Re: [csswg-drafts] [css-gaps-1] Define interpolation behavior (#12431)

In cases where there are no auto-repeaters, I think we can indeed be smarter.

I think it gets tricky when there are auto-repeaters that don't line up with each other, because then the gap-by-gap interpolations can depend on the total number of gaps, which we don't know at computed-value time. For example, if we have:

```css
from { column-rule-width: 1px repeat(auto, 2px) 3px 4px 5px; }
to   { column-rule-width: 6px 7px repeat(auto, 8px 9px) 10px; }
```

The pairs of values will line up as follows:

```
4 gaps:
1px 3px 4px  5px
6px 7px 8px 10px

5 gaps:
1px 2px 3px 4px  5px
6px 7px 8px 9px 10px

6 gaps:
1px 2px 2px 3px 4px  5px
6px 7px 8px 9px 8px 10px

7 gaps:
1px 2px 2px 2px 3px 4px  5px
6px 7px 8px 9px 8px 9px 10px
```

I can't figure out how to generalize that expansion without it being a function of the number of gaps. The values that pair with 3px and 4px would need to be pulled out of the end of the region covered by the auto repeater. But without knowing the number of gaps, how do you know where in the auto repeater to start pulling values from?

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Received on Tuesday, 15 July 2025 22:38:00 UTC