Re: [orca-list] Orca and MuseScore

[Joanmarie Diggs <jdiggs igalia com>]

Hey Mark.

Right now Orca is not listening for description change events. If you 
want to see if it magically fixes things, add a listener for them in 
default.py.

As for value-change: What event gets emitted by Qt for that? An 
accessible value is something in a range. It has a numeric value which 
can be represented as a percent. Think spin buttons, progress bars, 
sliders, scroll bars.

As for why Orca is so slow to present it: Depends on what Orca is doing. 
You can make Orca spew a metric crapton of debugging output to a file. 
See https://wiki.gnome.org/Projects/Orca/Debugging. Get a full 
debug.out, find your event emission and what Orca does in response.

Regarding the filler: If memory serves me, there was some selection 
dialog in which the object being chosen had role of filler and an 
accessible name. But I might be misremembering. In the middle of 
something else at the moment.

Hope the above hints help. And thanks for your interest!
-- joanie (Orca maintainer)

On 1/19/20 9:29 PM, Marc Sabatella wrote:
> Hello!  I am one of the developers of MuseScore, and I've been working 
> on accessibility on and off the last few years.  My spam folder and I 
> had a disagreement about my subscribing to this list (!), so I wasn't 
> able to participate in the recent discussion, but I learned a lot from 
> reading the exchanges.  Also from discussions on the Qt list and with 
> some JAWS scripters.  Bottom line, I've managed to get MuseScore working 
> with Orca, but I do still have some questions.
>
> What I was having trouble with is getting Orca to read changes to a 
> custom Qt widget representing a musical score.  The changes represent 
> the currently-selected note or symbol, so it changes on cursor 
> navigation.  After a ton of trial and error - different roles for the 
> widget, different properties for the info I wanted read, different 
> events to triggers the reading - I came up with something that works, 
> using a short Orca script.  But Orca responds more slowly than I expect 
> (more slowly than NVDA or JAWS on Windows), and I'm not sure why, so I'd 
> appreciate any suggestions.
>
> What I have right now is a role of image for my widget, although others 
> work too.  The name is the name of the score.  The value and description 
> are both set to the text I want read - a verbal description of the 
> selected score element.  I send a value change event the selection 
> changes, because try as I might, I just can't seem to get Orca to 
> recognize a description change event.  Orca doesn't read anything on 
> receipt of the value change event by default, but my script listens for 
> this event and reads the description (not the value, because that always 
> comes out as numeric 0).
>
> As I said, it works, but there is a pretty big lag - like a second or 
> more - between when I send the event from MuseScore and when Orca reads 
> the result.  Accerciser sees the event immediately, so I know the delay 
> is not on the MuseScore side.  What's weird is, spinboxes go through my 
> same onValueChanged handler, and it reads instantly.  Somehow my custom 
> widget takes much longer to get there.
>
> As I mentioned, I'd really rather use a description changed event, but 
> even though I'm installing a listener for 
> object.property-change.accessible-description, it never fires.  Probably 
> I'm doing it wrong, but it seems like the right syntax.  Running debug 
> info on Orca, though, it doesn't seem the event gets received (but 
> again, Accerciser sees it just fine).
>
> So, my questions at this point:
>
> 1) why Orca is so slow to read this?
> 2) anything special I need to do to get accessible-description events?
> 3) any other ideas for ways of eliminating the need for the script
>
> BTW, there was a question about the "filler" objects in the tree.  These 
> are widget layout elements used by Qt - to control whether controls are 
> laid out horizontally or vertically or in a grid, and not meant to be 
> directly accessible at all.  Not sure why Qt puts them in the accessible 
> object hierarchy.
>
> --
> Marc Sabatella
> marc outsideshore com <mailto:marc outsideshore com>
>
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