Transform-Origin

效果预览按下右侧的“点击预览”按钮可以在当前页面预览，点击链接可以全屏预览。https://codepen.io/comehope/pen/yxVYRL可交互视频此视频是可以交互的，你可以随时暂停视频，编辑视频中的代码。请用 chrome, safari, edge 打开观看。https://scrimba.com/p/pEgDAM/cmVLRc9源代码下载每日前端实战系列的全部源代码请从 github 下载：https://github.com/comehope/front-end-daily-challenges代码解读定义 dom，容器中包含 3 个子元素，分别表示机冀、螺旋桨和轮子，机冀有 4 片叶片，轮子左右各一只：<div class=“plane”> <div class=“wings”></div> <div class=“fans”> <span></span> <span></span> <span></span> <span></span> </div> <div class=“wheels”> <span class=“left”></span> <span class=“right”></span> </div></div>定义容器尺寸：.plane { width: 28em; height: 13em; font-size: 10px;}定义子元素整体布局和共有属性：.plane { display: flex; justify-content: center; position: relative;}.plane > * { position: absolute;}.plane > *::before,.plane > *::after { content: ‘’; position: absolute;}定义基本色：.plane { color: black;}画出双冀：.wings { width: inherit; display: flex; justify-content: center;}.wings::before { width: inherit; height: 0.5em; background-color: currentColor;}.wings::after { top: 4em; width: 90%; height: 0.4em; background-color: currentColor;}画出螺旋桨的中心：.fans { width: 11em; height: 11em; outline: 1px dashed; background: radial-gradient( black 2.5em, transparent 2.5em );}定义叶片的形状为半圆形：.fans span { width: inherit; height: inherit;}.fans span::before { width: inherit; height: 50%; background-color: rgba(255, 255, 255, 0.4); border-radius: 50% 50% 0 0 / 100% 100% 0 0;}分别旋转叶片的角度，使 4 个页片均匀分布在一个圆内：.fans span::before { transform-origin: bottom; transform: rotate(calc((var(–n) - 1) * 90deg));}.fans span:nth-child(1) { –n: 1;}.fans span:nth-child(2) { –n: 2;}.fans span:nth-child(3) { –n: 3;}.fans span:nth-child(4) { –n: 4;}画出 2 个轮子：.wheels { width: 16em; height: 2em; outline: 1px dashed; bottom: 0; display: flex; justify-content: space-between;}.wheels span { position: static; width: 1em; height: inherit; background-color: currentColor; border-radius: 0.5em;}画出轮子的 2 个支架：.wheels span { display: flex; justify-content: center;}.wheels span::before { width: 0.2em; height: 8em; background-color: currentColor; transform-origin: bottom; bottom: 1em; z-index: -1;}.wheels .left::before { transform: rotate(45deg);}.wheels .right::before { transform: rotate(-45deg);}接下来制作动画效果。增加螺旋桨旋转的动画效果：.fans span { animation: fans-rotating 0.8s linear infinite; animation-delay: calc(var(–n) * 0.1s);}@keyframes fans-rotating { to { transform: rotate(-1turn); }}增加飞机飞行的动画效果：.plane { animation: fly 5s infinite;}@keyframes fly { 10%, 50%, 100% { top: 0; } 25% { top: 1em; } 75% { top: -1em; }}再增加飞机旋转的动画效果：.plane { animation: plane-rotating 10s infinite, fly 5s infinite;}@keyframes plane-rotating { 10%, 30%, 50% { transform: rotate(0deg); } 20% { transform: rotate(-4deg); } 80% { transform: rotate(8deg); } 100% { transform: rotate(-1turn); }}大功告成！ ...

效果预览按下右侧的“点击预览”按钮可以在当前页面预览，点击链接可以全屏预览。https://codepen.io/comehope/pen/zJKwbO可交互视频此视频是可以交互的，你可以随时暂停视频，编辑视频中的代码。请用 chrome, safari, edge 打开观看。https://scrimba.com/p/pEgDAM/cDBZNUW源代码下载每日前端实战系列的全部源代码请从 github 下载：https://github.com/comehope/front-end-daily-challenges代码解读定义 dom，容器中包含 8 个元素，每个元素代表一个矩形色块：<div class=“icon”> <span></span> <span></span> <span></span> <span></span> <span></span> <span></span> <span></span> <span></span></div>居中显示：body { margin: 0; height: 100vh; display: flex; align-items: center; justify-content: center; background-color: #ccc;}定义容器尺寸：.icon { width: 10em; height: 10em; font-size: 30px; background-color: #eee; border-radius: 20%;}绘制出矩形的轮廓（边框为辅助线，最终会被删除），并放置在容器的中上方：.icon { position: relative; display: flex; justify-content: center; box-sizing: border-box; padding: 1em;}.icon span { position: absolute; width: 22.5%; height: 37.5%; border: 1px dashed black; border-radius: 50% / 30%;}为矩形设置下标变量 –n：.icon span:nth-child(1) { –n: 1;}.icon span:nth-child(2) { –n: 2;}.icon span:nth-child(3) { –n: 3;}.icon span:nth-child(4) { –n: 4;}.icon span:nth-child(5) { –n: 5;}.icon span:nth-child(6) { –n: 6;}.icon span:nth-child(7) { –n: 7;}.icon span:nth-child(8) { –n: 8;}让 8 个矩形依次旋转固定的角度，围合成一个圆形：.icon span { transform-origin: center 105%; transform: rotate(calc((var(–n) - 1) * 45deg));}为矩形设置颜色变量 –c：.icon span:nth-child(1) { –c: rgba(243, 156, 18, 0.7);}.icon span:nth-child(2) { –c: rgba(241, 196, 15, 0.7);}.icon span:nth-child(3) { –c: rgba(46, 204, 113, 0.7);}.icon span:nth-child(4) { –c: rgba(27, 188, 155, 0.7);}.icon span:nth-child(5) { –c: rgba(65, 131, 215, 0.7);}.icon span:nth-child(6) { –c: rgba(102, 51, 153, 0.7);}.icon span:nth-child(7) { –c: rgba(155, 89, 182, 0.7);}.icon span:nth-child(8) { –c: rgba(242, 38, 19, 0.7);}为 8 个矩形上色，并删除掉起辅助线作用的边框：.icon span { /* border: 1px dashed black; */ background-color: var(–c);}设置混色模式，使重叠颜色能叠加在一起：.icon span { mix-blend-mode: multiply;}增加鼠标悬停效果，当悬停时运行矩形色块展开的动画：.icon:hover span { animation: rotating 2s ease-in-out forwards;}@keyframes rotating { from { transform: rotate(0deg); } to { transform: rotate(calc((var(–n) - 1) * 45deg)); }}注意，在动画过程中第 1 个矩形并没有转动，因为它是从 0 度转到 0 度，为了让它转动，要把它的结束角度设置为 360 度，通过修改它的下标变量来实现：.icon span:nth-child(1) { –n: 9;}大功告成！ ...