put all split widgets inside the same directory

src/widgets/splits/SplitOverlay.hpp

@@ -0,0 +1,52 @@
+#pragma once
+
+#include <QGridLayout>
+#include <QPushButton>
+
+#include "pajlada/signals/signalholder.hpp"
+#include "widgets/BaseWidget.hpp"
+
+namespace chatterino {
+namespace widgets {
+
+class Split;
+
+class SplitOverlay : public BaseWidget, pajlada::Signals::SignalHolder
+{
+public:
+    explicit SplitOverlay(Split *parent = nullptr);
+
+protected:
+    //    bool event(QEvent *event) override;
+    void paintEvent(QPaintEvent *event) override;
+    void resizeEvent(QResizeEvent *event) override;
+    void mouseMoveEvent(QMouseEvent *event) override;
+
+private:
+    // fourtf: !!! preserve the order of left, up, right and down
+    enum HoveredElement { None, SplitMove, SplitLeft, SplitUp, SplitRight, SplitDown };
+    HoveredElement hoveredElement = None;
+    Split *split;
+    QGridLayout *_layout;
+    QPushButton *_left;
+    QPushButton *_up;
+    QPushButton *_right;
+    QPushButton *_down;
+
+    class ButtonEventFilter : public QObject
+    {
+        SplitOverlay *parent;
+        HoveredElement hoveredElement;
+
+    public:
+        ButtonEventFilter(SplitOverlay *parent, HoveredElement hoveredElement);
+
+    protected:
+        bool eventFilter(QObject *watched, QEvent *event) override;
+    };
+
+    friend class ButtonEventFilter;
+};
+
+}  // namespace widgets
+}  // namespace chatterino