[orca-list] Orca and MuseScore

[Marc Sabatella <marc outsideshore com>]

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.

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Marc Sabatella
marc outsideshore com