From 4be7b308f5b96bdf272e9ea8a45581f68ac1d6e4 Mon Sep 17 00:00:00 2001
From: Leonardo Zide <leozide@users.noreply.github.com>
Date: Wed, 8 Apr 2026 23:30:07 -0700
Subject: [PATCH] Support drag and drop of categories. Fixes #994.

---
 qt/lc_qpreferencesdialog.cpp | 25 ++++++++++
 qt/lc_qpreferencesdialog.h   |  1 +
 qt/lc_qpreferencesdialog.ui  | 89 +++++++++++++++++++-----------------
 3 files changed, 72 insertions(+), 43 deletions(-)

diff --git a/qt/lc_qpreferencesdialog.cpp b/qt/lc_qpreferencesdialog.cpp
index 61d16fc6..43a578d1 100644
--- a/qt/lc_qpreferencesdialog.cpp
+++ b/qt/lc_qpreferencesdialog.cpp
@@ -64,6 +64,7 @@ lcQPreferencesDialog::lcQPreferencesDialog(QWidget* Parent, lcPreferencesDialogO
 	connect(ui->ControlPointColorButton, &QToolButton::clicked, this, &lcQPreferencesDialog::ColorButtonClicked);
 	connect(ui->ControlPointFocusedColorButton, &QToolButton::clicked, this, &lcQPreferencesDialog::ColorButtonClicked);
 	connect(ui->categoriesTree, &QTreeWidget::itemSelectionChanged, this, &lcQPreferencesDialog::updateParts);
+	connect(ui->categoriesTree->model(), &QAbstractItemModel::rowsInserted, this, &lcQPreferencesDialog::CategoriesDropped);
 	ui->shortcutEdit->installEventFilter(this);
 	connect(ui->commandList, &QTreeWidget::currentItemChanged, this, &lcQPreferencesDialog::commandChanged);
 	connect(ui->mouseTree, &QTreeWidget::currentItemChanged, this, &lcQPreferencesDialog::MouseTreeItemChanged);
@@ -689,6 +690,7 @@ void lcQPreferencesDialog::updateCategories()
 {
 	QTreeWidgetItem* CategoryItem;
 	QTreeWidget* CategoriesTree = ui->categoriesTree;
+	QSignalBlocker Blocker(CategoriesTree->model());
 
 	CategoriesTree->clear();
 
@@ -696,10 +698,12 @@ void lcQPreferencesDialog::updateCategories()
 	{
 		CategoryItem = new QTreeWidgetItem(CategoriesTree, QStringList(mOptions->Categories[CategoryIndex].Name));
 		CategoryItem->setData(0, CategoryRole, QVariant(CategoryIndex));
+		CategoryItem->setFlags(CategoryItem->flags() & ~Qt::ItemFlag::ItemIsDropEnabled);
 	}
 
 	CategoryItem = new QTreeWidgetItem(CategoriesTree, QStringList(tr("Unassigned")));
 	CategoryItem->setData(0, CategoryRole, QVariant(-1));
+	CategoryItem->setFlags(CategoryItem->flags() & ~Qt::ItemFlag::ItemIsDropEnabled);
 }
 
 void lcQPreferencesDialog::updateParts()
@@ -757,6 +761,27 @@ void lcQPreferencesDialog::updateParts()
 	tree->resizeColumnToContents(1);
 }
 
