RE: Technolog Agnostic / Independent

Ø  People with low visual acuity will probably read very little on a mobile phone.

I and others I know with low vision read quite a bit on a mobile phone.  If a person can only see a few works in front of them – for reading content it doesn’t matter if the screen is big or small – with a small screen you don’t have to move your head around.  Many CCTVs such as the Visio Book use mobile tablet sized screen as well and students with low vision use them daily to read.  With the CCTV of course you would introduce horizontal scrolling which I agree is not effective for reading.

Jonathan


From: Wayne Dick [mailto:wayneedick@gmail.com]
Sent: Monday, April 10, 2017 1:41 PM
To: public-low-vision-a11y-tf; GLWAI Guidelines WG org
Subject: Technolog Agnostic / Independent

This 2.1 project has reached a breaking point for the old notion of one SC for all technologies. The idea is not to drop technology independence, but to expand it to fit things like geometric reality.

Screen size is so significant that SCs relating visual interface really need a concept like "break point". Developers certainly do not treat mobile phones like desktops. There are things you do not do on a small screen. Few people write code on a mobile phone. People with low visual acuity will probably read very little on a mobile phone.

It does not make sense to treat tiny screens like big screens when we are discussing visual accessibility. We need a concept like "technology agnostic where appropriate". Or a concept like break points for size.

Consider font size. There are two factors to consider. Screen size S and viewing distance D. If font size of s at distance d that is sufficient then 3/4(s) at 3/4(d) will also be sufficient.  So we need a break down for testable prescriptions:

Screen Size    Viewing Distance    Font-Size % of Height/Width
s0 to s1          d0 to d1                f1
s[n-1] to s[n] d[n-1] to d[n]         fn

Note that the Font-Size percent can be computed using pixels using breaks points.

This construct could be used for target size as well.