Re: [csswg-drafts] [css-text] pre-wrap and tabs at the end of the line (#3869)

The CSS Working Group just discussed `pre-wrap and tabs at the end of the line`, and agreed to the following:

* `RESOLVED: Tabs do not hang and you can break between for whitespace: break-spaces`
* `RESOLVED: For white-space:pre-wrap tabs hang like spaces do`

<details><summary>The full IRC log of that discussion</summary>
&lt;dael> Topic: pre-wrap and tabs at the end of the line<br>
&lt;dael> github: https://github.com/w3c/csswg-drafts/issues/3869#issuecomment-509811620<br>
&lt;dael> astearns: florian added example<br>
&lt;dael> florian: 2 parts to the discussion. one is hardly discussed and non-controversial. Other was and needed example<br>
&lt;dael> florian: The hardly discussed is just like spaces tabs do not hang and you can break between. Mentioned in issue and no one pushed back.<br>
&lt;dael> florian: I'd like to resolve on that before going to whitespace prewrap<br>
&lt;dael> astearns: Treat tabs the same as issues for this?<br>
&lt;fantasai> for break-spaces, right?<br>
&lt;dael> florian: They can't hang and you can wrap between two consecutive tabs<br>
&lt;dael> astearns: Tabs do not hang and you can break between for whitespace: break spaces<br>
&lt;dael> astearns: Objections?<br>
&lt;fantasai> s/break spaces/break-spaces/<br>
&lt;dael> RESOLVED: Tabs do not hang and you can break between for whitespace: break-spaces<br>
&lt;fantasai> s/whitespace/white-space/<br>
&lt;dael> florian: Now what happens with tabs at end of line with whitespace-prewrap<br>
&lt;dael> florian: Example in document with line empty with tabs at end. What happens if line is too short?<br>
&lt;dael> florian: First is what line is long enough, second is when tab hangs.<br>
&lt;dael> florian: If you disallow hanging and disallow breaking between tabs you get second rendoring. 3rd is disallow hanging but allow breaking between tabs. No one does 3rd, browsers are split between first 2.<br>
&lt;dael> florian: I don't have a strong preference. Weak for option 3 which no one does. But we should try and align on something. Would want to hear if anyone has preference.<br>
&lt;dael> florian: Questions on example? Thoughts on why one is preferable?<br>
&lt;dael> astearns: I don't have much of a preference. Not sure the 3rd is preferable either<br>
&lt;dael> astearns: I don't know why you have weak preference for that<br>
&lt;dael> dbaron: Drawing in example assumes tab stop lines up with end of container.<br>
&lt;dael> florian: I could be a different length, that's correct. I have a line length of 16 in this example. If you did 17 for example line breaking position wouldn't change in any example but you'd have empty space at end of it.<br>
&lt;dael> fantasai: Only difference visually is container is slight wider, but otherwise render same<br>
&lt;dael> dbaron: Complexity with not line up is you would also have to decide if can break in middle of tab<br>
&lt;dael> florian: I assumed you could not, but fair enough. it renders as a shift not a character.<br>
&lt;dael> dbaron: You'd have to decide if you have tab stop at beginning/end of line. If you don't you can break in middle of tab. If you don't have tab stop and your next position is early in next line but not start; I guess it doesn't matter if tab is on first line or part on each line<br>
&lt;dael> fantasai: Tab stop is at beginning of line, but not end of line unless lines up with a multiple of 8 spaces from start of the line<br>
&lt;dael> florian: If we don't have a use case driven preference we can ask the web author folks to fish for one. We have split between browsers now. We can ask who is easier to change.<br>
&lt;dael> florian: Going by use case would be better. Haven't ID'ed any. Should we draw in rachelandrew or jensimmons ?<br>
&lt;dael> dbaron: THis feel obsure to me.<br>
&lt;dael> florian: it does<br>
&lt;dael> astearns: Could resolve on behavior 1 since we have 2 engines doing it<br>
&lt;dael> florian: Yeah...not particular reason to think behavior 1 is terrible so I'm okay with that. It is similar to what happens to spaces in white-space:pre-wrap. That implies FF has to change.<br>
&lt;dael> dbaron: I think consistancy with spaces is reasonable thing. I don't have strong opinions.<br>
&lt;dael> florian: Suspect any impl difficulty?<br>
&lt;dael> dbaron: Hard to say<br>
&lt;dael> astearns: Main difficulty is reason to make the change. I could just be a bug in FF forever<br>
&lt;tantek> is there any way to apply the principle of least surprise here?<br>
&lt;tantek> all other things being equal?<br>
&lt;dael> myles_: Engines have special case for tabs. IT'll be a slightly smaller or larger special case then it would have been. Picking an option is more important then which<br>
&lt;dael> florian: And as to the point about no rush to fix I think this will be low in priority, but there will eventually be a lump of bugs to fix and this will be in.<br>
&lt;dael> astearns: tantek asked in IRC: [reads]. One of the problems is no one has strong opinion on actual expectation<br>
&lt;dael> florian: Being consistent with spaces goes slightly to least surprise. If you know one you know the other<br>
&lt;dael> astearns: Sounds like we are driving toward a preference for the first option since consistent with spaces<br>
&lt;dael> florian: Right, the tabs hang<br>
&lt;dael> astearns: In which?<br>
&lt;dael> astearns: Prop: for white-space:pre-wrap tabs hang like spaces do<br>
&lt;dael> astearns: Objections?<br>
&lt;tantek> that seems reasonable and less noisy (random tabs/ws at end of line won't change layout)<br>
&lt;dael> RESOLVED: For white-space:pre-wrap tabs hang like spaces do<br>
</details>


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Received on Wednesday, 17 July 2019 16:18:38 UTC