countdown.js

var WINDOW_WIDTH; //设备屏幕宽度
var WINDOW_HEIGHT; //设备屏幕高度
var RADIUS; //小球半径
var MARGIN_TOP; //距离屏幕左边的距离
var MARGIN_LEFT; //距离屏幕右边的距离

const endTime = new Date();
endTime.setTime(endTime.getTime() + 3600 * 1000); //设置倒计时的最终时间
var curShowTimeSeconds = 0;

var balls = [];
const colors = ["#33B5E5", "#0099CC", "#AA66CC", "#9933CC", "#99CC00", "#669900", "#FFBB33", "#FF8800", "#FF4444", "#CC0000"]; //小球颜色随机数组

window.onload = function () {
    WINDOW_WIDTH = document.body.clientWidth
    WINDOW_HEIGHT = document.body.clientHeight

    MARGIN_LEFT = Math.round(WINDOW_WIDTH / 10);
    RADIUS = Math.round(WINDOW_WIDTH * 4 / 5 / 108) - 1

    MARGIN_TOP = Math.round(WINDOW_HEIGHT / 5);

    var canvas = document.getElementById('canvas');
    var context = canvas.getContext("2d"); //申明画笔

    canvas.width = WINDOW_WIDTH; //设置画布宽高
    canvas.height = WINDOW_HEIGHT;

    curShowTimeSeconds = getCurrentShowTimeSeconds()
    setInterval( //刷新画布显示时间
        function () {
            render(context); //绘制小球
            update(); //更新时间及小球
        },
        50
    );
}

function getCurrentShowTimeSeconds() { //获取当前要显示的倒计时时间
    var curTime = new Date();
    var ret = endTime.getTime() - curTime.getTime();
    ret = Math.round(ret / 1000)

    return ret >= 0 ? ret : 0;
}

function update() {
    //获取下次要显示的时间
    var nextShowTimeSeconds = getCurrentShowTimeSeconds();

    var nextHours = parseInt(nextShowTimeSeconds / 3600);
    var nextMinutes = parseInt((nextShowTimeSeconds - nextHours * 3600) / 60)
    var nextSeconds = nextShowTimeSeconds % 60
    //获取现在显示的时间
    var curHours = parseInt(curShowTimeSeconds / 3600);
    var curMinutes = parseInt((curShowTimeSeconds - curHours * 3600) / 60)
    var curSeconds = curShowTimeSeconds % 60
    //判断二者是否相同，如果不相同则把将要显示的时间赋值到现在显示的时间
    if (nextSeconds != curSeconds) {
        if (parseInt(curHours / 10) != parseInt(nextHours / 10)) {
            addBalls(MARGIN_LEFT + 0, MARGIN_TOP, parseInt(curHours / 10));
        }
        if (parseInt(curHours % 10) != parseInt(nextHours % 10)) {
            addBalls(MARGIN_LEFT + 15 * (RADIUS + 1), MARGIN_TOP, parseInt(curHours / 10));
        }

        if (parseInt(curMinutes / 10) != parseInt(nextMinutes / 10)) {
            addBalls(MARGIN_LEFT + 39 * (RADIUS + 1), MARGIN_TOP, parseInt(curMinutes / 10));
        }
        if (parseInt(curMinutes % 10) != parseInt(nextMinutes % 10)) {
            addBalls(MARGIN_LEFT + 54 * (RADIUS + 1), MARGIN_TOP, parseInt(curMinutes % 10));
        }

        if (parseInt(curSeconds / 10) != parseInt(nextSeconds / 10)) {
            addBalls(MARGIN_LEFT + 78 * (RADIUS + 1), MARGIN_TOP, parseInt(curSeconds / 10));
        }
        if (parseInt(curSeconds % 10) != parseInt(nextSeconds % 10)) {
            addBalls(MARGIN_LEFT + 93 * (RADIUS + 1), MARGIN_TOP, parseInt(nextSeconds % 10));
        }

