Vertical tabs (#1815)

* Vertical tabs

* Vertical tab wrapping

* Fix formatting

* Cleanup code

* Updated changelog

* Hide button row if no buttons exist

* Fix tab width expansion

Co-authored-by: fourtf <tf.four@gmail.com>

src/widgets/Notebook.hpp

@@ -16,6 +16,8 @@ class NotebookButton;
 class NotebookTab;
 class SplitContainer;
 
+enum NotebookTabDirection { Horizontal = 0, Vertical = 1 };
+
 class Notebook : public BaseWidget
 {
     Q_OBJECT
@@ -52,6 +54,8 @@ public:
 
     void performLayout(bool animate = false);
 
+    void setTabDirection(NotebookTabDirection direction);
+
 protected:
     virtual void scaleChangedEvent(float scale_) override;
     virtual void resizeEvent(QResizeEvent *) override;
@@ -81,7 +85,8 @@ private:
 
     bool allowUserTabManagement_ = false;
     bool showAddButton_ = false;
-    int lineY_ = 20;
+    int lineOffset_ = 20;
+    NotebookTabDirection tabDirection_ = NotebookTabDirection::Horizontal;
 };
 
 class SplitNotebook : public Notebook, pajlada::Signals::SignalHolder