Fix incorrect double-snap when moving audio-locked tempi

diff --git a/libs/ardour/tempo.cc b/libs/ardour/tempo.cc
index 702490bc0d1aa9384ec6131502aa35184d239ceb..020f4390ce8d9a3a90ddd3cc28decfa82ce9394c 100644 (file)
--- a/libs/ardour/tempo.cc
+++ b/libs/ardour/tempo.cc
@@ -3243,25 +3243,24 @@ TempoMap::gui_set_tempo_position (TempoSection* ts, const framepos_t& frame, con
                        Glib::Threads::RWLock::WriterLock lm (lock);
                        TempoSection* tempo_copy = copy_metrics_and_point (_metrics, future_map, ts);
 
-                       if (solve_map_minute (future_map, tempo_copy, minute_at_frame (frame))) {
-                               if (sub_num != 0) {
-                                       /* We're moving the object that defines the grid while snapping to it...
-                                        * Placing the ts at the beat corresponding to the requested frame may shift the
-                                        * grid in such a way that the mouse is left hovering over a completerly different division,
-                                        * causing jittering when the mouse next moves (esp. large tempo deltas).
-                                        *
-                                        * This alters the snap behaviour slightly in that we snap to beat divisions
-                                        * in the future map rather than the existing one.
-                                        */
-                                       const double qn = exact_qn_at_frame_locked (future_map, frame, sub_num);
-                                       const framepos_t snapped_frame = frame_at_minute (minute_at_pulse_locked (future_map, qn / 4.0));
 
-                                       if (solve_map_minute (future_map, tempo_copy, minute_at_frame (snapped_frame))) {
-                                               solve_map_minute (_metrics, ts, minute_at_frame (snapped_frame));
-                                               ts->set_pulse (qn / 4.0);
-                                               recompute_meters (_metrics);
-                                       }
-                               } else {
+                       if (sub_num != 0) {
+                               /* We're moving the object that defines the grid while snapping to it...
+                                * Placing the ts at the beat corresponding to the requested frame may shift the
+                                * grid in such a way that the mouse is left hovering over a completerly different division,
+                                * causing jittering when the mouse next moves (esp. large tempo deltas).
+                                * We fudge around this by doing this in the musical domain and then swapping back for the recompute.
+                                */
+                               const double qn = exact_qn_at_frame_locked (_metrics, frame, sub_num);
+                               tempo_copy->set_position_lock_style (MusicTime);
+                               if (solve_map_pulse (future_map, tempo_copy, qn / 4.0)) {
+                                       ts->set_position_lock_style (MusicTime);
+                                       solve_map_pulse (_metrics, ts, qn / 4.0);
+                                       ts->set_position_lock_style (AudioTime);
+                                       recompute_meters (_metrics);
+                               }
+                       } else {
+                               if (solve_map_minute (future_map, tempo_copy, minute_at_frame (frame))) {
                                        solve_map_minute (_metrics, ts, minute_at_frame (frame));
                                        recompute_meters (_metrics);
                                }