Specify AXAPI behaviour for low, high, and optimum meter attributes.
#538
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I don't think it is as simple as this. As I understand it <meter> can have 3 segments,
- (1) below
low, - (2) between
lowandhigh - (3) above
high.
If theoptimumvalue fits into (1) then all values within this segment are optimal, values in (2) are suboptimal and values in (3) are critical
If the optimal value is in (2) then values in (1) and (3) are both suboptimal
If it is (3) then values in (1) are critical, (2) suboptimal and (3) optimal.
These correspond to the visual coloring of green (optimal), orange (suboptimal) and red (critical).
If no optimum value is specified then the optimal segment is segment (2)
Here is the webkit logic https://github.com/WebKit/WebKit/blob/c330ea99229f6bb478dde74497ee652e44a3d7d5/Source/WebCore/html/HTMLMeterElement.cpp#L156
Co-authored-by: James Nurthen <jnurthen@users.noreply.github.com>
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Hi @MReschenberg, I've added comments and recommendations that largely align with @jnurthen's assessment of optimum treatment.
| @@ -11709,7 +11709,7 @@ <h4 id=att-high>`high`</h4> | |||
| <tr> | |||
| <th><a href="https://developer.apple.com/reference/appkit/nsaccessibility">AX</a></th> | |||
| <td> | |||
| <div class="general">Not mapped</div> | |||
| <div class="general">Expose "optimal value" via `AXValueDescription` if <value> is greater than or equal to <high>. Expose "suboptimal value" if <value> is less than <high> and greater than or equal to <low>.</div> | |||
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Relevant WebKit code: https://github.com/WebKit/WebKit/blob/c330ea99229f6bb478dde74497ee652e44a3d7d5/Source/WebCore/html/HTMLMeterElement.cpp#L172
This looks correct for high. We'll also need to add the case for when the value is less than "low" (for which this is exposed as "critical value").
| @@ -12739,7 +12739,7 @@ <h4 id=att-low>`low`</h4> | |||
| <tr> | |||
| <th><a href="https://developer.apple.com/reference/appkit/nsaccessibility">AX</a></th> | |||
| <td> | |||
| <div class="general">Not mapped</div> | |||
| <div class="general">Expose "suboptial value" via `AXValueDescription` if <value> is greater than or equal to <low> and less than <high>. If <value> is less than <low>, expose "critical value".</div> | |||
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Relevant WebKit code: https://github.com/WebKit/WebKit/blob/c330ea99229f6bb478dde74497ee652e44a3d7d5/Source/WebCore/html/HTMLMeterElement.cpp#L163
For low:
- If
valueis less than or equal tolow, thenvalueis "optimal value" - if
valueis less than or equal tohigh(but greater thanlow), thenvalueis "suboptimal value" - else,
valueis "critical value"
Also, looks like there is a typo for the word "suboptimal" here.
| @@ -13995,7 +13995,7 @@ <h4 id=att-optimum>`optimum`</h4> | |||
| <tr> | |||
| <th><a href="https://developer.apple.com/reference/appkit/nsaccessibility">AX</a></th> | |||
| <td> | |||
| <div class="general">Not mapped</div> | |||
| <div class="general">Expose "optimal value" via `AXValueDescription` if <value> is greater than or equal to <optimum>.</div> | |||
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Relevant WebKit code: https://github.com/WebKit/WebKit/blob/c330ea99229f6bb478dde74497ee652e44a3d7d5/Source/WebCore/html/HTMLMeterElement.cpp#L184
For optimum:
- If
valueis greater than or equal tolowANDvalueis less than or equal tohighthenvalueis "optimal value" - Else,
valueis "suboptimal value"
Note that in this case, there is no "critical value".
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This issue should have an active test case showing this in a more common use case, like an audio meter bouncing quickly and showing critical peak line clipping.
I’m not sure if this will need new API, or if there is existing API, but I’m reasonably sure AXValueDescription is not the ideal way to vend this to AT like VO.
Update: dynamic meter test case added to a new WebKit Accessibility bug.
Do you have an alternative attribute in mind? |
|
Role/Subrole is already |
Closes #536
Specification based on Safari behaviour/attributes exposed.
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