TTML 1.0 (Editorial)
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Frans de Jong
Loretta Guarino Reid
Philippe Le Hégaret
Section 8.2.9 states:
"If a specified value of this attribute is not supported, then a presentation processor must interpret the attribute as if the value 1c were specified."
Let's say that 1c is equivalent to 24px, the device supports 12px and 24px fonts (as bitmaps without scaling support) and I specify tts:fontSize='12.1px'. Well 12.1px is not supported, so I would get a 24px font instead of 12px. This doesn't seem like a good idea.
I suggest changing this language to match what is used for "closest supported opacity" (8.3.1), namely, the following:
"If a presentation processor does not support a specific, valid font size value, then it must interpret it as being equal to the closest supported value."
Add notes (no markup allowed, URIs get automatically hyperlinked):
Fixed. https://dvcs.w3.org/hg/ttml/rev/70165fde28e1 (8.2.9)