nodedge.scene_history

Scene history module containing SceneHistory class.

class nodedge.scene_history.SceneHistory(scene: Scene, maxLength: int = 32)

Bases: object

SceneHistory class

It contains the code for storing all the previous actions of the user in a dictionary.

Parameters

scene (Scene) – reference to the Scene

property currentStep

Property representing the current step on the history stack loaded in the scene.

Returns

current step on the history stack

Return type

int

property stackSize

Number of elements that can be stored in the history stack.

Returns

History stack size

Return type

int

property stack

The stack is a private member of the history, it cannot be modified outside of the class. This property only has a getter to implement this constraint.

Returns

history stack

Return type

List[dict]

addHistoryModifiedListener(callback: Callable) → None

Register the callback associated with a HistoryModified event.

Parameters

callback – callback function

addHistoryStoredListener(callback: Callable) → None

Register the callback associated with a HistoryStored event.

Parameters

callback – callback function

addHistoryRestoredListener(callback: Callable) → None

Register the callback associated with a HistoryRestored event.

Parameters

callback – callback function

clear(storeInitialStamp: bool = True)

Reset the history stack.

Parameters

storeInitialStamp (bool) – if True, an initial stamp will be stored in the history after cleaning. Otherwise, the history will be empty after cleaning, leading to the first actions to be non cancellable.

storeInitialStamp() → None

Helper function usually used when new or open file operations are requested.

property canUndo

This property returns True if the undo operation is available for the current history stack.

Return type

bool

property canRedo

This property returns True if the redo operation is available for the current history stack.

Return type

bool

undo() → None

Perform the undo operation.

redo() → None

Perform the redo operation

store(desc: str, sceneIsModified: bool = True) → None

Store the history stamp into the history stack.

Parameters

  • desc (str) – Description of current history stamp

  • sceneIsModified (bool) – if True marks that Scene has been modified.

Triggers:

  • History Modified

  • History Stored

restore() → None

Restore history stamp from history stack.

Triggers:

  • History Modified event

  • History Restored event

restoreStep(step: int) → None

Restore the step of the stack given as argument.

Parameters

step (int) – index of the stack to be restored