Canvas实例之时钟

<canvas id="canvas">您的浏览器不支持canvas</canvas>

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]
        ]//:
    ];

//定义常量
var WINDOW_WIDTH = 1024;  //屏幕宽度
var WINDOW_HEIGHT = 768; //屏幕高度
var RADIUS = 8; //小球半径
var MARGIN_TOP = 60; //距顶部尺寸
var MARGIN_LEFT = 30; //据左侧尺寸

const endTime = new Date(); //倒计时结束时间
endTime.setHours(endTime.getHours()+2);
var curShowTimeSeconds = 0; //当前时间

var balls = []; //小球容器
const colors = ["#33B5E5","#0099CC","#AA66CC","#9933CC","#99CC00","#669900","#FFBB33","#FF8800","#FF4444","#CC0000"]; //小球随机颜色


window.onload = function(){


    WINDOW_WIDTH = document.body.clientWidth
    WINDOW_HEIGHT = document.body.clientHeight

    MARGIN_LEFT = Math.round(WINDOW_WIDTH /10);
    RADIUS = Math.round(WINDOW_WIDTH * 4 / 5 / 108)-1

    MARGIN_TOP = Math.round(WINDOW_HEIGHT /5);

    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 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(nextSeconds%10) );
        }
        curShowTimeSeconds = nextShowTimeSeconds;
    }
		
		updateBalls();
}

function updateBalls(){

    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;

        if( balls[i].y >= WINDOW_HEIGHT-RADIUS ){
            balls[i].y = WINDOW_HEIGHT-RADIUS;
            balls[i].vy = - balls[i].vy*0.75;
        }
    }
		
		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 > cnt ){
        balls.pop();
    }
}


function addBalls( x , y , num ){

    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 ){
                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,
                    vy:-5,
                    color: colors[ Math.floor( Math.random()*colors.length ) ]
                }

                balls.push( aBall )
            }
}

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

    return ret >= 0 ? ret : 0;
}

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);
		
		 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 ++ )
        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()
            }
}