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juce::UndoManager Class Reference

#include <juce_UndoManager.h>

Inheritance diagram for juce::UndoManager:
juce::ChangeBroadcaster

Public Member Functions

 UndoManager (int maxNumberOfUnitsToKeep=30000, int minimumTransactionsToKeep=30)
 
 ~UndoManager () override
 
void clearUndoHistory ()
 
int getNumberOfUnitsTakenUpByStoredCommands () const
 
void setMaxNumberOfStoredUnits (int maxNumberOfUnitsToKeep, int minimumTransactionsToKeep)
 
bool perform (UndoableAction *action)
 
bool perform (UndoableAction *action, const String &actionName)
 
void beginNewTransaction ()
 
void beginNewTransaction (const String &actionName)
 
void setCurrentTransactionName (const String &newName)
 
String getCurrentTransactionName () const
 
bool canUndo () const
 
bool undo ()
 
bool undoCurrentTransactionOnly ()
 
String getUndoDescription () const
 
StringArray getUndoDescriptions () const
 
Time getTimeOfUndoTransaction () const
 
void getActionsInCurrentTransaction (Array< const UndoableAction * > &actionsFound) const
 
int getNumActionsInCurrentTransaction () const
 
bool canRedo () const
 
bool redo ()
 
String getRedoDescription () const
 
StringArray getRedoDescriptions () const
 
Time getTimeOfRedoTransaction () const
 
bool isPerformingUndoRedo () const
 
- Public Member Functions inherited from juce::ChangeBroadcaster
 ChangeBroadcaster () noexcept
 
virtual ~ChangeBroadcaster ()
 
void addChangeListener (ChangeListener *listener)
 
void removeChangeListener (ChangeListener *listener)
 
void removeAllChangeListeners ()
 
void sendChangeMessage ()
 
void sendSynchronousChangeMessage ()
 
void dispatchPendingMessages ()
 

Detailed Description

Manages a list of undo/redo commands.

An UndoManager object keeps a list of past actions and can use these actions to move backwards and forwards through an undo history.

To use it, create subclasses of UndoableAction which perform all the actions you need, then when you need to actually perform an action, create one and pass it to the UndoManager's perform() method.

The manager also uses the concept of 'transactions' to group the actions together - all actions performed between calls to beginNewTransaction() are grouped together and are all undone/redone as a group.

The UndoManager is a ChangeBroadcaster, so listeners can register to be told when actions are performed or undone.

See also
UndoableAction

Definition at line 52 of file juce_UndoManager.h.

Constructor & Destructor Documentation

◆ UndoManager()

juce::UndoManager::UndoManager ( int  maxNumberOfUnitsToKeep = 30000,
int  minimumTransactionsToKeep = 30 
)

Creates an UndoManager.

Parameters
maxNumberOfUnitsToKeepeach UndoableAction object returns a value to indicate how much storage it takes up (UndoableAction::getSizeInUnits()), so this lets you specify the maximum total number of units that the undomanager is allowed to keep in memory before letting the older actions drop off the end of the list.
minimumTransactionsToKeepthis specifies the minimum number of transactions that will be kept, even if this involves exceeding the amount of space specified in maxNumberOfUnitsToKeep

Definition at line 69 of file juce_UndoManager.cpp.

◆ ~UndoManager()

juce::UndoManager::~UndoManager ( )
override

Destructor.

Definition at line 74 of file juce_UndoManager.cpp.

Member Function Documentation

◆ beginNewTransaction() [1/2]

void juce::UndoManager::beginNewTransaction ( )

Starts a new group of actions that together will be treated as a single transaction.

All actions that are passed to the perform() method between calls to this method are grouped together and undone/redone together by a single call to undo() or redo().

Definition at line 210 of file juce_UndoManager.cpp.

Referenced by beginNewTransaction(), redo(), and undo().

