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

On Thu, Jun 28, 2012 at 12:53 AM, 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.

When I checked, interop here was not good at all.  My research is on this bug:

https://www.w3.org/Bugs/Public/show_bug.cgi?id=15833

I observed significantly different behavior in basic test-cases in all
four major engines.

I think it's much preferable to simply ignore 'background-attachment:
fixed' on transformed elements than to implement it in a way that
makes a 90-degree rotation cause the background to move sideways when
you scroll up or down.  I find it really hard to believe anyone would
want the latter behavior.

Received on Thursday, 28 June 2012 10:18:58 UTC