FIx possible crash on subtitle resize, and allow cutting unselected subtitle.

Related to #936

src/bin/model/subtitlemodel.cpp

@@ -485,19 +485,26 @@ std::unordered_set<int> SubtitleModel::getItemsInRange(int startFrame, int endFr
             continue;
         }
         if (subtitles.first >= startTime || subtitles.second.second >= startTime) {
-            matching.emplace(getIdForStartPos(subtitles.first));
+            int sid = getIdForStartPos(subtitles.first);
+            if (sid > -1) {
+                matching.emplace(sid);
+            } else {
+                qDebug()<<"==== FOUND INVALID SUBTILE AT: "<<subtitles.first.frames(pCore->getCurrentFps());
+            }
         }
     }
     return matching;
 }
 
-void SubtitleModel::cutSubtitle(int position)
+bool SubtitleModel::cutSubtitle(int position)
 {
     Fun redo = []() { return true; };
     Fun undo = []() { return true; };
     if (cutSubtitle(position, undo, redo)) {
         pCore->pushUndo(undo, redo, i18n("Cut clip"));
+        return true;
     }
+    return false;
 }
 
 

src/bin/model/subtitlemodel.hpp

@@ -122,7 +122,7 @@ public:
     void setSelected(int id, bool select);
     bool isSelected(int id) const;
     /** @brief Cut a subtitle */
-    void cutSubtitle(int position);
+    bool cutSubtitle(int position);
     bool cutSubtitle(int position, Fun &undo, Fun &redo);
     QString getText(int id) const;
     int getRowForId(int id) const;

src/timeline2/view/timelinecontroller.cpp

@@ -1519,6 +1519,10 @@ void TimelineController::cutClipUnderCursor(int position, int track)
             if (cid >= 0 && TimelineFunctions::requestClipCut(m_model, cid, position)) {
                 foundClip = true;
             }
+        } else if (track == -2) {
+            // Subtitle cut
+            auto subtitleModel = pCore->getSubtitleModel();
+            foundClip = subtitleModel->cutSubtitle(position);
         }
     }
     if (!foundClip) {