JavaScript如何实现时钟滴答声效果

<!DOCTYPE html> <html> <head> <meta charset="utf8"> <meta http-equiv="X-UA-Compatible" content="IE=edge, chrome=1"> <meta name="keywords" content="clock"> <meta name="description" content="This is a clock"> <title>Clock</title> </head> <body> <audio id="ticktock"> <source = src="ticktock.mp3" type="audio/mp3"> </audio> <script type="text/javascript"> /* 年(y)可以用 1-4 个占位符月(M)、日(d)、时(H,24时)、时(h,12时)、分(m)、秒(s)、季度(q) 可以用 1-2 个占位符毫秒(S)只能用 1 个占位符(是 1-3 位数字) AM或PM只能用 1 个占位符(是 2 位英文) 上午或下午(T)只能用 1 个占位符(是 2 位中文) 星期(E)可以用 1-3 个占位符季度(q)只能用 1 个占位符(是 1 位数字) */ Date.prototype.format = function(fmt) { var map = { "M+" : this.getMonth() + 1, //月 "d+" : this.getDate(), //日 "H+" : this.getHours(), //24时 /* 上午12时只代表当天上午的12时,下午的12时代表当天下午的12时, 0时代表第二天的开始,即前面一天12时已过0时开始计算新一天的时间, 虽然说时间上跟前面那一天下午12时重合,但日期已经发生更改,所以不能说0时就是12时 */ "h+" : this.getHours()%12 == 0 ? 12 : this.getHours()%12,//12时 "m+" : this.getMinutes(), //分 "s+" : this.getSeconds(), //秒 "S" : this.getMilliseconds(), //毫秒 "t" : this.getHours() < 12 ? "AM" : "PM", "T" : this.getHours() < 12 ? "上午" : "下午", }; var week = { "0" : "日", "1" : "一", "2" : "二", "3" : "三", "4" : "四", "5" : "五", "6" : "六", } var quarter = { "0" : "一", "1" : "二", "2" : "三", "3" : "四", } if(/(y+)/.test(fmt)) { fmt = fmt.replace(RegExp.$1, (this.getFullYear()+"").substr(4 - RegExp.$1.length)); } if(/(E+)/.test(fmt)) { var weekPreStr; switch(RegExp.$1.length) { case 1: weekPreStr = ""; break; case 2: weekPreStr = "周"; break; default: weekPreStr = "星期"; break; } fmt = fmt.replace(RegExp.$1, weekPreStr + week[this.getDay()]); } if(/(q)/.test(fmt)) { fmt = fmt.replace(RegExp.$1, quarter[Math.floor(this.getMonth() / 3)]); } for(var key in map) { if(new RegExp("(" + key + ")").test(fmt)) { fmt = fmt.replace(RegExp.$1, RegExp.$1.length == 1 ? map[key] : ("00" + map[key]).substr((map[key]+"").length)); } } return fmt; } </script> <script> var canvas = document.createElement("canvas"); document.body.appendChild(canvas); var ctx = canvas.getContext("2d"); var halfPI = Math.PI / 2; var doublePI = Math.PI * 2; //阴影级别 var shadowBlur = 10; //阴影宽度 var shadowWidth = 8; //阴影在X方向上的偏移 var shadowOffsetX = 5; //阴影在Y方向上的便宜 var shadowOffsetY = 5; //深色阴影 var shadowDarkColor = "rgba(0,0,0,0.8)"; //浅色阴影 var shadowLightColor = "rgba(0,0,0,0.1)"; //画布中心到边缘的内切圆半径 var canvasRadius = 250; canvas.width = canvasRadius * 2; canvas.height = canvasRadius * 2; //获取画布中心的坐标 var cx = canvasRadius; var cy = canvasRadius; //时钟外圈的贝塞尔花纹个数 var bezierPatternCount = 36; //时钟外圈的贝塞尔花纹波峰处半径 var bezierPeakRadius = canvasRadius - 10; //时钟外圈的贝塞尔花纹一半的角度 var bezierHalfSpan = doublePI / bezierPatternCount / 2; //时钟外圈的贝塞尔花纹底部半径 var bezierRadius = bezierPeakRadius - 20; //时钟外圈的贝塞尔花纹颜色 var bezierPatternColor = "Plum"; //时钟外圈半径 var clockBorderRadius = bezierRadius - 10; //时钟外圈宽度 var clockBorderWidth = 10; //时钟外圈颜色 var clockBorderColor = "Aqua"; //时钟外圈阴影半径 var clockBorderShadowRadius = clockBorderRadius - shadowWidth + 1; //时钟整数时间刻度线宽 var clockScaleWidth = 2; //时钟整数时间刻度外半径 var clockScaleOuterRadius = clockBorderRadius - shadowWidth; //时钟整数时间刻度内半径 var clockScaleInnerRadius = clockScaleOuterRadius - 20; //时钟刻度颜色 var clockScaleColor = "Black"; //时钟非整数时间处半径 var clockScaleMiddleRadius = clockScaleOuterRadius - 10; //时钟数字半径 var clockNumRadius = clockBorderShadowRadius - 40; //时钟数字字体 var clockNumFont = "25px Arial"; //时钟数字颜色 var clockNumColor = "black"; //数字日期距中心的垂直距离 var digitalDateMarginCenter = 50; //数字日期颜色 var digitalDateColor = "Black"; //数字日期字体 var digitalDateFont = "bold 18px Arial"; //数字时间距中心的垂直距离 var digitalTimeMarginCenter = 100; //数字时间颜色 var digitalTimeColor = "white"; //数字时间背景颜色 var digitalTimeBgColor = "DarkSlateBlue"; //数字时间字体 var digitalTimeFont = "bold 25px Arial"; //数字时间高度的一半 var digitalTimeHeight = 40; //数字时间分隔线宽度 var digitalTimeSpanLineWidth = 2; //时钟中心点内圆的半径 var clockCenterInnerDotRadius = 7; //时钟中心点内圆的颜色 var clockCenterInnerDotColor = "FireBrick"; //时钟中心点外圆的半径 var clockCenterOuterDotRadius = 10; //时钟中心点外圆的颜色 var clockCenterOuterDotColor = "Maroon"; //时针线宽 var clockNeedleWidth = 5; //时针半径 var clockHourNeedleRadius = clockBorderShadowRadius - 120; //时针颜色 var clockHourNeedleColor = "DarkGreen"; //分针半径 var clockMinuteNeedleRadius = clockBorderShadowRadius - 80; //分针颜色 var clockMinuteNeedleColor = "DarkSlateGray"; //秒针半径 var clockSecondNeedleRadius = clockBorderShadowRadius - 40; //秒针尾部半径 var clockSecondNeedleBottomRadius = -20; //秒针颜色 var clockSecondNeedleColor = "FireBrick"; //画圆环 function strokeCircle(cx, cy, r) { ctx.beginPath(); ctx.arc(cx, cy, r, 0, doublePI); ctx.stroke(); } //画圆 function fillCircle(cx, cy, r) { ctx.beginPath(); ctx.arc(cx, cy, r, 0, doublePI); ctx.fill(); } //绘制线条 function strokeLine(x1, y1, x2, y2) { ctx.beginPath(); ctx.moveTo(x1, y1); ctx.lineTo(x2, y2); ctx.stroke(); } //根据角度和半径计算圆上相应位置的坐标(最右侧为起始角度,顺时针方向为正) function circlePos(cx, cy, theta, radius) { var pos = { x: cx + radius * Math.cos(theta), y: cy + radius * Math.sin(theta), }; return pos; } //在圆环上绘制刻度线 function strokeCircleLine(cx, cy, theta, r1, r2) { var pos1 = circlePos(cx, cy, theta, r1); var pos2 = circlePos(cx, cy, theta, r2); strokeLine(pos1.x, pos1.y, pos2.x, pos2.y); } //设置默认阴影 function setShadow(type) { ctx.lineWidth = shadowWidth; ctx.shadowBlur = shadowBlur; ctx.shadowOffsetX = shadowOffsetX; ctx.shadowOffsetY = shadowOffsetY; if(type === 1) { ctx.shadowColor = shadowLightColor; } else { ctx.shadowColor = shadowDarkColor; } } //取消阴影 function clearShadow() { ctx.shadowColor = "rgba(0,0,0,0)"; ctx.shadowBlur = 0; ctx.shadowOffsetX = 0; ctx.shadowOffsetY = 0; } //绘制时钟外圈的贝塞尔花纹 function renderBezierPattern() { ctx.fillStyle = bezierPatternColor; ctx.beginPath(); var theta = 0; //由于circlePos是顺时针方向正, 故圈也是顺时针方向 var beginPos = circlePos(cx, cy, theta, bezierRadius); ctx.moveTo(beginPos.x, beginPos.y); while(theta < doublePI) { //贝塞尔曲线控制点 var controlTheta = theta + bezierHalfSpan; var controlPos = circlePos(cx, cy, controlTheta, bezierPeakRadius); //贝塞尔曲线终止点 var endTheta = controlTheta + bezierHalfSpan; var endPos = circlePos(cx, cy, endTheta, bezierRadius); ctx.quadraticCurveTo(controlPos.x, controlPos.y, endPos.x, endPos.y); theta = endTheta; } //绘制圆counterclockwise=false, 即默认是顺时针方向 ctx.arc(cx, cy, clockBorderRadius, 0, doublePI, true); //注意: 两个相反方向的路径内部为填充范围 ctx.fill(); } //绘制时钟边框 function renderClockBorder() { //画外框 ctx.strokeStyle = clockBorderColor; ctx.lineWidth = clockBorderWidth; strokeCircle(cx, cy, clockBorderRadius); //画外框的内阴影 ctx.strokeStyle = shadowLightColor; setShadow(1); strokeCircle(cx, cy, clockBorderShadowRadius); clearShadow(); } //绘制时钟圆周上的数字和刻度部分 