- From: Patrick H. Lauke <redux@splintered.co.uk>
- Date: Fri, 18 Dec 2015 14:03:53 +0000
- To: David MacDonald <david100@sympatico.ca>
- Cc: "public-mobile-a11y-tf@w3.org" <public-mobile-a11y-tf@w3.org>
On 18/12/2015 14:01, David MacDonald wrote: > what is 44px on a retina display? Define "what". Do you mean the number of physical pixels being used? The physical dimension that can be measured with a ruler on the screen? And if so, which device? iPhone 5, iPhone 6, iPhone 6+, iPad 2, iPad Mini, iPad Air... P > Cheers, > David MacDonald > > *Can**Adapt**Solutions Inc.* > > Tel: 613.235.4902 > > LinkedIn > <http://www.linkedin.com/in/davidmacdonald100> > > twitter.com/davidmacd <http://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 <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 14:04:16 UTC