Description

template<typename T>
class SelectionDescriptor< T >

Describes a selection (various possibilities and the current one).

Usually a selection is presented as a combo box. Right now with SessionModel still in place, in many cases a selection changes the current item of a group item, i.e. it changes the class of a certain child item (e.g. XRotationItem*‍/YRotationItem*‍/...). Also a SessionItem holding only a ComboProperty (but not switching children like GroupItem) can be wrapped. For example IntensityDataItem::gradient() is simply a list of QStrings.

With the migration, more and more SelectionDescriptor operate on a SelectionProperty. Please refer to this class for more information.

The template parameter defines the type of the current item. This can be a pointer to a common base class (like RotationItem*), but it also can be a std::variant<...>, which is useful if no dedicated common base class exists (like for the roughness items LayerZeroRoughnessItem and LayerBasicRoughnessItem). If not used with a GroupItem, but with a "normal" ComboProperty holder, the template parameter can be a QString, so currentItem() returns the currently selected string.

Note that this class does not provide (implement) a selection, but provide information about a selection. For implementing a selection, please see SelectionProperty.

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 GroupItem, a simple pointer member, a std::variant or any other construction to define a selection.

For easy UI creation, there are functions like GUI:Util::createSelectionCombo() which take a descriptor and fully initialize the created combo box.

See also: SelectionProperty

Definition at line 70 of file SelectionDescriptor.h.

Inheritance diagram for SelectionDescriptor< T >:

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Collaboration diagram for SelectionDescriptor< T >:

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Public Member Functions
	SelectionDescriptor ()=default

	SelectionDescriptor (SessionItem *item)
	Initialize the members by means of a SessionItem containing a ComboProperty. This can be a GroupItem or any other property. More...

int	currentIndex () const override
	Get currently selected option. More...

	operator T () const

void	setCurrentIndex (int newIndex) const override
	Set currently selected option. More...

Public Attributes
function< int()>	currentIndexGetter
	Function to get currently selected option. More...

function< void(int)>	currentIndexSetter
	Function to set currently selected option. More...

function< T()>	currentItem
	Function to get currently selected item. More...

QString	label
	A label text (short, no trailing colon) More...

QStringList	options
	List of options, usually presented as combo entries. More...

QString	tooltip
	Tooltip text. More...

Constructor & Destructor Documentation

◆ SelectionDescriptor() [1/2]

template<typename T >

SelectionDescriptor< T >::SelectionDescriptor ( )

default

◆ SelectionDescriptor() [2/2]

template<typename T >

SelectionDescriptor< T >::SelectionDescriptor ( SessionItem * item )

inlineexplicit

Initialize the members by means of a SessionItem containing a ComboProperty. This can be a GroupItem or any other property.

currentItem can only be initialized if the template parameter is a pointer (like RotationItem*). If it is e.g. a std::variant<>, the currentItem has to be initialized by the caller. Only for easier migration. Should be removed after SessionItem refactoring.

Definition at line 80 of file SelectionDescriptor.h.

     {
         label = item->displayName();
         tooltip = item->toolTip();
         options = item->value().value<ComboProperty>().getValues();
         currentIndexSetter = [=](int index) {
             auto comboProperty = item->value().value<ComboProperty>();
  
             if (comboProperty.currentIndex() != index) {
                 comboProperty.setCurrentIndex(index);
                 item->setValue(QVariant::fromValue<ComboProperty>(comboProperty));
             }
         };
         currentIndexGetter = [=] { return item->value().value<ComboProperty>().currentIndex(); };
  
         if constexpr (std::is_pointer<T>::value) {
             if (auto* groupItem = dynamic_cast<GroupItem*>(item))
                 currentItem = [=] { return dynamic_cast<T>(groupItem->currentItem()); };
         } else if constexpr (std::is_same<T, QString>::value)
             currentItem = [=] { return item->value().value<ComboProperty>().getValue(); };
     }