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Re: [css3-images] Is the dppx unit needed?

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Tue, 24 May 2011 08:52:43 -0700
Message-ID: <BANLkTikM+q-EVAkhV8Q6gtQ1V9LD9KinGw@mail.gmail.com>
To: Sylvain Galineau <sylvaing@microsoft.com>
Cc: Brad Kemper <brad.kemper@gmail.com>, www-style list <www-style@w3.org>
On Tue, May 24, 2011 at 7:40 AM, Sylvain Galineau
<sylvaing@microsoft.com> wrote:
> [Brad Kemper:]
>> On May 23, 2011, at 8:30 PM, Sylvain Galineau wrote:
>> > [Tab Atkins:]
>> >> I'm rewriting the section on the <resolution> type in the Images spec
>> >> <http://dev.w3.org/csswg/css3-images/#resolution-units> to actually
>> >> explain what the unit does right now.  While writing an example, I
>> >> was struck by the fact that the dppx unit seems unnecessary, given
>> >> that we now have a guaranteed 96:1 ratio of 'px' per 'in'.
>> >>
>> >> Everything I know of that talks about image resolution uses dpi or
>> >> dpcm only.  I don't think I've ever seen anything equivalent to dppx.
>> >> Plus, 'dppx' is a hard unit to pronounce.  ^_^
>> >>
>> >> I suspect that dppx was created back when we couldn't actually say
>> >> that images were 96dpi by default, because the CSS 'in' wasn't tied
>> >> to a specific number of CSS 'px'.  Could I just drop it, and set the
>> >> initial value of 'image-resolution' to 96dpi?
>> >>
>> >> ~TJ
>> > I was going to ask as the dppx unit seemed to be a way to redefine CSS
>> pixels.
>> > What was(were) the use-case(s) ?
>>
>> DPI and its metric cousin are good enough for me. I suppose that since
>> dppx = dpi/96, someone maybe would want a non-fractional result, in which
>> case dppx could make that easier to pick the right number. But I don't
>> think that it is too big a deal to just do the math in that case and pick
>> something suitable.
>
> If that was a use-case I don't understand any of it.

I believe it's an explanation of why he doesn't think dppx is necessary.  ^_^

~TJ
Received on Tuesday, 24 May 2011 15:53:30 GMT

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