var WINDOW_WIDTH = 1024;

var WINDOW_HEIGHT = 768;

var RADIUS = 8;

var MARGIN_TOP = 60;

var MARGIN_LEFT = 30;

//endTime為截止的時間；小時為兩位數(shù)，所以最多就倒計(jì)時四天，（從現(xiàn)在到截止時間為止）；月份要+1,5是代表6月份；

//從現(xiàn)在到2015年6月15日倒計(jì)時

const endTime=new Date(2015,5,15,18,47,52);

var ?curShowTimeSeconds=0;

window.onload = function(){

? ? var canvas = document.getElementById('canvas');

? ? var context = canvas.getContext("2d");

//計(jì)算現(xiàn)在的時間

? ? curShowTimeSeconds=GetCurrentShowTimeSeconds();

? ??

? ? canvas.width = WINDOW_WIDTH;

? ? canvas.height = WINDOW_HEIGHT;

? ? setInterval(

//匿名函數(shù)。每幀的執(zhí)行內(nèi)容

? ?function()

{

render(context);

update();

},

//時間，單位：毫秒；50表示每隔多少毫秒執(zhí)行一幀

50

);

}

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-hours*3600)/60);

? ? var curSeconds =curShowTimeSeconds%60;

? ?if(nextSeconds != curSeconds){

? ? ? ?curShowTimeSeconds = nextShowTimeSeconds;

? ?}

}

function render( cxt ){

//對整個屏幕進(jìn)行刷新

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

? ? var hours =parseInt(curShowTimeSeconds/3600);

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

? ? var seconds =curShowTimeSeconds%60;

//數(shù)字是7*10的矩陣，冒號是4*10的矩陣

? ? 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);

}

function GetCurrentShowTimeSeconds()

{

var curTime=new Date();

//截止的時間距現(xiàn)在的秒數(shù)

var ret=endTime.getTime()-curTime.getTime();

//把ret轉(zhuǎn)化為毫秒數(shù)，現(xiàn)在距設(shè)定的endTime的的時間

ret=Math.round(ret/1000);

return ret>0?ret:0;

}

function renderDigit( x , y , num , cxt ){

? ? 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()

? ? ? ? ? ? }

}