[csswg-drafts] [css-text] text-transform should happen after white-space collapsing but before Trimming and Positioning (#4254)

frivoal has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-text] text-transform should happen after white-space collapsing but before Trimming and Positioning ==
The [definition of the `text-transform` property](https://drafts.csswg.org/css-text-3/#text-transform-property) includes this sentence:

> Text transformation happens after [white space processing](https://drafts.csswg.org/css-text-3/#white-space-rules), which means that full-width only transforms U+0020 spaces to U+3000 within preserved white space.

This puts it after [Phase I: Collapsing and Transformation](https://drafts.csswg.org/css-text-3/#white-space-phase-1), which seems intentional, but also after [Phase II: Trimming and Positioning](https://drafts.csswg.org/css-text-3/#white-space-phase-2), which does not. I don't see any reason why we'd want a space-converted-to-a-ideographic-space at the end of a line to be handled differently from a native ideographic-space at the end of a line.

I'm less sure about Segment Break Transformation Rules, but it feels like doing the transform after that is ok, and probably simpler for implementations.

I would therefore propose changing that sentence to:

> Text transformation happens after [Phase I: Collapsing and Transformation](https://drafts.csswg.org/css-text-3/#white-space-phase-1) and [Segment Break Transformation Rules](https://drafts.csswg.org/css-text-3/#line-break-transform) but before [Phase II: Trimming and Positioning](https://drafts.csswg.org/css-text-3/#white-space-phase-2). This means that full-width only transforms U+0020 spaces to U+3000 within preserved white space.

cc: @fantasai 

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/4254 using your GitHub account

Received on Friday, 30 August 2019 06:17:05 UTC