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Re: [css3-flexbox] Is painting order affected by 'flex-order'?

From: Daniel Holbert <dholbert@mozilla.com>
Date: Thu, 17 May 2012 09:49:38 -0700
Message-ID: <4FB52C22.9070901@mozilla.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
CC: www-style list <www-style@w3.org>, Alex Mogilevsky <alexmog@microsoft.com>
I asked this exact question back in January:

  http://lists.w3.org/Archives/Public/www-style/2012Jan/1232.html

and it appeared that we settled on flex-order _not_ affecting painting order:

  http://lists.w3.org/Archives/Public/www-style/2012Jan/1241.html

and as a result, we have this text in the spec right now:

 # ‘flex-order’ has no effect on stacking/layering; elements must
 # still be drawn over/under each other based on document order,
 # ‘z-index’, and other relevant means.

I prefer this behavior (no effect on painting order), but I'm OK with it
either way.  (though we should be sure that flexbox & grid end up being
consistent on this)

~Daniel

On 05/16/2012 06:04 PM, Tab Atkins Jr. wrote:
> Issue link: http://wiki.csswg.org/topics/css3-flexbox-painting-order
> 
> The 'flex-order' property “reorders” flexbox items, allowing them to
> display independently of their source order.
> 
> Does this reordering affect painting order? That is, given the following markup:
> 
> <flexbox> <a style=“flex-order:2;”>foo</a> <b
> style=“flex-order:1;”>bar</b> </flexbox>
> 
> If the <b> child overlaps the <a> child, should it paint above (that
> is, according to its source order) or below (according to its display
> order)?
> 
> A. 'flex-order' affects the painting order - items moved earlier paint
> underneath items moved later.
> 
> B. 'flex-order' has no effect on painting order - the original source
> order determines whether things are painted above/below others.
> 
> WebKit's implementation chooses option A, and I think this is sanest -
> as much as possible, the reordering should act exactly like it was
> *always* in that order.
> 
> Thoughts?
> 
> ~TJ
> 
Received on Thursday, 17 May 2012 16:50:13 GMT

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