fix some DnD thinko & edgecases.

* Handle large (delta > 1) movements into the DZ
which are not due to invalid-drop positions, but
caused by laggy GUI or rapid user movements.

* ignore busses when moving out of the DZ.

diff --git a/gtk2_ardour/editor_drag.cc b/gtk2_ardour/editor_drag.cc
index 302a2de6d0a46bf223d302650101eb546eba032d..6f1abba69cfe3d4a19e7af38429abce88c4b9021 100644 (file)
--- a/gtk2_ardour/editor_drag.cc
+++ b/gtk2_ardour/editor_drag.cc
@@ -800,7 +800,10 @@ RegionMotionDrag::motion (GdkEvent* event, bool first_move)
 
                /* Work out the change in y */
 
-               if (_last_pointer_time_axis_view < 0) {
+               RouteTimeAxisView* rtv = dynamic_cast<RouteTimeAxisView*> (tv);
+               if (!rtv || !rtv->is_track()) {
+                       /* ignore busses early on. we can't move any regions on them */
+               } else if (_last_pointer_time_axis_view < 0) {
                        /* Was in the drop-zone, now over a track.
                         * Hence it must be an upward move (from the bottom)
                         *
@@ -816,11 +819,7 @@ RegionMotionDrag::motion (GdkEvent* event, bool first_move)
                         */
                        delta_time_axis_view = current_pointer_time_axis_view - _time_axis_views.size () + _ddropzone - _pdropzone;
                } else {
-                       /* ignore busses early on. we can't move any regions on them */
-                       RouteTimeAxisView* rtv = dynamic_cast<RouteTimeAxisView*> (tv);
-                       if (rtv && rtv->is_track()) {
-                               delta_time_axis_view = current_pointer_time_axis_view - _last_pointer_time_axis_view;
-                       }
+                       delta_time_axis_view = current_pointer_time_axis_view - _last_pointer_time_axis_view;
                }
 
                /* TODO needs adjustment per DraggingView,
@@ -899,15 +898,17 @@ RegionMotionDrag::motion (GdkEvent* event, bool first_move)
                 * distance calculation is not needed (and would not work, either
                 * because the dropzone is "packed").
                 *
-                * Except when partially(!) moving regions out of dropzone in a large step.
+                * Except when [partially] moving regions out of dropzone in a large step.
                 * (the mouse may or may not remain in the DZ)
                 * Hidden tracks at the bottom of the TAV need to be skipped.
+                *
+                * This also handles the case if the mouse entered the DZ
+                * in a large step (exessive delta), either due to fast-movement,
+                * autoscroll, laggy UI. _ddropzone copensates for that (see "move into dz" above)
                 */
-               assert(_pdropzone >= _ddropzone);
-               if (delta_time_axis_view < 0 && -delta_time_axis_view >= _pdropzone - _ddropzone)
-               {
-                       const int dt = delta_time_axis_view + _pdropzone - _ddropzone;
-                       assert (dt <= 0);
+               if (delta_time_axis_view < 0 && (int)_ddropzone - delta_time_axis_view >= (int)_pdropzone) {
+                       const int dt = delta_time_axis_view + (int)_pdropzone - (int)_ddropzone;
+                       assert(dt <= 0);
                        delta_skip = apply_track_delta(_time_axis_views.size(), dt, 0, true)
                                -_time_axis_views.size() - dt;
                }
@@ -1161,13 +1162,19 @@ RegionMotionDrag::motion (GdkEvent* event, bool first_move)
                                 * DZ by grabbing the region in the bottom track.
                                 */
                                assert(current_pointer_time_axis_view >= 0);
-                               dtz = std::min((int)_pdropzone, -delta_time_axis_view);
+                               dtz = std::min((int)_pdropzone, (int)_ddropzone - delta_time_axis_view);
                                _pdropzone -= dtz;
                        }
 
                        /* only move out of the zone if the movement is OK */
                        if (_pdropzone == 0 && delta_time_axis_view != 0) {
+                               assert(delta_time_axis_view < 0);
                                _last_pointer_time_axis_view = current_pointer_time_axis_view;
+                               /* if all logic and maths are correct, there is no need to assign the 'current' pointer.
+                                * the current position can be calculated as follows:
+                                */
+                               assert (current_pointer_time_axis_view == _time_axis_views.size() - dtz + _ddropzone + delta_time_axis_view);
+                               // robin crosses his fingers, and looks at busses.
                        }
                } else {
                        /* last motion event was also over a time axis view */