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Re: [css3-values] Physical length units

From: Lea Verou <leaverou@gmail.com>
Date: Sun, 19 Feb 2012 22:37:42 +0200
Message-ID: <4F415D96.1050103@gmail.com>
To: Charles Pritchard <chuck@jumis.com>
CC: Felix Miata <mrmazda@earthlink.net>, www-style@w3.org
On 19/2/12 22:18, Charles Pritchard wrote:
> On 2/19/12 11:42 AM, Felix Miata wrote:
>> On 2012/02/19 09:15 (GMT-0800) Tab Atkins Jr. composed:
>>
>>> It's largely people using the pt unit for fonts, but the other
>>> units show up at times, and people expect them to have a dependable
>>> ratio with px.
>>
>> Others expect measuring units defined centuries ago to retain the 
>> same meaning in novel contexts as they do in traditional contexts. 
>> cf. the puter world's hijacking of decimal multiples MB, KB, GB, etc. 
>> http://en.wikipedia.org/wiki/Binary_prefix
>
> Is there any pushback with the truemm concept? I've seen this thread 
> pop up for awhile [years?] now.
> RoC put out a definition, it lacks any handling for browser zoom (if 
> the browser is zoomed in 2x, is it still 1mm?):
> http://lists.w3.org/Archives/Public/www-style/2010Jan/0343.html
Of course not. Zooming is zooming, so I'd expect it to be 2mm with a 2x 
zoom.
>
> I got a lot of pushback from Mozilla when I asked for pixel ratio to 
> be exposed in 2010/2011. Their entire model, up to the point they 
> introduced media queries, is built around not exposing this kind of 
> information. Once they introduced media queries, it simply became 
> obfuscated instead of obstructed. Mozilla was the only browser to take 
> such a rigid position, and it has loosened.
Since right now screen dpi can easily be detected by a simple binary 
search with resolution media queries in Gecko, I guess they're fine with 
it now. :)
>
> Are there any other use cases than the simple "put a ruler on the 
> screen" demo? I've used that one, cause I've worked with drawing apps. 
> If that is the only use case -- is simply exposing this information in 
> window.screen sufficient? I'm fine with css units too, but my uses are 
> going to be via scripting.
Any kind of length, really! Font-sizes, widths, heights, anything we 
want to have the same size in all screens (and we usually do). I 
remember this kind of size difference across screens was one of my first 
bad surprises when starting in this field. I think when support for such 
a unit becomes reliable across browsers/versions, we will start seeing 
it being used for everything, kinda like what happened with the em unit 
a few years ago after people realized how it could be used.
>
> All the back and forth on this topic really just relates to whether or 
> not Mozilla is willing to add information to the window.screen object. 
> For a few years, that's been an absolute no. I don't want to keep 
> carrying that fight. I think they're wrong, they think they're right.
>
> Microsoft updated window.screen awhile ago; webkit dev list gave the 
> green light on it last year, but no patches have surfaced yet.
> http://msdn.microsoft.com/en-us/library/ms535868(v=vs.85).aspx
>
>
> -Charles
>
>
>
> -- 
> Lea Verou (http://lea.verou.me | @LeaVerou)
Received on Sunday, 19 February 2012 20:38:15 GMT

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