chore: use DrawnButton instead of NotebookButton (#6371)

src/widgets/Notebook.cpp

@@ -10,8 +10,8 @@
 #include "singletons/StreamerMode.hpp"
 #include "singletons/Theme.hpp"
 #include "singletons/WindowManager.hpp"
+#include "widgets/buttons/DrawnButton.hpp"
 #include "widgets/buttons/InitUpdateButton.hpp"
-#include "widgets/buttons/NotebookButton.hpp"
 #include "widgets/buttons/PixmapButton.hpp"
 #include "widgets/buttons/SvgButton.hpp"
 #include "widgets/dialogs/SettingsDialog.hpp"
@@ -38,9 +38,35 @@ namespace chatterino {
 
 Notebook::Notebook(QWidget *parent)
     : BaseWidget(parent)
-    , addButton_(new NotebookButton(NotebookButton::Type::Plus, this))
+    , addButton_(new DrawnButton(DrawnButton::Symbol::Plus,
+                                 {
+                                     .padding = 6,
+                                     .thickness = 1,
+                                 },
+                                 this))
 {
     this->addButton_->setHidden(true);
+    this->addButton_->enableDrops({"chatterino/split"});
+
+    QObject::connect(
+        this->addButton_, &Button::dropEvent, this, [this](QDropEvent *event) {
+            auto *draggedSplit = dynamic_cast<Split *>(event->source());
+            if (!draggedSplit)
+            {
+                qCDebug(chatterinoWidget) << "Dropped something that wasn't a "
+                                             "split onto a notebook button";
+                return;
+            }
+
+            event->acceptProposedAction();
+
+            auto *page = new SplitContainer(this);
+            auto *tab = this->addPage(page);
+            page->setTab(tab);
+
+            draggedSplit->setParent(page);
+            page->insertSplit(draggedSplit);
+        });
 
     this->lockNotebookLayoutAction_ = new QAction("Lock Tab Layout", this);
 
@@ -673,6 +699,8 @@ void Notebook::setShowAddButton(bool value)
     this->showAddButton_ = value;
 
     this->addButton_->setHidden(!value);
+
+    this->refresh();
 }
 
 void Notebook::resizeAddButton()
@@ -1157,11 +1185,6 @@ void Notebook::addNotebookActionsToMenu(QMenu *menu)
     menu->addAction(this->toggleTopMostAction_);
 }
 
-NotebookButton *Notebook::getAddButton()
-{
-    return this->addButton_;
-}
-
 NotebookTab *Notebook::getTabFromPage(QWidget *page)
 {
     for (auto &it : this->items_)
@@ -1222,7 +1245,7 @@ bool Notebook::shouldShowTab(const NotebookTab *tab) const
 SplitNotebook::SplitNotebook(Window *parent)
     : Notebook(parent)
 {
-    this->connect(this->getAddButton(), &NotebookButton::leftClicked, [this]() {
+    QObject::connect(this->addButton_, &Button::leftClicked, [this]() {
         QTimer::singleShot(80, this, [this] {
             this->addPage(true);
         });