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Re: WCAG 2and high contrast

for

From: Jonathan Avila
Date: Oct 5, 2015 8:08PM

> The accessible name could be in a keyboard accessible tooltip.

In the situation where the image is not displayed but a keyboard and mouse accessible tooltip is present would require a user with low vision to either tab to or hover their mouse over blank areas of the page trying to figure out what elements are interactive. Only getting something on hover or focus isn't comparable access IMO.

> Most background images that are focusable are not decorative content, they're UI controls so don't hide them.

This is an intriguing idea but it isn't a given -- buttons with text can use background images as well -- I've seen this many times. Instead of using a hack -- authors should be able to more clearly state which ones are decorative and which are not.

> OS X has a high contrast mode that is different than invert colors.
The only settings I'm aware of are increase contrast, reduce transparency, and display contrast. I'm not aware of a setting allowing the user to choose colors. Increase contrast makes some small but helpful visual changes and reduce transparency is helpful. The display contras settings in my experience mostly makes things worse. In the settings dialog the slider seems to make the background whiter. Using the display contrast in many place such as the app > update screen slider seems to whiteout most things making most text less readable or even invisible in the standard display mode. What the display contrast slider is really good at is making the invert colors features work much better. Basically if you use invert colors and then the display contrast slider it produces better results -- but then again I don't want to use invert colors. The display contrast slider is a filter that lightens lighter colors -- which means if you have gray text it will make it lighter -- this is bad in standard display mode but good in inverse color mode.

In my experience most of these filters just don't work correctly across a broad spectrum of situations -- there are too many edge (or in this case I think middle) cases.

> I would rather Windows HCM not hide background images on focusable elements than to try and convince all web developers of the world to implement a specific hack for WinHCM.

You could make the same argument for just about anything -- why not have screen readers interpret the language so web developers don't need to set the language -- this is a valid argument I've seen in W3C lists. You could even say -- why have authors set the contrast of pages at all if the user can change the contrast?

We need to strike a balance between author and user agent settings.

Jonathan

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Jonathan Avila
Chief Accessibility Officer
SSB BART Group
<EMAIL REMOVED>

703-637-8957 (o)
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