        curShowTimeSeconds = nextShowTimeSeconds;
    }

    updateBalls();

    console.log(balls.length);
}

function updateBalls() {

    for (var i = 0; i < balls.length; i++) {

        balls[i].x += balls[i].vx;
        balls[i].y += balls[i].vy;
        balls[i].vy += balls[i].g;

        if (balls[i].y >= WINDOW_HEIGHT - RADIUS) {
            balls[i].y = WINDOW_HEIGHT - RADIUS;
            balls[i].vy = -balls[i].vy * 0.75;
        }
    } //更新小球状态

    var cnt = 0
    for (var i = 0; i < balls.length; i++) //判断小球是否已经出界，如果没出界则将它复制给数组前面
        if (balls[i].x + RADIUS > 0 && balls[i].x - RADIUS < WINDOW_WIDTH)
            balls[cnt++] = balls[i];

    while (balls.length > Math.min(300, cnt)) { //删除出界的小球
        balls.pop();
    }
}

function addBalls(x, y, num) {

    for (var i = 0; i < digit[num].length; i++)
        for (var j = 0; j < digit[num][i].length; j++)
            if (digit[num][i][j] == 1) {
                var aBall = {
                    x: x + j * 2 * (RADIUS + 1) + (RADIUS + 1),
                    y: y + i * 2 * (RADIUS + 1) + (RADIUS + 1),
                    g: 1.5 + Math.random(),
                    vx: Math.pow(-1, Math.ceil(Math.random() * 1000)) * 4,
                    vy: -5,
                    color: colors[Math.floor(Math.random() * colors.length)]
                }

                balls.push(aBall)
            }
}

function render(cxt) {

    cxt.clearRect(0, 0, WINDOW_WIDTH, WINDOW_HEIGHT);

    var hours = parseInt(curShowTimeSeconds / 3600);
    var minutes = parseInt((curShowTimeSeconds - hours * 3600) / 60)
    var seconds = curShowTimeSeconds % 60

    renderDigit(MARGIN_LEFT, MARGIN_TOP, parseInt(hours / 10), cxt)
    renderDigit(MARGIN_LEFT + 15 * (RADIUS + 1), MARGIN_TOP, parseInt(hours % 10), cxt)
    renderDigit(MARGIN_LEFT + 30 * (RADIUS + 1), MARGIN_TOP, 10, cxt)
    renderDigit(MARGIN_LEFT + 39 * (RADIUS + 1), MARGIN_TOP, parseInt(minutes / 10), cxt);
    renderDigit(MARGIN_LEFT + 54 * (RADIUS + 1), MARGIN_TOP, parseInt(minutes % 10), cxt);
    renderDigit(MARGIN_LEFT + 69 * (RADIUS + 1), MARGIN_TOP, 10, cxt);
    renderDigit(MARGIN_LEFT + 78 * (RADIUS + 1), MARGIN_TOP, parseInt(seconds / 10), cxt);
    renderDigit(MARGIN_LEFT + 93 * (RADIUS + 1), MARGIN_TOP, parseInt(seconds % 10), cxt);

    for (var i = 0; i < balls.length; i++) {
        cxt.fillStyle = balls[i].color;

        cxt.beginPath();
        cxt.arc(balls[i].x, balls[i].y, RADIUS, 0, 2 * Math.PI, true);
        cxt.closePath();

        cxt.fill();
    }
}

function renderDigit(x, y, num, cxt) { //绘制小球

    cxt.fillStyle = "rgb(0,102,153)";

    for (var i = 0; i < digit[num].length; i++)
        for (var j = 0; j < digit[num][i].length; j++)
            if (digit[num][i][j] == 1) {
                cxt.beginPath();
                cxt.arc(x + j * 2 * (RADIUS + 1) + (RADIUS + 1), y + i * 2 * (RADIUS + 1) + (RADIUS + 1), RADIUS, 0, 2 * Math.PI)
                cxt.closePath()

                cxt.fill()
            }
}