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, 1 insertions, 0 deletions

diff --git a/source/blender/sequencer/SEQ_iterator.h b/source/blender/sequencer/SEQ_iterator.h
index c7c2dc275ee..39d8a7241fb 100644
--- a/source/blender/sequencer/SEQ_iterator.h
+++ b/source/blender/sequencer/SEQ_iterator.h
@@ -71,6 +71,7 @@ bool SEQ_iterator_ensure(SeqCollection *collection,
 struct Sequence *SEQ_iterator_yield(SeqIterator *iterator);
 
 SeqCollection *SEQ_collection_create(void);
+uint SEQ_collection_count(SeqCollection *collection);
 bool SEQ_collection_append_strip(struct Sequence *seq, SeqCollection *data);
 bool SEQ_collection_remove_strip(struct Sequence *seq, SeqCollection *data);
 void SEQ_collection_free(SeqCollection *collection);