如何用纯 CSS 绘制一个世界上不存在的彭罗斯三角形

怼烎@ 2022-04-15 04:07 155阅读 0赞

![1504647-20181121121508162-1711082862.png][]

## 效果预览 ##

[在线演示][Link 1]

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/RyvgMZ][https_codepen.io_comehope_pen_RyvgMZ]

## 可交互视频教程 ##

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/c/czPkasr][https_scrimba.com_c_czPkasr]

## 源代码下载 ##

[本地下载][Link 2]

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][https_github.com_comehope_front-end-daily-challenges]

## 代码解读 ##

定义 dom，一个容器中包含 3 个 <span>：

居中显示：

html,
    body {
        height: 100%;
        display: flex;
        align-items: center;
        justify-content: center;
        background-color: black;
    }

定义容器尺寸：

.penrose {
        width: 20em;
        height: 20em;
    }

画出包含 3 条边的容器：

.penrose {
        position: relative;
    }
    
    .penrose span {
        position: absolute;
        width: 100%;
        height: 100%;
    }
    
    .penrose span:nth-child(1) {
        transform: rotate(0deg);
    }
    
    .penrose span:nth-child(2) {
        transform: rotate(120deg);
    }
    
    .penrose span:nth-child(3) {
        transform: rotate(240deg);
    }

为 3 条边所属的容器上色：

.penrose {
        color: red;
    }
    
    .penrose span {
        background-color: currentColor;
    }
    
    .penrose span:nth-child(1) {
        filter: brightness(1);
    }
    
    .penrose span:nth-child(2) {
        filter: brightness(0.66);
    }
    
    .penrose span:nth-child(3) {
        filter: brightness(0.33);
    }

用遮罩切出每一条边，组成彭罗斯三角形：

.penrose span {
        clip-path: polygon(57% 0, 75% 0, 26% 85%, 89.5% 85%, 98.4% 100%, 0 100%);
    }
    
    .penrose span:nth-child(2) {
        top: 18.3%;
        left: 43.3%;
    }
    
    .penrose span:nth-child(3) {
        top: 46.5%;
        left: 5.9%;
    }

定义旋转动画效果：

.penrose {
        animation: rotating 30s linear infinite;
        transform-origin: 66% 66%;
    }
    
    @keyframes rotating {
        0% {
            transform: rotate(0deg);
        }
    
        100% {
            transform: rotate(360deg);
        }
    }

最后，增加旋转时变色的效果：

@keyframes rotating {
        0% {
            color: red;
            transform: rotate(0deg);
        }
    
        20% {
            color: yellow;
        }
    
        40% {
            color: lime;
        }
    
        60% {
            color: blue;
        }
    
        80% {
            color: fuchsia;
        }
    
        100% {
            color: red;
            transform: rotate(720deg);
        }
    }

大功告成！

原文地址：[https://segmentfault.com/a/1190000014946883][https_segmentfault.com_a_1190000014946883]

[1504647-20181121121508162-1711082862.png]: /images/20220415/cd69cf63ce854c89a9953b72c7d84ab4.png
[Link 1]: https://www.jqhtml.com/yanshi?demourl=%2Fwp-content%2Fuploads%2F2018%2F11%2Ffront-end-daily-challenges-master%2F028-penrose-triangle&demotitle=%E7%BA%AF%20CSS%20%E7%BB%98%E5%88%B6%E4%B8%80%E4%B8%AA%E4%B8%96%E7%95%8C%E4%B8%8A%E4%B8%8D%E5%AD%98%E5%9C%A8%E7%9A%84%E5%BD%AD%E7%BD%97%E6%96%AF%E4%B8%89%E8%A7%92%E5%BD%A2
[https_codepen.io_comehope_pen_RyvgMZ]: https://codepen.io/comehope/pen/RyvgMZ
[https_scrimba.com_c_czPkasr]: https://scrimba.com/c/czPkasr
[Link 2]: https://www.jqhtml.com/19271.html
[https_github.com_comehope_front-end-daily-challenges]: https://github.com/comehope/front-end-daily-challenges
[https_segmentfault.com_a_1190000014946883]: https://segmentfault.com/a/1190000014946883