canvas基础绘制-绚丽倒计时的实例

2019-11-19 15:25:38

字体：大中小

来源：转载

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效果图：

html：

<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>ball</title> <script src="digit_1.js"></script> <script src="countdown.js"></script></head><body ><canvas id="canvas" ></canvas></body></html>

digit_1.js在之前的 canvas基础绘制-倒计时中有贴

countdown.js:

var WINDOW_WIDTH = 1024;var WINDOW_HEIGHT = 768;var RADIUS = 8;var MARGIN_TOP = 60;var MARGIN_LEFT = 30;var endTime = new Date();//const声明变量，不可修改，必须声明时赋值；endTime.setTime( endTime.getTime() + 3600*1000);//当前时间向后一小时；var curShowTimeSeconds = 0;var balls =[];const colors = ["#33B5E5","#0099CC","#AA66CC","#9933CC","#99CC00","#669900","#FFBB33","#FF8800","#FF4444","#CC0000"];window.onload = function () { //屏幕自适应 WINDOW_WIDTH = document.body.clientWidth; WINDOW_HEIGHT = document.body.clientHeight; RADIUS = Math.round(WINDOW_WIDTH*4/5/108)-1; MARGIN_TOP = Math.round(WINDOW_HEIGHT/5); MARGIN_LEFT = Math.round(WINDOW_WIDTH/10); var canvas = document.getElementById("canvas"); var context = canvas.getContext("2d"); canvas.width = WINDOW_WIDTH; canvas.height = WINDOW_HEIGHT; curShowTimeSeconds = getCurrentShowTimeSeconds(); setInterval(  function () {   update();   render(context); },50)};function getCurrentShowTimeSeconds() { var curTime = new Date();//获取目前时间； var ret = endTime.getTime()-curTime.getTime(); ret = Math.round(ret/1000);//获取秒数差值； return ret>=0?ret:0;}

function update() { var nextShowTimeSeconds = getCurrentShowTimeSeconds(); var nextHours = parseInt(nextShowTimeSeconds/3600); var nextMinutes = parseInt((nextShowTimeSeconds-nextHours*3600)/60); var nextSeconds = nextShowTimeSeconds%60; var curHours = parseInt(curShowTimeSeconds/3600); var curMinutes = parseInt((curShowTimeSeconds-curHours*3600)/60); var curSeconds = curShowTimeSeconds%60; 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(curSeconds%10));  }  curShowTimeSeconds = nextShowTimeSeconds; }  updateBalls();}function updateBalls() { //循环遍历每一个彩色动画小球 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;  //落到画布最底部时反弹起来  if(balls[i].y>=WINDOW_HEIGHT){   balls[i].y = WINDOW_HEIGHT-RADIUS;   balls[i].vy = -balls[i].vy*0.75;  } } // 如果小球出了画布，就清除小球,性能优化 var cnt = 0; for(var i=0;i<balls.length;i++){  if(balls[i].x-RADIUS>0&&balls[i].x+RADIUS<WINDOW_WIDTH){   balls[cnt++] = balls[i];  } } while (balls.length>Math.min(300,cnt)){  balls.pop(); }}

function addBalls(x,y,num) { for (var i = 0; i < digit[num].length; i++) {//数组行  for (var j = 0; j < digit[num][i].length; j++) {//数组列   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,//pow(x,y),x 的 y 次幂;ceil()可对一个数进行上舍入;     vy: -5,     color: colors[Math.floor(Math.random() * colors.length)]//floor()对一个数进行下舍入    };    balls.push(aBall);   }  } }}function render(cxt) { //每一帧都要对动画进行刷新，不然就会新的旧的叠在一起； cxt.clearRect(0,0,WINDOW_WIDTH,WINDOW_HEIGHT);//对一个矩形空间里的动画进行刷新； //倒计时的时间绘制 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); //彩色动画小球的绘制 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) { cxt.fillStyle = "rgb(0,102,153)"; for (var i = 0; i < digit[num].length; i++) {//数组行  for (var j = 0; j < digit[num][i].length; j++) {//数组列   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();   }  } }}

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