Image Export

Mind Elixir provides two APIs for exporting images:

exportSvg: (
  this: MindElixirInstance,
  noForeignObject?: boolean,
  injectCss?: string | undefined
) => Blob
exportPng: (
  this: MindElixirInstance,
  noForeignObject?: boolean,
  injectCss?: string | undefined
) => Promise<Blob | null>

If noForeignObject is set to true, the SVG export will not use foreignObject.

Not all SVG renderers support foreignObject, so in specific scenarios where exported SVG cannot be used, you can disable foreignObject. The trade-off is that long text inside nodes won't wrap. (Alternatively, you can choose to directly output PNG.)

injectCss is for cases using dangerouslySetInnerHTML. If you need to supplement custom CSS inside nodes, you can directly pass a CSS string. The provided CSS will be added to the generated SVG, ensuring the rendering is not too different from the browser.

warning

When using dangerouslySetInnerHTML, as it allows injecting arbitrary content, there may be situations where the export algorithm cannot accommodate. In such cases, unexpected issues may arise when exporting images.

Practice

Here is an example of encapsulating a download function. In this example, style + katex represents the necessary styles for custom CSS and Katex (refer to this link for specific content). By passing this to the export functions, you can ensure correct styling when exporting SVG.

const download = (type) => {
  return async () => {
    try {
      let blob = null
      if (type === 'png') blob = await mind.exportPng(false, style + katex)
      else blob = await mind.exportSvg(false, style + katex)
      if (!blob) return
      const url = URL.createObjectURL(blob)
      const a = document.createElement('a')
      a.href = url
      a.download = 'filename.' + type
      a.click()
      URL.revokeObjectURL(url)
    } catch (e) {
      console.error(e)
    }
  }
}