[csswg-drafts] [css-align] fully specify the "Overflow and Scroll Positions" section

dbaron has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-align] fully specify the "Overflow and Scroll Positions" section ==
I think the current [Overflow and Scroll Positions section](https://drafts.csswg.org/css-align/#overflow-scroll-position), whose entire normative contents are currently:

> The content distribution properties also affect the initial scroll position, setting it to display the appropriate portion of the scrollable area. In other words, the scrollable overflow region is aligned relative to the viewport as specified by the content distribution properties. Additionally, so that the content remains in the scrollable overflow region in order to be scrollable, the scroll and auto values of overflow trigger safe content alignment always.

is insufficient for what it's trying to specify.

I think there are a number of issues here:
* In the first sentence, "also affect" doesn't say *how* it affects the initial scroll position.  For example, what does baseline do?  What does center do?  Do `safe` and `unsafe` influence the decision?
  * I'd note that I think it's a bad idea for the initial scroll position not to be at the edge of the scrollport, since existing scrolling user interfaces can make it hard to get back to a position that's not at the edge.
* The second sentence appears to confuse [viewport](https://drafts.csswg.org/css2/visuren.html#viewport) and [scrollport](https://drafts.csswg.org/css-overflow-3/#scrollport).
* The third sentence appears to completely contradict the first two, at least as I understand them.  In other words, there only exists an initial scroll position when the content overflows, so this forces content-alignment on anything that is scrollable with more than one possible scroll position to be content-aligned to `start`.  That, in turn, seems to imply that the initial scroll position would always be at the start edge like it's always been.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/1425 using your GitHub account

Received on Saturday, 20 May 2017 20:48:42 UTC