本系列是對(duì)canvas(一)的實(shí)際運(yùn)用
首先來回顧下上節(jié)的相關(guān)知識(shí):
beginPath()
closePath()
moveTo()
lineTo()
fill()
stroke()
fillRect()
arc(x蕉堰,y垫言,radius,startAngle,endAngle,anticlockwise)
清除繪制
clearRect()
接下來我們來繪制一個(gè)電子時(shí)鐘:
效果圖:
電子時(shí)鐘.png
思路:
第一步:我們要?jiǎng)?chuàng)建個(gè)二維數(shù)組放置我們從0-9的點(diǎn)陣圖形伯顶,當(dāng)元素的值為1的時(shí)候,就要將其繪制出來坷澡;當(dāng)元素的值為0時(shí)讨便,則不進(jìn)行繪制。而我們 要做的就是將 0 - 9 個(gè)數(shù)字用二維數(shù)組表示出來演熟。以下是二維數(shù)組的片段:
[ [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: 畫個(gè)小圓
首先我們來分析鞭执,每個(gè)小圓的圓心位置:圖片來源于(慕課網(wǎng)--侵刪)
Screenshot_2016-10-22-22-28-09.png
//首先來繪制簡(jiǎn)單的數(shù)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:繪制時(shí)鐘
// 我們需要定義一個(gè)函數(shù)draw()來繪制我們的電子時(shí)鐘。
function draw(context){
context.clearRect(0,0,1400,1200);
var currentDate =new Date();//獲取當(dāng)前時(shí)間
var getHours =currentDate.getHours();//獲取當(dāng)前的時(shí)
var getMin =currentDate.getMinutes();//獲取當(dāng)前的分
var getSeconds=currentDate.getSeconds();//獲取當(dāng)前的秒
drawNum(Margin_X,Margin_Y,parseInt(getHours/10),context);//獲取hours的十位
drawNum(Margin_X+(RADIUS+1)*15,Margin_Y,parseInt(getHours%10),context);//個(gè)位
drawNum(Margin_X+(RADIUS+1)*30,Margin_Y,10,context);//中間冒號(hào)
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:設(shè)置一個(gè)定時(shí)器芒粹,讓時(shí)鐘動(dòng)起來
setInterval(function(){
draw(context);
},1000);
}
完整代碼:
<!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;">
您的瀏覽器不支持canvas兄纺,請(qǐng)升級(jí)瀏覽器!
</canvas>
<script type="text/javascript" src="js/digital.js" ></script>
<script>
var RADIUS = 4; // 圓的半徑
var Margin_X = 30; // 離 canvas 原點(diǎn)的坐標(biāo)值 x
var Margin_Y = 30; // 離 canvas 原點(diǎn)的坐標(biāo)值 y
// drawNum(0, 0, 1, context);
window.onload=function(){
var canvas =document.getElementById('canvas');
var context=canvas.getContext("2d");
//1化漆、 drawNum(0, 0, 1, context); //首先繪制一個(gè)小圓估脆,并填充
setInterval(function(){
draw(context);
},1000);
}
// draw(context);
//2、可以先把時(shí)間全部 數(shù)字化表示:housr=12座云,min=34疙赠,seconds=45
// 我們需要定義一個(gè)函數(shù)draw()來繪制我們的電子時(shí)鐘。
function draw(context){
context.clearRect(0,0,1400,1200);
var currentDate =new Date();//獲取當(dāng)前時(shí)間
var getHours =currentDate.getHours();//獲取當(dāng)前的時(shí)
var getMin =currentDate.getMinutes();//獲取當(dāng)前的分
var getSeconds=currentDate.getSeconds();//獲取當(dāng)前的秒
drawNum(Margin_X,Margin_Y,parseInt(getHours/10),context);//獲取hours的十位
drawNum(Margin_X+(RADIUS+1)*15,Margin_Y,parseInt(getHours%10),context);//個(gè)位
drawNum(Margin_X+(RADIUS+1)*30,Margin_Y,10,context);//中間冒號(hào)
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);
}
//首先來繪制簡(jiǎn)單的數(shù)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>
點(diǎn)陣代碼:
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]
]//:
];
效果圖:
電子時(shí)鐘.png