The CSS Working Group just discussed [css-ruby] visibility:collapse on ruby annotations.

Note: implementation wise, this ought to be pretty simple: both the syntax (visibility:collapse) and the behavior (the type of hiding performed in ruby auto-hiding) already exist.

More use-cases that would be addressed by this were previously raised in https://lists.w3.org/Archives/Public/www-style/2016Dec/0108.html

Since an email I authored was cited, it's probably worth noting the use case:

I had a list of official song titles in English for many songs that had lyrics and titles in other languages, particularly Japanese. As ruby annotations, I provided the official song title in the native language of the song on a word for word and punctuation for punctuation basis. However, this would cause autohiding (i.e., text equivalency) problems because, for example:

• the Japanese script titles used fullwidth variants of characters such as the wave dash instead of the tilde and the fullwidth asterisk instead of the (regular) asterisk.
• the Japanese script titles were missing spacing around (e.g., mathematical) punctuation expected in English script.
• the Japanese script titles would need extra punctuation such as middle dots to separate transliterated names where English would instead use a space character.
• the Japanese script titles would need extra words such as the Japanese particle "の" to join adjectives to nouns in Japanese where English, again, uses space characters.
• the Japanese script titles would use different punctuation structures; for example, in the "Main Title: Subordinate Title" format of English versus "Main Title〜Subordinate Title〜" of Japanese. In this case, one would have a colon and space equivalent to a wave dash and nothing (i.e., an empty ruby base) equivalent to a wave dash.
• the English script titles would use hyphens, but these weren't present in the Japanese script or were replaced by middle dots.

Also keep in mind that these were official titles being documented, so changing the punctuation to match in a way that worked better inter-language by, for example, omitting spaces in one of the matching titles wasn't acceptable.

Additionally, I later wrote a polyfill script that would auto-merge annotations (a feature currently missing from browser implementations), so simply omitting the punctuation from the annotations was out of the question since this punctuation would need to magically reappear when ruby bases and annotations were merged.

Obviously, this solution doesn't address all of these cases, though I can see how removing noise by hiding punctuation in annotations could be useful. For example, for the Japanese song title "✱〜アスタリスク〜", one might just want to use the English word "Asterisk" as an annotation without the punctuation while fully annotating the text as *~Asterisk~* anyway to futureproof the code in case stylistic preferences change at a later date.

(*I had to mark this song title as code since GitHub apparently uses tildes to invoke the strikethrough text style.)

Hello CSS WG,

The Accessible Platform Architecture (APA) WG have discussed this, and have a few comments to offer:

Toggling: While the requested feature has value to users with disabilities, there will need to be a simple toggling feature to 'collapse' or 'expand' the Ruby annotation (think Details & Summary), ideally authored on the page, or provided via a clear and easy to access toggle in the browser UI. While applying this in a fashion similar to 'prefers-reduced-motion' and using browser-based user-settings is useful, we anticipate a more time-sensitive context of application by some users (i.e. the 'toggling' need).

Relationship to Personalization TF activities: Currently the Personalization Task Force has some draft ideas around a similar use-case, which may work either as an alternative-to, or possibly in concert with this CSS proposal. Relevant information can be found at: https://www.w3.org/TR/personalization-semantics-content-1.0/#simplification-explanation

(NOTE: The Task Force welcomes the CSS WG's feedback on this, or other aspects of our Draft Spec.)

The CSS Working Group just discussed [css-ruby] visibility:collapse on ruby annotations, and agreed to the following:

• RESOLVED: Add this defined hiding behavior to spec and ping engines to impl it

@johnfoliot Wrt toggling, I think that has to be handled by either the UA or the page because it requires some kind of UI affordance. The proposal here however enables the ruby layout support that such an affordance would require.

Wrt data simplification, it might be relevant to remove some annotations in response to that, but removing annotations generally (particularly those required as a pronunciation aid) does not seem appropriate.

APA is ok with the disposition but wants to see test results demonstrating keyboard accessible collapse / expand.

I'm only just now reading this, and surprised that the CSS can't simply be .easy { display: none; }, but then i tried it out and was surprised that the layout renderer gets the pairings out of synch. Shouldn't the pairing be established before the relevant rt element is undisplayed?