JavaScript html5 canvas绘制时钟效果
这篇文章主要介绍了JavaScript html5绘制时钟效果的相关资料,使用HTML5的canvas标签和Javascript脚本,模拟显示了一个时钟,感兴趣的小伙伴们可以参考一下
本文实例讲述了JavaScript+html5 canvas绘制时钟效果。分享给大家供大家参考,具体如下:
HTML部分:
1 2 3 4 5 6 7 8 9 10 11 | <!DOCTYPE html> < html lang = "en" > < head > < meta charset = "UTF-8" > < meta name = "viewport" content = "width=device-width, initial-scale=1.0,minimum-scale=1.0,maximum-scale=1.0" > < title >canvas绘图</ title > </ head > < body onload = "init()" > < canvas id = "canvas" width = "200px" height = "200px" ></ canvas > </ body > </ html > |
JavaScript部分:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 | function init(){ var canvas = document.getElementById( "canvas" ), context = canvas.getContext( "2d" ); setInterval( function (){draw(canvas, context)},1000); } function draw(canvas, context){ var x = canvas.width, y = canvas.height, r = Math.min(x/2, y/2); context.clearRect(0, 0, x, y); //清除绘画历史 //绘画钟框 context.fillStyle = "#f1f1f1" ; drawCircle(context, x, y, r); //绘画文字 var tx = x/2,ty = y/2,tr = 0.8*r; context.font = "bold 12px 微软雅黑" ; context.fillStyle = "#000" ; drawText(context, "1" , tx + 0.5*tr,ty - 0.866*tr); drawText(context, "2" , tx + 0.866*tr, ty - 0.5*tr); drawText(context, "3" , tx + tr, ty); drawText(context, "4" , tx + 0.866*tr, ty + 0.5*tr); drawText(context, "5" , tx + 0.5*tr, ty + 0.866*tr); drawText(context, "6" , tx, ty + tr); drawText(context, "7" , tx - 0.5*tr, ty + 0.866*tr); drawText(context, "8" , tx - 0.866*tr, ty + 0.5*tr); drawText(context, "9" , tx - tr, ty); drawText(context, "10" , tx - 0.866*tr, ty - 0.5*tr); drawText(context, "11" , tx - 0.5*tr, ty - 0.866*tr); drawText(context, "12" , tx, ty - tr); //获取当前时间 var date = new Date(), h = date.getHours(), m = date.getMinutes(), s = date.getSeconds(), angleH = (360/12)*Math.PI/180, angleM = (360/60)*Math.PI/180 context.strokeSyle = "#000" ; //绘制时刻度 drawScale(context, x, y, r, angleH, -0.88*r, -0.96*r, 3); //绘制分刻度 drawScale(context, x, y, r, angleM, -0.93*r, -0.96*r, 1); //绘画时分秒针 drawCircle(context, x, y, 3); drawNeedle(context, x, y, r, h*angleH + m*angleM/12, -0.5*r); drawNeedle(context, x, y, r, m*angleM + s*angleM/60, -0.6*r); drawNeedle(context, x, y, r, s*angleM, -0.75*r); } //绘画圆 function drawCircle(context, x, y, r){ context.save(); context.beginPath(); context.arc(x/2, y/2, r, 0, Math.PI*2, 0); context.fill(); context.closePath(); context.restore(); } //绘画文字方法 function drawText(context, text, x, y){ context.save(); x -= (context.measureText(text).width/2); y += 4; context.translate(x, y); context.fillText(text, 0, 0); context.restore(); } //绘制刻度方法 function drawScale(context, x, y, r, rotate, start, end, lineWidth){ context.save(); context.beginPath(); context.translate(x/2,y/2); context.lineWidth = lineWidth; for ( var i = 0; i < 60; i++) { context.rotate(rotate); context.moveTo(0, start); context.lineTo(0, end); } context.closePath(); context.stroke(); context.restore(); } //绘画时分秒针方法 function drawNeedle(context, x, y, r, rotate, line){ context.save(); context.translate(x/2,y/2); context.beginPath(); context.rotate(rotate); context.moveTo(0, 0.1*r); context.lineTo(0, line); context.closePath(); context.stroke(); context.restore(); } |
希望本文所述对大家JavaScript程序设计有所帮助。