... TrackPanelAx now sends an event to the project when track focus changes,
and TrackPanel listens for it.
TrackPanel also initializes TrackPanelAx with a callback to do the details of
rectangle calculation.
Problem. When an effect is applied, whatever track is the original focus, there is a focus event for track one. This causes NVDA to read out the track name of track 1, which is unnecessary noise.
The reason for this is that the execution of the Progress dialog destructor causes AudacityProject::OnActivate() to be called which causes a set focus on the TrackPanel. When this happens, the pointers to the selected tracks have changed, but the final focus has not been set (at the end of AudacityProject::DoEffect()). So TrackPanelAx::GetFocus returns the first track.
Fix: Modify TrackPanelAx::GetFocus so that if the existing pointer to the focused track is null, then use the track at the same position, if it exists.
The main change in wx accessibility is this:
7dab555f71 (diff-04f5191d86f95b1c4d5d9c979da65878)
However wxWindowAccessible has not been updated to take into account of that change. In particular wxWindowAccessible::GetParent() was always wrong, but it was consistent with the rest of the framework. Now it's wrong and inconsistent. This function should return an object with role window, and which has the same name.
The fix is to introduce class WindowAccessible, which is effectively our own version of wxWindowAccessible. This class does not override GetParent(), and so just relies on a standard accessible object to to the right thing in wxIAccessible::get_accParent() (which is does). This class also allows us to have our own version of GetName(), which allows us to set the accessibility names of buttons.
These changes will break the accessibility of Audacity if it is built with wxWidgets 3.0.X. If this is a problem, then there could be some #if stuff in WindowAccessible.h to turn the WindowAccessible class into one which simply inherits from wxWindowAccessible, and doesn't override anything.
The two commands are "selection to next label" and "selection to previous label".
They have default shortcuts alt+right and alt+left.
A label track does not have to be the focus. If there is a single label track in the project, that it used. If there is more than one label track, then the first label track, if any, starting at the focused track is used.
If the commands are used during playback of the project, playback continues from the new cursor/selection.
The commands provide feedback to screen readers: the name of the label, and position in the form of "i of n".
... for functions in final classes.
override is like const -- it's not necessary, but it helps the compiler to
catch mistakes.
There may be some overriding functions not explicitly declared virtual and I did
not identify such cases, in which I might also add override.
... Should have no effect on generated code, except perhaps some slight faster
virtual function calls. Mostly useful as documentation of design intent.
Tried to mark every one of our classes that inherits from another, or is a
base for others, or has abstract virtual functions, and a few others besides.
