- From: Patrick H. Lauke <redux@splintered.co.uk>
- Date: Mon, 14 Nov 2016 15:27:20 +0100
- To: public-mobile-a11y-tf@w3.org
On 14/11/2016 14:52, David MacDonald wrote: > I presented the touch target size proposal to the Toronto accessibility > group... their response regarding the 48 vs 24 coarse vs fine point > requirements was > > "How do we know when when we should serve up one vs another. Seems like > a difficult thin."g to sniff accurately for give the wide rage of > devices..." > > We'll need to solve that I think... Assuming this would then be part of understanding/techniques again, following approaches come to mind: - seeing that it's not possible to reliably detect a touchscreen, and - particularly in multi-input scenarios - it's not easy to know for sure even if a touchscreen can be detected whether or not a user will actually use that or some other input device instead: unless you are designing/developing for a closed system where you know for a fact which type of input(s) will be available (e.g. embedded system only to be used for touchscreen-enabled point of sales terminals, or a system for content only to be used on an ATM style device without touchscreen but with physical keyboard-like buttons on the side of the display), developers should assume that at some point or other their content/app will be used on a touchscreen; see also "when any [...] machine could have a touch interface, [...] proceed as if they all do" https://medium.com/let-me-repost-that-for-you-zeldman/jason-grigsby-on-design-beyond-touch-e862b699d426#.9go7knctr - offer the user a mechanism as part of the app/site UI to switch between "mouse-friendly" and "touch-friendly" interface. this is the approach that, for instance, Microsoft Office 2013 uses (See slide 137 https://patrickhlauke.github.io/getting-touchy-presentation/#137) - use CSS Media Queries Level 4's "any-pointer" feature to ascertain if a coarse pointer is present (indicating at least one of the inputs available to the user is coarse, e.g. a touchscreen) https://drafts.csswg.org/mediaqueries-4/ (note my article on using CSS MQ4 detection carefully https://dev.opera.com/articles/media-features/, as well as recent discussion on changing the spec to drop the idea of "primary" vs "rare" inputs https://github.com/w3c/csswg-drafts/issues/690) - use third-party libraries like https://github.com/ten1seven/what-input to detect as soon as a user switches between using a mouse/touchscreen - then it's up to the app/site to decide what to do (immediately switch out the interface to coarse or fine pointer optimized? present the user with a dialog asking if they now want to switch to the type of input that they just used? etc) 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
Received on Monday, 14 November 2016 14:27:40 UTC