- From: Gérard Talbot <www-style@gtalbot.org>
- Date: Wed, 22 May 2013 14:28:11 -0400
- To: "fantasai" <fantasai.lists@inkedblade.net>
- Cc: "W3C www-style mailing list" <www-style@w3.org>
Le Mer 22 mai 2013 12:53, fantasai a écrit : > On 05/22/2013 12:27 PM, fantasai wrote: >> We were looking implementing 'background-attachment: local' in Gecko, >> and >> ran across the following problem in its definition: >> >> The goal of 'background-attachment: local' is to allow authors to get >> the behavior of 'background-attachment: scroll' on the canvas background >> when setting the background of an element with 'overflow: scroll'. IMHO >> this should have been the behavior of 'background-attachment: scroll' >> in the first place, but the WG at the time decided it should behave like >> 'fixed' on such elements; therefore we added a new keyword, 'local', in >> level 3. >> >> The spec defines this for the background's "attachment", but it doesn't >> for its positioning. Case to consider: a background image positioned to >> the bottom right corner. In the case of 'background-attachment: scroll' >> on the canvas, it is at the bottom of the scrollable area, not the >> bottom >> of the viewport. Similarly, 'background-attachment: local' should put >> such an image at the bottom of the scrollable area, not the bottom of >> the viewport. However, the spec doesn't specify this, so would need to >> be amended to fix that. > > Here's a diagram: > > +------------------------------------+ > |+---------------------------------+A| > || | | > || | | > || | | > || | | > || | | > || | | > || +------+| | > || |+++++ || | <-- bottom right of scrolling box > || |+image|| | > || +------+|V| > +|---------------------------------|-+ > | | > | | > | | > | | > | | > | | > | | > | | > | | > | | > | +------+| > | |+++++ || > | |+image|| <-- bottom right of scrolled > content > | +------+| > +---------------------------------+ > > ~fantasai Interactive test on 'background-attachment': 'local' versus 'scroll' values http://www.gtalbot.org/BrowserBugsSection/CSS3Backgrounds/background-attachment-345.xht Gérard -- CSS 2.1 Test suite RC6, March 23rd 2011 http://test.csswg.org/suites/css2.1/20110323/html4/toc.html Contributions to CSS 2.1 test suite http://www.gtalbot.org/BrowserBugsSection/css21testsuite/ Web authors' contributions to CSS 2.1 test suite http://www.gtalbot.org/BrowserBugsSection/css21testsuite/web-authors-contributions-css21-testsuite.html
Received on Wednesday, 22 May 2013 18:28:46 UTC