Re: notes on 320 CSS Pixels to inches

On 18/01/2018 19:09, Hakkinen, Mark T wrote:
> I should have been clearer, I am not suggesting in any way that authors define size using the problematic CSS physical lengths. My question for this SC is: will 44 CSS Pixels result in meeting what research tells us should be a 10 mm (or 9 or 12) minimum physical size on any device from which the user is trying to select a target with their finger tip?  I assume the answer is no. Larger is always better, we know that. Smaller on the other hand?

In most cases, it results in a size that is, generally, near enough that 
particular physical size in most devices/OSs.

> So, what's the point of this SC?  Aren't we, for the user's sake, effectively mandating a minimum physical size?

It's mandating a minimum CSS size which, in most cases, on most devices, 
gets close to a good physical size - give or take a certain degree of 

As the uncertainty can't be magicked away, it's the next best thing that 
can be mandated.

If, instead, an SC mandated an actual physical size, it would make it 
impossible for authors to guarantee they're meeting the SC on all 
possible past, current and future devices/user agents. Ditto for 
testing. And if a new device came out which, for whatever reason, 
decided to have a different logical viewport dimension / CSS px to 
real-world physical measurement ratio, it wouldn't retrospectively make 
a pass now fail when tested on that device.

> Agree. Let's not make this mistake.  The only alternative I can think of is (quickly):  All touch targets must have role, state, and name specified so that assistive technologies (or user agent features) can provide alternative selection methods (for example, enlarge target areas).

role/state/values would already fall under 4.1.2.

Not all users that require large-enough targets (note this isn't just 
touch, but also mouse) run AT.

(But as noted, in the worst case users can zoom (as long as it's not 
suppressed) to make targets, and all other content, larger).

Patrick H. Lauke | |
twitter: @patrick_h_lauke | skype: patrick_h_lauke

Received on Thursday, 18 January 2018 19:49:54 UTC