VSE: Transform overwrite mode

Add mode to overwrite strips on overlap instead of resolving overlap.

When overlap is created, 3 things can happen:
 - On partial overlap, handles of overlapped strip are moved
 - On complete overlap with smaller strip, overlapped strip is split
 - On complete overlap with larger strip, overlapped strip is removed

This mode can be enabled in header.

Reviewed By: fsiddi, mano-wii

Differential Revision: https://developer.blender.org/D11805

3 files changed, 29 insertions, 3 deletions

diff --git a/source/blender/sequencer/intern/iterator.c b/source/blender/sequencer/intern/iterator.c
index a9cbf4879f1..58f68205f51 100644
--- a/source/blender/sequencer/intern/iterator.c
+++ b/source/blender/sequencer/intern/iterator.c
@@ -341,6 +341,24 @@ SeqCollection *SEQ_query_selected_strips(ListBase *seqbase)
 }
 
 /**
+ * Query all unselected strips in seqbase.
+ *
+ * \param seqbase: ListBase in which strips are queried
+ * \return strip collection
+ */
+SeqCollection *SEQ_query_unselected_strips(ListBase *seqbase)
+{
+  SeqCollection *collection = SEQ_collection_create(__func__);
+  LISTBASE_FOREACH (Sequence *, seq, seqbase) {
+    if ((seq->flag & SELECT) != 0) {
+      continue;
+    }
+    SEQ_collection_append_strip(seq, collection);
+  }
+  return collection;
+}
+
+/**
  * Query all effect strips that are directly or indirectly connected to seq_reference.
  * This includes all effects of seq_reference, strips used by another inputs and their effects, so
  * that whole chain is fully independent of other strips.
diff --git a/source/blender/sequencer/intern/sequencer.c b/source/blender/sequencer/intern/sequencer.c
index 2863af8fb2e..a62b76cd832 100644
--- a/source/blender/sequencer/intern/sequencer.c
+++ b/source/blender/sequencer/intern/sequencer.c
@@ -323,6 +323,8 @@ SequencerToolSettings *SEQ_tool_settings_init(void)
   tool_settings->snap_mode = SEQ_SNAP_TO_STRIPS | SEQ_SNAP_TO_CURRENT_FRAME |
                              SEQ_SNAP_TO_STRIP_HOLD;
   tool_settings->snap_distance = 15;
+  tool_settings->overlap_mode = SEQ_OVERLAP_SHUFFLE;
+
   return tool_settings;
 }
 
@@ -372,6 +374,12 @@ void SEQ_tool_settings_fit_method_set(Scene *scene, eSeqImageFitMethod fit_metho
   tool_settings->fit_method = fit_method;
 }
 
+eSeqOverlapMode SEQ_tool_settings_overlap_mode_get(Scene *scene)
+{
+  const SequencerToolSettings *tool_settings = SEQ_tool_settings_ensure(scene);
+  return tool_settings->overlap_mode;
+}
+
 /**
  * Get seqbase that is being viewed currently. This can be main seqbase or meta strip seqbase
  *
diff --git a/source/blender/sequencer/intern/strip_transform.c b/source/blender/sequencer/intern/strip_transform.c
index 9f69f434ca0..3a5f93a72b0 100644
--- a/source/blender/sequencer/intern/strip_transform.c
+++ b/source/blender/sequencer/intern/strip_transform.c
@@ -208,7 +208,7 @@ bool SEQ_transform_sequence_can_be_translated(Sequence *seq)
   return !(seq->type & SEQ_TYPE_EFFECT) || (SEQ_effect_get_num_inputs(seq->type) == 0);
 }
 
-static bool seq_overlap(Sequence *seq1, Sequence *seq2)
+bool SEQ_transform_test_overlap_seq_seq(Sequence *seq1, Sequence *seq2)
 {
   return (seq1 != seq2 && seq1->machine == seq2->machine &&
           ((seq1->enddisp <= seq2->startdisp) || (seq1->startdisp >= seq2->enddisp)) == 0);
@@ -220,7 +220,7 @@ bool SEQ_transform_test_overlap(ListBase *seqbasep, Sequence *test)
 
   seq = seqbasep->first;
   while (seq) {
-    if (seq_overlap(test, seq)) {
+    if (SEQ_transform_test_overlap_seq_seq(test, seq)) {
       return true;
     }
 
@@ -316,7 +316,7 @@ static int shuffle_seq_time_offset_test(SeqCollection *strips_to_shuffle,
 
   SEQ_ITERATOR_FOREACH (seq, strips_to_shuffle) {
     LISTBASE_FOREACH (Sequence *, seq_other, seqbasep) {
-      if (!seq_overlap(seq, seq_other)) {
+      if (!SEQ_transform_test_overlap_seq_seq(seq, seq_other)) {
         continue;
       }
       if (UNLIKELY(SEQ_collection_has_strip(seq_other, strips_to_shuffle))) {