Does tts:display affect audio presentation?

[nigelmegitt]

It is unclear whether setting tts:display="none" prevents visual presentation only or also affects audio presentation. Clarify this, potentially by adding a keyword audio to mean "present in audio form only, not in visual form", and where none means "don't present in any form, visual or audio".

[palemieux]

The tts:display attribute is used to specify a style property that defines whether an element is a candidate for layout and composition in a region.

I do not see how this applies to audio, and recommend defining a new attribute.

[nigelmegitt]

The text later on in that section introduces the ambiguity:

if the value is none, then the affected element and its descendants must be considered ineligible for region layout and presentation.

The term presentation is not clearly scoped to visual or audio presentation, or both.

[palemieux]

The term presentation is not clearly scoped to visual or audio presentation, or both.

I do not disagree. tts:display by its very name (and intro) seems pretty scoped.

Isn't there a gain attribute that can be used to mute the audio?

[nigelmegitt]

Isn't there a gain attribute that can be used to mute the audio?

There is, but it's not obvious that "not participating in audio presentation" is the same thing as muting the audio.

[nigelmegitt]

Looking at prior examples here, the current CSS Display spec points out that display: none; does affect speech, but if you go to CSS 3 Speech then there's a banner to say that it's no longer being worked on. Aside from that, it is clear that setting display: none; results in no text to speech synthesis occurring.

[palemieux]

@nigelmegitt To summarize our earlier discussion: tts:display applies to the span and its contents, regardless of the nature of the latter, and thus presumably audio content, even if display is a misnomer for audio.

[skynavga]

So, shall I add a note saying that tts:display='none' suppresses contribution from audio/speech?

[nigelmegitt]

@skynavga your proposed note would match current implementation reality I believe; nevertheless I would like to hold off on this for the time being, pending the CSS WG's task force (see w3c/csswg-drafts#560 (comment) and following comments) about this. It could be that we need to make a more significant change.

[skynavga]

Moving to 3ED milestone per request to hold off on further action.