--User changes

-Add backward compatibility option for the following variations: cos, cosh, cot, coth, csc, csch, sec, sech, sin, sinh, tan, tanh.
 -Add the ability to re-order variations by dragging them in the Info tab.

Source/Fractorium/LibraryTreeWidget.cpp

@@ -93,4 +93,112 @@ void LibraryTreeWidget::dropEvent(QDropEvent* de)
 
 		m_Fractorium->m_Controller->MoveLibraryItems(items, row);
 	}
-}
+}
+
+/// <summary>
+/// Set a pointer to the main window.
+/// </summary>
+/// <param name="f">Pointer to the main Fractorium object</param>
+void InfoTreeWidget::SetMainWindow(Fractorium* f)
+{
+	m_Fractorium = f;
+}
+
+/// <summary>
+/// Called on each mouse movement while dragging, validate whether the area
+/// being dragged over can be dropped on.
+/// Can only drop on like (pre/reg/post) variation section of the same xform
+/// of the variation being dragged.
+/// </summary>
+/// <param name="dme">Pointer to the drag move event</param>
+void InfoTreeWidget::dragMoveEvent(QDragMoveEvent* dme)
+{
+	QModelIndex index = indexAt(dme->pos());
+
+	if (!index.isValid())//Don't process drop because it's outside of the droppable area.
+	{
+		dme->ignore();
+		return;
+	}
+
+	QList<QTreeWidgetItem*> dragItems = selectedItems();
+
+	if (dragItems.size())
+	{
+		auto drag0 = dragItems[0];
+
+		if (auto itemat = itemFromIndex(index))
+		{
+			auto dragpre = drag0->text(0).startsWith("pre_", Qt::CaseInsensitive);
+			auto droppre = itemat->text(0).startsWith("pre_", Qt::CaseInsensitive);
+			auto dragpost = drag0->text(0).startsWith("post_", Qt::CaseInsensitive);
+			auto droppost = itemat->text(0).startsWith("post_", Qt::CaseInsensitive);
+
+			if (auto par = itemat->parent())
+			{
+				if (drag0->parent() == par &&
+						(par->text(0).startsWith("xform ", Qt::CaseInsensitive) ||
+						 par->text(0).startsWith("final", Qt::CaseInsensitive)))
+				{
+					if (auto vitemat = dynamic_cast<VariationTreeWidgetItem*>(itemat))
+					{
+						bool dopre = dragpre && droppre;
+						bool dopost = dragpost && droppost;
+						bool doreg = !dragpre && !droppre && !dragpost && !droppost;
+
+						if (dopre || doreg || doreg)
+						{
+							QTreeWidget::dragMoveEvent(dme);
+							return;
+						}
+					}
+				}
+			}
+		}
+	}
+
+	dme->ignore();
+}
+
+/// <summary>
+/// Process the drop event to allow for moving items around inside of the tree.
+/// This will only allow variations to be moved around within the variation section of the tree
+/// and nowhere else.
+/// </summary>
+/// <param name="de">Pointer to the QDropEvent object</param>
+void InfoTreeWidget::dropEvent(QDropEvent* de)
+{
+	QModelIndex droppedIndex = indexAt(de->pos());
+	auto items = selectionModel()->selectedRows();
+
+	if (!droppedIndex.isValid())//Don't process drop because it's outside of the droppable area.
+	{
+		de->ignore();
+		return;
+	}
+	else if (!items.empty())//Actually do the drop and move the item to a new location.
+	{
+		QList<QTreeWidgetItem*> dragItems = selectedItems();
+
+		if (dragItems.size())
+		{
+			auto drag0 = dragItems[0];
+			auto itemat = itemFromIndex(droppedIndex);
+
+			if (auto par = itemat->parent())
+			{
+				if (auto vdropitem = dynamic_cast<VariationTreeWidgetItem*>(itemat))
+				{
+					if (auto vdragitem = dynamic_cast<VariationTreeWidgetItem*>(drag0))
+					{
+						QTreeWidget::dropEvent(de);//This internally changes the order of the items.
+						m_Fractorium->ReorderVariations(par);
+						return;
+					}
+				}
+			}
+		}
+
+		de->ignore();
+	}
+}