The code was calling the Gtk::Widget::can_focus() getter as on odd
statement without side effects.
It seems like it meant to call set_can_focus, and thus prepare for
actually grabbing the focus in the next line.
This commit leaves two issues outstanding:
1. unclear/ugly semantics for drag operations that reset the GUI thread's tempo map to the writable copy
2. undo/redo for the tempo map
These will be addressed in future commits
Found via `codespell -q 3 -S *.po,./share/patchfiles,./libs -L ba,buss,busses,doubleclick,hsi,ontop,ro,seh,siz,sord,sur,te,trough,ue`
Follow-up to 364f2f078
Both of these are currently needed: idle_resize() is required for
::set_height() to take effect on all affected tracks, and
::redisplay_track_views() is needed to reposition all other tracks as
necessary.
This may be incorrect, since track height changes may be driven
directly (e.g. via menu items) rather than by mouse drags. This may
need revisiting and there may need to be a way to separate dragged height
changes from others.
This allows it to be used in an idle callback. If we use
::redisplay_track_views() directly, we do not disconnect the idle
connection. This will happen automatically since the callback will return
false, but it seems better to explicit about this. Even better would be to use
::connect_once() but this may not be available in the version of glibmm that we
are using at present.
It appears that GDK/glib will not run idle callbacks with a lower priority than
HIGH_IDLE+10 *if* a new user input event is pending. This means that if mouse
motion events are arriving and causing resizes of selected tracks, the call
to ::redisplay_track_views() which is needed to update all the other tracks,
will not take place if a new motion event arrives. Changing the priority to
same as is used for the ::idle_resize() callback prevents new motion events
from being handled before ::redisplay_track_views() is called.
::model_changed() is used when the model has changed (eg. new notes or some
notes deleted); ::view_changed() is used when only some view parameter (e.g.
zoom, scroll, track height etc) has been altered.
Not fully functional yet (::view_chanted() ignores scroll)
