W3C home > Mailing lists > Public > www-style@w3.org > April 2005

Re: Anti-aliasing border corners [spin-off of Style confirmation descriptors]

From: Emrah BASKAYA <emrahbaskaya@hesido.com>
Date: Mon, 11 Apr 2005 03:15:55 +0300
To: "www-style@w3.org" <www-style@w3.org>
Message-ID: <opso1kctzv8nstxa@lomarnona>

On Sun, 10 Apr 2005 18:52:31 -0400, Barry <wassercrats@hotmail.com> wrote:

> I don't know enough about anti-aliasing to know how aggressive the  
> anti-aliasing would need to be before an entire top border would be an  
> extra pixel thick. I'm just raising this issue incase it really could be  
> an issue.

A straight vertical or horizontal line canNOT produce extra pixels if they  
are not positioned with a sub-pixel accurate method or given sub-pixel  
accurate widths. The 'aggressiveness' of anti-aliasing is a non-issue. The  
accuracy of AA is something else, and there are many many methods for AA  
that produces different results in terms of clarity and accuracy. A  
sub-pixel positoned horizontal vertical border would be an extra-pixel  
wide "almost immediately" (with little sampling amounts) with any sane AA  
method! Also as David Woolley explained, functions be implemented that can  
produce infinitely accurate AA in a single pass. So that sould be called  
'aggresive' because it is infinitely accurate, but did it not work 'less'  
to produce a more accurate result?? There are also methods for sampling  
like super-sampling and multi-sampling. And multi-sampling has different  
methods for their sampling locations (straight grid vs rotated grid) which  
all have small differences in output. Should CSS worry about that too??

So in conclusion: If you define things in sub-pixel accuracy, and you know  
the user-agent has that support, don't worry, leave it to the user-agent.  
We already have the power to define things in mm instead of px, so maybe  
in future there maybe user agents with totally anti-aliased ultra-slick  
look. And that will be EXACTLY the time when you won't have to worry about  
how many pixels a border is, but how many milimeters a border is, which is  
also the user-agents problem! But as long as you are designing in px, and  
that there aren't vector only browsers, you should not worry about a thing  
for vertical and horizontal straight lines being anti-aliased or not.

Whether the 'corners' will be anti-aliased should be left to the user  
agent. And I bet I'll like the one with a proper-anti-alias.

Received on Monday, 11 April 2005 00:16:03 UTC

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