This is a common operation used for zooming in other DAWs like Ableton Live and
Cubase. To support such a usage pattern without changing the existing behaviour
of the ruler area I've made it an option that is false by default.
The behaviour of RulerDragZoom is intentionally different than a CursorDrag
that occurs in the rest of the ruler area in that it doesn't follow the snap to
grid setting and no locate related stuff occurs until button release.
There are some issues with responsiveness with more than a few hundred regions
or a large amount of MIDI events/notes.
Implements feature #6768
Editor::mouse_frame only works within the track canvas. If a zoom drag is
initiated and the mouse cursor goes outside of the track canvas the zoom
position should still based on the current x position of the cursor.
There are a couple of header files where we use a reference to class ARDOUR::MidiCursor (rather than a pointer). To keep MSVC happy we need to #include its header file, rather than simply using a forward reference.
- in an ideal world, this wouldn't be here at all,
but is required to support framewalk_to_qn().
if Beats are at tick resolution, the frame-induced
temporal rounding is acceptable.
- adds quarter_notes_per_minute(), note_divisions_per_minute (double)
pulses_per_minute() and frames_per_quarter_note()
- this should be a no-op except for the use of tempo by
the vst callback which definitely uses quarter notes per minute.
- the XML node for TempoSection named 'beats-per-minute'
has been renamed.
- Tempo beats_per_minute() is currently implemented as note types per minute.
a further patch will change Tempo to reflect this and provide some helpers.
