Re: Graphics contrast comments overview

There is no language requiring a contrast minimum between the states 
themselves. I would really like that to at least be captured in the 
Understanding doc, if it can't be part of the SC, because being unable to 
differentiate between states is as much of a problem as not being able to 
differentiate between controls.
The same concern applies for disabled versus enabled controls.

Speaking of disabled controls, we exclude disabled controls from contrast 
considerations completely, but I've always felt that if a designer bothers 
to put a disabled element in the UI, that element's visual presence is 
important, and should be discernible with some minimum contrast (even if 
it is reduced). Every designer balks when I say 'Okay, if it's not 
important, why not remove it from your design entirely until it is 
active?'

At the least, can we work disabled controls into the AAA SC discussed? 
Alastair, I'd be happy to help try to craft that.

Michael Gower
IBM Accessibility
Research

1803 Douglas Street, Victoria, BC  V8T 5C3
gowerm@ca.ibm.com
voice: (250) 220-1146 * cel: (250) 661-0098 *  fax: (250) 220-8034



From:   Alastair Campbell <acampbell@nomensa.com>
To:     Jonathan Avila <jon.avila@levelaccess.com>, WCAG 
<w3c-wai-gl@w3.org>
Date:   2017-11-15 08:28 AM
Subject:        Re: Graphics contrast comments overview



Hi Jon,

> if the author uses a border to communicate the role of something 
> then the aspect has to meet the contrast requirements.

Agree. Also, I noticed we missed out the default-appearance exception, so 
I’ve updated that to say:
“Visual information used to indicate state for active user interface 
components, except where the appearance of the component is determined by 
the user agent and not modified by the author.”

> It doesn't require an author provide that affordance if they didn't.  So 
if I choose to make a piece of text blue and have it function like a 
button nothing needs to be done other than the contrast of the blue text 
in the non-focused state or non-pressed state of that button. 

Agree.

> If I use a solid background to make something look like a button then I 
have to make sure the edge of the background has sufficient contrast from 
the surrounding pixels outside of the focused or pressed state. 

Agree.

> If I have multiple buttons with some in pressed and others in 
non-pressed states the difference between the colors used for the pressed 
states need to have a 3:1 ratio as well. 

Agree. It is also worth considering the ‘adjacent’ aspect, if buttons are 
not immediately adjacent, then they do not have to contrast with each 
other.

> Focus indicators need to provide 3:1 contrast as well.  Is that right?
 
Yes, although with-what depends on what they are adjacent to.

Cheers,

-Alastair