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JS+Canvas实现动态时钟效果

作者：javscp_q

这篇文章主要为大家详细介绍了JS+Canvas实现动态时钟效果，文中示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下

基于Canvas制作的动态时钟demo，供大家参考，具体内容如下

<!DOCTYPE html>
<html>
 <head>
  <meta charset="utf-8">
  <title>动态时钟</title>
  <script type="text/javascript" src="js/lattice.js"></script>
  <script type="text/javascript" src="js/script.js"></script>
  <style type="text/css">
   *{
    padding: 0;
    margin: 0;
   }
   #canvasBox{
    border-width: 2px;
    border-color: black;
    border-style: solid;
    width: 80%;
    margin: 0 auto;
   }
  </style>
 </head>
 <body>
  <!-- 将canvas放到一个盒子中，用盒子控制canvas的位置 -->
  <div id="canvasBox">
   <canvas id="canvas">
    此浏览器不支持canvas
   </canvas>
  </div>
 </body>
</html>

lattice.js

lattice =
    [
        [
            [0,0,1,1,1,0,0],
            [0,1,1,0,1,1,0],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [0,1,1,0,1,1,0],
            [0,0,1,1,1,0,0]
        ],//0
        [
            [0,0,0,1,1,0,0],
            [0,1,1,1,1,0,0],
            [0,0,0,1,1,0,0],
            [0,0,0,1,1,0,0],
            [0,0,0,1,1,0,0],
            [0,0,0,1,1,0,0],
            [0,0,0,1,1,0,0],
            [0,0,0,1,1,0,0],
            [0,0,0,1,1,0,0],
            [1,1,1,1,1,1,1]
        ],//1
        [
            [0,1,1,1,1,1,0],
            [1,1,0,0,0,1,1],
            [0,0,0,0,0,1,1],
            [0,0,0,0,1,1,0],
            [0,0,0,1,1,0,0],
            [0,0,1,1,0,0,0],
            [0,1,1,0,0,0,0],
            [1,1,0,0,0,0,0],
            [1,1,0,0,0,1,1],
            [1,1,1,1,1,1,1]
        ],//2
        [
            [1,1,1,1,1,1,1],
            [0,0,0,0,0,1,1],
            [0,0,0,0,1,1,0],
            [0,0,0,1,1,0,0],
            [0,0,1,1,1,0,0],
            [0,0,0,0,1,1,0],
            [0,0,0,0,0,1,1],
            [0,0,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [0,1,1,1,1,1,0]
        ],//3
        [
            [0,0,0,0,1,1,0],
            [0,0,0,1,1,1,0],
            [0,0,1,1,1,1,0],
            [0,1,1,0,1,1,0],
            [1,1,0,0,1,1,0],
            [1,1,1,1,1,1,1],
            [0,0,0,0,1,1,0],
            [0,0,0,0,1,1,0],
            [0,0,0,0,1,1,0],
            [0,0,0,1,1,1,1]
        ],//4
        [
            [1,1,1,1,1,1,1],
            [1,1,0,0,0,0,0],
            [1,1,0,0,0,0,0],
            [1,1,1,1,1,1,0],
            [0,0,0,0,0,1,1],
            [0,0,0,0,0,1,1],
            [0,0,0,0,0,1,1],
            [0,0,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [0,1,1,1,1,1,0]
        ],//5
        [
            [0,0,0,0,1,1,0],
            [0,0,1,1,0,0,0],
            [0,1,1,0,0,0,0],
            [1,1,0,0,0,0,0],
            [1,1,0,1,1,1,0],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [0,1,1,1,1,1,0]
        ],//6
        [
            [1,1,1,1,1,1,1],
            [1,1,0,0,0,1,1],
            [0,0,0,0,1,1,0],
            [0,0,0,0,1,1,0],
            [0,0,0,1,1,0,0],
            [0,0,0,1,1,0,0],
            [0,0,1,1,0,0,0],
            [0,0,1,1,0,0,0],
            [0,0,1,1,0,0,0],
            [0,0,1,1,0,0,0]
        ],//7
        [
            [0,1,1,1,1,1,0],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [0,1,1,1,1,1,0],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [0,1,1,1,1,1,0]
        ],//8
        [
            [0,1,1,1,1,1,0],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [1,1,0,0,0,1,1],
            [0,1,1,1,0,1,1],
            [0,0,0,0,0,1,1],
            [0,0,0,0,0,1,1],
            [0,0,0,0,1,1,0],
            [0,0,0,1,1,0,0],
            [0,1,1,0,0,0,0]
        ],//9
        [
            [0,0,0,0],
            [0,0,0,0],
            [0,1,1,0],
            [0,1,1,0],
            [0,0,0,0],
            [0,0,0,0],
            [0,1,1,0],
            [0,1,1,0],
            [0,0,0,0],
            [0,0,0,0]
        ]//:
    ];

