- From: Tab Atkins Jr. <jackalmage@gmail.com>
- Date: Mon, 23 Jan 2012 11:38:26 -0800
- To: Brian Manthos <brianman@microsoft.com>
- Cc: "L. David Baron" <dbaron@dbaron.org>, www-style list <www-style@w3.org>, fantasai <fantasai@inkedblade.net>
On Mon, Jan 23, 2012 at 11:28 AM, Brian Manthos <brianman@microsoft.com> wrote: > I find this proposed behavior bizarre, personally. I'm not sure I would fight against it yet (because I need to consider it some more), but on the surface it's very counterintuitive to me. > > For the example > Width: 200px; > Height: 400px; > Background-position: calc(100% - 5px) calc(100% - 10px); > Background-repeat: no-repeat; > > As I understand it, the computed value for background-position is something like > 195px 390px > with the upper left of the image at > (195px, 390px) from the upper-left origin > as the Background specs currently stand. > > With the proposal below, a bunch of new confusing stuff pops out in both computed value and rendering. Good luck with getting authors to have good results when inheriting values under such conditions. Yes, that's a correct interpretation of the current spec behavior. This is counter-intuitive given the traditional behavior of percentages in bg-position, though. It seems odd that "background-position: 100% 100%" positions the image such that its right and bottom edges are flush with the right and bottom edges of the background area, but "background-position: calc(100% - 5px) calc(100% - 5px)" positions the image such that its right and bottom edges are way off beyond the right/bottom. At minimum, you expect the position of the image to shift by 5px in some direction, not several hundred pixels. ~TJ
Received on Monday, 23 January 2012 19:39:14 UTC