背景：我一直在研究一个图像创建器包装器，它允许使用光栅（OpenCV/numpy/PIL）和矢量图形（svgwrite）创建图像。问题在于使用 svgwrite 创建矢量图时。
问题：图像创建过程需要一个 qrcode，上面和下面都覆盖了一些图像。所以它类似于 Image#1 --> Qrcode --> Image#2。其中每一个都是矢量格式，qrcode 是使用 pyqrcode 创建的，它被保存到 BytesIO 中，然后转换为 base64 以将其作为图像嵌入到更大的 SVG 中。
奇怪的是，当将绘图句柄保存为 SVG 或 PNG 等格式时，QRCode 部分会丢失。绘图句柄的字符串转储虽然有它并且能够通过 SVGViewer 看到图像。关于可能出现问题的想法？
svgwrite 的字符串转储绘图句柄（drawing.tostring()）：
<svg baseProfile="full" height="425" version="1.1" viewBox="0 0 425 425" width="425" xmlns="http://www.w3.org/2000/svg" xmlns:ev="http://www.w3.org/2001/xml-events" xmlns:
xlink="http://www.w3.org/1999/xlink"><defs /><g transform="translate(11, 11)"><image xlink:href="data:image/svg+xml;base64,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" /></g><g transform="translate(132, 132)"><g><circle cx="80" cy="80" fill="none" r="12" stroke="rgb(0,0,0)" stroke-width="4" /><circle cx="80" cy="80" fill="none" r="68" stroke="rgb(0,0,0)" stroke-width="4" /><circle cx="93" cy="115" fill="rgb(0,0,0)" r="10" stroke="rgb(0,0,0)" stroke-width="1" /><circle cx="117" cy="86" fill="rgb(0,0,0)" r="10" stroke="rgb(0,0,0)" stroke-width="1" /><circle cx="57" cy="109" fill="rgb(0,0,0)" r="10" stroke="rgb(0,0,0)" stroke-width="1" /><circle cx="43" cy="74" fill="rgb(0,0,0)" r="8" stroke="rgb(0,0,0)" stroke-width="1" /><circle cx="103" cy="51" fill="rgb(0,0,0)" r="8" stroke="rgb(0,0,0)" stroke-width="1" /><circle cx="67" cy="45" fill="rgb(0,0,0)" r="8" stroke="rgb(0,0,0)" stroke-width="1" /></g></g></svg>
使用 svgwrite.save() 保存的 SVG：
<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="51pt" height="51pt" viewBox="0 0 51 51" version="1.1">
<g id="surface6">
<path style="fill:none;stroke-width:4;stroke-linecap:butt;stroke-linejoin:miter;stroke:rgb(0%,0%,0%);stroke-opacity:1;stroke-miterlimit:4;" d="M 91.990885 80.011719 C 91.990885 95.994792 68 95.994792 68 80.011719 C 68 63.996094 91.990885 63.996094 91.990885 80.011719 " transform="matrix(0.12,0,0,0.12,15.84,15.84)"/>
<path style="fill:none;stroke-width:4;stroke-linecap:butt;stroke-linejoin:miter;stroke:rgb(0%,0%,0%);stroke-opacity:1;stroke-miterlimit:4;" d="M 148.013021 80.011719 C 148.013021 117.544271 117.544271 148.013021 80.011719 148.013021 C 42.446615 148.013021 12.010417 117.544271 12.010417 80.011719 C 12.010417 42.446615 42.446615 12.010417 80.011719 12.010417 C 117.544271 12.010417 148.013021 42.446615 148.013021 80.011719 " transform="matrix(0.12,0,0,0.12,15.84,15.84)"/>
<path style="fill-rule:nonzero;fill:rgb(0%,0%,0%);fill-opacity:1;stroke-width:1;stroke-linecap:butt;stroke-linejoin:miter;stroke:rgb(0%,0%,0%);stroke-opacity:1;stroke-miterlimit:4;" d="M 62.986979 54.002604 C 62.986979 67.348958 43 67.348958 43 54.002604 C 43 40.65625 62.986979 40.65625 62.986979 54.002604 " transform="matrix(0.12,0,0,0.12,15.84,15.84)"/>
<path style="fill-rule:nonzero;fill:rgb(0%,0%,0%);fill-opacity:1;stroke-width:1;stroke-linecap:butt;stroke-linejoin:miter;stroke:rgb(0%,0%,0%);stroke-opacity:1;stroke-miterlimit:4;" d="M 54.002604 90.005208 C 54.002604 103.31901 34.015625 103.31901 34.015625 90.005208 C 34.015625 76.658854 54.002604 76.658854 54.002604 90.005208 " transform="matrix(0.12,0,0,0.12,15.84,15.84)"/>
<path style="fill-rule:nonzero;fill:rgb(0%,0%,0%);fill-opacity:1;stroke-width:1;stroke-linecap:butt;stroke-linejoin:miter;stroke:rgb(0%,0%,0%);stroke-opacity:1;stroke-miterlimit:4;" d="M 116.990885 105.988281 C 116.990885 119.334635 97.003906 119.334635 97.003906 105.988281 C 97.003906 92.674479 116.990885 92.674479 116.990885 105.988281 " transform="matrix(0.12,0,0,0.12,15.84,15.84)"/>
<path style="fill-rule:nonzero;fill:rgb(0%,0%,0%);fill-opacity:1;stroke-width:1;stroke-linecap:butt;stroke-linejoin:miter;stroke:rgb(0%,0%,0%);stroke-opacity:1;stroke-miterlimit:4;" d="M 97.003906 44.009115 C 97.003906 54.653646 80.988281 54.653646 80.988281 44.009115 C 80.988281 33.332031 97.003906 33.332031 97.003906 44.009115 " transform="matrix(0.12,0,0,0.12,15.84,15.84)"/>
<path style="fill-rule:nonzero;fill:rgb(0%,0%,0%);fill-opacity:1;stroke-width:1;stroke-linecap:butt;stroke-linejoin:miter;stroke:rgb(0%,0%,0%);stroke-opacity:1;stroke-miterlimit:4;" d="M 123.989583 69.985677 C 123.989583 80.66276 108.00651 80.66276 108.00651 69.985677 C 108.00651 59.341146 123.989583 59.341146 123.989583 69.985677 " transform="matrix(0.12,0,0,0.12,15.84,15.84)"/>
<path style="fill-rule:nonzero;fill:rgb(0%,0%,0%);fill-opacity:1;stroke-width:1;stroke-linecap:butt;stroke-linejoin:miter;stroke:rgb(0%,0%,0%);stroke-opacity:1;stroke-miterlimit:4;" d="M 79.002604 116.014323 C 79.002604 126.658854 62.986979 126.658854 62.986979 116.014323 C 62.986979 105.33724 79.002604 105.33724 79.002604 116.014323 " transform="matrix(0.12,0,0,0.12,15.84,15.84)"/>
</g>
</svg>