Powers on units with 'tall' characters (i.e. ångström) are typeset higher than other powers

[lkkmpn]

When combining a unit whose symbol extends past the cap height of the font, like ångström (Å), with a power, the power is typeset relative to the top of the unit symbol, causing it to be typeset higher than powers on other units. If this is done in a longer paragraph, it causes the line where the unit is present to take up more height than other lines, leaving an undesired gap between lines.

MWE:

\documentclass{article}
\usepackage{siunitx}

\DeclareSIUnit{\angstrom}{\text{Å}}

\begin{document}
Reference output: m\textsuperscript{2}, A\textsuperscript{2}, Å\textsuperscript{2}

\textsf{siunitx} output: \unit{\metre\squared}, \unit{\ampere\squared}, \unit{\angstrom\squared}
\end{document}

(I know the ångström is deprecated in siunitx and there are probably not many other units with accents, but I feel this would still be a reasonable change to include given it is still a fairly common unit in some fields.)

[daleif]

You probably cannot check if a letter has an accent from a code point of view, but since Å has to be manually defined one can always do

\DeclareSIUnit{\angstrom}{\text{\smash{Å}\vphantom{A}}}

[josephwright]

The reference rendering here should I think be

Reference output: $\mathrm{m}^{2}$, $\mathrm{A}^{2}$, $\mathrm{\textrm{Å}}^{2}$

which shows exactly the same effect as TeX is adjusting the superscript height for the taller letter.

[lkkmpn]

Ah, I didn't realize that siunitx uses math mode internally for unit typesetting. Would you say the raised superscript is a desirable output, though?

@daleif Thanks for the suggestion, I didn't think of using \smash as a workaround.

[josephwright]

I think that as the output matches the reference, this is something that should work as-now: I'll think about whether to add a hint about adjustments for those who feel this appearance is desirable.