Re: [csswg-drafts] [css-contain] Add contain-paint-margin CSS property (#4934)

> If you allow ink overflow to escape, even by some known distance, how can you still do the optimizations enabled by the fact that contain:overflow usually allows nothing to escape?

`contain:paint` on an element allows the browser to be sure that nothing in the painted subtree of the element exceeds that element's border box. This can be use to optimized away/schedule raster and related rendering work when the element is scrolled offscreen.

Expanding the border box by a fixed, and known-to-the-browser amount, still allows such optimizations to apply, but the browser just needs to account for the additional space. The same optimizations can still apply. It's just a somewhat bigger raster area.


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Received on Friday, 10 April 2020 15:23:41 UTC