rework tempo editing.

most changes are due to a new design where tempo discontinuities at the
beginning of a ramped section may be set.
this allows easier mapping of live performance, especially in
the common case of a ramped ritard before the beginning of a new section.

feature summary:

holding constraint modifier (shift) while dragging the BBT ruler area
drags the tempo lines by changing the start tempo (as before)

holding copy modifier (control) while dragging the BBT ruler area
drags the tempo lines by changing the end tempo (ahem. not quite there)

dragging a tempo mark while holding constraint (shift) will change the
previous end tempo to match the marker position *worth trying*.

holding constraint and copy modifier (control + shift) while dragging
the BBT ruler area attempts to'pinch' or twist the surrounding tempi
sp that later ones are not repositioned (currently suffereng from
rounding errors)

1 files changed, 58 insertions, 1 deletions

diff --git a/gtk2_ardour/editor_drag.h b/gtk2_ardour/editor_drag.h
index 711b5095c7..d190c54424 100644
--- a/gtk2_ardour/editor_drag.h
+++ b/gtk2_ardour/editor_drag.h
@@ -792,7 +792,8 @@ private:
 
 	bool _copy;
 	bool _movable;
-	double _grab_bpm;
+	ARDOUR::Tempo _grab_bpm;
+	double _grab_qn;
 	XMLNode* before_state;
 };
 
@@ -823,6 +824,62 @@ private:
 	XMLNode* before_state;
 };
 
+/** tempo curve twist drag */
+class TempoTwistDrag : public Drag
+{
+public:
+	TempoTwistDrag (Editor *, ArdourCanvas::Item *);
+
+	void start_grab (GdkEvent *, Gdk::Cursor* c = 0);
+	void motion (GdkEvent *, bool);
+	void finished (GdkEvent *, bool);
+	void aborted (bool);
+
+	bool allow_vertical_autoscroll () const {
+		return false;
+	}
+
+	bool y_movement_matters () const {
+		return true;
+	}
+
+	void setup_pointer_frame_offset ();
+
+private:
+	double _grab_qn;
+	ARDOUR::Tempo  _grab_tempo;
+	ARDOUR::TempoSection* _tempo;
+	XMLNode* before_state;
+};
+
+
+/** tempo curve twist drag */
+class TempoEndDrag : public Drag
+{
+public:
+	TempoEndDrag (Editor *, ArdourCanvas::Item *);
+
+	void start_grab (GdkEvent *, Gdk::Cursor* c = 0);
+	void motion (GdkEvent *, bool);
+	void finished (GdkEvent *, bool);
+	void aborted (bool);
+
+	bool allow_vertical_autoscroll () const {
+		return false;
+	}
+
+	bool y_movement_matters () const {
+		return true;
+	}
+
+	void setup_pointer_frame_offset ();
+
+private:
+	double _grab_qn;
+	ARDOUR::TempoSection* _tempo;
+	XMLNode* before_state;
+};
+
 /** Drag of the playhead cursor */
 class CursorDrag : public Drag
 {