Nigel Megitt

@palemieux The spec [(pdf, see Appendix D)](https://tech.ebu.ch/docs/tech/tech3380v1_0_1.pdf) for `ebutts:linePadding` says it applies to _line areas_. I'm not sure, in a CSS world, how the area in which ruby is painted...

@btsimonh I'm struggling to see how the renders you pasted are an improvement looking at the ruby? In particular, if we were applying linePadding to ruby then I would expect...

Ah, I see it now, thank you @btsimonh - this is an improvement for those test cases. For the line beginning 6, why is the background colour on the right...

> The outer element has been padded, resulting in the grey (half opacity black) This is a bit confusing from a terminology perspective. To pad the outer element (the ``?)...

Incidentally, it would be worth checking that a similar issue does not arise with`linePadding` which would be demonstrated by the same test content. If there is no background being drawn...

Does the test at https://github.com/w3c/imsc-tests/blob/main/imsc1_1/ttml/textCombine/textCombine001.ttml expose this behaviour?

@palemieux Yes that was the intent, but I think we did not have test cases for `textCombine` and the code goes through a different path in that case. It should...

@BasBastian It would really help me if you could explain the motivation behind these changes. What problems are you seeking to solve?

Thanks for that. The lack of discussion on #214 suggests we haven't yet got a clear view of whether that's the agreed direction to take. It looks like #229 is...

@tairt Can I ask a clarification question: in https://github.com/immersive-web/proposals/issues/40#issuecomment-511315747 when you talk about "the coordinate system of a 360 video", are you talking about 3-axis angular positioning only, or also...