javascript - 有没有办法从生成的条形码创建图像或矢量文件？

Question

生成的条形码将自身显示为 HTML 标签，因此无法右键单击它们并将其另存为图像。下面是生成的条形码的示例。我的浏览器(Chrome、Firefox、Safari)中是否有任何方法可以将其转换为图像文件，或者可能是我可以使用的 SVG(矢量)文件？如果可能的话，我宁愿不必更改源代码。

<svg class="barcode" jsbarcode-width="1" jsbarcode-height="22" jsbarcode-textalign="center" jsbarcode-textposition="bottom" jsbarcode-displayvalue="true" jsbarcode-font="monospace" jsbarcode-fontstyle="monospace" jsbarcode-fontsize="14" jsbarcode-background="#FFFFFF"
  jsbarcode-linecolor="#000000" jsbarcode-textmargin="5" jsbarcode-fontoptions="0 0" jsbarcode-format="code128" jsbarcode-value="0219000780318" width="143px" height="61px" x="0px" y="0px" viewBox="0 0 143 61" xmlns="http://www.w3.org/2000/svg" version="1.1"
  style="transform: translate(0px, 0px);">
        <rect x="0" y="0" width="143" height="61" style="fill:#FFFFFF;"></rect>
        <g transform="translate(10, 10)" style="fill:#000000;">
            <rect x="0" y="0" width="2" height="22"></rect>
            <rect x="3" y="0" width="1" height="22"></rect>
            <rect x="6" y="0" width="3" height="22"></rect>
            <rect x="11" y="0" width="2" height="22"></rect>
            <rect x="15" y="0" width="2" height="22"></rect>
            <rect x="19" y="0" width="2" height="22"></rect>
            <rect x="22" y="0" width="2" height="22"></rect>
            <rect x="26" y="0" width="1" height="22"></rect>
            <rect x="28" y="0" width="3" height="22"></rect>
            <rect x="33" y="0" width="2" height="22"></rect>
            <rect x="36" y="0" width="2" height="22"></rect>
            <rect x="40" y="0" width="2" height="22"></rect>
            <rect x="44" y="0" width="1" height="22"></rect>
            <rect x="47" y="0" width="2" height="22"></rect>
            <rect x="52" y="0" width="1" height="22"></rect>
            <rect x="55" y="0" width="1" height="22"></rect>
            <rect x="57" y="0" width="1" height="22"></rect>
            <rect x="60" y="0" width="4" height="22"></rect>
            <rect x="66" y="0" width="2" height="22"></rect>
            <rect x="69" y="0" width="2" height="22"></rect>
            <rect x="74" y="0" width="2" height="22"></rect>
            <rect x="77" y="0" width="3" height="22"></rect>
            <rect x="81" y="0" width="1" height="22"></rect>
            <rect x="83" y="0" width="4" height="22"></rect>
            <rect x="88" y="0" width="3" height="22"></rect>
            <rect x="92" y="0" width="1" height="22"></rect>
            <rect x="95" y="0" width="2" height="22"></rect>
            <rect x="99" y="0" width="2" height="22"></rect>
            <rect x="103" y="0" width="1" height="22"></rect>
            <rect x="107" y="0" width="1" height="22"></rect>
            <rect x="110" y="0" width="2" height="22"></rect>
            <rect x="115" y="0" width="3" height="22"></rect>
            <rect x="119" y="0" width="1" height="22"></rect>
            <rect x="121" y="0" width="2" height="22"></rect>
            <text style="font:0 0 14px monospace" text-anchor="middle" x="61.5" y="41">0219000780318</text>
        </g>
    </svg>

