[css overflow-clip-margin] What does overflow-clip-margin impact?

[sky2]

Hello,
I'm in the process of implementing overflow-clip-margin in chrome and a question has come up as to what overflow-clip-margin applies to. Does it only impact the paint effects of the box itself? What about child paint effects and child spill out?

[sky2]

We are planning on doing the following:

1. box decorations of overflow:clip element remain as-is and are not clipped in presence of overflow-clip-margin
2. area of descendants exposed by overflow-clip-margin contribute to layout overflow of ancestor

[tabatkins]

overflow-clip-margin doesn't affect anything on its own; it just expands the overflow clip box, which is used by overflow: clip and contain: paint.

Those latter properties define how they interact with paint and geometry.