var WINDOW_WIDTH = 1024;
var WINDOW_HEIGHT = 768;
var RADIUS = 8;
var MARGIN_TOP = 60;? //每一個數字距離畫布上邊距的距離
var MARGIN_LEFT = 30;? //第一個數字距離畫布左側的距離

const endTime = new Date(2014,6,11,18,47,52);
var curShowTimeSeconds = 0

window.onload = function(){

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

??? canvas.width = WINDOW_WIDTH;
??? canvas.height = WINDOW_HEIGHT;

??? curShowTimeSeconds = getCurrentShowTimeSeconds()
??? setInterval(
??????? function(){
??????????? render( context );
??????????? update();
??????? }
??????? ,
??????? 50
??? );
}

function getCurrentShowTimeSeconds() {
??? var curTime = new Date();
??? var ret = endTime.getTime() - curTime.getTime();
??? ret = Math.round( ret/1000 )

??? 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 ){

??????? curShowTimeSeconds = nextShowTimeSeconds;
??? }
}
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 ){

??????? curShowTimeSeconds = nextShowTimeSeconds;
??? }
}

function render( cxt ){

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

??? 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);
}

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()
??????????? }
}