enhance UIntDescriptor

GUI/Model/Types/UIntDescriptor.cpp

@@ -49,6 +49,14 @@ UIntDescriptor::UIntDescriptor(QString label, QString tooltip, const RealLimits&
 {
 }
 
+UIntDescriptor::UIntDescriptor(const QString& label, const uint* var,
+                               const variant<QString, Unit>& unit)
+    : UIntDescriptor(
+        label, "", RealLimits::nonnegative(), [=](uint v) { *const_cast<uint*>(var) = v; },
+        [=] { return *var; }, unit)
+{
+}
+
 UIntDescriptor::operator uint() const
 {
     return get();

GUI/Model/Types/UIntDescriptor.h

@@ -35,6 +35,7 @@ using std::variant;
 //! member, or any other construction to hold a uint value.
 class UIntDescriptor {
 public:
+    UIntDescriptor() = default;
     //! Operates on a session item. The settings (like limits) are taken from the session
     //! item.
     //! Only for easier migration. Should be removed after SessionItem refactoring.
@@ -45,6 +46,8 @@ public:
     //! Only for easier migration. Should be removed after SessionItem refactoring.
     UIntDescriptor(const QString& label, SessionItem* item, const variant<QString, Unit>& unit);
 
+    UIntDescriptor(const QString& label, const uint* var, const variant<QString, Unit>& unit);
+
 private:
     //! Operates on any kind of storage (e.g. session items), by using setter/getter methods
     UIntDescriptor(QString label, QString tooltip, const RealLimits& limits,