◆ beginNewTransaction() [2/2]

void juce::UndoManager::beginNewTransaction ( const String actionName)

Starts a new group of actions that together will be treated as a single transaction.

All actions that are passed to the perform() method between calls to this method are grouped together and undone/redone together by a single call to undo() or redo().

Parameters
actionNamea description of the transaction that is about to be performed

Definition at line 215 of file juce_UndoManager.cpp.

◆ canRedo()

bool juce::UndoManager::canRedo ( ) const

Returns true if there's at least one action in the list to redo.

See also
getRedoDescription, redo, canUndo

Definition at line 244 of file juce_UndoManager.cpp.

◆ canUndo()

bool juce::UndoManager::canUndo ( ) const

Returns true if there's at least one action in the list to undo.

See also
getUndoDescription, undo, canRedo

Definition at line 243 of file juce_UndoManager.cpp.

◆ clearUndoHistory()

void juce::UndoManager::clearUndoHistory ( )

Deletes all stored actions in the list.

Definition at line 79 of file juce_UndoManager.cpp.

Referenced by redo(), and undo().

◆ getActionsInCurrentTransaction()

void juce::UndoManager::getActionsInCurrentTransaction ( Array< const UndoableAction * > &  actionsFound) const

Returns a list of the UndoableAction objects that have been performed during the transaction that is currently open.

Effectively, this is the list of actions that would be undone if undoCurrentTransactionOnly() were to be called now.

The first item in the list is the earliest action performed.

Definition at line 353 of file juce_UndoManager.cpp.

◆ getCurrentTransactionName()

String juce::UndoManager::getCurrentTransactionName ( ) const

Returns the name of the current transaction.

See also
setCurrentTransactionName

Definition at line 229 of file juce_UndoManager.cpp.

◆ getNumActionsInCurrentTransaction()

int juce::UndoManager::getNumActionsInCurrentTransaction ( ) const

Returns the number of UndoableAction objects that have been performed during the transaction that is currently open.

See also
getActionsInCurrentTransaction

Definition at line 361 of file juce_UndoManager.cpp.

◆ getNumberOfUnitsTakenUpByStoredCommands()

int juce::UndoManager::getNumberOfUnitsTakenUpByStoredCommands ( ) const

Returns the current amount of space to use for storing UndoableAction objects.

See also
setMaxNumberOfStoredUnits

Definition at line 87 of file juce_UndoManager.cpp.

◆ getRedoDescription()

String juce::UndoManager::getRedoDescription ( ) const

Returns the name of the transaction that will be redone when redo() is called.

See also
redo, canRedo, getRedoDescriptions

Definition at line 292 of file juce_UndoManager.cpp.

◆ getRedoDescriptions()

StringArray juce::UndoManager::getRedoDescriptions ( ) const

Returns the names of the sequence of transactions that will be performed if redo() is repeatedly called. Note that for transactions where no name was provided, the corresponding string will be empty.

See also
redo, canRedo, getRedoDescription

Definition at line 313 of file juce_UndoManager.cpp.

◆ getTimeOfRedoTransaction()

Time juce::UndoManager::getTimeOfRedoTransaction ( ) const

Returns the time to which the state would be restored if redo() was to be called. If a redo isn't currently possible, it'll return Time::getCurrentTime().

See also
redo, canRedo

Definition at line 334 of file juce_UndoManager.cpp.

◆ getTimeOfUndoTransaction()

Time juce::UndoManager::getTimeOfUndoTransaction ( ) const

Returns the time to which the state would be restored if undo() was to be called. If an undo isn't currently possible, it'll return Time().

Definition at line 326 of file juce_UndoManager.cpp.

◆ getUndoDescription()

String juce::UndoManager::getUndoDescription ( ) const

Returns the name of the transaction that will be rolled-back when undo() is called.

See also
undo, canUndo, getUndoDescriptions

Definition at line 284 of file juce_UndoManager.cpp.

