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这篇“JavaScript如何实现时钟特效”文章的知识点大部分人都不太理解，所以小编给大家总结了以下内容，内容详细，步骤清晰，具有一定的借鉴价值，希望大家阅读完这篇文章能有所收获，下面我们一起来看看这篇“JavaScript如何实现时钟特效”文章吧。
简单时间实现：
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
function startTime()
{
var today=new Date()
var h=today.getHours()
var m=today.getMinutes()
var s=today.getSeconds()
// add a zero in front of numbers<10
m=checkTime(m)
s=checkTime(s)
document.getElementById('txt').innerHTML=h+":"+m+":"+s
t=setTimeout('startTime()',500)
}
function checkTime(i)
{
if (i<10)
{i="0" + i}
return i
}
</script>
</head>
<body onload="startTime()">
<div id="txt"></div>
</body>
</html>时钟特效代码：
<!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 type="text/javascript">
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 = 10;
//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 = 10;
//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>以上就是关于“JavaScript如何实现时钟特效”这篇文章的内容，相信大家都有了一定的了解，希望小编分享的内容对大家有帮助，若想了解更多相关的知识内容，请关注亿速云行业资讯频道。
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