更改SVG视口的高度会更改viewBox起始原点<min-x>

问题描述

更改视口的坐标系高度会更改用户的坐标系在X轴上的起始原点，我不明白为什么。这里有什么关系？因为我们正在更改视口的高度（Y轴），它是否会影响用户坐标系的Y轴？

视口坐标系：1250x1250。用户坐标系：500x500。当宽高比为此类数时，viewBox的{​​{1}}属性（viewBox = <min-x> <min-y> <width> <height>）min-x的宽度和高度总是从0开始，即从屏幕。但是，例如，如果我将视口坐标系更改为1250x329，则viewbox值为0时将从屏幕中间开始而不是从左侧开始。为什么呢？

这是一个实时的Codepen https://codepen.io/Limpuls/pen/LYNXQPK，其中CSS的SVG元素的高度设置为min-x，从而从左角提供了完美的居中和原点起点，因为此时视口为1250x1250。改为将其更改为100vh（在CSS中注释掉代码），然后视口将变为1250x329，并抛出viewBox的起点，这打破了我的Java居中将SVG路径居中的逻辑。

是什么原因导致这种现象，以及如何修改JS中的计算以适应任何视口高度，而不仅仅是像1250x1250或700x700这样的理想数字？

代码：

100%

CSS

<div class="container-fluid">
        <section class="row first">
            <div class="col-lg-12">
                <div class="svg">
                    <svg viewBox="0 0 500 500" 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>
</div>

使用以下公式计算section { height: 100vh; width: 100vw; } svg { height: 100%; //height: 100vh; width: 100%; display: flex; justify-content: center; align-items: center; } 来动态居中SVG <path>的Javascript摘录：（（视口宽度-SVG总viewBox <min-x>宽度）/ 2）/视口与viewBox的宽度比

<path>

解决方法

您需要阅读viewBox的工作原理。

但总而言之，如果视口（即<svg> width和height）的viewBox宽度和高度的宽高比不同，则默认情况下， viewBox代表的区域将在视口中居中。

下面的代码段试图代表这种行为。

<svg width="1250" height="329" viewBox="0 0 500 500">
   <rect x="-700" width="1898" height="500" fill="none" stroke="green" stroke-width="2"/>
   <text x="-600" y="100" fill="green" font-size="20">1250 x 329 viewport</text>
   
   <rect width="500" height="500" fill="red" fill-opacity="0.05" stroke="red" stroke-width="2"/>
   <text x="10" y="20" fill="red" font-size="20">(0,0)</text>
   <text x="250" y="250" fill="red" font-size="20" text-anchor="middle">500 x 500 viewBox area</text>
</svg>

（0,0）保留在 viewBox 区域的左上方。不是视口。

通过preserveAspectRatio属性，可以控制纵横比不匹配时发生的情况。如果您希望viewBox区域始终停留在视口的左上方，请使用preserveAspectRatio="xMinYMin meet"。

<svg width="1250" height="329" viewBox="0 0 500 500" preserveAspectRatio="xMinYMin meet">
   <rect x="0" width="1898" height="500" fill="none" stroke="green" stroke-width="2"/>
   <text x="-600" y="100" fill="green" font-size="20">1250 x 329 viewport</text>
   
   <rect width="500" height="500" fill="red" fill-opacity="0.05" stroke="red" stroke-width="2"/>
   <text x="10" y="20" fill="red" font-size="20">(0,0)</text>
   <text x="250" y="250" fill="red" font-size="20" text-anchor="middle">500 x 500 viewBox area</text>
</svg>