Re: [csswg-drafts] [css-text] Letter spacing is inserted after RTL reordering

The Working Group just discussed `Letter spacing is inserted after RTL reordering`, and agreed to the following resolutions:

* `RESOLVED: bidi resolution will result in splitting an inline finante space and already create 2 fragments even if they end up adjacent.`

<details><summary>The full IRC log of that discussion</summary>
&lt;dael> Topic: Letter spacing is inserted after RTL reordering<br>
&lt;dael> github: https://github.com/w3c/csswg-drafts/issues/1509<br>
&lt;fantasai> https://github.com/w3c/csswg-drafts/issues/1509#issuecomment-371384680<br>
&lt;dael> Rossen: koji brought this up, we discussed, and it's back again. Proposal is to resolve on #105<br>
&lt;dael> Rossen: This comment from fantasai<br>
&lt;dael> s/105/1509<br>
&lt;fantasai> “Proposed that bidi resolution would result in splitting an inline in infinite space will always create two fragments, even if they end up adjacent due to line breaking.<br>
&lt;fantasai> Behavior for letter-spacing (and other things affected, like box-decoration-break), falls out of this definition: in this case, if the two letters end up adjacent but are part of different fragments, the spacing between them will be given by the parent (according to the letter-spacing rules that control letter-spacing at element boundaries). This avoids the measuring problem.”<br>
&lt;dael> myles: I'm a little confused about what fantasai said<br>
&lt;dael> fantasai: Issue was that let's say the p has letter spacing of 2ema nd span has 0. As you try and layout the line you try to...you stop laying out when you run out of space. If the point wher eyou break introduces space as how the bidi reordering happens and then you add 2em to what the chracters take up your line layout is confused. For tex tyou want a predictable amount of space.<br>
&lt;dael> fantasai: What happens here is bidi reordering splits the span. You have abc and 123 and they'll be 321 in left to right. Last 2 characters are 3 and 2 and they push to another page. 3 and 2 were separating the b and c so letter spacing came from the &lt;p> When you take out the 2 and 3 you get the c and 1 next to.<br>
&lt;dael> fantasai: Now that they're both a part of the span do you take the spacing from the span or the p. If you take from the span it's unpredictable<br>
&lt;dael> fantasai: proposal is when you know the span will split you make that be an element boundary always. Even if they end up nex to each other. Letter spacing between those needs to use the nearest common ancestor which is the &lt;p> That's consistant with what spacing you would use if you have more space on the line.<br>
&lt;dael> fantasai: That's what we're trying to solve. Get a consistant idea of how much spacing is used for each letter.<br>
&lt;dael> myles: I think that's what webkit does as I understand. We'll break the c and 1 into separate objects. Later realizing they're 2 objects and apply letter spacing indenendant. If I understand.<br>
&lt;dael> fantasai: All impl don't handle the bounderies well. We have problems with letter spacing at the end of the line which makes authors unhappy. Spec is clear about no letter spacing at the end of the line or after an element. No one has that impl, but if you do letter spacing is tied to a pair of letters and needs to be determined by the nearest ancestor of those letters. So we need a more sophisticated letter.<br>
&lt;dael> myles: It's coming abck to me. I agreed to investigate in Paris and I still want to do so. I think I said in Paris I'd do it in a year and I'm still in that window ^-^<br>
&lt;dael> fantasai: We never resolved so we do need a resoution to do this.<br>
&lt;dael> Rossen: I was trying to read minutes, sounds like there was agreement.  myles your investigation, are you okay to resolve now?<br>
&lt;dael> myles: Oh, yeah, we can resolve now. If I investigate and it's all wrong we can change.<br>
&lt;dael> Rossen: Proposal: bidi resolution will result in splitting an inline finante space and already create 2 fragments even if they end up adjacent.<br>
&lt;dbaron> yeah, I'm fine with this -- Gecko does this sort of splitting already<br>
&lt;dael> Rossen: Objections?<br>
&lt;fantasai> :)<br>
&lt;dbaron> we just don't do the letter-spacing thing yet<br>
&lt;dael> RESOLVED: bidi resolution will result in splitting an inline finante space and already create 2 fragments even if they end up adjacent.<br>
&lt;dael> Rossen: We're at the top of the hour.<br>
</details>


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Received on Wednesday, 14 March 2018 17:00:52 UTC