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Re: Making pt a non-physical unit

From: fantasai <fantasai.lists@inkedblade.net>
Date: Tue, 05 Jan 2010 11:45:15 -0800
Message-ID: <4B4396CB.1000105@inkedblade.net>
To: robert@ocallahan.org
CC: Alex Mogilevsky <alexmog@microsoft.com>, www-style <www-style@w3.org>, Melinda Grant <Melinda.Grant@gmx.com>
Robert O'Callahan wrote:
> On Wed, Jan 6, 2010 at 6:45 AM, Alex Mogilevsky <alexmog@microsoft.com 
> <mailto:alexmog@microsoft.com>> wrote:
>  >  Robert O'Callahan wrote in <http://lists.w3.org/Archives/Public/www-style/2010Jan/0058.html>
>  >  >   My understanding from a conversation I had on #webkit is that Webkit
>  >  >   avoids the problem by treating 1pt as 4/3px regardless of the display
>  >  >   DPI. I think we probably need to do this in Gecko for Web compatibility
>  >  >   reasons, and so for the sake of honesty in Web specifications, I
>  >  >   propose that the definition of pt in CSS be altered accordingly
>  >
>  >  For the record, IE treats “pt” the way you propose for a number of
>  >  versions already.
> 
> Thanks for the info! Then we should definitely change the spec.

What about locking things the other way, 1px == 3/4pt? That seems
less drastic, because at least you're keeping the 1pt = 1/72in.

I'm wondering how this will play out for other media, like print.

>  >  At this time there is no physical units in IE (that is there is no
>  >  unit that doesn’t grow or shrink with zoom) .
> 
> In Gecko, physical lengths still change with zoom. So if you zoom in by 
> 2x, a 1in length will be exactly 2 inches (if the OS didn't lie to us 
> about the screen characteristics).

This is as it should be. Zoom should zoom all lengths equally. It's
zoom level 0 that we need to sort out here.

~fantasai
Received on Tuesday, 5 January 2010 19:45:58 GMT

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