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Re: Making pt a non-physical unit

From: Brad Kemper <brad.kemper@gmail.com>
Date: Tue, 19 Jan 2010 23:50:17 -0800
Message-Id: <287F8659-F613-4EDA-80D5-CA935F3E6D79@gmail.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
Cc: David Singer <singer@apple.com>, "robert@ocallahan.org" <robert@ocallahan.org>, www-style <www-style@w3.org>


On Jan 19, 2010, at 9:31 PM, "Tab Atkins Jr." <jackalmage@gmail.com>  
wrote:

> On Mon, Jan 18, 2010 at 6:04 PM, David Singer <singer@apple.com>  
> wrote:
>> ...
>> Manufacturers may choose how these units map to their device, and  
>> may also offer users control over the mapping.
>>
>>
>> * * * *
>
>
> Two, Brad has suggested a slightly different take on the matter, that
> ends up having the same effect.  For screen media, still use the ratio
> of 96px to the in, as suggested here.  However, he suggests mapping 1
> css pixel to 1 device pixel, and then assuming a >1 zoom value for all
> elements by default when the dpi is high enough.  The only noticeable
> difference is that in Brad's suggestion the author could easily get
> access to device pixels in an element by setting zoom:1 on it.

Yes, and that author-set zoom on the root, default zoom by the UI  
(when the dpi is high enough), and user-set magnification through the  
UI (as it's done already) or through user style sheets, are all  
manipulations of the same property. So the author can override the UA,  
and the user can easily override the author and/or the UA.

I am also thinking that if a parent had a used zoom value of 2, and a  
child had 'zoom:3', then the parent would have 2x2 device pixels per  
px, and the child would have 6x6 device pixels per px (2*3=6). 
       
Received on Wednesday, 20 January 2010 07:50:55 GMT

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