+void lcQPreferencesDialog::CategoriesDropped(const QModelIndex& Parent, int First, int Last)
+{
+	std::vector<lcLibraryCategory> Categories;
+
+	for (int Row = 0; Row < ui->categoriesTree->topLevelItemCount(); Row++)
+	{
+		QTreeWidgetItem* CategoryItem = ui->categoriesTree->topLevelItem(Row);
+		size_t CategoryIndex = CategoryItem->data(0, CategoryRole).toInt();
+
+		if (CategoryIndex >= 0 && CategoryIndex < mOptions->Categories.size())
+		{
+			Categories.emplace_back(mOptions->Categories[CategoryIndex]);
+			CategoryItem->setData(0, CategoryRole, Row);
+		}
+	}
+
+	mOptions->CategoriesModified = true;
+	mOptions->CategoriesDefault = false;
+	mOptions->Categories = std::move(Categories);
+}
+
 void lcQPreferencesDialog::on_newCategory_clicked()
 {
 	lcLibraryCategory category;
diff --git a/qt/lc_qpreferencesdialog.h b/qt/lc_qpreferencesdialog.h
index c7f23ce2..75c42f4c 100644
--- a/qt/lc_qpreferencesdialog.h
+++ b/qt/lc_qpreferencesdialog.h
@@ -81,6 +81,7 @@ public slots:
 	void on_ViewSphereSizeCombo_currentIndexChanged(int Index);
 	void on_PreviewViewSphereSizeCombo_currentIndexChanged(int Index);
 	void updateParts();
+	void CategoriesDropped(const QModelIndex& Parent, int First, int Last);
 	void on_newCategory_clicked();
 	void on_editCategory_clicked();
 	void on_deleteCategory_clicked();
diff --git a/qt/lc_qpreferencesdialog.ui b/qt/lc_qpreferencesdialog.ui
index 9fa2d883..d28579a3 100644
--- a/qt/lc_qpreferencesdialog.ui
+++ b/qt/lc_qpreferencesdialog.ui
@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>621</width>
-    <height>503</height>
+    <width>726</width>
+    <height>638</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -25,7 +25,7 @@
       </attribute>
       <layout class="QFormLayout" name="formLayout">
        <property name="fieldGrowthPolicy">
-        <enum>QFormLayout::ExpandingFieldsGrow</enum>
+        <enum>QFormLayout::FieldGrowthPolicy::ExpandingFieldsGrow</enum>
        </property>
        <item row="1" column="0" colspan="2">
         <widget class="QGroupBox" name="ApplicationGroup">
@@ -84,7 +84,7 @@
           <item row="1" column="2">
            <spacer name="horizontalSpacer_8">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -352,10 +352,10 @@
              </sizepolicy>
             </property>
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="tickPosition">
-             <enum>QSlider::NoTicks</enum>
+             <enum>QSlider::TickPosition::NoTicks</enum>
             </property>
            </widget>
           </item>
@@ -448,7 +448,7 @@
           <item row="0" column="3">
            <spacer name="horizontalSpacer_2">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -524,7 +524,7 @@
           <item row="3" column="3">
            <spacer name="horizontalSpacer_9">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -550,10 +550,10 @@
              </sizepolicy>
             </property>
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="tickPosition">
-             <enum>QSlider::NoTicks</enum>
+             <enum>QSlider::TickPosition::NoTicks</enum>
             </property>
            </widget>
           </item>
@@ -584,7 +584,7 @@
        <item>
         <spacer name="verticalSpacer">
          <property name="orientation">
-          <enum>Qt::Vertical</enum>
+          <enum>Qt::Orientation::Vertical</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
@@ -679,7 +679,7 @@
           <item row="0" column="4">
            <spacer name="horizontalSpacer_7">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -739,7 +739,7 @@
           <item row="1" column="3">
            <spacer name="horizontalSpacer_5">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -861,7 +861,7 @@
           <item row="1" column="4">
            <spacer name="horizontalSpacer_11">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -877,7 +877,7 @@
        <item>
         <spacer name="verticalSpacer_2">
          <property name="orientation">
-          <enum>Qt::Vertical</enum>
+          <enum>Qt::Orientation::Vertical</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
@@ -994,7 +994,7 @@
           <item row="0" column="5">
            <spacer name="horizontalSpacer_16">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -1014,10 +1014,10 @@
           <item row="0" column="2">
            <spacer name="horizontalSpacer_18">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeType">
-             <enum>QSizePolicy::Fixed</enum>
+             <enum>QSizePolicy::Policy::Fixed</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -1053,10 +1053,10 @@
           <item>
            <spacer name="horizontalSpacer_21">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeType">
-             <enum>QSizePolicy::Fixed</enum>
+             <enum>QSizePolicy::Policy::Fixed</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -1083,10 +1083,10 @@
           <item>
            <spacer name="horizontalSpacer_22">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeType">
-             <enum>QSizePolicy::Fixed</enum>
+             <enum>QSizePolicy::Policy::Fixed</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -1113,7 +1113,7 @@
           <item>
            <spacer name="horizontalSpacer_14">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -1129,7 +1129,7 @@
        <item row="6" column="0">
