Canvas 绘制时钟_技术笔记

qq_阳光你好_03224775 2018-02-27

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>clock</title> <style> div{ text-align:center; margin:250px auto; } #clock{ border:1px solid #CCC; } </style> </head> <body> <div> <canvas id="clock" height="200" width="200"></canvas> </div> <script type="text/javascript" src="clock.js"></script> </body> </html>

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qq_阳光你好_03224775 2018-02-27

function draw(){ ctx.clearRect(0,0,width,height); var now = new Date(); var hour = now.getHours(); var minute = now.getMinutes(); var second = now.getSeconds(); drawBackground(); drawHour(hour,minute); drawMinute(minute); drawSecond(second); drawDot(); ctx.restore(); } draw(); setInterval(draw,1000);

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qq_阳光你好_03224775 2018-02-27

function drawHour(hour,minute){ ctx.save(); ctx.beginPath(); var rad = 2 * Math.PI / 12 * hour; var mrad = 2 * Math.PI / 12 / 60 * minute; ctx.rotate(rad + mrad); ctx.lineWidth = 6* rem; ctx.lineCap = 'round'; ctx.moveTo(0,10* rem); ctx.lineTo(0,-r/2); ctx.stroke(); ctx.restore(); } function drawMinute(minute){ ctx.save(); ctx.beginPath(); var rad = rad = 2*Math.PI/60 * minute; ctx.rotate(rad); ctx.lineWidth = 3* rem; ctx.lineCap = 'round'; ctx.moveTo(0,10* rem); ctx.lineTo(0,-r + 15* rem); ctx.stroke(); ctx.restore(); } function drawSecond(second){ ctx.save(); ctx.beginPath(); ctx.fillStyle = '#f00'; var rad = rad = 2*Math.PI/60 * second; ctx.rotate(rad); ctx.moveTo(-2* rem , 10* rem); ctx.lineTo(2* rem , 15* rem); ctx.lineTo(1, -r + 10* rem); ctx.lineTo(-1, -r + 10* rem); ctx.fill(); ctx.restore(); } function drawDot(){ ctx.beginPath(); ctx.fillStyle = '#fff'; ctx.arc(0,0,3* rem,0,2*Math.PI,false); ctx.stroke(); }

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qq_阳光你好_03224775 2018-02-27

function drawBackground(){ ctx.save(); ctx.translate(r,r); ctx.beginPath(); ctx.lineWidth = 4 * rem; ctx.arc(0,0,r - ctx.lineWidth / 2,0,2*Math.PI,false); ctx.stroke(); var hourNumbers = [3,4,5,6,7,8,9,10,11,12,1,2]; ctx.font=18* rem + 'px Arial'; ctx.textAlign='center';//左右居中 ctx.textBaseline='middle';//上下居中 hourNumbers.forEach(function(number,i){//遍历数组 var rad = 2*Math.PI/12 *i; var x = Math.cos(rad) * ( r - 20* rem); var y = Math.sin(rad) * (r - 20* rem); ctx.fillText(number,x,y);//按路径填充文本 }); for(var i = 0;i < 60; i++){ var rad = 2*Math.PI/60 *i; var x = Math.cos(rad) * ( r - 8* rem); var y = Math.sin(rad) * (r - 8* rem); ctx.beginPath(); if(i%5 === 0){ ctx.fillStyle = '#000'; ctx.arc(x,y,2* rem,0,2*Math.PI,false); }else{ ctx.fillStyle = '#ccc'; ctx.arc(x,y,2* rem,0,2*Math.PI,false); } ctx.fill(); } }

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qq_阳光你好_03224775 2018-02-27

var dom = document.getElementById('clock'); var ctx = dom.getContext('2d');//获取上下文 var width = ctx.canvas.width; var height = ctx.canvas.height;//获取canvas的宽高 var r = width / 2; var rem = width/200;

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依依若蝶 2018-02-14

动态绘制时钟

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qq_喵呜我姓易_04380998 2017-01-24

清除之前的

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qweqwe13123123 2016-12-08

每秒清除内容重新绘画 clearRect 清除宽度高度

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慕工程2957023 2016-11-29

function draw(){ ctx.clearRect(0,0,width,height);//清除画布 ctx.save();//保存原始画布状态，即基准点位于左上角 var now=new Date(); var hour=now.getHours(); var minute=now.getMinutes(); var second=now.getSeconds(); drawbackground();//此函数中会使基准点移到画布中央 drawHour(hour,minute); drawMinute(minute); drawSecond(second); drawDot(); ctx.restore();//还原基准点到左上角 } draw(); setInterval(draw,1000);

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qq__1939 2016-10-08

使用计时器，每秒重新绘制。在drawBackground()第一行中添加save。在draw中添加restore

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数据加载中...