Where should tone marks be positioned when bopomofo appears over horizontal text?

[r12a]

Normally, bopomofo annotations appear to the right side of each base Han character. However, in some cases, bopomofo can appear over horizontal text (much like pinyin). In those cases, are the non-neutral tone marks displayed after the bopomofo characters on the same line, or are they rendered above the other bopomofo characters?

See https://r12a.github.io/scripts/bopomofo/ontheweb#horhor

@fantasai is asking this question so that she can set the default expectation in CSS where bopomofo is displayed without the inter-character value for ruby-position.

[bobbytung]

Hello Richard,

Normally, bopomofo annotations appear to the right side of each base Han character. However, in some cases, bopomofo can appear over horizontal text (much like pinyin). In those cases, are the non-neutral tone marks displayed after the bopomofo characters on the same line, or are they rendered above the other bopomofo characters?

Yes, according to the "The Manual", when texts flow horizontally and bopomofo on upper side. Tone marks(2nd, 3rd, 4th tone) should always be on upper-right.

Normal fonts without any design for tone marks (ˊˇˋ）will display in this way.

Early Fonts from local foundry designed tone marks as full width glyph as figure above.
It's acceptable and if do so, better with alternative design with font feature switch to fulfill the requirement in the Manual.

@fantasai is asking this question so that she can set the default expectation in CSS where bopomofo is displayed without the inter-character value for ruby-position.

[xfq]

After our discussion, we think the non-neutral tone marks should be rendered above the other bopomofo characters, in the upper right corner. @r12a Does this answer your question?

[r12a]

Thank you @xfq and @bobbytung.

@fantasai please note the preference for 'layered' tone positioning, ie.

and let us know if your question is now answered, thanks. If so, we can close this issue.