◆ getUndoDescriptions()

StringArray juce::UndoManager::getUndoDescriptions ( ) const

Returns the names of the sequence of transactions that will be performed if undo() is repeatedly called. Note that for transactions where no name was provided, the corresponding string will be empty.

See also
undo, canUndo, getUndoDescription

Definition at line 300 of file juce_UndoManager.cpp.

◆ isPerformingUndoRedo()

bool juce::UndoManager::isPerformingUndoRedo ( ) const

Returns true if the caller code is in the middle of an undo or redo action.

Definition at line 241 of file juce_UndoManager.cpp.

Referenced by perform().

◆ perform() [1/2]

bool juce::UndoManager::perform ( UndoableAction action)

Performs an action and adds it to the undo history list.

Parameters
actionthe action to perform - this object will be deleted by the UndoManager when no longer needed
Returns
true if the command succeeds - see UndoableAction::perform
See also
beginNewTransaction

Definition at line 112 of file juce_UndoManager.cpp.

Referenced by perform().

◆ perform() [2/2]

bool juce::UndoManager::perform ( UndoableAction action,
const String actionName 
)

Performs an action and also gives it a name.

Parameters
actionthe action to perform - this object will be deleted by the UndoManager when no longer needed
actionNameif this string is non-empty, the current transaction will be given this name; if it's empty, the current transaction name will be left unchanged. See setCurrentTransactionName()
Returns
true if the command succeeds - see UndoableAction::perform
See also
beginNewTransaction

Definition at line 99 of file juce_UndoManager.cpp.

◆ redo()

bool juce::UndoManager::redo ( )

Tries to redo the last transaction that was undone.

Returns
true if the transaction can be redone, and false if it fails, or if there aren't any transactions to redo

Definition at line 265 of file juce_UndoManager.cpp.

◆ setCurrentTransactionName()

void juce::UndoManager::setCurrentTransactionName ( const String newName)

Changes the name stored for the current transaction.

Each transaction is given a name when the beginNewTransaction() method is called, but this can be used to change that name without starting a new transaction.

Definition at line 221 of file juce_UndoManager.cpp.

Referenced by perform().

◆ setMaxNumberOfStoredUnits()

void juce::UndoManager::setMaxNumberOfStoredUnits ( int  maxNumberOfUnitsToKeep,
int  minimumTransactionsToKeep 
)

Sets the amount of space that can be used for storing UndoableAction objects.

Parameters
maxNumberOfUnitsToKeepeach UndoableAction object returns a value to indicate how much storage it takes up (UndoableAction::getSizeInUnits()), so this lets you specify the maximum total number of units that the undomanager is allowed to keep in memory before letting the older actions drop off the end of the list.
minimumTransactionsToKeepthis specifies the minimum number of transactions that will be kept, even if this involves exceeding the amount of space specified in maxNumberOfUnitsToKeep
See also
getNumberOfUnitsTakenUpByStoredCommands

Definition at line 92 of file juce_UndoManager.cpp.

Referenced by UndoManager().

◆ undo()

bool juce::UndoManager::undo ( )

Tries to roll-back the last transaction.

Returns
true if the transaction can be undone, and false if it fails, or if there aren't any transactions to undo
See also
undoCurrentTransactionOnly

Definition at line 246 of file juce_UndoManager.cpp.

Referenced by undoCurrentTransactionOnly().

◆ undoCurrentTransactionOnly()

bool juce::UndoManager::undoCurrentTransactionOnly ( )

Tries to roll-back any actions that were added to the current transaction.

This will perform an undo() only if there are some actions in the undo list that were added after the last call to beginNewTransaction().

This is useful because it lets you call beginNewTransaction(), then perform an operation which may or may not actually perform some actions, and then call this method to get rid of any actions that might have been done without it rolling back the previous transaction if nothing was actually done.

Returns
true if any actions were undone.

Definition at line 342 of file juce_UndoManager.cpp.


The documentation for this class was generated from the following files: