Various fixes for spacer operation with subtitle track

src/bin/model/subtitlemodel.cpp

@@ -1385,6 +1385,13 @@ int SubtitleModel::getBlankEnd(int pos) const
     return found ? min.frames(pCore->getCurrentFps()) : 0;
 }
 
+int SubtitleModel::getBlankSizeAtPos(int frame) const
+{
+    int bkStart = getBlankStart(frame);
+    int bkEnd = getBlankEnd(frame);
+    return bkEnd - bkStart;
+}
+
 int SubtitleModel::getBlankStart(int pos) const
 {
     GenTime matchPos(pos, pCore->getCurrentFps());

src/bin/model/subtitlemodel.hpp

@@ -136,6 +136,8 @@ public:
     int getBlankStart(int pos) const;
     /** @brief Returns the position of the first subtitle after the blank at @position */
     int getBlankEnd(int pos) const;
+    /** @brief Returns the duration of the blank at @position */
+    int getBlankSizeAtPos(int frame) const;
     /** @brief If pos is blank, returns the position of the blank start. Otherwise returns the position of the next blank frame */
     int getNextBlankStart(int pos) const;
     /** @brief Returns true is track is empty at pos */

src/timeline2/model/timelinefunctions.cpp

@@ -454,12 +454,23 @@ std::pair<int, int> TimelineFunctions::requestSpacerStartOperation(const std::sh
                     firstCid = it.value();
                 }
             }
-            if (timeline->getTrackById_const(it.key())->isBlankAt(clipPos - 1)) {
-                if (spaceDuration == -1) {
-                    spaceDuration = timeline->getTrackById_const(it.key())->getBlankSizeAtPos(clipPos - 1);
-                } else {
-                    int blank = timeline->getTrackById_const(it.key())->getBlankSizeAtPos(clipPos - 1);
-                    spaceDuration = qMin(blank, spaceDuration);
+            if (timeline->isSubtitleTrack(it.key())) {
+                if (timeline->getSubtitleModel()->isBlankAt(clipPos - 1)) {
+                    if (spaceDuration == -1) {
+                        spaceDuration = timeline->getSubtitleModel()->getBlankSizeAtPos(clipPos - 1);
+                    } else {
+                        int blank = timeline->getSubtitleModel()->getBlankSizeAtPos(clipPos - 1);
+                        spaceDuration = qMin(blank, spaceDuration);
+                    }
+                }
+            } else {
+                if (timeline->getTrackById_const(it.key())->isBlankAt(clipPos - 1)) {
+                    if (spaceDuration == -1) {
+                        spaceDuration = timeline->getTrackById_const(it.key())->getBlankSizeAtPos(clipPos - 1);
+                    } else {
+                        int blank = timeline->getTrackById_const(it.key())->getBlankSizeAtPos(clipPos - 1);
+                        spaceDuration = qMin(blank, spaceDuration);
+                    }
                 }
             }
             if (relatedMaxSpace.contains(it.key())) {

src/timeline2/model/timelinemodel.cpp

@@ -263,6 +263,10 @@ int TimelineModel::getItemTrackId(int itemId) const
     if (isComposition(itemId)) {
         return getCompositionTrackId(itemId);
     }
+    if (isSubTitle(itemId)) {
+        // TODO: fix when introducing multiple subtitle tracks
+        return -2;
+    }
     return -1;
 }
 
@@ -2114,7 +2118,7 @@ std::unordered_set<int> TimelineModel::getItemsInRange(int trackId, int start, i
     Q_UNUSED(listCompositions)
 
     std::unordered_set<int> allClips;
-    if (isSubtitleTrack(trackId)) {
+    if (isSubtitleTrack(trackId) || trackId == -1) {
         // Subtitles
         if (m_subtitleModel) {
             std::unordered_set<int> subs = m_subtitleModel->getItemsInRange(start, end);