... Breaking up an s.c.c. of 6 into 3 components:
ODManager, ODTask, ODWaveTrackTaskQueue
UndoManager
WaveClip, WaveTrack
Rewrite the OD tasks and queues to hold weak pointers to tracks, so the
track destructor need not notify them.
... because we undo the move,
"Demote vertical zooming code into WaveTrack.cpp ..." done at 1f4bf26
That was done so that WaveTrack would not depend on WaveTrackVZoomHandle, but
made it instead depend on ProjectHistory, which is undesirable.
But since then, commit 3797a52 moved the special minimizing code for WaveTrack
into WaveTrackView.
... and eliminate some unnecessary calls to SubstitutePendingChangedTrack,
because the track and the substitute store Y and height in their shared
TrackView object.
Also make GetMinimizedHeight() virtual to avoid inclusion of TrackPanel.h in
TrackView.cpp.
... which makes Project.cpp a bit less dependent on some details of other
classes
This puts Tags.cpp back into the big strongly connected component of the
dependency graph. That will be remedied later when Project.cpp becomes a
low-level file
... Unnecessary because transitively included.
But each .cpp file still includes its own .h file near the top to ensure
that it compiles indenendently, even if it is reincluded transitively later.
... except Audacity.h; and in no others.
Do so even if Experimental.h gets multiply included, as in both the .h and
.cpp files.
This makes it easier to do a text scan to be sure there are no unintended quiet
changes of meaning because of omission of Experimental.h when the flag is
an enabled one.
Also move inclusions of Experimental.h earlier.
Also don't require Experimental.h to be preceded by Audacity.h to define
EXPERIMENTAL_MIDI_OUT correctly.
... so that we can use Track::SharedPointer without undefined behavior even on
tracks that don't yet belong to any TrackList.
Also fix the return type of function template TrackList::Add and remove some
casts.
... for wxString and wxArrayStringEx, holding file paths (absolute or relative,
directory or plain file); to be replaced later with different types
(not yet using std::vector, becase of some uses of wxArrayString::Index with
two arguments)
... Also rewrote some of the existing event handling so all events from
TrackList are of the same, custom event class, and distinguishing addition
from resizing events, though this distinction is not yet used
Rather than 'cut' (i.e. drop, not cut as in 'cut preview') channels immediately, we now only do so
if their last gain was already 0.0. Instead they micro-fade out. Later when the channels come back,
their last gain will be 0.0, so they will micro-fade in.
A comment explains that the code would be cleaner if we just computed gains, and not whether to
drop channels.
