Jamie, I have to agree with Dominic that you have a lot of different what ifs for determining where to go when a cell is empty. I think you need to be able to pass a parameter that asks the browser to go where you want based on a set of criteria.
For example, So, what if several rows are skipped? When does the situation become problematic? What condition do you want to be met? e.g. a parameter that tells us what to do if an empty cell is encountered: GOTO_FIRST_NONEMPTY_ADJACENT_CELL What I am getting at is what is the algorithm you want the user agent to follow when an empty cell is encountered. Does it Vary based on a parameter. Do you want hidden cells to be ignored? Rich Rich Schwerdtfeger From: James Teh <[email protected]> To: Richard Schwerdtfeger/Austin/IBM@IBMUS, Dominic Mazzoni <[email protected]> Cc: IAccessible2 mailing list <[email protected]>, [email protected] Date: 01/05/2016 04:50 PM Subject: Re: [Accessibility-ia2] aria-colcount and aria-rowcount mapping, again On 5/01/2016 7:53 AM, Richard Schwerdtfeger wrote: Although it is possible to have 2 cells I don't think this even close to the norm. Two cells was just an extreme example to demonstrate the issue. The point is that gaps at the start or middle of a row are problematic. Why would we we not just have the screen reader ask to go to a row and column number? Because if there is a gap, incrementing row or column by one isn't sufficient. It could be 1, 2 or an arbitrary number. It is not difficult to ask the user agent to navigate to compute the effective cell to the right and ask for the user agent to navigate there. It's probably always true that navigating to the adjacent cell in the next column is as simple as accNavigate with NAVDIR_NEXT. However, navigating to the adjacent cell in the next row is not so simple. What if several rows are skipped? We can add a parameter that states to navigate to the first non-empty cell to the ... or whatever algorithm we choose. Add a parameter to what? I think this would require a new function, which is what I was suggesting. Dominic wrote: Jamie, as an alternative, couldn't the screen reader try navigating to the next / previous cell using the row, column index, but if that fails, fall back on DOM navigation? For example, given a current cell (x, y), if the user wants to go right - to the next cell in the same row, try (x + 1, y) but if that's empty, use the accessibility tree to navigate to the next sibling. I suppose we could do that, but it's pretty inelegant. Oh look, we have a table interface... but uh, sometimes it's not very useful, so you might need to use tree navigation. It's not so bad for columns i guess, but see below for rows. Similarly, given (x, y) if the user wants to go down - to the same column in the next row, try (x, y + 1), but if that's empty, use the accessibility tree to navigate to the next row, Navigating to the next row has two problems: 1. It's not a simple navigation, since there might be thead/tbody/rowgroup elements to think about. Sure, it's just a depth-first traversal, but now we're starting to get fairly complicated for what should be a simple operation. 2. What if the next row doesn't include that column, but there is a row 3 rows beyond that that does? Surely we should move to the row with the matching column. That's not possible with your algorithm. then try column x in that row, and if that fails, navigate to the first cell in that row. We never want to fall back to the first column like that. If a user moves down a row, they expect to move down a row, not down and across (excepting column spans). Jamie -- James Teh Executive Director, NV Access Limited Ph +61 7 3149 3306 www.nvaccess.org Facebook: http://www.facebook.com/NVAccess Twitter: @NVAccess SIP: [email protected]
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