Merge branch 'docu' into 'main'

add documentation

See merge request !713

Doc/Doxygen/gui/mainpage.md

@@ -26,3 +26,47 @@ See file [AUTHORS](https://github.com/scgmlz/BornAgain/blob/master/AUTHORS).
 ### Citation
 
 See file [CITATION](https://github.com/scgmlz/BornAgain/blob/master/CITATION).
+
+
+### Classes for representing the UI data
+
+For representing the UI data there are classes which provide
+* storing the value
+* serializing the value
+* accessing the value
+* additional properties like label, tooltip, unit, limits
+* creating a UI element for this value
+
+The most important classes regarding data representation are
+
+Class                     | Description
+--------------------------|------------
+@ref DoubleProperty       | @copybrief DoubleProperty
+@ref UIntProperty         | @copybrief UIntProperty
+@ref VectorProperty       | @copybrief VectorProperty
+@ref SelectionProperty    | @copybrief SelectionProperty
+@ref AxisProperty         | @copybrief AxisProperty
+
+as well as their direct associates
+
+Class                     | Description
+--------------------------|------------
+@ref DoubleDescriptor     | @copybrief DoubleDescriptor
+@ref UIntDescriptor       | @copybrief UIntDescriptor
+@ref VectorDescriptor     | @copybrief VectorDescriptor
+@ref SelectionDescriptor  | @copybrief SelectionDescriptor
+
+
+### Migration to eliminate SessionModel/SessionItem
+
+The descriptions in the following issues contain detailed explanations and best-practices how to eliminate SessionModel and SessionItem dependency:
+
+[Refactor signaling of value changes (less generic, more explicit)](https://jugit.fz-juelich.de/mlz/bornagain/-/issues/88)
+
+[Refactor dynamic hierarchy in SessionItems (less generic, more explicit)](https://jugit.fz-juelich.de/mlz/bornagain/-/issues/89)
+
+[Refactor serialization of SessionItem (less generic, more explicit)](https://jugit.fz-juelich.de/mlz/bornagain/-/issues/90)
+
+Also mentioned should be the explanations in [merge request 695](https://jugit.fz-juelich.de/mlz/bornagain/-/merge_requests/695). In 
+this merge request the UI-code was greatly simplified by using descriptors and related functions like GUI::Util::createSpinBox().
+

GUI/Model/Descriptor/DoubleDescriptor.h

@@ -44,7 +44,7 @@ using std::variant;
 //! and fully initialize the created spin box.
 //!
 //! \sa DoubleProperty
-//! \sa GUI:Util::createSpinBox
+//! \sa GUI:Util::createSpinBox()
 //!
 class DoubleDescriptor {
 private: // private as long as path initialization is not included in params (to be done after

GUI/Model/Descriptor/UIntProperty.h

@@ -28,12 +28,14 @@ class SessionItem;
 using std::function;
 using std::variant;
 
-//! Class for representing a double value, its attributes and its accessors.
+//! Class for representing a uint value, its attributes and its accessors.
 //!
 //! For a complete description please refer to the documentation of DoubleProperty. Everything said
 //! there also applies to this class, of course not for double values but for uint values.
 //!
 //! \sa DoubleProperty
+//! \sa UIntDescriptor
+//!
 class UIntProperty {
 public:
     void init(const QString& label, const QString& tooltip, uint value,

GUI/Model/Descriptor/VectorDescriptor.h

@@ -24,6 +24,10 @@
 //! By using this class, the underlying data scheme is hidden from the user of the data. This e.g.
 //! eases SessionItem migration. The underlying implementation can be a R3 vector, a member array
 //! of three doubles, three double members, or any other construction to hold the three values.
+//!
+//! \a VectorProperty
+//! \a DoubleDescriptor
+//!
 class VectorDescriptor {
 public:
     VectorDescriptor() = default;

GUI/Model/Descriptor/VectorProperty.h

@@ -24,7 +24,12 @@ class Streamer;
 //!
 //! Use this as a member in your class to hold a 3D vector if you want to have support for
 //! serialization, and if this vector is editable on the UI.
-
+//!
+//! For a more complete documentation about property classes, please refer to DoubleProperty.
+//!
+//! \sa VectorDescriptor
+//! \sa DoubleProperty
+//!
 class VectorProperty {
 public:
     void init(const QString& label, const QString& tooltip, const variant<QString, Unit>& unit,