所以，第一步是先要判断是哪个或哪些数字在时间更新时发生了变化。然后，通过这些变化信息，生成要运动的小球。在定时器的运行间隔内，对运动小球的状态进行更新。最后，对时钟和运行的小球进行统一渲染
<canvas>当前浏览器不支持canvas，请更换浏览器后再试</canvas> <script src="https://files.cnblogs.com/files/xiaohuochai/digit.js"></script> <script> var canvas = document.getElementById('canvas'); if(canvas.getContext){ var cxt = canvas.getContext('2d'); } //声明canvas的宽高 var H = 100,W = 700; canvas.height = H; canvas.width = W; //存储时间数据 var data = []; //存储运动的小球 var balls = []; //设置粒子半径 var R = canvas.height/20-1; (function(){ var temp = /(\d)(\d):(\d)(\d):(\d)(\d)/.exec(new Date()); //存储时间数字，由十位小时、个位小时、冒号、十位分钟、个位分钟、冒号、十位秒钟、个位秒钟这7个数字组成 data.push(temp[1],temp[2],10,temp[3],temp[4],10,temp[5],temp[6]); })(); /*生成点阵数字*/ function renderDigit(index,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){ cxt.beginPath(); cxt.arc(14*(R+2)*index + j*2*(R+1)+(R+1),i*2*(R+1)+(R+1),R,0,2*Math.PI); cxt.closePath(); cxt.fill(); } } } } /*更新时钟*/ function updateDigitTime(){ var changeNumArray = []; var temp = /(\d)(\d):(\d)(\d):(\d)(\d)/.exec(new Date()); var NewData = []; NewData.push(temp[1],temp[2],10,temp[3],temp[4],10,temp[5],temp[6]); for(var i = data.length-1; i >=0 ; i--){ //时间发生变化 if(NewData[i] !== data[i]){ //将变化的数字值和在data数组中的索引存储在changeNumArray数组中 changeNumArray.push(i+'_'+(Number(data[i])+1)%10); } } //增加小球 for(var i = 0; i< changeNumArray.length; i++){ addBalls.apply(this,changeNumArray[i].split('_')); } data = NewData.concat(); } /*更新小球状态*/ function updateBalls(){ for(var i = 0; i < balls.length; i++){ balls[i].stepY += balls[i].disY; balls[i].x += balls[i].stepX; balls[i].y += balls[i].stepY; if(balls[i].x > W + R || balls[i].y > H + R){ balls.splice(i,1); i--; } } } /*增加要运动的小球*/ function addBalls(index,num){ var numArray = [1,2,3]; var colorArray = ["#3BE","#09C","#A6C","#93C","#9C0","#690","#FB3","#F80","#F44","#C00"]; 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 ball = { x:14*(R+2)*index + j*2*(R+1)+(R+1), y:i*2*(R+1)+(R+1), stepX:Math.floor(Math.random() * 4 -2), stepY:-2*numArray[Math.floor(Math.random()*numArray.length)], color:colorArray[Math.floor(Math.random()*colorArray.length)], disY:1 }; balls.push(ball); } } } } /*渲染*/ function render(){ //重置画布宽度，达到清空画布的效果 canvas.height = 100; //渲染时钟 for(var i = 0; i < data.length; i++){ renderDigit(i,data[i]); } //渲染小球 for(var i = 0; i < balls.length; i++){ cxt.beginPath(); cxt.arc(balls[i].x,balls[i].y,R,0,2*Math.PI); cxt.fillStyle = balls[i].color; cxt.closePath(); cxt.fill(); } } clearInterval(oTimer); var oTimer = setInterval(function(){ //更新时钟 updateDigitTime(); //更新小球状态 updateBalls(); //渲染 render(); },50); </script>
公告栏扩展
将canvas粒子时钟js部分封装为canvasTime.js，在公告栏添加如下代码，即可以实现在公告栏插入时钟的效果
<canvas>当前浏览器不支持canvas，请更换浏览器后再试</canvas> <script src="https://files.cnblogs.com/files/xiaohuochai/canvasTime.js"></script>
