- From: Tab Atkins Jr. <jackalmage@gmail.com>
- Date: Mon, 16 Jul 2012 16:15:24 -0700
- To: Lea Verou <leaverou@gmail.com>
- Cc: www-style list <www-style@w3.org>
On Mon, Jul 16, 2012 at 4:07 PM, Lea Verou <leaverou@gmail.com> wrote: > A common visual design pattern that has emerged in the past few years is the > content area having a fixed width, with the background extending to cover > the entire viewport width. Here is a quick list of websites doing this: > http://lesscss.org/ > http://www.opera.com/ > http://www.mozilla.org/ > http://www.kaleidoscopeapp.com/ > http://daneden.me/type/ > http://www.alfredapp.com/ > http://grabaperch.com/ > http://twostepmedia.co.uk/jsquery/ > http://whiteboard.is/ > > For given viewport dimensions, this could be done by adjusting the left & > right padding to be equal to (viewport width - width) / 2. However, > viewports are not fixed, and therefore authors almost always resort to using > a wrapper element for the content, with fixed dimensions and margin: auto, > and assign the background to its parent element. calc() enables this to be > expressed in pure CSS with something along the lines of: > width: 20em; > padding: calc(50vw - 20em / 2); > > This is certainly an improvement, but still suboptimal. Not only it’s not > very readable, but the width needs to be duplicated or assigned to a > variable to keep the code DRY. Given that this is not an isolated case, but > an incredibly common pattern, I believe it should be addressed by something > more straightforward. > > Basically, what’s needed is an `auto` value for padding, that makes it > behave as `auto` does for margin. In the latest ED there *is* a new `auto` > value allowed for the padding properties [1], but the way it’s supposed to > work is not explained anywhere. > > [1]: http://dev.w3.org/csswg/css3-box/#the-padding-properties An alternative way to do this would be to have a way to opt-in to <body>'s special handling, where its background gets hoisted to the canvas. That's how you achieve this effect when you're not varying the background within the page. ~TJ
Received on Monday, 16 July 2012 23:16:11 UTC