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Re: [css3-values] [css3-images] no units for default 'image-resolution'

From: Shelby Moore <shelby@coolpage.com>
Date: Tue, 26 Oct 2010 16:15:32 -0400
Message-ID: <1cb9383e8ed3542416591c61ddab41af.squirrel@sm.webmail.pair.com>
To: shelby@coolpage.com
Cc: "Tab Atkins Jr." <jackalmage@gmail.com>, www-style@w3.org
>> On Tue, Oct 26, 2010 at 9:50 AM, Shelby Moore <shelby@coolpage.com>
>> wrote:
>>> The 'px' is defined to respect relative ocular psychophysics:
>>>
>>> http://www.w3.org/TR/CSS21/syndata.html#numbers
>>> http://www.w3.org/TR/css3-values/#relative0
>>>
>>> The 'image-resolution' is by default 1 device pixel ('dppx'):
>>>
>>> http://dev.w3.org/csswg/css3-images/#image-resolution
>>> http://www.w3.org/TR/css3-images/#resolution-units
>>>
>>> But there exists no image pixel unit, i.e. 'px' is not equivalent to an
>>> image pixel.
>>
>> Yes it is: "By default, CSS assumes a resolution of one image pixel
>> per CSS ?px? unit; however, the ?image-resolution? property allows
>> using some other resolution."
>>
>> 1dppx means "1 image pixel = 1 CSS px".
>
> My mistake.  For some reason in my haste, I thought dppx meant number of
> device pixels, but of course it says "dots per ‘px’ unit".
>
> Juggling too many balls today I guess. Sorry.

I think it is the 'dppx', the 'dp' registers in my mind as an abbreviation
for 'device per' or 'device pixels'. Now I see it means 'dots per', but 
I've never seen 'image pixels' referred to as dots. Is there any
precedent?

[snip]
Received on Tuesday, 26 October 2010 20:16:07 GMT

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