- From: Simon Sapin <simon.sapin@exyr.org>
- Date: Wed, 19 Jun 2013 11:17:16 +0100
- To: www-style@w3.org
- CC: fantasai <fantasai.lists@inkedblade.net>, Robert O'Callahan <robert@ocallahan.org>
Le 14/06/2013 16:57, Simon Sapin a écrit : > So, we recently decided that with 'background-attachment: local', the > background positioning area is based on the "inner" scrolled content, > not the "outer" box: > > http://lists.w3.org/Archives/Public/www-style/2013May/0516.html > http://lists.w3.org/Archives/Public/www-style/2013May/0783.html > > What about the background *painting* area? I think it should be the > same. Specifically: > > > When 'background-attachment' is 'local' for a given background layer: To clarify, there are two things here. > 1. Both the positioning and painting area are based on the scrolled > content. (The difference between padding-box and border-box includes any > non-overlay scrollbars in addition to borders.) This is the part I find more important. In particular, the portion of the image that is clipped by 'background-clip: content-box' compared to 'padding-box' can scroll out of view As an example, these two document should behave roughly the same when scrolling: http://lists.w3.org/Archives/Public/www-archive/2013Jun/att-0075/background-attachment-local-painting-area-test.html http://lists.w3.org/Archives/Public/www-archive/2013Jun/att-0075/background-attachment-local-painting-area-ref.html > 2. Values of 'overflow' other than 'visible' also affect the > background layer: the background layer is only visible at the > intersection of the painting area and the "outer" padding area. > > Note: This means that 'background-clip: border-box' is > indistinguishable from 'padding-box'. This part I’m not too attached to. 'overflow' need to clip at least at the "outer" (w.r.t. scrolling) border-box, otherwise you get background images painted completely overflowing the box this is not supposed to overflow. I just think it makes more sense to clip at the outer padding-box, like the rest of the scrolled content. Note that given the first part, this is *not* the same as replacing 'background-clip: border-box' with 'padding-box', since the inner/scrolled padding-box can intersect with the border. Cheers, -- Simon Sapin
Received on Wednesday, 19 June 2013 10:17:37 UTC