W3C home > Mailing lists > Public > www-style@w3.org > February 2009

Re: Proposal for overflow painting order

From: Robert O'Callahan <robert@ocallahan.org>
Date: Thu, 5 Feb 2009 14:43:52 +1300
Message-ID: <11e306600902041743w27344fa3ldc0f06c04c37849c@mail.gmail.com>
To: David Hyatt <hyatt@apple.com>
Cc: "www-style@w3.org List" <www-style@w3.org>
On Thu, Feb 5, 2009 at 1:30 PM, David Hyatt <hyatt@apple.com> wrote:

> Sure, but in an accelerated compositing world, you can imagine the overflow
> object having an offscreen buffer associated with it.  In the example you
> just cited, blitting would still be possible, since you would be able to
> blit in the buffer itself when scrolling happens.  It wouldn't matter that
> the scrollable element was transparent or that the content behind is not a
> single solid color.

OK, thanks for explaining that.

I also think authors using negative margins could cause unintentional
> overlap that could negatively impact performance of these overflow sections.

That sounds rare, assuming your hypothetical "is it OK to blit?" code
ignores transparent backgrounds. If it wasn't rare, that would be a backward
compatibility argument for not changing the spec :-).

"He was pierced for our transgressions, he was crushed for our iniquities;
the punishment that brought us peace was upon him, and by his wounds we are
healed. We all, like sheep, have gone astray, each of us has turned to his
own way; and the LORD has laid on him the iniquity of us all." [Isaiah
Received on Thursday, 5 February 2009 01:44:30 UTC

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