script.js

var CANVAS_WIDTH;
var CANVAS_HEIGHT = 600;
//设置点阵中圆的半径
var RADIUS = 8;
//设置时钟距离边框的位置
var MARGIN_LEFT = 100;
var MARGIN_TOP = 40;
 
//获取初始状态的时间
var time = new Date();
var hours = time.getHours();
var minutes = time.getMinutes();
var seconds = time.getSeconds();
 
//用于存储小球对象
var balls = [];
//小球颜色
var colors = ["red","orenge","yellow","green","blue","purple","pink"]
 
window.onload = function(){
 //获得canvas外部盒子的宽度，使canvas与外部盒子宽度相同
 var canvasBox = document.getElementById("canvasBox");
 var boxWidth = getComputedStyle(canvasBox,null);
 CANVAS_WIDTH = parseInt(boxWidth.width);
 
 //设置canvas宽高并获得画笔对象
 var canvas = document.getElementById("canvas");
 canvas.width = CANVAS_WIDTH;
 canvas.height = CANVAS_HEIGHT;
 var context = canvas.getContext("2d");
 
 //定时调用，50毫秒调用一次
 setInterval(function(){
  //绘制函数
  draw(context);
 },50);
 
 function draw(ctx){
  //刷新屏幕
  ctx.clearRect(0,0,CANVAS_WIDTH,CANVAS_HEIGHT);
  
  //获取当前时间
  var curTime = new Date();
  var curHours = curTime.getHours();
  var curMinutes = curTime.getMinutes();
  var curSeconds = curTime.getSeconds();
 
  //画小时
  drawLattice(MARGIN_LEFT,MARGIN_TOP,parseInt(curHours/10),ctx);
  drawLattice(MARGIN_LEFT+15*(RADIUS+1),MARGIN_TOP,parseInt(curHours%10),ctx);
  //画冒号
  drawLattice(MARGIN_LEFT+30*(RADIUS+1),MARGIN_TOP,10,ctx);
  //画分钟
  drawLattice(MARGIN_LEFT+39*(RADIUS+1),MARGIN_TOP,parseInt(curMinutes/10),ctx);
  drawLattice(MARGIN_LEFT+54*(RADIUS+1),MARGIN_TOP,parseInt(curMinutes%10),ctx);
  //画冒号
  drawLattice(MARGIN_LEFT+69*(RADIUS+1),MARGIN_TOP,10,ctx);
  //画秒
  drawLattice(MARGIN_LEFT+78*(RADIUS+1),MARGIN_TOP,parseInt(curSeconds/10),ctx);
  drawLattice(MARGIN_LEFT+93*(RADIUS+1),MARGIN_TOP,parseInt(curSeconds%10),ctx);
  
  //更新时间并绘制小球
  update(context,curHours,curMinutes,curSeconds);
  
  //观察小球数量
  //console.log(balls.length);
 }
 
 //参数：
 //x：绘制数字点阵的左上角的横坐标
 //y：绘制数字点阵的左上角的纵坐标
 //num：要绘制的数字，实际上是lattice的索引，10表示冒号
 //ctx：画笔
 function drawLattice(x,y,num,ctx){
  for(var i=0;i<lattice[num].length;i++){
   for(var j=0;j<lattice[num][i].length;j++){
    if(lattice[num][i][j]==1){
     ctx.beginPath();
     ctx.fillStyle = "blue";
     ctx.arc(x+j*2*(RADIUS+1)+(RADIUS+1),y+i*2*(RADIUS+1)+(RADIUS+1),RADIUS,0,2*Math.PI);
     ctx.fill();
     ctx.closePath();
    }
   }
  }
 }
 
