Re: let's bump to 10mm from 9mm

I'm guessing it is about 4.5mm

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David MacDonald



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On Fri, Dec 18, 2015 at 9:01 AM, David MacDonald <david100@sympatico.ca>
wrote:

> what is 44px on a retina display?
>
> Cheers,
> David MacDonald
>
>
>
> *Can**Adapt* *Solutions Inc.*
> Tel:  613.235.4902
>
> LinkedIn
> <http://www.linkedin.com/in/davidmacdonald100>
>
> twitter.com/davidmacd
>
> GitHub <https://github.com/DavidMacDonald>
>
> www.Can-Adapt.com <http://www.can-adapt.com/>
>
>
>
> *  Adapting the web to all users*
> *            Including those with disabilities*
>
> If you are not the intended recipient, please review our privacy policy
> <http://www.davidmacd.com/disclaimer.html>
>
> On Fri, Dec 18, 2015 at 5:21 AM, Patrick H. Lauke <redux@splintered.co.uk>
> wrote:
>
>> On 17/12/2015 22:32, Patrick H. Lauke wrote:
>>
>>> On 17/12/2015 22:06, Richards, Jan wrote:
>>>
>> [...]
>>
>>> So 44px was 11 mm on my desktop monitor but 8.5mm on my Samsung Note
>>>> phone.
>>>>
>>>> Maybe the SC wording needs to be more vague and then CSS px and mm
>>>> measurements can be offered as sufficient techniques?
>>>>
>>>
>>> I'd be in favor of having the *normative* text be more vague.
>>>
>>> I fear though that even if it was softened to something like "must be at
>>> least as large as an average person's fingertip" (see for instance the
>>> note on "Size and positioning of UI" in
>>> https://msdn.microsoft.com/en-us/library/windows/apps/hh465370.aspx),
>>> the end result is still that there's now a hard requirement to achieve a
>>> minimum physical size, but that there's no way for a developer to
>>> actually *guarantee* this as they can't check for physical device size,
>>> whether or not that device has implemented a sensible device pixel
>>> ratio, and they can't test on every possible device out in the wild and
>>> coming out in the future. Unless a strong note/exemption can be added
>>> somehow to the normative text which puts the onus on device/OS/UA having
>>> implemented a sensible mapping?
>>>
>>> In a further *informative* note we could then provide commonly
>>> used/suggested sizes such as 44x44px, and clarify that it may not always
>>> be possible for a developer to explicitly know the exact physical size
>>> that this will map to, as it depends on multiple factors outside of
>>> their control.
>>>
>>
>>
>> Having slept on this, I *think* it may be appropriate to to have the
>> actual wording of the SC provide a hard value in CSS pixels, e.g. "Touch
>> Target Size: One dimension of any touch target measures at least 44px ...".
>>
>> In the explanatory text, it would then ideally mention that we're talking
>> CSS pixels, rather than hardware pixels (with a reference back to CSS 2
>> http://www.w3.org/TR/CSS2/syndata.html#length-units); additionally, in
>> that text it should clearly state that authors cannot directly control the
>> actual physical size that 44px are rendered at on a screen, as this depends
>> on hardware/OS/UA, but that 44px was chosen because "generally" it renders
>> at an approximate size of 9mm.
>>
>> This way, the SC is consistently testable (by checking the dimensions in
>> CSS pixels), and it clarifies at which point authors are not in control
>> anymore of how things are *actually* rendered.
>>
>>
>> P
>> --
>> Patrick H. Lauke
>>
>> www.splintered.co.uk | https://github.com/patrickhlauke
>> http://flickr.com/photos/redux/ | http://redux.deviantart.com
>> twitter: @patrick_h_lauke | skype: patrick_h_lauke
>>
>>
>>
>