[whatwg] Outline style to use for drawSystemFocusRing

Dominic Mazzoni dmazzoni at google.com
Fri Oct 4 01:56:51 PDT 2013

> if as a web author I call drawCustomFocusRing and it returns false, I'm
>> not supposed to draw anything according to the spec. That's what doesn't
>> make sense to me.
Why not?
> It means that either the element was not focused or the user selected high
> contrast focus rings.
> The return value of true means that you as an author can draw the focus
> ring in any style.

Yes, I agree that's exactly what the spec says.

What I don't understand is how a browser is supposed to implement the high
contrast focus ring support on a real operating system that exists today.
Are there other apps that do this? Are there published guidelines anywhere?

Windows has a system setting for high-contrast mode. When you turn on high
contrast mode, it changes the default color palette. There's no other
effect on the focus ring that I know of.

Windows also has settings for the focus ring width. I agree those should
affect the system focus ring, but I don't think users would expect that to
override a canvas author's focus ring.

High contrast mode may affect the system focus ring color, it's true - but
there's no reason to believe that this system focus ring would look better
on a canvas when high contrast mode is on, and in fact it might look much

Third-party accessibility tools that draw focus rings aren't relevant here.
They draw independently of applications; applications like browsers are not
supposed to draw anything different.

Or, here's another argument: a canvas can contain absolutely anything. It
might contain a wild and crazy color palette. Only the canvas author knows
what focus ring is going to be visible on top of that canvas. If the canvas
is white text on a black background, then a dark-colored focus ring is
going to be practically invisible, and vice versa.

It just doesn't make any sense to me that we're providing an API that says,
if you want to draw your own focus ring, use this - BUT, under some
circumstances we're going to tell you not to draw it and the browser or
operating system is going to draw it for you, even though the browser has
no idea what colors are on your canvas and what type of focus ring would be
visible against it.

If the author wants to draw their own focus ring, it's probably for a good
reason. We should let them.

We may also want to give web authors visibility into the system color
palette so they can adjust the entire canvas - and not just focus rings -
for high contrast mode. But that's out of the scope of this discussion.

On Wed, Oct 2, 2013 at 8:20 PM, Rik Cabanier <cabanier at gmail.com> wrote:

> I just tried this with canary and your demo file, and it is not scrolling
> to the focus ring. Is this what you are asking for?


> If so, I agree that we should update the spec. There is not much point
> that you can tab into fallback content but the browser doesn't scroll to
> the path.


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