Answer 1

如果您想要图像文件，可以使用 Canvas 将 svg 转换为 base64 png，然后使用下载链接下载。

Demo online

document.querySelector("#download").onclick = () => {
  svgToPng(document.querySelector('.barcode').outerHTML, (imgData) => {
    const download = document.createElement('a');
    download.href = imgData;
    download.download = 'barcode.png';
    download.click();
  });
}

const svgToPng = (svg, callback) => {
  const url = URL.createObjectURL(new Blob([svg], {
    type: 'image/svg+xml'
  }));
  svgUrlToPng(url, (imgData) => {
    callback(imgData);
    URL.revokeObjectURL(url);
  });
}

const svgUrlToPng = (svgUrl, callback) => {
  const svgImage = document.createElement('img');
  svgImage.style.position = 'absolute';
  svgImage.style.top = '-9999px';
  document.body.appendChild(svgImage);
  svgImage.onload = function() {
    const canvas = document.createElement('canvas');
    canvas.width = svgImage.clientWidth;
    canvas.height = svgImage.clientHeight;
    const canvasCtx = canvas.getContext('2d');
    canvasCtx.drawImage(svgImage, 0, 0);
    const imgData = canvas.toDataURL('image/png');
    callback(imgData);
    document.body.removeChild(svgImage);
  };
  svgImage.src = svgUrl;
}

<svg class="barcode" jsbarcode-width="1" jsbarcode-height="22" jsbarcode-textalign="center" jsbarcode-textposition="bottom" jsbarcode-displayvalue="true" jsbarcode-font="monospace" jsbarcode-fontstyle="monospace" jsbarcode-fontsize="14" jsbarcode-background="#FFFFFF" jsbarcode-linecolor="#000000" jsbarcode-textmargin="5" jsbarcode-fontoptions="0 0" jsbarcode-format="code128" jsbarcode-value="0219000780318" width="143px" height="61px" x="0px" y="0px" viewBox="0 0 143 61" xmlns="http://www.w3.org/2000/svg" version="1.1" style="transform: translate(0px, 0px);">
  <rect x="0" y="0" width="143" height="61" style="fill:#FFFFFF;"></rect>
  <g transform="translate(10, 10)" style="fill:#000000;">
    <rect x="0" y="0" width="2" height="22"></rect>
    <rect x="3" y="0" width="1" height="22"></rect>
    <rect x="6" y="0" width="3" height="22"></rect>
    <rect x="11" y="0" width="2" height="22"></rect>
    <rect x="15" y="0" width="2" height="22"></rect>
    <rect x="19" y="0" width="2" height="22"></rect>
    <rect x="22" y="0" width="2" height="22"></rect>
    <rect x="26" y="0" width="1" height="22"></rect>
    <rect x="28" y="0" width="3" height="22"></rect>
    <rect x="33" y="0" width="2" height="22"></rect>
    <rect x="36" y="0" width="2" height="22"></rect>
    <rect x="40" y="0" width="2" height="22"></rect>
    <rect x="44" y="0" width="1" height="22"></rect>
    <rect x="47" y="0" width="2" height="22"></rect>
    <rect x="52" y="0" width="1" height="22"></rect>
    <rect x="55" y="0" width="1" height="22"></rect>
    <rect x="57" y="0" width="1" height="22"></rect>
    <rect x="60" y="0" width="4" height="22"></rect>
    <rect x="66" y="0" width="2" height="22"></rect>
    <rect x="69" y="0" width="2" height="22"></rect>
    <rect x="74" y="0" width="2" height="22"></rect>
    <rect x="77" y="0" width="3" height="22"></rect>
    <rect x="81" y="0" width="1" height="22"></rect>
    <rect x="83" y="0" width="4" height="22"></rect>
    <rect x="88" y="0" width="3" height="22"></rect>
    <rect x="92" y="0" width="1" height="22"></rect>
    <rect x="95" y="0" width="2" height="22"></rect>
    <rect x="99" y="0" width="2" height="22"></rect>
    <rect x="103" y="0" width="1" height="22"></rect>
    <rect x="107" y="0" width="1" height="22"></rect>
    <rect x="110" y="0" width="2" height="22"></rect>
    <rect x="115" y="0" width="3" height="22"></rect>
    <rect x="119" y="0" width="1" height="22"></rect>
    <rect x="121" y="0" width="2" height="22"></rect>
    <text style="font:0 0 14px monospace" text-anchor="middle" x="61.5" y="41">0219000780318</text>
  </g>
</svg>

<br />

<button type="button" id="download">
download
</button>

来源:

• https://stackoverflow.com/a/14107475/1248177
• https://stackoverflow.com/a/58142441/1248177