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Re: [css3-images][css4-images] Replace 'dppx' with 'x'?

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Thu, 14 Jun 2012 12:18:19 -0700
Message-ID: <CAAWBYDC_uBF4WCRhuYVhJYQebCM-V9GAnRQe_o_aEeeX0i-WdQ@mail.gmail.com>
To: Simon Fraser <smfr@me.com>
Cc: Florian Rivoal <florianr@opera.com>, www-style@w3.org
On Thu, Jun 14, 2012 at 11:25 AM, Simon Fraser <smfr@me.com> wrote:
> On May 29, 2012, at 4:22 PM, Tab Atkins Jr. wrote:
>> On Tue, May 29, 2012 at 1:08 AM, Florian Rivoal <florianr@opera.com> wrote:
>>> On Fri, 25 May 2012 20:07:53 +0200, Christoph Päper
>>> <christoph.paeper@crissov.de> wrote:
>>>> Of course, all the reciprocal length units are plain stupid and
>>>> unnecessary – and always have been.
>>>>
>>>>  image-resolution: <count> [ / <length> ]?;
>>>>  image-resolution: 1dot; /* with 1px default */
>>>>  image-resolution: 300dot/1in;
>>>>  image-resolution: 100dot / 1mm;
>>>
>>> I wasn't there when you initially suggested that, but I think I like it. It
>>> may be too late to introduce something like that, but I wouldn't mind being
>>> proven wrong about this.
>>
>> The 'image-resolution' property was reverse-implemented based on what
>> already existed, so we can't remove what exists, but we can always add
>> more syntax later.  However, I don't think adding ratios for
>> expressing resolution is a good thing unless we do it everywhere.
>
> My problem with the dppx unit is that the ratio of device pixels to CSS pixels only makes
> sense when the page is unscaled. Most mobile devices (and, increasingly, desktop browsers)
> present pages at a non-unit scale, and allow users to zoom the page in and out. When zoomed,
> there's an additional scale factor applied that needs to be taken into account in the relationship
> between device pixels and CSS pixels. The 'dppx' unit pretends that such a scale factor does not
> exist, which is confusing.
>
> In addition, I still think that most authors will interpret "resolution" in terms of physical screen size,
> not the 1:96 fixed CSS inch:pixel ratio.
>
> Both are strong arguments for a simple multiplier factor in media queries, as used by device-pixel-ratio.

You're saying that the value of device-pixel-ratio is sensitive to
zoom?  So that on a high-res (2x) phone viewing a page that is also
initially viewport-zoomed to half its size, the device-pixel-ratio is
4?

~TJ
Received on Thursday, 14 June 2012 19:19:09 GMT

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