         <spacer name="verticalSpacer_3">
          <property name="orientation">
-          <enum>Qt::Vertical</enum>
+          <enum>Qt::Orientation::Vertical</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
@@ -1162,10 +1162,10 @@
           <item>
            <spacer name="horizontalSpacer_20">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeType">
-             <enum>QSizePolicy::Fixed</enum>
+             <enum>QSizePolicy::Policy::Fixed</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -1192,7 +1192,7 @@
           <item>
            <spacer name="horizontalSpacer_13">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -1230,10 +1230,10 @@
             <item>
              <spacer name="horizontalSpacer_19">
               <property name="orientation">
-               <enum>Qt::Horizontal</enum>
+               <enum>Qt::Orientation::Horizontal</enum>
               </property>
               <property name="sizeType">
-               <enum>QSizePolicy::Fixed</enum>
+               <enum>QSizePolicy::Policy::Fixed</enum>
               </property>
               <property name="sizeHint" stdset="0">
                <size>
@@ -1260,7 +1260,7 @@
             <item>
              <spacer name="horizontalSpacer_10">
               <property name="orientation">
-               <enum>Qt::Horizontal</enum>
+               <enum>Qt::Orientation::Horizontal</enum>
               </property>
               <property name="sizeHint" stdset="0">
                <size>
@@ -1298,7 +1298,7 @@
             <item>
              <spacer name="horizontalSpacer_12">
               <property name="orientation">
-               <enum>Qt::Horizontal</enum>
+               <enum>Qt::Orientation::Horizontal</enum>
               </property>
               <property name="sizeHint" stdset="0">
                <size>
@@ -1336,10 +1336,10 @@
           <item row="0" column="2">
            <spacer name="horizontalSpacer_15">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeType">
-             <enum>QSizePolicy::Fixed</enum>
+             <enum>QSizePolicy::Policy::Fixed</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -1422,7 +1422,7 @@
           <item row="0" column="5">
            <spacer name="horizontalSpacer_17">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -1457,7 +1457,7 @@
              </sizepolicy>
             </property>
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <widget class="QTreeWidget" name="categoriesTree">
              <property name="sizePolicy">
@@ -1466,6 +1466,9 @@
                <verstretch>0</verstretch>
               </sizepolicy>
              </property>
+             <property name="dragDropMode">
+              <enum>QAbstractItemView::DragDropMode::InternalMove</enum>
+             </property>
              <property name="rootIsDecorated">
               <bool>false</bool>
              </property>
@@ -1492,7 +1495,7 @@
               </sizepolicy>
              </property>
              <property name="selectionMode">
-              <enum>QAbstractItemView::NoSelection</enum>
+              <enum>QAbstractItemView::SelectionMode::NoSelection</enum>
              </property>
              <property name="rootIsDecorated">
               <bool>false</bool>
@@ -1551,7 +1554,7 @@
             <item>
              <spacer name="horizontalSpacer_4">
               <property name="orientation">
-               <enum>Qt::Horizontal</enum>
+               <enum>Qt::Orientation::Horizontal</enum>
               </property>
               <property name="sizeHint" stdset="0">
                <size>
@@ -1596,7 +1599,7 @@
           <item>
            <spacer name="horizontalSpacer">
             <property name="orientation">
-             <enum>Qt::Horizontal</enum>
+             <enum>Qt::Orientation::Horizontal</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -1679,7 +1682,7 @@
                 <item>
                  <spacer name="horizontalSpacer_3">
                   <property name="orientation">
-                   <enum>Qt::Horizontal</enum>
+                   <enum>Qt::Orientation::Horizontal</enum>
                   </property>
                   <property name="sizeHint" stdset="0">
                    <size>
@@ -1812,7 +1815,7 @@
                 <item>
                  <spacer name="horizontalSpacer_6">
                   <property name="orientation">
-                   <enum>Qt::Horizontal</enum>
+                   <enum>Qt::Orientation::Horizontal</enum>
                   </property>
                   <property name="sizeHint" stdset="0">
                    <size>
@@ -1938,7 +1941,7 @@
             <number>5</number>
            </property>
            <property name="orientation">
-            <enum>Qt::Horizontal</enum>
+            <enum>Qt::Orientation::Horizontal</enum>
            </property>
           </widget>
          </item>
@@ -1951,10 +1954,10 @@
    <item>
     <widget class="QDialogButtonBox" name="buttonBox">
      <property name="orientation">
-      <enum>Qt::Horizontal</enum>
+      <enum>Qt::Orientation::Horizontal</enum>
      </property>
      <property name="standardButtons">
-      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+      <set>QDialogButtonBox::StandardButton::Cancel|QDialogButtonBox::StandardButton::Ok</set>
      </property>
     </widget>
    </item>