- From: Luca Frosini <w3c@lucafrosini.com>
- Date: Fri, 07 Sep 2012 17:22:58 +0200
- To: www-style@w3.org
Il 06/09/2012 23:03, Tab Atkins Jr. ha scritto: > On Wed, Sep 5, 2012 at 12:27 AM, James Ide <ide@fb.com> wrote: > Excellent use-case description! Thanks so much for that; most > proposals skimp on that, so it's hard to tell what improvements can be > made to their proposal. ^_^ +1 >> One currently feasible solution is to use JavaScript to measure the >> dimensions >> of an inserted node and scroll its overflow ancestor's contents by the same >> amount to compensate as necessary. Deciding when to compensate for the >> inserted node sometimes requires a heuristic since the intent is to maintain >> the position of the content that the user is reading. >> >> I'd like to propose a CSS property, "pinning", that tells the layout engine >> to >> maintain the position of visible content relative to its overflow box. I >> imagine the most common use cases will be for scrollable boxes, but this >> behavior seems desirable for any box with clipped overflow and a positive >> scrollTop. +1 >> >> The "pinning" property takes up to two values for vertical and horizontal >> pinning, respectively: [<length>|<percentage>]{1,2}. Each determines a >> threshold from the top and left of the element's content box; nodes that are >> laid out before these thresholds do not cause their siblings to be shifted. > I have a few problems with this proposal. I suspect that the details > of your proposal were strongly influenced by the JS library you were > using; we can do better when we control the language. > > 1. It's way too specific. You need to predict what zone of the > element you'll be inserting things in. I think we can do this > automatically. > 2. It's not general enough. You only cover element insertion. > Element deletion, or just an element changing size, still causes > shifting in the scroll area. We can generalize this and cover those > cases automatically. > > Here's an alternate proposal: > > scroll-adjust: none | stable (not super happy with the property name, > but roll with it) I sounds better also for me. Regards Luca
Received on Friday, 7 September 2012 15:26:11 UTC