base pointer movement in timeline

app/node/output/timeline/timeline.cpp

@@ -63,6 +63,7 @@ void TimelineOutput::AttachTimeline(TimelinePanel *timeline)
 
     //disconnect(view, SIGNAL(RequestInsertBlockAtIndex(Block*, int)), this, SLOT(InsertBlockAtIndex(Block*, int)));
     disconnect(view, SIGNAL(RequestPlaceBlock(Block*, rational, int)), this, SLOT(PlaceBlock(Block*, rational, int)));
+    disconnect(view, SIGNAL(RequestReplaceBlock(Block*, Block*, int)), this, SLOT(ReplaceBlock(Block*, Block*, int)));
 
     // Remove existing UI objects from TimelinePanel
     attached_timeline_->Clear();
@@ -84,6 +85,7 @@ void TimelineOutput::AttachTimeline(TimelinePanel *timeline)
 
     //connect(view, SIGNAL(RequestInsertBlockAtIndex(Block*, int)), this, SLOT(InsertBlockAtIndex(Block*, int)));
     connect(view, SIGNAL(RequestPlaceBlock(Block*, rational, int)), this, SLOT(PlaceBlock(Block*, rational, int)));
+    connect(view, SIGNAL(RequestReplaceBlock(Block*, Block*, int)), this, SLOT(ReplaceBlock(Block*, Block*, int)));
   }
 }
 
@@ -240,9 +242,16 @@ void TimelineOutput::TrackEdgeRemoved(NodeEdgePtr edge)
 
 void TimelineOutput::PlaceBlock(Block *block, rational start, int track)
 {
+  Q_ASSERT(track >= 0);
+
   while (track >= track_cache_.size()) {
     AddTrack();
   }
 
   track_cache_.at(track)->PlaceBlock(block, start);
 }
+
+void TimelineOutput::ReplaceBlock(Block *old, Block *replace, int track)
+{
+  track_cache_.at(track)->ReplaceBlock(old, replace);
+}

app/node/output/timeline/timeline.h

@@ -101,9 +101,17 @@ private slots:
 
   /**
    * @brief Forwards a PlaceBlock signal to the requested track
+   *
+   * If the track index doesn't exist, tracks are automatically created until a track at that index does exist
+   * (provided the track index is positive). A negative track index fails immediately.
    */
   void PlaceBlock(Block* block, rational start, int track);
 
+  /**
+   * @brief Forwards a ReplaceBlock signal to the appropriate track
+   */
+  void ReplaceBlock(Block* old, Block* replace, int track);
+
 };
 
 #endif // TIMELINEOUTPUT_H

app/node/output/track/track.cpp

@@ -245,12 +245,12 @@ void TrackOutput::AddBlockToGraph(Block *block)
 
 void TrackOutput::PlaceBlock(Block *block, rational start)
 {
-  AddBlockToGraph(block);
-
-  if (block->in() == start) {
+  if (block_cache_.contains(block) && block->in() == start) {
     return;
   }
 
+  AddBlockToGraph(block);
+
   // Check if the placement location is past the end of the timeline
   if (start >= in()) {
     if (start > in()) {
@@ -408,3 +408,22 @@ void TrackOutput::RippleRemoveArea(rational in, rational out, Block *insert)
     }
   }
 }
+
+void TrackOutput::ReplaceBlock(Block *old, Block *replace)
+{
+  Block* previous = old->previous();
+  Block* next = old->next();
+
+  AddBlockToGraph(replace);
+
+  // Disconnect old block from its surroundings
+  if (previous != nullptr) {
+    Block::DisconnectBlocks(previous, old);
+    Block::ConnectBlocks(previous, replace);
+  }
+
+  if (next != nullptr) {
+    Block::DisconnectBlocks(old, next);
+    Block::ConnectBlocks(replace, next);
+  }
+}

app/node/output/track/track.h

@@ -125,6 +125,13 @@ public:
    */
   void RippleRemoveArea(rational in, rational out, Block* insert = nullptr);
 
+  /**
+   * @brief Replaces Block `old` with Block `replace`
+   *
+   * Makes no modification to the lengths of either Blocks
+   */
+  void ReplaceBlock(Block* old, Block* replace);
+
 signals:
   /**
    * @brief Signal emitted when a Block is added to this Track