function renderClockNums() { ctx.textAlign = "center"; ctx.textBaseline = "middle"; ctx.font = clockNumFont; var span = doublePI / 60; for(var i = 1, radian = -halfPI + span; i <= 60; i++, radian += span) { if(i % 5 == 0) { //绘制刻度 ctx.strokeStyle = clockScaleColor; ctx.lineWidth = clockScaleWidth; strokeCircleLine(cx, cy, radian, clockScaleInnerRadius, clockScaleOuterRadius); //绘制数字 var pos = circlePos(cx, cy, radian, clockNumRadius); var num = i / 5; ctx.fillStyle = clockNumColor; ctx.fillText(num, pos.x, pos.y); } else { ctx.strokeStyle = clockScaleColor; ctx.lineWidth = clockScaleWidth; strokeCircleLine(cx, cy, radian, clockScaleMiddleRadius, clockScaleOuterRadius); } } } //绘制数字时钟 function renderDigital(date) { //绘制日期 ctx.textAlign = "center"; ctx.textBaseline = "middle"; ctx.font = digitalDateFont; ctx.fillStyle = digitalDateColor; var text = date.format("yyyy年MM月dd日 EEE"); ctx.fillText(text, cx, cy + digitalDateMarginCenter); //绘制时间 ctx.font = digitalTimeFont; text = date.format(" HH mm ss "); ctx.fillStyle = digitalTimeBgColor; var textWidth = ctx.measureText(text).width; var textBgX = cx - textWidth / 2; var textBgY = cy + digitalTimeMarginCenter - digitalTimeHeight / 2; ctx.fillRect(textBgX, textBgY, textWidth, digitalTimeHeight); ctx.fillStyle = digitalTimeColor; ctx.fillText(text, cx, cy + digitalTimeMarginCenter); //绘制事件中间的分隔线 ctx.lineWidth = digitalTimeSpanLineWidth; ctx.strokeStyle = digitalTimeColor; var textSpan = textWidth / 6; var leftLineX = cx - textSpan; strokeLine(leftLineX, textBgY, leftLineX, textBgY + digitalTimeHeight); var rightLineX = cx + textSpan; strokeLine(rightLineX, textBgY, rightLineX, textBgY + digitalTimeHeight); } //绘制时钟中心最下方红点 function renderClockCenterOuterDot() { ctx.fillStyle = clockCenterOuterDotColor; fillCircle(cx, cy, clockCenterOuterDotRadius); } //绘制时钟中心最上方红点 function renderClockCenterInnerDot() { ctx.fillStyle = clockCenterInnerDotColor; fillCircle(cx, cy, clockCenterInnerDotRadius); } //绘制时钟指针 function renderClockNeedle(date) { var hourRadian = date.getHours() % 12 / 12 * doublePI - halfPI; var minuteRadian = date.getMinutes() / 60 * doublePI - halfPI; var secondRadian = date.getSeconds() / 60 * doublePI - halfPI; setShadow(); ctx.lineCap = "round"; ctx.lineWidth = clockNeedleWidth; ctx.strokeStyle = clockHourNeedleColor; strokeCircleLine(cx, cy, hourRadian, 0, clockHourNeedleRadius); ctx.strokeStyle = clockMinuteNeedleColor; strokeCircleLine(cx, cy, minuteRadian, 0, clockMinuteNeedleRadius); ctx.strokeStyle = clockSecondNeedleColor; strokeCircleLine(cx, cy, secondRadian, clockSecondNeedleBottomRadius, clockSecondNeedleRadius); ctx.lineCap = "square"; clearShadow(); } function render(date) { ctx.clearRect(0, 0, canvas.width, canvas.height); renderBezierPattern(); renderClockBorder(); renderClockNums(); renderDigital(date); renderClockCenterOuterDot(); renderClockNeedle(date); renderClockCenterInnerDot(); } var lastTime = 0; var audio = document.getElementById("ticktock"); function loop() { var date = new Date(); var currentTime = date.getTime(); if(currentTime - lastTime >= 1000) { lastTime = currentTime; //注意：这里设0非常关键，否则虽然会循环播放，但会从上一次暂停的地方开始播放，造成延迟 audio.currentTime = 0; audio.play(); render(date); } requestAnimationFrame(loop); } loop(); </script> </body> </html>

相关阅读