Bug 147215 – Coordinates-based snap offsets don't update correctly when container is scrolled

• Component: WebCore Misc.
• Status: RESOLVED FIXED

[Wenson Hsieh]

If a snap scrolling container with child snap-coordinate elements is scrolled and then snap offsets are recomputed, the snap offset computation will not take the parent scroll offset into account, resulting in incorrectly computed snap offsets. You can reproduce this behavior by following these steps:

  1. Go to whsieh.github.io/examples/grid.html
  2. Scroll somewhere near the lower right corner
  3. Resize the window by any amount
  4. Try scrolling again. Observe that scroll snapping is completely broken

[Wenson Hsieh]

Created attachment 257321 [details]
Patch

[Brent Fulgham]

Comment on attachment 257321 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=257321&action=review

This looks great! If the tests pass I think this is ready to go!

> LayoutTests/css3/scroll-snap/scroll-snap-coordinate-overflow-resize.html:33
> +            container.style.width = "425px";

Great! We're finally testing resize cases. Nice work!

[WebKit Commit Bot]

Comment on attachment 257321 [details]
Patch

Clearing flags on attachment: 257321

Committed r187210: <http://trac.webkit.org/changeset/187210>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Wenson Hsieh]

<rdar://problem/22044550>