javascript - 如何使用偏移路径 CSS 属性从其原始位置偏移 SVG 路径

Question

我有一堆 SVG 路径是文本字母。在滚动时，我想从它们的原始位置开始沿着 offset-path 为它们设置动画。所以我将 0x 和 0y 的起始位置赋予 offset-path 属性，然后将随机的 Line 赋予 偏移路径，我想沿着它设置 SVG 字母的动画，如下所示:

path.setAttribute("style", "offset-path: path('M" + 0 +" " + 0 + " L " + generateRandomAnimationPathLine() + " " + generateRandomAnimationPathLine() + "')"); 

但是一旦我给所有 SVG 路径 offset-path 随机 L 属性，它们已经遍布整个屏幕并设置了 offset-distance到 0%。这是为什么？如果 offset-distance 设置为 0，它们不应该留在原点吗？为什么 offset-path: path() 中的 L 从原点移动 SVG，即使 M 设置为 0？

您可以检查每个 SVG 字母并勾选 offset-distance 以查看它们是否已经超出原点。如何从原始位置开始对 SVG 路径进行动画处理？我正在尝试实现一种效果，当您滚动它时，它会慢慢破坏“Hello, World”，而当您向上滚动时，它会恢复到原始形式。

图像来解释我想要实现的目标。当 SVG 在屏幕上时，将 offset-path 设置为随机 Lines/L 我想通过更改 offset-distance< 沿其从原始位置为 SVG 字母设置动画 相对于滚动条从 0% 到 100%，如下所示:

path.style.offsetDistance = element.intersectionRatio * 100 + "%";

实例:https://codepen.io/Limpuls/pen/KKzZWEm

代码:

