canvas 制作动效线条背景（可与鼠标交互）

小灰灰 2023-06-30 04:24 25阅读 0赞

完整代码：

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
    <canvas id="canvas"></canvas>
    
    <style> canvas{ display: block;width: 100%;height: 100%;position:absolute;z-index: -1;} </style>
    
    <script> class Circle { //创建对象 //以一个圆为对象 //设置随机的 x，y坐标，r半径，_mx，_my移动的距离 //this.r是创建圆的半径，参数越大半径越大 //this._mx,this._my是移动的距离，参数越大移动 constructor(x, y) { this.x = x; this.y = y; this.r = Math.random() * 10 ; this._mx = Math.random() ; this._my = Math.random() ; } //canvas 画圆和画直线 //画圆就是正常的用canvas画一个圆 //画直线是两个圆连线，为了避免直线过多，给圆圈距离设置了一个值，距离很远的圆圈，就不做连线处理 drawCircle(ctx) { ctx.beginPath(); //arc() 方法使用一个中心点和半径，为一个画布的当前子路径添加一条弧。 ctx.arc(this.x, this.y, this.r, 0, 360) ctx.closePath(); ctx.fillStyle = 'rgba(204, 204, 204, 0.3)'; ctx.fill(); } drawLine(ctx, _circle) { let dx = this.x - _circle.x; let dy = this.y - _circle.y; let d = Math.sqrt(dx * dx + dy * dy) if (d < 180) { ctx.beginPath(); //开始一条路径，移动到位置 this.x,this.y。创建到达位置 _circle.x,_circle.y 的一条线： ctx.moveTo(this.x, this.y); //起始点 ctx.lineTo(_circle.x, _circle.y); //终点 ctx.closePath(); ctx.strokeStyle = 'rgba(204, 204, 204, 0.3)'; ctx.stroke(); } } // 圆圈移动 // 圆圈移动的距离必须在屏幕范围内 move(w, h) { this._mx = (this.x < w && this.x > 0) ? this._mx : (-this._mx); this._my = (this.y < h / 4 && this.y > 0) ? this._my : (-this._my); this.x += this._mx / 2; this.y += this._my / 2; } } //鼠标点画圆闪烁变动 class currentCirle extends Circle { constructor(x, y) { super(x, y) } drawCircle(ctx) { ctx.beginPath(); //注释内容为鼠标焦点的地方圆圈半径变化 // this.r = (this.r < 14 && this.r > 1) ? this.r + (Math.random() * 2 - 1) : 2; this.r = 8; ctx.arc(this.x, this.y, this.r, 0, 360); ctx.closePath(); // ctx.fillStyle = 'rgba(0,0,0,' + (parseInt(Math.random() * 100) / 100) + ')' ctx.fillStyle = 'rgba(0, 0, 0, 0.3)' ctx.fill(); } } //更新页面用requestAnimationFrame替代setTimeout window.requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame || window.msRequestAnimationFrame; let canvas = document.getElementById('canvas'); let ctx = canvas.getContext('2d'); let w = canvas.width = canvas.offsetWidth; let h = canvas.height = canvas.offsetHeight; let circles = []; let current_circle = new currentCirle(0, 0) let draw = function () { ctx.clearRect(0, 0, w, h); for (let i = 0; i < circles.length; i++) { circles[i].move(w, h); circles[i].drawCircle(ctx); for (j = i + 1; j < circles.length; j++) { circles[i].drawLine(ctx, circles[j]) } } if (current_circle.x) { current_circle.drawCircle(ctx); for (var k = 1; k < circles.length; k++) { current_circle.drawLine(ctx, circles[k]) } } requestAnimationFrame(draw) } let init = function (num) { for (var i = 0; i < num; i++) { circles.push(new Circle(Math.random() * w, Math.random() * h)); } draw(); } window.addEventListener('load', init(60)); window.onmousemove = function (e) { e = e || window.event; current_circle.x = e.clientX; current_circle.y = e.clientY; } window.onmouseout = function () { current_circle.x = null; current_circle.y = null; }; </script>
    </body>
    </html>

效果图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0h1YW5nc1Rpbmc_size_16_color_FFFFFF_t_70]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0h1YW5nc1Rpbmc_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200115101100662.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0h1YW5nc1Rpbmc=,size_16,color_FFFFFF,t_70