valign not working on mglyph

[wspilot]

I am using an svg (also tried an .png) as mglyph and it has to align with the descender line of the preceding character. Whatever value or unit I use, the glyph stays on the base line.
Ubuntu 19.10
Firefox 73.0.1
Chrome Version 80.0.3987.87 (Official Build) (64-bit)
See attached html and svg file. Note: I had to rename the files toto .txt because .svg and .html are not accepted as type. Please remove the .txt extension.
bugTest0.svg.txt
bugtest0.html.txt

[dpvc]

OK, it turns out that the mglyph code is looking for voffset rather than valign, and that the alignment direction is reversed. Not sure how that happened, but thanks for reporting the issue. I will fix it in the next release.

In the meantime, you can use the following code

    <script>
      MathJax = {
        startup: {
          ready() {
            MathJax.startup.defaultReady();
            MathJax.startup.input[1].postFilters.add((args) => {
              args.data.walkTree((node) => {
                if (node.isKind('mglyph')) {
                  const attributes = node.attributes;
                  if (attributes.isSet('valign')) {
                    const y = attributes.get('valign');
                    attributes.set('voffset', y.charAt(0) === '-' ? y.slice(1) : '-' + y);
                  }
                }
              });
            });
          }
        }
      }
    </script>

to post-filter the MathML input to look for mglyph elements and convert the valign attributes to voffset (switching the direction of the shift so that it displays properly).

[dpvc]

I've made a pull request to resolve the issue.

[wspilot]

FYI
I just found out that it does work in V 2.7.5

[dpvc]

Yes, the error occurred during the v3 rewrite. The name of the attribute was incorrectly entered in the v3 code.