canvas系列(二)canvas绘制电子钟

作者: 落花夕拾 | 来源:发表于2017-02-07 23:38 被阅读0次

本系列是对canvas（一）的实际运用

首先来回顾下上节的相关知识：

    beginPath()
    closePath()
    moveTo()
    lineTo()
    fill()
    stroke()
    fillRect()
    arc（x，y，radius，startAngle,endAngle,anticlockwise）

清除绘制

    clearRect()

接下来我们来绘制一个电子时钟：
效果图：

电子时钟.png

思路：
第一步：我们要创建个二维数组放置我们从0-9的点阵图形，当元素的值为1的时候，就要将其绘制出来；当元素的值为0时，则不进行绘制。而我们要做的就是将 0 － 9 个数字用二维数组表示出来。以下是二维数组的片段：

[ [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]]//1

第二步：画个小圆
首先我们来分析，每个小圆的圆心位置：图片来源于（慕课网--侵删）

Screenshot_2016-10-22-22-28-09.png

    //首先来绘制简单的数字
    function drawNum(x,y,num,ctx){
        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){                               
                   ctx.beginPath();                         
    ctx.arc(x+(RADIUS+1)*2*j+(RADIUS+1), y+(RADIUS+1)*2*i+(RADIUS+1), RADIUS, 0, Math.PI*2)                        
        ctx.closePath();    
        ctx.fillStyle="aqua";
         ctx.fill();
        }
    }
}
}

第三步：绘制时钟

//  我们需要定义一个函数draw()来绘制我们的电子时钟。
function draw(context){
    context.clearRect(0,0,1400,1200);
    var currentDate =new Date();//获取当前时间
    var getHours =currentDate.getHours();//获取当前的时
    var getMin =currentDate.getMinutes();//获取当前的分
var getSeconds=currentDate.getSeconds();//获取当前的秒        
    drawNum(Margin_X,Margin_Y,parseInt(getHours/10),context);//获取hours的十位
        drawNum(Margin_X+(RADIUS+1)*15,Margin_Y,parseInt(getHours%10),context);//个位
        drawNum(Margin_X+(RADIUS+1)*30,Margin_Y,10,context);//中间冒号
        drawNum(Margin_X+(RADIUS+1)*45,Margin_Y,parseInt(getMin/10),context);
        drawNum(Margin_X+(RADIUS+1)*60,Margin_Y,parseInt(getMin%10),context);
        drawNum(Margin_X+(RADIUS+1)*75,Margin_Y,10,context);
        drawNum(Margin_X+(RADIUS+1)*90,Margin_Y,parseInt(getSeconds/10),context);
        drawNum(Margin_X+(RADIUS+1)*105,Margin_Y,parseInt(getSeconds%10),context);
    }

最后：设置一个定时器，让时钟动起来

   setInterval(function(){
                    draw(context);
                 },1000);
                 }

完整代码：

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    <style>
            body{
                background-color: black;
                margin: 10 auto;
                padding: 0 auto;
            }
            #canvas{
                margin: 200px;
                
            }
        </style>
    </head>
    <body>
        <canvas id="canvas" width="1400" height="1200" style="border: 1px solid #c3c3c3;">
            您的浏览器不支持canvas，请升级浏览器！
        </canvas>
        <script type="text/javascript" src="js/digital.js" ></script>
        <script>
        
        var RADIUS = 4;  // 圆的半径
        var Margin_X = 30;  //  离 canvas 原点的坐标值 x
        var Margin_Y = 30;  //  离 canvas 原点的坐标值 y
//              drawNum(0, 0, 1, context);
            window.onload=function(){
                var canvas =document.getElementById('canvas');
                var context=canvas.getContext("2d");
//1、                drawNum(0, 0, 1, context); //首先绘制一个小圆，并填充
                 setInterval(function(){
                    draw(context);
                 },1000);
                 }
//              draw(context);
   //2、可以先把时间全部 数字化表示：housr=12，min=34，seconds=45
                
//              我们需要定义一个函数draw()来绘制我们的电子时钟。
                function draw(context){
                    context.clearRect(0,0,1400,1200);
                    var currentDate =new Date();//获取当前时间
                    var getHours =currentDate.getHours();//获取当前的时
                    var getMin =currentDate.getMinutes();//获取当前的分
                    var getSeconds=currentDate.getSeconds();//获取当前的秒
                    
                    drawNum(Margin_X,Margin_Y,parseInt(getHours/10),context);//获取hours的十位
                    drawNum(Margin_X+(RADIUS+1)*15,Margin_Y,parseInt(getHours%10),context);//个位
                    drawNum(Margin_X+(RADIUS+1)*30,Margin_Y,10,context);//中间冒号
                    drawNum(Margin_X+(RADIUS+1)*45,Margin_Y,parseInt(getMin/10),context);
                    drawNum(Margin_X+(RADIUS+1)*60,Margin_Y,parseInt(getMin%10),context);
                    drawNum(Margin_X+(RADIUS+1)*75,Margin_Y,10,context);
                    drawNum(Margin_X+(RADIUS+1)*90,Margin_Y,parseInt(getSeconds/10),context);
                    drawNum(Margin_X+(RADIUS+1)*105,Margin_Y,parseInt(getSeconds%10),context);
    
                }
                
                
                
                
                //首先来绘制简单的数字
                function drawNum(x,y,num,ctx){
                    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){
                            ctx.beginPath();                            
                            ctx.arc(x+(RADIUS+1)*2*j+(RADIUS+1), y+(RADIUS+1)*2*i+(RADIUS+1), RADIUS, 0, Math.PI*2)                        
                            ctx.closePath();    
                            ctx.fillStyle="aqua";
                             ctx.fill();
                                
                            }
                        }
                    }
                }
        
                
                
            
        </script>
    </body>
</html>

点阵代码：

digit =
    [
        [
            [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]
        ]//:
    ];

效果图：

电子时钟.png

canvas系列(二)canvas绘制电子钟

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