SVG href links with mtextInheritFont:true are misplaced

[dpvc]

Also, note that there are some bugs with mtextInheritFont: true in v3 in both CommonHTML and SVG output. See #2257 and #2189.

mtextInheritFont: true in v3 in SVG output also upsets the scrolling to labelled equations, targeting the baseline instead of the top of the equation. (This doesn't happen in CHTML output.)

For example, add this option to the equation-refs demo and change the output to SVG, then click on a link to (1): only the lower part of the equation is visible (using Safari and Firefox).

Originally posted by @pdmosses in #2329 (comment)

[dpvc]

This seems to affect Safari only when mtextInheritFont is true, but affects Firefox all the time.

I suspect it is due to the transform that inverts the y-coordinates not being handled properly, but haven't verified that. SVG usually has the y-axis pointing down rather than up, so height would be negative and depth positive. We may eliminate that transform in the font update in 2021.

[pdmosses]

Thanks for this. (I originally intended to submit it as a separate issue, but when I noticed your comment in #2329 about bugs with mtextInheritFont: true in v3, I thought it might be related.)

I'm now using \smash{\raise{2.4ex}{\cssId{#1}{}}} to make targets of href links visible, following a suggestion for addressing a similar issue with hyperref. It's not a general solution, but it works well enough for me in Firefox.