Markus Stange [:mstange] Assignee
	Description • 10 years ago

When an empty rect is transformed, its origin can move to a fractional position, and calling RoundOut() on the result gives a 1x1 rect. Doing region operations on lots of those can be expensive.

At the bottom of http://www.jasondavies.com/factorisation-diagrams/ , almost 50% of the slow scrolling can be attributed to AddTransformedBoundsToRegion processing empty rects.

I think I've fixed a similar issue before. Should we make RoundOut() keep empty rects empty?

	Robert O'Callahan (:roc) (email my personal email if necessary)
	Comment 1 • 10 years ago

Comment on attachment 8429469 [details] [diff] [review]
ignore empty rects in AddTransformedBoundsToRegion

Review of attachment 8429469 [details] [diff] [review]:
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Yes!

	Markus Stange [:mstange] Assignee
	Comment 2 • 10 years ago

https://hg.mozilla.org/integration/mozilla-inbound/rev/883ebdb850ac

	Ryan VanderMeulen [:RyanVM]
	Comment 3 • 10 years ago

https://hg.mozilla.org/mozilla-central/rev/883ebdb850ac