昨天晚上心血来潮，整了一下blog的模板，目前使用的是 BootCDN 1.0 ，根据自己的需求，修改了一些css，去除了一些暂时用不到的功能。
之前 banner 的背景是白色的，整站比较单调，就想整个背景上去，博主前端水平比较爪机，于是乎去找了一些资源，发现用有大婶用 canvas 模拟出了知乎的登录背景于是copy之。
最终用 canvas 做背景特效的代码( header.php 文件，部分代码根据自己的需求进行微调 ):
代码语言：javascript复制 <canvas id="Mycanvas" style="display: none;"></canvas>
<header class="main-header" id="banner">
<div class="container">
<div class="row">
<div class="col-sm-12">
<h1><?php echo $blogname; ?></h1>
</div>
</div>
</div>
</header>
<script>
//定义画布宽高和生成点的个数
var WIDTH = window.innerWidth,
HEIGHT = 300,
// HEIGHT = window.innerHeight,
POINT = 35;
var canvas = document.getElementById('Mycanvas');
canvas.width = WIDTH,
canvas.height = HEIGHT;
var context = canvas.getContext('2d');
context.strokeStyle = 'rgba(0,0,0,0.2)',
context.strokeWidth = 1,
context.fillStyle = 'rgba(0,0,0,0.1)';
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();
document.getElementById('banner').style.backgroundImage = 'url("' context.canvas.toDataURL() '")';
}, 16);
}
</script>get了别人的资源必须贴链接:
- 仿知乎背景canvas特效源码 http://www.5iweb.com.cn/html5-css3-effects/653.html
- 使用Canvas绘制背景图 http://www.tuicool.com/articles/ue2ARr
