Support svg images when going from markdown to docx

[agusmba]

In a similar way to #1793 for pdf generation, it would be nice to automatically convert svg images to png (or any word supported format) when going from markdown to docx.

[iandol]

Hi, the latest version of Word 2016 finally supports SVG:

https://support.office.com/en-us/article/edit-svg-images-in-microsoft-office-2016-69f29d39-194a-4072-8c35-dbe5e7ea528c?ui=en-US&rs=en-US&ad=US#id0eaafaaa=office_2016_on_mac

[agusmba]

Thanks for the pointer!

It took them a while for a 1999 standard, and it seems it's only for whose with active subscriptions to 365

Anyway, better late than never. Nice!

[mb21]

Posting the relevant part of the attached docx here for reference. Apparently, the docx contains both the svg and a fallback png.

    <w:drawing>
      <wp:inline distT="0" distB="0" distL="0" distR="0" wp14:anchorId="589F1FF2" wp14:editId="553CEC71">
        <wp:extent cx="5943600" cy="3608070"/>
        <wp:effectExtent l="0" t="0" r="0" b="0"/>
        <wp:docPr id="1" name="Graphic 1"/>
        <wp:cNvGraphicFramePr>
          <a:graphicFrameLocks xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main" noChangeAspect="1"/>
        </wp:cNvGraphicFramePr>
        <a:graphic xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main">
          <a:graphicData uri="http://schemas.openxmlformats.org/drawingml/2006/picture">
            <pic:pic xmlns:pic="http://schemas.openxmlformats.org/drawingml/2006/picture">
              <pic:nvPicPr>
                <pic:cNvPr id="1" name="cars.svg"/>
                <pic:cNvPicPr/>
              </pic:nvPicPr>
              <pic:blipFill>
                <a:blip r:embed="rId8"> <!-- pretty sure this is the file Id of the PNG -->
                  <a:extLst>
                    <a:ext uri="{28A0092B-C50C-407E-A947-70E740481C1C}">
                      <a14:useLocalDpi xmlns:a14="http://schemas.microsoft.com/office/drawing/2010/main" val="0"/>
                    </a:ext>
                    <a:ext uri="{96DAC541-7B7A-43D3-8B79-37D633B846F1}">  <!-- this is a constant, identifying the svg extension -->
                      <asvg:svgBlip xmlns:asvg="http://schemas.microsoft.com/office/drawing/2016/SVG/main"
                        r:embed="rId9"/>  <!-- pretty sure this is the file Id of the SVG -->
                    </a:ext>
                  </a:extLst>
                </a:blip>
                <a:stretch>
                  <a:fillRect/>
                </a:stretch>
              </pic:blipFill>
              <pic:spPr>
                <a:xfrm>
                  <a:off x="0" y="0"/>
                  <a:ext cx="5943600" cy="3608070"/>
                </a:xfrm>
                <a:prstGeom prst="rect">
                  <a:avLst/>
                </a:prstGeom>
              </pic:spPr>
            </pic:pic>
          </a:graphicData>
        </a:graphic>
      </wp:inline>
    </w:drawing>

Word_Markdown_with_SVG.docx

[mb21]

Since we need to generate a fallback-png for this anyway, this seems as good a time as any, to factor out the svg-to-png rendering features that was added for LaTeX/PDF output, and generalize it to docx and epub output (#2766).

btw. see #2211 for some code that may be usable.

[mb21]

@jgm What do you think of factoring out the rsvg-convert-related code from PDF.hs? I'm not sure where it should go: in Text.Pandoc.Shared (where PDF.hs lives) or Text.Pandoc.Writers.Shared (where EPUB.hs etc. are). Or even Text.Pandoc.ImageSize which already has morphed into a kind of general-purpose image module, or a new module?

[agusmba]

The nice thing is that even older word (2013) can open documents with SVGs (I guess they fall back to showing the png)

[jgm]

Are you talking about convertImage from the PDF module, or are you thinking of something more special-purpose, just for SVG?

[mb21]

I don't remember, it's been a while ;-) But yes, maybe LaTeX and Word understand about the same subset of image formats, then we could just move the whole convertImage function...

[ociule]

As a heavy user of the docx output format, I'm really interested in this issue. It would allow outputting better quality documents.

[leonidlezner]

The issue is still there: When convertig Markdown to PDF the SVGs are embedded, in DOCX files the images are not present, only placeholders (Broken image...). Is there any way to deal with Word documents?