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RE: [css3-background] background-size and zero length

From: Brian Manthos <brianman@microsoft.com>
Date: Tue, 11 May 2010 18:17:39 +0000
To: Boris Zbarsky <bzbarsky@MIT.EDU>
CC: "www-style@w3.org" <www-style@w3.org>
Message-ID: <FA122FEC823D524CB516E4E0374D9DCF014F9A8E@TK5EX14MBXC136.redmond.corp.microsoft.com>
Having a limitation is fine.

there are a growing number of property that have special behavior "at" zero.  Background-size and border-radius with box-shadow are two that have been discussed recently.

I would prefer that CSS define "numbers within X of zero should be treated identically to zero".  Doing so makes interoperability a likelihood rather than luck.

Another example that comes to mind is unit-less.  IIRC, <length> values require units except for zero.  Given that the "near-zero" region is open to UA-discretion, what does that imply about "0.016" as a <length>?


-----Original Message-----
From: Boris Zbarsky [mailto:bzbarsky@MIT.EDU] 
Sent: Tuesday, May 11, 2010 10:55 AM
To: Brian Manthos
Cc: www-style@w3.org
Subject: Re: [css3-background] background-size and zero length

On 5/11/10 1:49 PM, Brian Manthos wrote:
> For values below 0.00833333331px, Firefox continues to show no image.

Right.  Lengths in Gecko are stored as integers in units that are 1/60 
of a CSS px.  The number above is about 1/120.  So things smaller than 
that would would round to 0.

> More fun with near-zero values in the land of interoperable browsing
> challenges.

It's a general problem.  You have similar issues with large values.  At 
some point, either the browser is using an infinite-precision arithmetic 
package for layout (unlikely given the performance impact) or you get 
arbitrary limitations on your values.


Received on Tuesday, 11 May 2010 18:18:17 UTC

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