- From: Matt Woodrow <mwoodrow@mozilla.com>
- Date: Tue, 10 Nov 2015 15:23:13 +1300
- To: "www-style@w3.org" <www-style@w3.org>
Take the following example: https://bug1198135.bmoattachments.org/attachment.cgi?id=8684006 In Firefox, you can scroll well beyond the end of the content. This is because we're computing the overflow area of the elements (with perspective transforms included) as they exist at scrollTop == 0. This doesn't take into account that the perspective transform is dependent on scroll position, and the 'real' overflow area actually shrinks as you scroll. In both Safari and Chrome you can't scroll the entire orange element into view. This appears to be because overflow is being computed without the perspective transforms applied, and perspective is just a rendering effect. Commenting out the perspective rule from the css helps show this. The Transforms spec says: > Therefore, if the value of the overflow property is scroll or auto, scrollbars will appear as needed to see content that is transformed outside the visible area. Should the spec be updated to reflect what Safari/Chrome are implementing? Or should it remain as is (probably with some clarification), and the browser behaviour be fixed? The latter seems to make more sense to me (why single out perspective as not contributing to overflow?), though it is admittedly considerably harder to implement. I'm not sure how this change would affect web-compat. David Baron and I have drafted a plan for fixing this in Firefox [1], if we decide to go that route. Thanks! - Matt [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1198135
Received on Tuesday, 10 November 2015 02:23:48 UTC