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

On 18/12/2015 14:06, David MacDonald wrote:
> I'm guessing it is about 4.5mm

What makes you say that?

Ok, so it seems you mean "what actual physical dimensions as measured on 
screen"...testing this (and the illustrate the problem even on a small 
scale), 44px is 7mm on iPhone5c, just over 8mm on the Google Nexus 5, 
7.5mm on a Google Nexus 10, about 9mm on an older iPad (2nd gen, non retina)

Other phones will have slightly different physical dimensions.

P

> Cheers,
> David MacDonald
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> On Fri, Dec 18, 2015 at 9:01 AM, David MacDonald <david100@sympatico.ca
> <mailto:david100@sympatico.ca>> wrote:
>
>     what is 44px on a retina display?
>
>     Cheers,
>     David MacDonald
>
>     *Can**Adapt**Solutions Inc.*
>
>     Tel: 613.235.4902 <tel:613.235.4902>
>
>     LinkedIn
>     <http://www.linkedin.com/in/davidmacdonald100>
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>     twitter.com/davidmacd <http://twitter.com/davidmacd>
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>     GitHub <https://github.com/DavidMacDonald>
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>     www.Can-Adapt.com <http://www.can-adapt.com/>
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>     On Fri, Dec 18, 2015 at 5:21 AM, Patrick H. Lauke
>     <redux@splintered.co.uk <mailto: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 <http://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
>
>
>
>


-- 
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

Received on Friday, 18 December 2015 14:16:59 UTC