 <section class="row first">
                <div class="col-lg-12">
                    <div class="svg">
                        <svg viewBox="-145 -90 500 500" fill="none" xmlns="http://www.w3.org/2000/svg">
                            <path d="M26 2V30H19.52V18.52H6.80001V30H0.320007V2H6.80001V13.04H19.52V2H26Z" fill="black"/>
                            <path d="M53.2647 19.32C53.2647 19.4 53.2247 19.96 53.1447 21H36.8647C37.158 22.3333 37.8514 23.3867 38.9447 24.16C40.038 24.9333 41.398 25.32 43.0247 25.32C44.1447 25.32 45.1314 25.16 45.9847 24.84C46.8647 24.4933 47.678 23.96 48.4247 23.24L51.7447 26.84C49.718 29.16 46.758 30.32 42.8647 30.32C40.438 30.32 38.2914 29.8533 36.4247 28.92C34.558 27.96 33.118 26.64 32.1047 24.96C31.0914 23.28 30.5847 21.3733 30.5847 19.24C30.5847 17.1333 31.078 15.24 32.0647 13.56C33.078 11.8533 34.4514 10.5333 36.1847 9.6C37.9447 8.64 39.9047 8.16 42.0647 8.16C44.1714 8.16 46.078 8.61333 47.7847 9.52C49.4914 10.4267 50.8247 11.7333 51.7847 13.44C52.7714 15.12 53.2647 17.08 53.2647 19.32ZM42.1047 12.88C40.6914 12.88 39.5047 13.28 38.5447 14.08C37.5847 14.88 36.998 15.9733 36.7847 17.36H47.3847C47.1714 16 46.5847 14.92 45.6247 14.12C44.6647 13.2933 43.4914 12.88 42.1047 12.88Z" fill="black"/>
                            <path d="M57.4191 0.319998H63.6591V30H57.4191V0.319998Z" fill="black"/>
                            <path d="M69.4503 0.319998H75.6903V30H69.4503V0.319998Z" fill="black"/>
                            <path d="M91.7216 30.32C89.4549 30.32 87.4149 29.8533 85.6016 28.92C83.8149 27.96 82.4149 26.64 81.4016 24.96C80.3882 23.28 79.8816 21.3733 79.8816 19.24C79.8816 17.1067 80.3882 15.2 81.4016 13.52C82.4149 11.84 83.8149 10.5333 85.6016 9.6C87.4149 8.64 89.4549 8.16 91.7216 8.16C93.9882 8.16 96.0149 8.64 97.8016 9.6C99.5882 10.5333 100.988 11.84 102.002 13.52C103.015 15.2 103.522 17.1067 103.522 19.24C103.522 21.3733 103.015 23.28 102.002 24.96C100.988 26.64 99.5882 27.96 97.8016 28.92C96.0149 29.8533 93.9882 30.32 91.7216 30.32ZM91.7216 25.2C93.3216 25.2 94.6282 24.6667 95.6416 23.6C96.6816 22.5067 97.2016 21.0533 97.2016 19.24C97.2016 17.4267 96.6816 15.9867 95.6416 14.92C94.6282 13.8267 93.3216 13.28 91.7216 13.28C90.1216 13.28 88.8016 13.8267 87.7616 14.92C86.7216 15.9867 86.2016 17.4267 86.2016 19.24C86.2016 21.0533 86.7216 22.5067 87.7616 23.6C88.8016 24.6667 90.1216 25.2 91.7216 25.2Z" fill="black"/>
                            <path d="M109.819 22.56C110.939 22.56 111.859 22.92 112.579 23.64C113.299 24.3333 113.659 25.2533 113.659 26.4C113.659 26.9333 113.592 27.4667 113.459 28C113.326 28.5333 113.032 29.3333 112.579 30.4L110.299 36.16H106.339L108.099 29.8C107.432 29.5333 106.899 29.1067 106.499 28.52C106.126 27.9067 105.939 27.2 105.939 26.4C105.939 25.2533 106.299 24.3333 107.019 23.64C107.766 22.92 108.699 22.56 109.819 22.56Z" fill="black"/>
                            <path d="M171.976 2L162.816 30H155.856L149.696 11.04L143.336 30H136.416L127.216 2H133.936L140.256 21.68L146.856 2H152.856L159.256 21.84L165.776 2H171.976Z" fill="black"/>
                            <path d="M183.792 30.32C181.525 30.32 179.485 29.8533 177.672 28.92C175.885 27.96 174.485 26.64 173.472 24.96C172.459 23.28 171.952 21.3733 171.952 19.24C171.952 17.1067 172.459 15.2 173.472 13.52C174.485 11.84 175.885 10.5333 177.672 9.6C179.485 8.64 181.525 8.16 183.792 8.16C186.059 8.16 188.085 8.64 189.872 9.6C191.659 10.5333 193.059 11.84 194.072 13.52C195.085 15.2 195.592 17.1067 195.592 19.24C195.592 21.3733 195.085 23.28 194.072 24.96C193.059 26.64 191.659 27.96 189.872 28.92C188.085 29.8533 186.059 30.32 183.792 30.32ZM183.792 25.2C185.392 25.2 186.699 24.6667 187.712 23.6C188.752 22.5067 189.272 21.0533 189.272 19.24C189.272 17.4267 188.752 15.9867 187.712 14.92C186.699 13.8267 185.392 13.28 183.792 13.28C182.192 13.28 180.872 13.8267 179.832 14.92C178.792 15.9867 178.272 17.4267 178.272 19.24C178.272 21.0533 178.792 22.5067 179.832 23.6C180.872 24.6667 182.192 25.2 183.792 25.2Z" fill="black"/>
                            <path d="M205.723 11.32C206.469 10.28 207.469 9.49333 208.723 8.96C210.003 8.42667 211.469 8.16 213.123 8.16V13.92C212.429 13.8667 211.963 13.84 211.723 13.84C209.936 13.84 208.536 14.3467 207.523 15.36C206.509 16.3467 206.003 17.84 206.003 19.84V30H199.763V8.48H205.723V11.32Z" fill="black"/>
                            <path d="M216.833 0.319998H223.073V30H216.833V0.319998Z" fill="black"/>
                            <path d="M250.784 0.319998V30H244.824V27.52C243.278 29.3867 241.038 30.32 238.104 30.32C236.078 30.32 234.238 29.8667 232.584 28.96C230.958 28.0533 229.678 26.76 228.744 25.08C227.811 23.4 227.344 21.4533 227.344 19.24C227.344 17.0267 227.811 15.08 228.744 13.4C229.678 11.72 230.958 10.4267 232.584 9.52C234.238 8.61333 236.078 8.16 238.104 8.16C240.851 8.16 242.998 9.02667 244.544 10.76V0.319998H250.784ZM239.184 25.2C240.758 25.2 242.064 24.6667 243.104 23.6C244.144 22.5067 244.664 21.0533 244.664 19.24C244.664 17.4267 244.144 15.9867 243.104 14.92C242.064 13.8267 240.758 13.28 239.184 13.28C237.584 13.28 236.264 13.8267 235.224 14.92C234.184 15.9867 233.664 17.4267 233.664 19.24C233.664 21.0533 234.184 22.5067 235.224 23.6C236.264 24.6667 237.584 25.2 239.184 25.2Z" fill="black"/>
                            </svg>                       
                    </div>           
                </div>
    </section>

