canvas绘制时钟
2017-07-26 10:53
267 查看
效果图
可以实时获取当前时间,有动态旋转的效果,如果在html里改变height和width 不改变图片样式
<canvas id="clock" height="200px" width="200px">
html
<DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>canvas clock</title> <style type="text/css"> div{ text-align:center; margin-top:250px; } #clock{ border:1px solid #ccc; } </style> </head> <body> <div> <canvas id="clock" height="200px" width="200px"></canvas> </div> <script type="text/javascript" src="clock.js"></script> </body> </html>
JS
var dom =document.getElementById('clock'); var ctx =dom.getContext('2d'); var width =ctx.canvas.width; var height = ctx.canvas.height; var r = width/2; var rem =width/200; function drawBackground(){ ctx.save(); ctx.translate(r,r); ctx.beginPath(); ctx.lineWidth=10*rem; ctx.arc(0,0,r-ctx.lineWidth/2,0,2*Math.PI,false); ctx.stroke(); var hourNumber = [3,4,5,6,7,8,9,10,11,12,1,2]; ctx.font=18*rem+'px,Arial'; ctx.textAlign='center'; ctx.textBaseline='middle'; hourNumber.forEach(function(number , i ){ var rad=2*Math.PI/12*i; var x=Math.cos(rad)*(r-30*rem); var y=Math.sin(rad)*(r-30*rem); ctx.fillText(number, x, y); }); for(var i=0;i<60;i++){ var rad=2*Math.PI/60*i; var x=Math.cos(rad)*(r-18*rem); var y=Math.sin(rad)*(r-18*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(); } } 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); ctx.lineTo(0,-r/2); ctx.stroke(); ctx.restore(); } function drawMinute(minute){ ctx.save(); ctx.beginPath(); var 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+30*rem); ctx.stroke(); ctx.restore(); } function drawSecond(second){ ctx.save(); ctx.beginPath(); ctx.fillStyle='#c14543'; var rad=2*Math.PI/60*second; ctx.rotate(rad); ctx.moveTo(-2*rem,20*rem); ctx.lineTo(2*rem,20*rem); ctx.lineTo(1,-r+18*rem); ctx.lineTo(-1,-r+18*rem); ctx.fill(); ctx.restore(); } function drawDot(){ ctx.beginPath(); ctx.fillStyle='#fff'; ctx.arc(0,0,3*rem,0,2*Math.PI,false); ctx.fill(); } 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);
相关文章推荐
- Canvas绘制时钟
- Html5 Canvas 绘制 时钟
- 用 Canvas 绘制实时时钟
- JavaScript html5 canvas绘制时钟效果
- 使用canvas绘制时钟
- 使用canvas绘制一个时钟
- Canvas绘制时钟
- Canvas绘制时钟
- canvas自适应圆形时钟绘制
- 使用canvas绘制时钟
- 使用canvas绘制时钟
- android 用canvas 绘制简单圆形时钟
- HTML5 Canvas绘制实时时钟
- HTML5 Canvas 绘制时钟
- Canvas - 时钟绘制
- Canvas绘制时钟
- 使用HTML5 Canvas绘制一个时钟
- android 用canvas 绘制简单圆形时钟
- HTML5 Canvas 绘制时钟
- 自定义View之canvas绘制时钟