AbstractAspect

A description for AbstractAspect.

class AbstractAspect : public QObject

Base class of all persistent objects in a Project.

Before going into the details, it’s useful to understand the ideas behind the Aspect Framework.

Aspects organize themselves into trees, where a parent takes ownership of its children. Usually, though not necessarily, a Project instance will sit at the root of the tree (without a Project ancestor, project() will return 0 and undo does not work). Children are organized using addChild(), removeChild(), child(), indexOfChild() and childCount() on the parent’s side as well as the equivalent convenience methods index() and remove() on the child’s side. In contrast to the similar feature of QObject, Aspect trees are fully undo/redo aware and provide signals around object adding/removal.

AbstractAspect manages for every Aspect the properties name, comment, captionSpec and creationTime. All of these translate into the caption() as described in the documentation of setCaptionSpec().

If an undoStack() can be found (usually it is managed by Project), changes to the properties as well as adding/removing children support multi-level undo/redo. In order to support undo/redo for problem-specific data in derived classes, make sure that all changes to your data are done by handing appropriate commands to exec().

Subclassed by AbstractColumn, AbstractFilter, AbstractPart, Background, DatapickerCurve, DatapickerPoint, ErrorBar, Folder, Line, Symbol, Value, WorksheetElement

void setSelected(bool): this function is called when the selection in ProjectExplorer was changed. forwards the selection/deselection to the parent aspect via emitting a signal.

void setUndoAware(bool value): enables the undo awareness of the aspect (modifications are put onto the undo stack) if value is set to true, disables it otherwise. Note, this function doesn’t modify the behavior of aspects’s children, the behavior of the children needs to be handled separately, if needed.

bool isUndoAware() const: returns true if the aspect is undo aware (modifications are put onto the undo stack), returns false otherwise.

virtual QUndoStack *undoStack() const

Return the undo stack of the Project, or 0 if this Aspect is not part of a Project.

It’s also possible to construct undo-enabled Aspect trees without Project. The only requirement is that the root Aspect reimplements undoStack() to get the undo stack from somewhere (the default implementation just delegates to parentAspect()).

void exec(QUndoCommand*): Execute the given command, pushing it on the undoStack() if available.

void exec(QUndoCommand *command, const char *preChangeSignal, const char *postChangeSignal, QGenericArgument val0 = QGenericArgument(), QGenericArgument val1 = QGenericArgument(), QGenericArgument val2 = QGenericArgument(), QGenericArgument val3 = QGenericArgument())

Execute command and arrange for signals to be sent before/after it is redone or undone.

command The command to be executed.
preChangeSignal The name of the signal to be triggered before re-/undoing the command.
postChangeSignal The name of the signal to be triggered after re-/undoing the command.
val0,val1,val2,val3 Arguments to the signals; to be given using Q_ARG().

Signal arguments are given using the macro Q_ARG(typename, const value&). Since the variable given as “value” will likely be out of scope when the signals are emitted, a copy needs to be created. This uses QMetaType, which means that (non-trivial) argument types need to be registered using qRegisterMetaType() before giving them to exec() (in particular, this also goes for pointers to custom data types).