Duplication of text regarding property on anonymous spans.

[cconcolato]

The following sentence is repeated 31 times in TTML2:

For the purpose of determining applicability of this style property, each character child of a p element is considered to be enclosed in an anonymous span.

IIUC, it is meant to cover the case where a property is applicable on spans but the content has no span. I find it very confusing (it was already in TTML1) because:

• it talks about "applicability" already covered the "Applies to" row of the property definition,
• and because it is used in weird places:
  • properties already directly applicable on p elements: tts:backgroundClip, tts:backgroundColor, tts:backgroundImage, tts:backgroundOrigin, tts:backgroundPosition, tts:backgroundRepeat, tts:border, tts:direction, tts:display, tts:fontFamily, etc.

I would propose to have either:

• 'anonymous span' be present in the "Applies to" row in the property definition,
• and/or a general note (maybe in the introduction to section 10) such as:

The definitions of some properties indicate that they apply only to 'span' elements. It should be noted that for the purpose of applying this style property, each character child of a p element is considered to be enclosed in an anonymous span, making the property applicable even in the absence of span element.

[nigelmegitt]

@cconcolato a point in favour of the current text is that it implies that a style attribute that applies to a <p> element does not apply to that <p>'s character content children since they are enclosed in an anonymous span.

Edit: the following comment no longer applies thanks to @palemieux pointing me to the relevant spec text:

I would also add into this issue the question of whether each individual character child must be enclosed in a separate anonymous span, or if consecutive character children can be enclosed in a single anonymous span. This question affects the timing of presentation of character children of <p> elements that set timeContainer="seq".

[palemieux]

I would also add into this issue the question of whether each individual character child must be enclosed
in a separate anonymous span, or if consecutive character children can be enclosed in a single anonymous span.

See the following clause at Section 7.1.5:

If a sequence of children of a p element consists solely of character information items, then that sequence must be considered to be an anonymous span for the purpose of applying style properties that apply to span elements.

I interpret this as meaning that, unless specified otherwise, individual character children are not wrapped in individual anonymous spans.

[nigelmegitt]

Thanks @palemieux I hadn't spotted that. I'll edit my comment.

[cconcolato]

@palemieux Thanks for the pointer to that sentence. I would then question why we have all those repeated sentences in each property. Note that you quoted TTML1 but the same text exists in TTML2 in section 8.1.5. Note also that the algorithm in 11.3.1.4 Synchronic Flow Processing already specifies the creation of anonymous spans. My recommendations would be:

• remove the 31 sentences indicated above
• add a reference from the sentence in section 8.1.5 to section 11.3.1.4.