W3C home > Mailing lists > Public > www-style@w3.org > November 2010

RE: [css3-2d-transforms] Should a transformed element reflow its content ?

From: Sylvain Galineau <sylvaing@microsoft.com>
Date: Thu, 4 Nov 2010 09:07:21 +0000
To: "robert@ocallahan.org" <robert@ocallahan.org>
CC: Simon Fraser <smfr@me.com>, Øyvind Stenhaug <oyvinds@opera.com>, "www-style@w3.org" <www-style@w3.org>
Message-ID: <045A765940533D4CA4933A4A7E32597E287CF5C2@TK5EX14MBXC115.redmond.corp.microsoft.com>
Well, I find this behavior to be really weird. The content did *not* cause any overflow, the transform did. So this visual effect that supposedly happens post-layout turns out to change the rendering of the object being transformed to reflect the presence of scrollbars that wouldn’t be there if it wasn’t for the transform. It doesn’t seem that great perf-wise either.

But whatever we choose, it needs to be specified.

From: rocallahan@gmail.com [mailto:rocallahan@gmail.com] On Behalf Of Robert O'Callahan
Sent: Thursday, November 04, 2010 8:32 AM
To: Sylvain Galineau
Cc: Simon Fraser; Øyvind Stenhaug; www-style@w3.org
Subject: Re: [css3-2d-transforms] Should a transformed element reflow its content ?

On Thu, Nov 4, 2010 at 6:35 PM, Sylvain Galineau <sylvaing@microsoft.com<mailto:sylvaing@microsoft.com>> wrote:
It *is* different from the content without a transform, that’s why it’s confusing. The pre-transform content causes no overflow whatsoever. Since scaling of that content is what causes the overflow I can’t expect the scrollbar to affect what the transform scales.

I understand the rendering for overflow:scroll. For overflow:auto, it’s as if you figure out whether the transformed element will cause overflow then reflow it as if scrollbars where there before transforming it. I don’t think that makes sense.

I continue to claim that exactly the same thing can happen with non-transformed content. You "figure out whether the content will cause overflow, then reflow it as if scrollbars were there."

Of course, what we all actually do in that situation is iterate. In Gecko our scrollbar layout code needed no additional work to handle the presence of transforms.
 Modulo the scrollbars needed to see the content, I think expect the overflow:auto case to look just like the overflow:visible one.

I think that would be weird. You'd be saying that with overflow:auto, the presence of a scrollbar affects the layout of descendant elements, except for those that are transformed.

Rob
--
"Now the Bereans were of more noble character than the Thessalonians, for they received the message with great eagerness and examined the Scriptures every day to see if what Paul said was true." [Acts 17:11]
Received on Thursday, 4 November 2010 09:08:09 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 17:20:34 GMT