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一个简易的 LED 数字时钟实现方法

这个应该是已经有很多人做过的东西,我应该只是算手痒,想写一下,所以,花了点时间折腾了这个,顺便把 Dark Mode 的处理也加上了。

首先可以很明确的一点,这个真没技术含量存在,只是需要点耐心。

LED 数字包含了左右各两条线,中间三条线,一共 7 条线。所以,为了能够更容易辨识,在写 demo 的时候,我直接这样写了。

<div class="digital digital_0">
  <span class="c1"></span>
  <span class="c2"></span>
  <span class="c3"></span>
  <span class="l1"></span>
  <span class="l2"></span>
  <span class="r1"></span>
  <span class="r2"></span>
</div>

至于 digital_0 这个的作用,其实很简单,就是控制从 0 ~ 9 这十个数字的变化而存在的。

.digital_1 .c1,
.digital_1 .c2,
.digital_1 .c3,
.digital_1 .l1,
.digital_1 .l2,
.digital_2 .l1,
.digital_2 .r2,
.digital_3 .l1,
.digital_3 .l2,
.digital_4 .c1,
.digital_4 .c3,
.digital_4 .l2,
.digital_5 .l2,
.digital_5 .r1,
.digital_6 .r1,
.digital_7 .c2,
.digital_7 .c3,
.digital_7 .l1,
.digital_7 .l2,
.digital_9 .l2,
.digital_0 .c2 {
  animation: changeDigital 200ms 0ms 1 ease-in forwards;
}

这里使用了一个 animation 动画,并且时间是 200ms,主要是为了让某些部分消失的时候,有一个过渡效果。

@keyframes changeDigital {
  form {
    opacity: 1;
  }
  to {
    opacity: 0;
  }
}

那么剩下来的就是最需要耐心的地方了,调整控制那 7 条线的位置,同时还要考虑每条线是带有斜角的,而且还稍微有点圆弧的感觉。带点圆弧的感觉那么直接使用 border-radius 就可以了,至于那个斜角的话,如果各位知道 CSS 中用边框画三角的方法,那么就应该明白怎么做这个斜角了。

当我们要画三角的时候,width 和 height 都是为 0,然后用过控制 border-width 而得到最终的三角的大小,那么这里如果我们根据线条的位置,适当选择 width 和 height 有具体的值,是不是就有斜角的感觉了呢。

接着,需要注意横着的中间那根线,也就是 .c2 这个元素,线条两边是三角突出的,可以实现的方式也很多,这里我选择使用 :after 和 :before 相叠加。

最后就是对每个元素的位置做调整,控制好大小位置就可以了,因为是使用定位的方式来操作,所以,调整起来还是很简单的。

.digital span {
  position: absolute;
  border-radius: 50vh;
  box-sizing: border-box;
}
.digital .c1,
.digital .c2,
.digital .c3 {
  height: 0;
  width: 26px;
  border-left: 4px solid transparent;
  border-right: 4px solid transparent;
}
.digital .c1 {
  top: 0;
  left: 0;
  border-top: 4px solid currentColor;
}
.digital .c2 {
  top: 50%;
  left: 0;
  margin-top: -2px;
}
.digital .c2:before,
.digital .c2:after {
  content: "";
  height: 0;
  width: 24px;
  border-left: 2px solid transparent;
  border-right: 2px solid transparent;
  box-sizing: border-box;
}
.digital .c2:before {
  position: absolute;
  top: 0;
  left: -3px;
  border-bottom: 2px solid currentColor;
}
.digital .c2:after {
  position: absolute;
  top: 2px;
  left: -3px;
  border-top: 2px solid currentColor;
}
.digital .c3 {
  bottom: 0;
  left: 0;
  border-bottom: 4px solid currentColor;
}
.digital .l1,
.digital .l2 {
  height: 21px;
  width: 0;
  left: 0;
  border-top: 2px solid transparent;
  border-bottom: 2px solid transparent;
  border-left: 4px solid currentColor;
}
.digital .l1 {
  top: 1px;
  border-top-width: 4px;
}
.digital .l2 {
  top: 24px;
  border-bottom-width: 4px;
}
.digital .r1,
.digital .r2 {
  height: 21px;
  width: 0;
  right: 0;
  border-top: 2px solid transparent;
  border-bottom: 2px solid transparent;
  border-right: 4px solid currentColor;
}
.digital .r1 {
  top: 1px;
  border-top-width: 4px;
}
.digital .r2 {
  top: 24px;
  border-bottom-width: 4px;
}

做完这些,剩下的就是简单的对外层元素做点优化,比如稍微倾斜一点。

.digital {
  position: relative;
  width: 26px;
  height: 46px;
  margin-left: 10px;
  transform: skew(-6deg);
}

哦,忘了说了,这里的边框颜色我选择使用 currentColor 的方式,这样可以在暗黑模式切换的过程中,只需要修改 body 中的文字颜色和背景色就可以了。currentColor 会选择文字颜色来使用。

样式处理完之后,接着就是添加点 JS 来显示时钟了,只要把两个数字整出来放到不同的 div 中就好了。这里我取个位数的时候,是用 m%10 的方式取余;取十位数的时候是通过 parseInt(m/10) 的方式取整。取出来之后分别放到想对应的 div 中就 ok 了。

完整代码如下:

