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Re: [CSS21] 4.3.2 Lengths (reference pixel?)

From: Anton Prowse <prowse@moonhenge.net>
Date: Mon, 13 Dec 2010 21:41:27 +0100
Message-ID: <4D0684F7.4070501@moonhenge.net>
To: www-style@w3.org
On 13/12/2010 20:56, Tab Atkins Jr. wrote:
> On Mon, Dec 13, 2010 at 11:40 AM, Anton Prowse<prowse@moonhenge.net>  wrote:
>> On 13/12/2010 20:10, Tab Atkins Jr. wrote:
>>> Those authors have never truly had good physical units.  I don't
>>> recall the precise details of which browsers do what, but more than
>>> one browser, at least, has done the "1in = 96px" thing for a long
>>> time.
>>>
>>> So there never was a way to do it "correctly" because the physical
>>> units never were truly physical, in practice.
>>
>> Sure, but an author who attempted to do it correctly (testing on a monitor
>> of a certain, common resolution) cannot be blamed much for not knowing that
>> the software he relied upon was letting him down in practice on monitors of
>> different resolution.
>
> Sure.  But we similarly can't change all the pages written by authors
> who used both pt and px in their pages and expected them to maintain a
> steady ratio.
>
> It appears that this group of authors is much larger than the group of
> authors who wrote pages expecting an absolute length to exactly
> correspond with the analogous real-world units (especially since they
> never did, except perhaps by accident on some screens with particular
> resolutions).
>
> Further, absolute units *do* correspond closely to the analogous
> real-world units in print media and other high-dpi media, and as
> screen resolutions increase the same will happen there.  The
> disconnect between CSS in and real-world inches is a temporary
> aberration caused by the particular circumstances of how screens work
> (requiring us to make CSS px correspond to integer multiples of screen
> pixels) and the current common dpi ratio.

I agree.  (Note that I'm not arguing one way or the other here; I'm 
merely clarifying another's arguments in the hope of being able to draw 
a line under this issue soon.)

Cheers,
Anton Prowse
http://dev.moonhenge.net
Received on Monday, 13 December 2010 20:42:01 GMT

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