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Technolog Agnostic / Independent

From: Wayne Dick <wayneedick@gmail.com>
Date: Mon, 10 Apr 2017 10:40:35 -0700
Message-ID: <CAJeQ8SCcOJicmvD57q_7fr8fxoy32rf-G3O_oF6QRER_wNe0-A@mail.gmail.com>
To: public-low-vision-a11y-tf <public-low-vision-a11y-tf@w3.org>, GLWAI Guidelines WG org <w3c-wai-gl@w3.org>
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.
Received on Monday, 10 April 2017 17:41:09 UTC

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