样式:

body {
  color: #393e4d;
  background-color: #f5f5f5;
}
@media screen and (prefers-color-scheme: dark) {
  body {
    color: #59f6fb;
    background-color: #1c1b1e;
  }
}
.digital {
    position: relative;
    width: 26px;
    height: 46px;
  margin-left: 10px;
    transform: skew(-6deg);
}
.digital span {
    position: absolute;
    border-radius: 50vh;
    box-sizing: border-box;
}
.digital .c1,
.digital .c2,
.digital .c3 {
    height: 0;
    width: 26px;
    border-left: 4px solid transparent;
    border-right: 4px solid transparent;
}
.digital .c1 {
    top: 0;
    left: 0;
    border-top: 4px solid currentColor;
}
.digital .c2 {
    top: 50%;
    left: 0;
    margin-top: -2px;
}
.digital .c2:before,
.digital .c2:after {
    content: "";
    height: 0;
    width: 24px;
    border-left: 2px solid transparent;
    border-right: 2px solid transparent;
    box-sizing: border-box;
}
.digital .c2:before {
    position: absolute;
    top: 0;
    left: -3px;
    border-bottom: 2px solid currentColor;
}
.digital .c2:after {
    position: absolute;
    top: 2px;
    left: -3px;
    border-top: 2px solid currentColor;
}
.digital .c3 {
    bottom: 0;
    left: 0;
    border-bottom: 4px solid currentColor;
}
.digital .l1,
.digital .l2 {
    height: 21px;
    width: 0;
    left: 0;
    border-top: 2px solid transparent;
    border-bottom: 2px solid transparent;
    border-left: 4px solid currentColor;
}
.digital .l1 {
    top: 1px;
    border-top-width: 4px;
}
.digital .l2 {
    top: 24px;
    border-bottom-width: 4px;
}
.digital .r1,
.digital .r2 {
    height: 21px;
    width: 0;
    right: 0;
    border-top: 2px solid transparent;
    border-bottom: 2px solid transparent;
    border-right: 4px solid currentColor;
}
.digital .r1 {
    top: 1px;
    border-top-width: 4px;
}
.digital .r2 {
    top: 24px;
    border-bottom-width: 4px;
}

.digital_1 .c1, .digital_1 .c2, .digital_1 .c3, .digital_1 .l1, .digital_1 .l2, .digital_2 .l1, .digital_2 .r2, .digital_3 .l1, .digital_3 .l2, .digital_4 .c1, .digital_4 .c3, .digital_4 .l2, .digital_5 .l2, .digital_5 .r1, .digital_6 .r1, .digital_7 .c2, .digital_7 .c3, .digital_7 .l1, .digital_7 .l2, .digital_9 .l2, .digital_0 .c2 { animation: changeDigital 200ms 0ms 1 ease-in forwards; }

@keyframes changeDigital { form { opacity: 1; } to { opacity: 0; } }

.clock { display: flex; justify-content: center; padding-top: 20px; } .gap { height: 46px; padding-left: 10px; font-size: 50px; font-weight: bold; line-height: 0.8; transform: skew(-6deg); }

结构:

<div class="clock">
  <div class="digital digital_0">
    <span class="c1"></span>
    <span class="c2"></span>
    <span class="c3"></span>
    <span class="l1"></span>
    <span class="l2"></span>
    <span class="r1"></span>
    <span class="r2"></span>
  </div>
  <div class="digital digital_0">
    <span class="c1"></span>
    <span class="c2"></span>
    <span class="c3"></span>
    <span class="l1"></span>
    <span class="l2"></span>
    <span class="r1"></span>
    <span class="r2"></span>
  </div>
  <div class="gap">:</div>
  <div class="digital digital_0">
    <span class="c1"></span>
    <span class="c2"></span>
    <span class="c3"></span>
    <span class="l1"></span>
    <span class="l2"></span>
    <span class="r1"></span>
    <span class="r2"></span>
  </div>
  <div class="digital digital_0">
    <span class="c1"></span>
    <span class="c2"></span>
    <span class="c3"></span>
    <span class="l1"></span>
    <span class="l2"></span>
    <span class="r1"></span>
    <span class="r2"></span>
  </div>
  <div class="gap">:</div>
  <div class="digital digital_0">
    <span class="c1"></span>
    <span class="c2"></span>
    <span class="c3"></span>
    <span class="l1"></span>
    <span class="l2"></span>
    <span class="r1"></span>
    <span class="r2"></span>
  </div>
  <div class="digital digital_0">
    <span class="c1"></span>
    <span class="c2"></span>
    <span class="c3"></span>
    <span class="l1"></span>
    <span class="l2"></span>
    <span class="r1"></span>
    <span class="r2"></span>
  </div>
</div>

JS:

var s1 = document.getElementsByClassName("digital")[5],
    s2 = document.getElementsByClassName("digital")[4],
    m1 = document.getElementsByClassName("digital")[3],
    m2 = document.getElementsByClassName("digital")[2],
    h1 = document.getElementsByClassName("digital")[1],
    h2 = document.getElementsByClassName("digital")[0];

setInterval(function(){ var date = new Date(); var h = date.getHours(); var m = date.getMinutes(); var s = date.getSeconds(); if (h < 10) { h1.className = 'digital digital_' + h; h2.className = 'digital digital_0'; } else { h1.className = 'digital digital_' + parseInt(h%10); h2.className = 'digital digital_' + parseInt(h/10); } if (m < 10) { m1.className = 'digital digital_' + m; m2.className = 'digital digital_0'; } else { m1.className = 'digital digital_' + parseInt(m%10); m2.className = 'digital digital_' + parseInt(m/10); } if (s < 10) { s1.className = 'digital digital_' + s; s2.className = 'digital digital_0'; } else { s1.className = 'digital digital_' + parseInt(s%10); s2.className = 'digital digital_' + parseInt(s/10); } }, 1000)

这样一个简易的 LED 数字时钟就大功告成啦。

本文转载自博客园,原文链接:https://www.cnblogs.com/zml1023/p/12206007.html

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