 //更新时间并绘制小球
 function update(ctx,curHours,curMinutes,curSeconds){
  if(seconds!=curSeconds){
   //更新小时
   if(parseInt(curHours/10)!=parseInt(hours/10)){
    addBalls(MARGIN_LEFT,MARGIN_TOP,parseInt(curHours/10));
   }
   if(parseInt(curHours%10)!=parseInt(hours%10)){
    addBalls(MARGIN_LEFT+15*(RADIUS+1),MARGIN_TOP,parseInt(curHours%10));
   }
   //更新分钟
   if(parseInt(curMinutes/10)!=parseInt(minutes/10)){
    addBalls(MARGIN_LEFT+39*(RADIUS+1),MARGIN_TOP,parseInt(curMinutes/10));
   }
   if(parseInt(curMinutes%10)!=parseInt(minutes%10)){
    addBalls(MARGIN_LEFT+54*(RADIUS+1),MARGIN_TOP,parseInt(curMinutes%10));
   }
   //更新秒
   if(parseInt(curSeconds/10)!=parseInt(seconds/10)){
    addBalls(MARGIN_LEFT+78*(RADIUS+1),MARGIN_TOP,parseInt(curSeconds/10));
   }
   if(parseInt(curSeconds%10)!=parseInt(seconds%10)){
    addBalls(MARGIN_LEFT+93*(RADIUS+1),MARGIN_TOP,parseInt(curSeconds%10));
   }
   
   //更新所有时间
   hours = curHours;
   minutes = curMinutes;
   seconds = curSeconds;
  }
  //绘制小球
  drawBalls(ctx);
  //更新小球运动
  updateBalls();
 }
 
 //添加单个小球
 //参数：
 //x：小球的横坐标
 //y：小球的纵坐标
 //num：变化的时间数字
 function addBalls(x,y,num){
  for(var i=0;i<lattice[num].length;i++){
   for(var j=0;j<lattice[num][i].length;j++){
    if(lattice[num][i][j]==1){
     //添加一个小球对象
     var ball = {
      //坐标
      x:x+j*2*(RADIUS+1)+(RADIUS+1),
      y:y+i*2*(RADIUS+1)+(RADIUS+1),
      //重力加速度
      g:1.5+Math.random(),
      //x、y方向的速度
      vx:Math.pow(-1,Math.ceil(Math.random()*1000))*5,
      vy:-5,
      //小球颜色
      color:colors[Math.floor(Math.random()*colors.length)]
     }
     //将小球添加进储存队列中
     balls.push(ball);
    }
   }
  }
 }
 
 //绘制小球
 function drawBalls(ctx){
  for(var i=0;i<balls.length;i++){
   ctx.beginPath();
   ctx.fillStyle = balls[i].color;
   ctx.arc(balls[i].x,balls[i].y,RADIUS,0,2*Math.PI,true);
   ctx.fill();
   ctx.closePath();
  }
 }
 
 //更新小球运动
 function updateBalls(){
  //更新储存数组中的小球的动态
  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;
   
   //边缘碰撞检测
   if(balls[i].y>=CANVAS_HEIGHT-RADIUS){
    balls[i].y=CANVAS_HEIGHT-RADIUS;
    //模拟碰撞反弹和阻力
    balls[i].vy=-balls[i].vy*0.6;
   }
  }
  //当小球滚出画布便可以从数组中删除，以下是删除算法
  //储存应当保留的小球的数量
  var numBall = 0;
  for(var i=0;i<balls.length;i++){
   if(balls[i].x+RADIUS>0&&balls[i].x-RADIUS<CANVAS_WIDTH){
    //若判断当前小球在屏幕内，则将此小球尽量靠前，则每次循环后，数组最后面的小球就是滚出画布的小球
    balls[numBall] = balls[i];
    numBall++;
   }
  }
  //从数组后面删除小球
  while(balls.length>numBall){
   balls.pop();
  }
 }
};

效果图：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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