Re: Focus appearance update

Hi Wilco,

I’m not following that so I’ll try to walk it through… The new definition is:
minimum bounding box
the smallest enclosing rectangle aligned to the horizontal axis within which all the points of a shape lie. For components which wrap onto multiple lines as part of a sentence or block of text (such has hypertext links), the bounding box can be established based on how the component would appear on a single line.

So, the default is to enclose the whole component in a bounding box. For most things, that’s fine/normal.

For wrapped links you’d get something like this, with a 2-line high value >40px:
[Link wrapped onto 2 lines with a bounding box 2 lines high.]

Then it says “For components which wrap onto multiple lines as part of a sentence or block of text”.

So you’d get something like this, with a single line value of around 16px:
As it says “established based on how the component would appear on a single line”, I’m not sure what the separate bounding boxes (for each part of the link?) is about?

The value of the minimum area is based on the single-line version. The area of the focus indicator is the total of both parts of a separated link (as it is an area of the total), so it doesn’t matter if you have differently sized parts of the link.

What am I missing?


From: Wilco Fiers <>
Date: Monday, 4 July 2022 at 14:58
To: Alastair Campbell <>
Cc: WCAG list ( <>
Subject: Re: Focus appearance update
Hey Alastair,
It isn't clear in this version when to use the real bounding box, and when to use this imagined one-line variation of the bounding box. My guess based on the discussion is that this should be "whichever of the two bounding boxes has the shortest side", but that's not at all obvious from the text. You can take that to mean different things. Like whichever results in the largest minimum focus indicator, or whichever bounding box has the smallest / largest area / perimeter. Different versions of that change the calculation on different edge cases.

On Fri, Jul 1, 2022 at 6:49 PM Alastair Campbell <<>> wrote:
Hi everyone,

In the last update before CFC we’re integrating the text from the last meeting to deal with wrapped links.

After the meeting Michael Gower noticed that we already have (clashing) text in the definition of “minimum bounding box”, and it would make more sense to include it there.

So the branch has been updated to include that:

If anyone has any concerns about this change, please let me know.

Kind regards,



@alastc /<>

Wilco Fiers
Axe-core & Axe-linter product owner - WCAG 3 Project Manager - Facilitator ACT Task Force

Received on Monday, 4 July 2022 14:37:24 UTC