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Manages a list of undo/redo commands. More...
#include <juce_UndoManager.h>
Public Member Functions | |
| UndoManager (int maxNumberOfUnitsToKeep=30000, int minimumTransactionsToKeep=30) | |
| Creates an UndoManager. | |
| ~UndoManager () override | |
| Destructor. | |
| void | clearUndoHistory () |
| Deletes all stored actions in the list. | |
| int | getNumberOfUnitsTakenUpByStoredCommands () const |
| Returns the current amount of space to use for storing UndoableAction objects. | |
| void | setMaxNumberOfStoredUnits (int maxNumberOfUnitsToKeep, int minimumTransactionsToKeep) |
| Sets the amount of space that can be used for storing UndoableAction objects. | |
| bool | perform (UndoableAction *action) |
| Performs an action and adds it to the undo history list. | |
| bool | perform (UndoableAction *action, const String &actionName) |
| Performs an action and also gives it a name. | |
| void | beginNewTransaction () |
| Starts a new group of actions that together will be treated as a single transaction. | |
| void | beginNewTransaction (const String &actionName) |
| Starts a new group of actions that together will be treated as a single transaction. | |
| void | setCurrentTransactionName (const String &newName) |
| Changes the name stored for the current transaction. | |
| String | getCurrentTransactionName () const |
| Returns the name of the current transaction. | |
| bool | canUndo () const |
| Returns true if there's at least one action in the list to undo. | |
| bool | undo () |
| Tries to roll-back the last transaction. | |
| bool | undoCurrentTransactionOnly () |
| Tries to roll-back any actions that were added to the current transaction. | |
| String | getUndoDescription () const |
| Returns the name of the transaction that will be rolled-back when undo() is called. | |
| StringArray | getUndoDescriptions () const |
| Returns the names of the sequence of transactions that will be performed if undo() is repeatedly called. | |
| Time | getTimeOfUndoTransaction () const |
| Returns the time to which the state would be restored if undo() was to be called. | |
| void | getActionsInCurrentTransaction (Array< const UndoableAction * > &actionsFound) const |
| Returns a list of the UndoableAction objects that have been performed during the transaction that is currently open. | |
| int | getNumActionsInCurrentTransaction () const |
| Returns the number of UndoableAction objects that have been performed during the transaction that is currently open. | |
| bool | canRedo () const |
| Returns true if there's at least one action in the list to redo. | |
| bool | redo () |
| Tries to redo the last transaction that was undone. | |
| String | getRedoDescription () const |
| Returns the name of the transaction that will be redone when redo() is called. | |
| StringArray | getRedoDescriptions () const |
| Returns the names of the sequence of transactions that will be performed if redo() is repeatedly called. | |
| Time | getTimeOfRedoTransaction () const |
| Returns the time to which the state would be restored if redo() was to be called. | |
| bool | isPerformingUndoRedo () const |
| Returns true if the caller code is in the middle of an undo or redo action. | |
 Public Member Functions inherited from ChangeBroadcaster | |
| ChangeBroadcaster () noexcept | |
| Creates an ChangeBroadcaster. | |
| virtual | ~ChangeBroadcaster () |
| Destructor. | |
| void | addChangeListener (ChangeListener *listener) |
| Registers a listener to receive change callbacks from this broadcaster. | |
| void | removeChangeListener (ChangeListener *listener) |
| Unregisters a listener from the list. | |
| void | removeAllChangeListeners () |
| Removes all listeners from the list. | |
| void | sendChangeMessage () |
| Causes an asynchronous change message to be sent to all the registered listeners. | |
| void | sendSynchronousChangeMessage () |
| Sends a synchronous change message to all the registered listeners. | |
| void | dispatchPendingMessages () |
| If a change message has been sent but not yet dispatched, this will call sendSynchronousChangeMessage() to make the callback immediately. | |
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.
| UndoManager::UndoManager | ( | int | maxNumberOfUnitsToKeep = 30000, |
| int | minimumTransactionsToKeep = 30 ) |
Creates an UndoManager.
| maxNumberOfUnitsToKeep | each 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. |
| minimumTransactionsToKeep | this specifies the minimum number of transactions that will be kept, even if this involves exceeding the amount of space specified in maxNumberOfUnitsToKeep |
|
override |
Destructor.
| void UndoManager::clearUndoHistory | ( | ) |
Deletes all stored actions in the list.
| int UndoManager::getNumberOfUnitsTakenUpByStoredCommands | ( | ) | const |
Returns the current amount of space to use for storing UndoableAction objects.
| void UndoManager::setMaxNumberOfStoredUnits | ( | int | maxNumberOfUnitsToKeep, |
| int | minimumTransactionsToKeep ) |
Sets the amount of space that can be used for storing UndoableAction objects.
| maxNumberOfUnitsToKeep | each 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. |
| minimumTransactionsToKeep | this specifies the minimum number of transactions that will be kept, even if this involves exceeding the amount of space specified in maxNumberOfUnitsToKeep |
| bool UndoManager::perform | ( | UndoableAction * | action | ) |
Performs an action and adds it to the undo history list.
| action | the action to perform - this object will be deleted by the UndoManager when no longer needed |
| bool UndoManager::perform | ( | UndoableAction * | action, |
| const String & | actionName ) |
Performs an action and also gives it a name.
| action | the action to perform - this object will be deleted by the UndoManager when no longer needed |
| actionName | if 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() |
| void UndoManager::beginNewTransaction | ( | ) |
| void 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().
| actionName | a description of the transaction that is about to be performed |
| void 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.
| String UndoManager::getCurrentTransactionName | ( | ) | const |
Returns the name of the current transaction.
| bool UndoManager::canUndo | ( | ) | const |
Returns true if there's at least one action in the list to undo.
| bool UndoManager::undo | ( | ) |
Tries to roll-back the last transaction.
| bool 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.
| String UndoManager::getUndoDescription | ( | ) | const |
Returns the name of the transaction that will be rolled-back when undo() is called.
| StringArray 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.
| Time UndoManager::getTimeOfUndoTransaction | ( | ) | const |
| void 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.
| int UndoManager::getNumActionsInCurrentTransaction | ( | ) | const |
Returns the number of UndoableAction objects that have been performed during the transaction that is currently open.
| bool UndoManager::canRedo | ( | ) | const |
Returns true if there's at least one action in the list to redo.
| bool UndoManager::redo | ( | ) |
Tries to redo the last transaction that was undone.
| String UndoManager::getRedoDescription | ( | ) | const |
Returns the name of the transaction that will be redone when redo() is called.
| StringArray 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.
| Time 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().
| bool UndoManager::isPerformingUndoRedo | ( | ) | const |
Returns true if the caller code is in the middle of an undo or redo action.
