RestoreObj Class Reference

This reference page is linked to from the following overview topics: How to Enable Undo and Redo, Undo and Redo Example, Deriving from RestoreObj, Undo Memory Limits, The Undo Mechanism and Transform Controllers, Stabilizing Changes.

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#include <hold.h>

Inheritance diagram for RestoreObj:

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Class Description

See also:

Class Hold, Undo and Redo.

Description:

This class is the restore object used in the undo / redo system of 3ds Max.

Public Member Functions
	RestoreObj ()
virtual	~RestoreObj ()
virtual void	Restore (int isUndo)=0
virtual void	Redo ()=0
virtual int	Size ()
virtual void	EndHold ()
virtual MSTR	Description ()
virtual INT_PTR	Execute (int cmd, ULONG_PTR arg1=0, ULONG_PTR arg2=0, ULONG_PTR arg3=0)
Friends
class	HoldStore
class	GenUndoObject
class	CheckForFlush

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Constructor & Destructor Documentation

RestoreObj

(

)

[inline]

{ next = prev = NULL; }

virtual ~RestoreObj

(

)

[inline, virtual]

{};

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Member Function Documentation

virtual void Restore

(

int

isUndo

)

[pure virtual]

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Remarks:

The developer implements this method to restore the state of the database to as it was when theHold.Put() was called with this restore object.

Regardless of the value of the isUndo parameter, the method must restore the state of the scene to the one it was in when theHold.Put() was called with this restore object.

RestoreObj::Restore and RestoreObj::Redo may be called several times in a row: these methods must protect against any problems that may arise because of this, such as trying to undo multiple times in a row what has been undone already.

Parameters:

isUndo

Nonzero if Restore() is being called in response to the Undo command; otherwise zero. If isUndo is nonzero, the developer needs to save whatever data they need to allow the user to redo the operation.

Implemented in JPLimitsRestore, ConvertToRestore, AssignControllerRestore, PatchObjectRestore, RealWorldScaleRecord< T >, DeletedRestore, RefMgrAddDeleteRestore< T >, AppendGizmoRestore, and DeleteGizmoRestore.

virtual void Redo

(

)

[pure virtual]

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Remarks:

This method is called when the user selects the Redo command. The developer should restore the database to the state prior to the last Undo command.

Implemented in JPLimitsRestore, ConvertToRestore, AssignControllerRestore, PatchObjectRestore, RealWorldScaleRecord< T >, DeletedRestore, RefMgrAddDeleteRestore< T >, AppendGizmoRestore, and DeleteGizmoRestore.

virtual int Size

(

)

[inline, virtual]

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Remarks:

Returns the size of the restore object in bytes. This size does not need to be exact but should be close. This is used to make sure all the accumulated restore objects do not grow beyond a manageable size.

Default Implementation:

{ return 1; }

Returns:

The size of the restore object in bytes.

Reimplemented in PatchObjectRestore.

{ return sizeof(RestoreObj); }

virtual void EndHold

(

)

[inline, virtual]

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Remarks:

This method is called when theHold.Accept() or theHold.Cancel() is called. This means the restore object is no longer held, it was either tossed out or sent to the undo system. The developer may then call ClearAFlag(A_HELD) to indicate the restore object is no longer being held.

Reimplemented in JPLimitsRestore, and PatchObjectRestore.

{ }

virtual MSTR Description

(

)

[inline, virtual]

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Remarks:

This method is used internally to 3ds Max in debugging only. It is used to display a symbolic name for the restore object.

Returns:

The name of the restore object.

Default Implementation:

{ return MSTR(_M("---")); }

Reimplemented in ConvertToRestore, AssignControllerRestore, PatchObjectRestore, DeletedRestore, RefMgrAddDeleteRestore< T >, AppendGizmoRestore, and DeleteGizmoRestore.

{ return MSTR(_M("---")); }

virtual INT_PTR Execute	(	int	cmd,
		ULONG_PTR	arg1 = 0,
		ULONG_PTR	arg2 = 0,
		ULONG_PTR	arg3 = 0
	)		[inline, virtual]

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Remarks:

This is a general purpose function that allows the API to be extended in the future. The 3ds Max development team can assign new cmd numbers and continue to add functionality to this class without having to 'break' the API.

This is reserved for future use.

Default Implementation:

{return -1;}

                {
                        UNUSED_PARAM(cmd);
                        UNUSED_PARAM(arg1);
                        UNUSED_PARAM(arg2);
                        UNUSED_PARAM(arg3);
                        return -1;
                }

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Friends And Related Function Documentation

friend class HoldStore [friend]

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friend class GenUndoObject [friend]

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friend class CheckForFlush [friend]

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