Class: QgsLayoutUndoStack

class qgis.core.QgsLayoutUndoStack

Bases: PyQt5.QtCore.QObject

An undo stack for QgsLayouts.

New in version 3.0.

QgsLayoutUndoStack(layout: QgsLayout) Constructor for QgsLayoutUndoStack, for the specified parent layout.

Methods

beginCommand

Begins a new undo command for the specified object.

beginMacro

Starts a macro command, with the given descriptive commandText.

blockCommands

Sets whether undo commands for the layout should be temporarily blocked.

cancelCommand

Cancels the active command, discarding it without pushing to the undo history.

childEvent

connectNotify

customEvent

disconnectNotify

endCommand

Saves final state of an object and pushes the active command to the undo history.

endMacro

Ends a macro command.

isBlocked

Returns True if undo commands are currently blocked.

isSignalConnected

notifyUndoRedoOccurred

Notifies the stack that an undo or redo action occurred for a specified item.

push

Manually pushes a command to the stack, and takes ownership of the command.

receivers

sender

senderSignalIndex

stack

Returns a pointer to the internal QUndoStack.

timerEvent

Signals

undoRedoOccurredForItems

Emitted when an undo or redo action has occurred, which affected a set of layout itemUuids.

beginCommand(self, object: QgsLayoutUndoObjectInterface, commandText: str, id: int = 0)

Begins a new undo command for the specified object.

This must be followed by a call to endCommand() or cancelCommand() after the desired changes have been made to object.

The id argument can be used to specify an id number for the source event - this is used to determine whether QUndoCommand command compression can apply to the command.

See also

endCommand()

See also

cancelCommand()

Parameters
beginMacro(self, commandText: str)

Starts a macro command, with the given descriptive commandText.

Any commands added to the stack (either via direct manipulation of stack() or via beginCommand()/endCommand() calls) between a beginMacro() and endMacro() block are collapsed into a single undo command, which will be applied or rolled back in a single step.

See also

endMacro()

Parameters

commandText (str) –

blockCommands(self, blocked: bool)

Sets whether undo commands for the layout should be temporarily blocked.

If blocked is True, subsequent undo commands will be blocked until a follow-up call to blockCommands( False ) is made.

Note that calls to blockCommands are stacked, so two calls blocking the commands will take two calls unblocking commands in order to release the block.

See also

isBlocked()

Parameters

blocked (bool) –

cancelCommand(self)

Cancels the active command, discarding it without pushing to the undo history.

See also

endCommand()

See also

cancelCommand()

childEvent(self, QChildEvent)
connectNotify(self, QMetaMethod)
customEvent(self, QEvent)
disconnectNotify(self, QMetaMethod)
endCommand(self)

Saves final state of an object and pushes the active command to the undo history.

See also

beginCommand()

See also

cancelCommand()

endMacro(self)

Ends a macro command. This must be called after beginMacro(), when all child undo commands which form part of the macro have been completed.

Any commands added to the stack (either via direct manipulation of stack() or via beginCommand()/endCommand() calls) between a beginMacro() and endMacro() block are collapsed into a single undo command, which will be applied or rolled back in a single step.

See also

beginMacro()

isBlocked(self)bool

Returns True if undo commands are currently blocked.

See also

blockCommands()

Return type

bool

isSignalConnected(self, QMetaMethod)bool
notifyUndoRedoOccurred(self, item: QgsLayoutItem)

Notifies the stack that an undo or redo action occurred for a specified item.

Parameters

item (QgsLayoutItem) –

push(self, command: QUndoCommand)

Manually pushes a command to the stack, and takes ownership of the command.

Parameters

command (QUndoCommand) –

receivers(self, PYQT_SIGNAL)int
sender(self)QObject
senderSignalIndex(self)int
stack(self)QUndoStack

Returns a pointer to the internal QUndoStack.

Return type

QUndoStack

timerEvent(self, QTimerEvent)
undoRedoOccurredForItems

Emitted when an undo or redo action has occurred, which affected a set of layout itemUuids. [signal]

Parameters

itemUuids (Iterable[str]) –