JS:

let thresholdArray = []
for (let i = 10; i < 100; i += 1){    
    thresholdArray.push(i / 100);    
}

let options = {
  root: null,
  rootMargin: "20px",
  threshold: thresholdArray
};

let pathGenerated = false;
let callback = (entries, observer) => {
    entries.forEach(element => {
        element.target.querySelectorAll("path").forEach(path => {
        if (element.isIntersecting) {
            if (!pathGenerated) {           
              path.setAttribute("style", "offset-path: path('M" + 0 +" " + 0 + " L " + generateRandomAnimationPathLine() + " " + generateRandomAnimationPathLine() + "')"); 
            }
            path.style.offsetDistance = element.intersectionRatio * 100 + "%";          
        } else {           
            pathGenerated = false;
            path.style.removeProperty("offset-path");            
        }
        
    });
    }); 
    pathGenerated = true;  
}

let generateRandomAnimationPathLine = (element) => {
    return Math.floor(Math.random() * Math.floor(100));
}

let observer = new IntersectionObserver(callback, options);

document.querySelectorAll('section').forEach(section => {
    console.log(section)
    observer.observe(section);
});

Answer 1

我不得不说我找到了 offset-path 的用法对于你想要实现的目标来说是次优的。对 Motion path CSS 模块的几个属性的支持是不完整的，正如我们发现的那样，旋转与路径的关系是违反直觉的。 SVG 本身有一种在文本中移动和旋转单个字母的机制，可以在没有任何兼容性问题的情况下执行此操作。这假设您可以使用 <text>元素而不是转换为路径的字母。

<text>和 <tspan>元素接受许多属性，这些属性以空格分隔的数字列表作为参数。第 n 个数字应用于元素内的第 n 个字母:

• dx 和 dy 将每个字母从其呈现的位置移开。转移是累积的。换句话说:在第一个字母根据第一个值移动后，第二个字母呈现在移动后的第一个字母旁边，并根据第二个值从那个位置移动。
• rotate 旋转每个字母，但不累加:每个数字代表偏离其原始方向的旋转。

下面的例子从你的笔中减少了一点，用 slider 而不是使用观察者来设置“距离”。最大距离和旋转存储在全局对象中。在每个 slider 更改时，dx 中的值列表, dy和 rotate属性被重新计算为最大距离和 Angular 一小部分。由于距离值的累积性质，通过减去前一个字母的偏移量来“重置”每个字母的偏移量。

const offsets = [];

for (let i = 0; i < 11; i++) {
    offsets.push({
        x: Math.random() * 60 - 30,
        y: Math.random() * 60 - 30,
        a: Math.random() * 360 - 180
    });
}

const text = document.querySelector('.mesg');

document.querySelector('#distance').addEventListener('change', (ev) => {
    const dist = parseFloat(ev.target.value);

    const attrs = offsets.reduce((attr, o, i) => {
        attr.dx.push((i ? o.x - offsets[i-1].x : o.x) * dist);
        attr.dy.push((i ? o.y - offsets[i-1].y : o.y) * dist);
        attr.rotate.push(o.a * dist);
        return attr;
    }, {dx: [], dy: [], rotate: []});

    for (let [key, value] of Object.entries(attrs)) {
        text.setAttribute(key, value.join(" "));
    }
})

text {
  font-size: 20px;
  font-family: sans-serif;
}

<div><input id="distance" type="range" min="0" max="1" step="0.05" value="0"></input></div>

<svg viewBox="0 0 200 100" width="100%" height="150">
  <text x="10" y="60" class="mesg">Hello World</text>
</svg>