TTML2 retains the wording from TTML1 regarding percentage units for the tts:padding attribute:
relative to width and height of region
However TTML1 only specifies padding for region. Now that TTML2 also specifies padding for the elements body, div, p and span, this text no longer matches CSS.
https://www.w3.org/TR/CSS2/box.html#propdef-padding specifies that percentages:
refer to width of containing block
TTML2 should follow CSS here and make percentages be relative to the area generated for the element on which the padding attribute is specified.
TTML2 retains the wording from TTML1 regarding percentage units for the
tts:paddingattribute:However TTML1 only specifies padding for
region. Now that TTML2 also specifies padding for the elementsbody,div,pandspan, this text no longer matches CSS.https://www.w3.org/TR/CSS2/box.html#propdef-padding specifies that percentages:
TTML2 should follow CSS here and make percentages be relative to the area generated for the element on which the padding attribute is specified.