JS+canvas绘制的动态机械表动画效果

2019-11-19 15:28:55

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本文实例讲述了JS+canvas绘制的动态机械表动画效果。分享给大家供大家参考，具体如下：

先来看看运行效果：

完整实例代码：

<!DOCTYPE html><html><head lang="en">  <meta charset="UTF-8">  <title>www.VeVB.COm canvas时钟</title>  <style>    canvas {      border: 1px solid red;    }  </style></head><body><canvas width="800" height="600"></canvas></body><script>  function Clock(opt) {    for (var key in opt) {      this[key] = opt[key];    }    this.init();  }  Clock.prototype = {    init: function () {      var self = this;      var ctx = this.ctx;      this.timer = setInterval(function(){        ctx.clearRect(0,0,ctx.canvas.width,ctx.canvas.height);        self.drawDial();        self.drawDegreeScale();        self.drawNumber();        self.drawPointers();      },1000);    },    drawDial: function () {      var ctx = this.ctx;      ctx.save();      ctx.beginPath();      ctx.lineWidth = this.clockDialW;      ctx.strokeStyle = this.clockDialColor;      ctx.arc(this.clockX, this.clockY, this.clockRadius, 0, 2 * Math.PI);      ctx.stroke();      ctx.restore();    },    drawDegreeScale: function () {      var ctx = this.ctx;      var clockRadius = this.clockRadius;      var clockX = this.clockX;      var clockY = this.clockY;      var bigDegreeScaleL = this.bigDegreeScaleL;      var smallDegreeScale = this.smallDegreeScale;      var startX, startY, endX, endY, radian;      ctx.save();      for (var i = 0; i < 12; i++) {        radian = i * Math.PI / 6;        endX = clockX + clockRadius * Math.cos(radian);        endY = clockY + clockRadius * Math.sin(radian);        if (radian % (Math.PI / 2) == 0) {          startX = clockX + (clockRadius - bigDegreeScaleL) * Math.cos(radian);          startY = clockY + (clockRadius - bigDegreeScaleL) * Math.sin(radian);          ctx.lineWidth = this.bigDCWidth;        } else {          startX = clockX + (clockRadius - smallDegreeScale) * Math.cos(radian);          startY = clockY + (clockRadius - smallDegreeScale) * Math.sin(radian);          ctx.lineWidth = this.smallDCWidth;        }        ctx.beginPath();        ctx.moveTo(startX, startY);        ctx.lineTo(endX, endY);        ctx.stroke();        ctx.restore();      }    },    drawNumber: function () {      var ctx = this.ctx;      var textX, textY, textRadian;      var clockX = this.clockX;      var clockY = this.clockY;      var clockRadius = this.clockRadius;      ctx.font = '20px 微软雅黑';      ctx.fillStyle = 'red';      ctx.textAlign = 'center';      ctx.textBaseline = 'middle';      ctx.save();      for (var i = 0; i < 12; i++) {        textRadian = i * Math.PI / 6 - Math.PI/3;        textX = clockX + (clockRadius - 40) * Math.cos(textRadian);        textY = clockY + (clockRadius - 40) * Math.sin(textRadian);        ctx.beginPath();        ctx.fillText(i + 1, textX, textY);      }      ctx.restore();    },    drawPointers: function () {      var date = new Date();      var h = date.getHours();      var m = date.getMinutes();      var s = date.getSeconds();      h = h % 12;      var hRadian = 2 * Math.PI / 12 * h - Math.PI / 2;      this.drawPoint(hRadian,30,'red',8);      var mRadian = 2 * Math.PI / 60 * m - Math.PI / 2;      this.drawPoint(mRadian,50,'blue',6);      var sRadian = 2 * Math.PI / 60 * s - Math.PI / 2;      this.drawPoint(sRadian,70,'green',2);    },    drawPoint: function (radian, length,color,lineWidth) {      var x = this.clockX + Math.cos(radian) * length;      var y = this.clockY + Math.sin(radian) *　length;      var ctx = this.ctx;      ctx.save();      ctx.beginPath();      ctx.strokeStyle = color;      ctx.lineWidth = lineWidth;      ctx.moveTo(this.clockX,this.clockY);      ctx.lineTo(x,y);      ctx.stroke();      ctx.restore();    }  };</script><script>  var canvas = document.querySelector('canvas');  var ctx = canvas.getContext('2d');  var clock = new Clock({    ctx: this.ctx,    clockRadius: 150,    clockX: 300,    clockY: 300,    clockDialW: 6,    clockDialColor: 'blue',    bigDegreeScaleL: 20,    bigDCWidth: 6,    smallDegreeScale: 10,    smallDCWidth: 4  });</script></html>

更多关于JavaScript相关内容感兴趣的读者可查看本站专题：《JavaScript+HTML5特效与技巧汇总》、《JavaScript动画特效与技巧汇总》、《JavaScript图形绘制技巧总结》、《JavaScript切换特效与技巧总结》、《JavaScript错误与调试技巧总结》、《JavaScript数据结构与算法技巧总结》及《JavaScript数学运算用法总结》

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