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RE: Graphics contrast comments overview

From: Repsher, Stephen J <stephen.j.repsher@boeing.com>
Date: Wed, 15 Nov 2017 18:29:34 +0000
To: James Nurthen <james.nurthen@oracle.com>, Alastair Campbell <acampbell@nomensa.com>, Michael Gower <michael.gower@ca.ibm.com>
CC: Jonathan Avila <jon.avila@levelaccess.com>, WCAG <w3c-wai-gl@w3.org>
Message-ID: <073fef65c1f74e8cb790b1dd2bc1f03e@XCH15-08-08.nw.nos.boeing.com>
Commenting on Alastair’s latest version at http://rawgit.com/alastc/wcag21/graphics-contrast/guidelines/#graphics-contrast

1.       It should be named something like “Graphics and Controls Contrast” or similar since only half is actually about graphics.

2.       I don’t see any need for confusingly mentioning “non-text content” in the initial sentence since the SC is defining the 2 things.  They should be the subject of the sentence grammatically, such as: “The following have a contrast ratio of at least 3:1 against adjacent color(s): …”.

3.       It might go a long way to provide a normative definition for “state” similar to how it is defined in ARIA<https://www.w3.org/TR/wai-aria-1.1/#dfn-state> with a few examples such as: “a dynamic property expressing characteristics of a user interface component that may change in response to user action or automated processes. States do not affect the nature of the component, but represent data associated with the component or user interaction possibilities.  Examples include focus, hover, select, press, check, and expand/collapse.”

4.       I thought there was discussion on the subject, but I’m unclear how the mere boundaries of a component fit In here now.  Text boxes don’t really have default states as, unless we’re expecting the interpretation that empty or filled is a state, in which case that’s a big stretch.  Why not just say “boundaries” too, i.e. “Visual information used to indicate state or boundaries of active user interface components, …”?


From: James Nurthen [mailto:james.nurthen@oracle.com]
Sent: Wednesday, November 15, 2017 12:18 PM
To: Alastair Campbell <acampbell@nomensa.com>; Michael Gower <michael.gower@ca.ibm.com>
Cc: Jonathan Avila <jon.avila@levelaccess.com>; WCAG <w3c-wai-gl@w3.org>
Subject: Re: Graphics contrast comments overview

On Nov 15, 2017, 8:46 AM -0800, Michael Gower <michael.gower@ca.ibm.com<mailto:michael.gower@ca.ibm.com>>, wrote:

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.
I always fail this on 1.4.1<http://www.w3.org/TR/2008/REC-WCAG20-20081211/#visual-audio-contrast-without-color> Use of Color: Color is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element. (Level A)

If the ratio is 3:1 or greater then it is no longer color alone (hue and lightness) so no longer fails 1.4.1. As such I don’t think this needs to be in this SC.

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

1803 Douglas Street, Victoria, BC  V8T 5C3
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From:        Alastair Campbell <acampbell@nomensa.com<mailto:acampbell@nomensa.com>>
To:        Jonathan Avila <jon.avila@levelaccess.com<mailto:jon.avila@levelaccess.com>>, WCAG <w3c-wai-gl@w3.org<mailto: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.


> 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.


> 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.



Received on Wednesday, 15 November 2017 18:30:12 UTC

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