Re: [csswg-drafts] Setting the primary scrolling direction for a scroll container (#10060)

> I think UAs should be doing this automatically, based on the [principal writing mode](https://www.w3.org/TR/css-writing-modes-4/#principal-flow).

It's absolutely reasonable to do this automatically based on the principal writing mode. However, as an alternate solution, I would also like to further introduce just my two cents on adding a new property (For the sake of concise description, I didn't mention the other reason behind adding a new property in my previous text):

Although what this issue mainly aims to handle is about vertical writing mode. But there might also be cases where it's desirable for pages even when it's principal writing mode is horizontal. For example, a `horizontal` page can use the property if it contains a bunch of extremely wide cityscape pictures:

```
<div style="primary-overflow-direction: horizontal; overflow: auto">
    <!--a bunch of extrememly wide cityscape pictures-->
    <picture ...>
    <picture ...>
    <picture ...>
    ...
</div>
```

>     * Are there bugs filed against implementations for this?

Yes, there're at least bugs filed for this kind of issues, as far as I know, on bugzilla.mozilla.org:

Years ago, [the issue was mentioned by David Baron](https://bugzilla.mozilla.org/show_bug.cgi?id=autodir), and then I implemented `autodir` feature for Firefox.

later on, [the Firefox Desktop team also utilise the `autodir` feature to improve UX](https://bugzilla.mozilla.orgshow_bug.cgi?id=1749825).

Unfortunately, the big disadvantage of `autodir` is that it's not a CSS thing, so it's unaware of any element's style. Turning `autodir` on by default would mean pages all over the world that contain any horizontally scrollable elements could be affected. So Firefox had to turn `autodir` off by default.

Things are much better if we solve this issue with CSS: the issue that `autodir` couldnot resolve can be resolved perfectly by CSS: Because with CSS, we can **selectively** affect pages or elements according to it's style(Whether automatically based on the principal writing mode, as you said, or manually set using a new property, as I said).



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Received on Wednesday, 13 March 2024 05:23:32 UTC