Mappings for <meter> should be different from <progress>

[jasonkiss]

From ARIA issue 451 raised by @fstorr.

The element has an incorrect default ARIA role of progressbar which causes some assistive technology (I've tested in VoiceOver on OSX 10.11) to announce the element as a "progress indicator" and the value of the element as a percentage rather than the defined value (for example "80%" instead of "4 out of 5").

The HTML AAM specifies no corresponding ARIA role for meter, but it looks like the separate mappings for meter in MSAA+IA2, UIA, and AX reflect the progressbar role and progress element, which isn't correct.

@asurkov, the definition for ROLE_SYSTEM_PROGRESSBAR is wrong for meter. The meter element has semantics distinct from progressbar. Any suggestions? I note that ATK is using ATK_ROLE_LEVEL_BAR (as recommended in ARIA issue #150), which is certainly closer to the semantic for meter, but IA2 doesn't have a similar role.

@cyns, you raised the question of UIA mapping for meter in ARIA issue #344. What's there looks to be the same as the mapping for the progressbar role. How do you suggest UIA distinguish the meter and progress elements?

@cookiecrook, same question: the AX mappings for meter and progress elements are the same and don't reflect the different semantics. Is there a better role/roledescription for meter?

[asurkov]

I think I agree that HTML5 progress and HTML5 meter have different semantics, I'd say that HTML5 progress is a special case of HTML5 meter concept, i.e. HTML5 progress is a meter that is used to track the progress.

I started IA2 thread on this issue [1].

[1] https://lists.linuxfoundation.org/pipermail/accessibility-ia2/2016-October/002198.html

[cookiecrook]

I filed: https://webkit.org/b/164051

[jasonkiss]

Looks like mostly agreement that current mappings are wrong for MSAA+IA2, UIA, and AX. We need more information on what these mappings should be. In the meantime, I'm replacing (via 5ca8528) the incorrect mappings with '?' in the mapping table to indicate that more data on appropriate mappings is required.

[asurkov]

pushed IA2 change ef13d52 for new IA2_ROLE_LEVEL_BAR (LinuxA11y/IAccessible2@0447f85)

[jasonkiss]

@cookiecrook has filed a bug for this for Webkit/AX.

UIA still maps meter to ProgressBar Control Type. @boggydigital: any plans to create new Control Type or map meter differently, given that it is not a progress bar?