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Re: [css3-transforms] Proposal for behavior of background-attachment:fixed inside transformed elements

From: Simon Fraser <smfr@me.com>
Date: Wed, 27 Jun 2012 15:19:55 -0700
Cc: www-style list <www-style@w3.org>
Message-id: <D29617DB-DA6B-46B3-ABA1-ADBE9F200700@me.com>
To: robert@ocallahan.org
On Jun 27, 2012, at 2:53 PM, Robert O'Callahan <robert@ocallahan.org> wrote:

> On Thu, Jun 28, 2012 at 9:50 AM, Robert O'Callahan <robert@ocallahan.org> wrote:
> On Thu, Jun 28, 2012 at 4:40 AM, Simon Fraser <smfr@me.com> wrote:
> David Baron suggested that the backgrounds are rendered as if there are no transforms, then the transforms applied. This would cause surprising behavior in some cases; for example, on an element with a 90deg rotation and a fixed background, the background would move sideways when scrolling vertically.
> 
> Modulo a few bugs, this is what Firefox, Chrome and (I'm told) IE10 already do.
> 
> Opera too.
> 
> Let's just keep doing this. In Gecko at least, I think the bugs are not very hard to fix.

I'd prefer to avoid doing this, for two reasons:
1. It just looks wrong for things that aren't simply translated.
2. We want to avoid having to repaint an element when scrolling in as many cases as possible, because it adds complexity to hardware-accelerated scrolling in some UAs.I'd prefer that backgrounds on transformed elements don't move around when scrolling, ever.

Simon
Received on Wednesday, 27 June 2012 22:20:24 GMT

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