInterval(function () {
- for (var i = 0; i <POINT; i++) {
- var cir = circleArr[i];
- cir.x += cir.moveX;
- cir.y += cir.moveY;
- if (cir.x> WIDTH) cir.x = 0;
- else if (cir.x <0) cir.x = WIDTH;
- if (cir.y> HEIGHT) cir.y = 0;
- else if (cir.y <0) cir.y = HEIGHT;
- }
- draw();
- }, 16);
- }
- </script>
- </body>
- </html>
来源: http://www.qdfuns.com/article/25573/c983d0def24ac412b22d53a9bec3ae89.html