VSE: Improved Snapping

Change snapping behavior to snap strip edges when they are close to snap point.
Default behavior is, that each transformed strip is snapped to any other strip.

Implement snapping controls in sequencer tool settings. These controls include:

 - Snapping on/off
 - Ability to snap to playhead and strip hold offset points
 - Filter snap points by excluding sound or muted strips
 - Control snapping distance

Snapping controls are placed in timeline header similar to 3D viewport

Reviewed By: mano-wii

Differential Revision: https://developer.blender.org/D11646

1 files changed, 5 insertions, 2 deletions

diff --git a/source/blender/editors/transform/transform_snap.h b/source/blender/editors/transform/transform_snap.h
index bf14e564380..e0989418c1c 100644
--- a/source/blender/editors/transform/transform_snap.h
+++ b/source/blender/editors/transform/transform_snap.h
@@ -58,8 +58,6 @@ bool transform_snap_increment_ex(const TransInfo *t, bool use_local_space, float
 bool transform_snap_increment(const TransInfo *t, float *val);
 bool transform_snap_grid(TransInfo *t, float *val);
 
-void snapSequenceBounds(TransInfo *t, const int mval[2]);
-
 bool activeSnap(const TransInfo *t);
 bool activeSnap_with_project(const TransInfo *t);
 
@@ -82,3 +80,8 @@ eRedrawFlag updateSelectedSnapPoint(TransInfo *t);
 void removeSnapPoint(TransInfo *t);
 
 float transform_snap_distance_len_squared_fn(TransInfo *t, const float p1[3], const float p2[3]);
+
+/* transform_snap_sequencer.c */
+struct TransSeqSnapData *transform_snap_sequencer_data_alloc(const TransInfo *t);
+void transform_snap_sequencer_data_free(struct TransSeqSnapData *data);
+bool transform_snap_sequencer_apply(struct TransInfo *t, float *vec, float *snap_point);