- From: Patrick H. Lauke <redux@splintered.co.uk>
- Date: Thu, 17 Dec 2015 22:00:07 +0000
- Cc: "public-mobile-a11y-tf@w3.org" <public-mobile-a11y-tf@w3.org>
On 17/12/2015 21:33, Jonathan Avila wrote: > Patrick, I agree with your concern. I've seen the number 44x44 pixels mentioned before for a minimum device independ pixel size. That value I believe originally comes from Apple's human interface guidelines, and it's 44x44 points (see https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/MobileHIG/LayoutandAppearance.html), not pixels. Note that the "points" unit used by Apple is not the same as "CSS points" (where 1pt = 1.333px), but their own way of talking about resolution independent pixels - so for all intents and purposes, 1 apple point = 1 css pixel (see https://developer.apple.com/library/ios/documentation/2DDrawing/Conceptual/DrawingPrintingiOS/GraphicsDrawingOverview/GraphicsDrawingOverview.html#//apple_ref/doc/uid/TP40010156-CH14-SW7) It's doubly ironic, then, that despite Apple's aim to use points to "provide a consistent size of output that is device independent", their very own products (iPad and iPad Mini) actually don't follow the idea: with the iPad Mini having the same resolution in pixels/points as the iPad, but with a smaller physical screen...meaning that even diligently using "points" in the hope that they're indeed device-independent and adapted correctly to provide consistency won't actually work...and that's only looking at two models from a single manufacturer - now consider the myriad of different physical screen sizes of "mobile/tablet/laptop/etc" devices out there (some call it "fragmentation") and the disparate (virtual) resolutions they run at, and you can see that it's effectively impossible for a developer to guarantee (or even specifiy) any specific *physical* size that can then be measured with an actual ruler held up against an actual physical screen. 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 Thursday, 17 December 2015 22:00:31 UTC