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2.新建决策报表后添加body初始化后事件

添加js代码:

$("body").prepend('<canvas id="canvas" style="position:absolute;z-index:-2;"></canvas>');

var canvas = document.getElementById('canvas'),

ctx = canvas.getContext('2d'),

w = canvas.width = window.innerWidth,

h = canvas.height = window.innerHeight,

hue = 217,

stars = [],

count = 0,

maxStars = 1100;                //星星数量,默认1300

var canvas2 = document.createElement('canvas'),

ctx2 = canvas2.getContext('2d');

canvas2.width = 100;

canvas2.height = 100;

var half = canvas2.width / 2,

gradient2 = ctx2.createRadialGradient(half, half, 0, half, half, half);

gradient2.addColorStop(0.025, '#CCC');

gradient2.addColorStop(0.1, 'hsl(' + hue + ', 61%, 33%)');

gradient2.addColorStop(0.25, 'hsl(' + hue + ', 64%, 6%)');

gradient2.addColorStop(1, 'transparent');

ctx2.fillStyle = gradient2;

ctx2.beginPath();

ctx2.arc(half, half, half, 0, Math.PI * 2);

ctx2.fill();

// End cache

function random(min, max) {

    if (arguments.length < 2) {

        max = min;

        min = 0;

    }

    if (min > max) {

        var hold = max;

        max = min;

        min = hold;

    }

    return Math.floor(Math.random() * (max - min + 1)) + min;

}

function maxOrbit(x, y) {

    var max = Math.max(x, y),

    diameter = Math.round(Math.sqrt(max * max + max * max));

    return diameter / 2;

    //星星移动范围，值越大范围越小，

}

var Star = function() {

    this.orbitRadius = random(maxOrbit(w, h));

    this.radius = random(60, this.orbitRadius) / 10;       //星星大小,值越大星星越小,默认8

    this.orbitX = w / 2;

    this.orbitY = h / 2;

    this.timePassed = random(0, maxStars);

    this.speed = random(this.orbitRadius) / 80000;        //星星移动速度,值越大越慢,默认5W

    this.alpha = random(2, 10) / 10;

    count++;

    stars[count] = this;

}

Star.prototype.draw = function() {

    var x = Math.sin(this.timePassed) * this.orbitRadius + this.orbitX,

    y = Math.cos(this.timePassed) * this.orbitRadius + this.orbitY,

    twinkle = random(10);

    if (twinkle === 1 && this.alpha > 0) {

        this.alpha -= 0.05;

    } else if (twinkle === 2 && this.alpha < 1) {

        this.alpha += 0.05;

    }

    ctx.globalAlpha = this.alpha;

    ctx.drawImage(canvas2, x - this.radius / 2, y - this.radius / 2, this.radius, this.radius);

    this.timePassed += this.speed;

}

for (var i = 0; i < maxStars; i++) {

    new Star();

}

function animation() {

    ctx.globalCompositeOperation = 'source-over';

    ctx.globalAlpha = 0.5;                                 //尾巴

    ctx.fillStyle = 'hsla(' + hue + ', 64%, 6%, 2)';

    ctx.fillRect(0, 0, w, h)

    ctx.globalCompositeOperation = 'lighter';

    for (var i = 1,

    l = stars.length; i < l; i++) {

        stars[i].draw();

    };

    window.requestAnimationFrame(animation);

}

animation(); 

3.保存预览