Re: [csswg-drafts] [css-images-4] Gradient interpolation doesn't specify how to handle positionless stops at computed-value time (#10374)

The CSS Working Group just discussed `[css-images-4] Gradient interpolation doesn't specify how to handle positionless stops at computed-value time`, and agreed to the following:

* `RESOLVED: move the missing position fixup to computed value time`

<details><summary>The full IRC log of that discussion</summary>
&lt;emilio> TabAtkins: Right now images defines fixup steps to supply default positions and shift stops that are mis-ordered<br>
&lt;emilio> ... The second one requires layout-time information<br>
&lt;emilio> ... so that step has to happen at used value time<br>
&lt;emilio> ... for simplicity at the time I put all the fixups over there<br>
&lt;emilio> ... But that means that stops without a position don't have a position at computed value time when interpolating<br>
&lt;emilio> ... And there's no reason for doing that, can be done at computed-value time<br>
&lt;emilio> ... Proposal is to split the fix-up between computed-value and used-value time fixup<br>
&lt;ChrisL> q+ to wonder what the syntax is for the interpolated value<br>
&lt;emilio> ... where computed fixup would assign positions<br>
&lt;astearns> ack ChrisL<br>
&lt;Zakim> ChrisL, you wanted to wonder what the syntax is for the interpolated value<br>
&lt;emilio> ... and used would reorder fixups<br>
&lt;emilio> ChrisL: what do you actually get?<br>
&lt;emilio> TabAtkins: just calc()s<br>
&lt;emilio> ... just evenly spacing the missing values<br>
&lt;emilio> astearns: So proposal is moving the missing position fixup to computed value time<br>
&lt;emilio> q+<br>
&lt;astearns> ack emilio<br>
&lt;TabAtkins> emilio: my concern is - to be clear, i think every browser does this at used-value time righ tnow<br>
&lt;TabAtkins> emilio: this changes the computed value serialization in a somewhat non-trivial way, hope this isn't an issue<br>
&lt;ChrisL> q+ to mention missing values and one-stop gradients<br>
&lt;TabAtkins> emilio: this is potentially a concern<br>
&lt;emilio> TabAtkins: I haven't done a test to see if browsers currently interpolate missing positions or not<br>
&lt;emilio> ... I think the gradient interpolation text doesn't take that into account<br>
&lt;emilio> ... The serialization one is a meaningful change, we can fix that if it becomes a problem<br>
&lt;emilio> emilio: at that point you could just change the interpolation algorithm right?<br>
&lt;emilio> TabAtkins: yeah that'd probably be better<br>
&lt;astearns> ack ChrisL<br>
&lt;Zakim> ChrisL, you wanted to mention missing values and one-stop gradients<br>
&lt;emilio> ChrisL: If we're fixing this this, I think a one-stop gradient would go to a 50% rather than 0 or 100%<br>
&lt;emilio> TabAtkins: happy to take that up but let's do this resolution first<br>
&lt;emilio> RESOLVED: move the missing position fixup to computed value time<br>
&lt;ChrisL> OK, the other issue is #10092<br>
&lt;ChrisL> https://github.com/w3c/csswg-drafts/issues/10092#issuecomment-2230892477<br>
&lt;emilio> emilio: does this _need_ to happen at computed value time? Could be done at parse time right?<br>
&lt;emilio> TabAtkins: yeah, but we usually don't do this at parse time<br>
&lt;emilio> emilio: yeah just wanted to clarify whether it could be done or I was missing anything<br>
&lt;emilio> ChrisL: just wanted to make sure we didn't stomp on the other resolution<br>
&lt;emilio> TabAtkins: Yeah it doesn't matter very much<br>
</details>


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Received on Wednesday, 17 July 2024 16:46:34 UTC