C++ API Reference

Expression function set. More...

#include <MFnExpression.h>

+ Inheritance diagram for MFnExpression:

Public Types

enum  UnitConversion { kAll, kNone, kAngularOnly }
 Unit conversion modes. More...
 
- Public Types inherited from MFnDependencyNode
enum  MAttrClass { kLocalDynamicAttr = 1, kNormalAttr, kExtensionAttr, kInvalidAttr }
 Specifies the scope of the attribute. More...
 
enum  MdgTimerState { kTimerOff, kTimerOn, kTimerUninitialized, kTimerInvalidState }
 Possible states for the node's timer. More...
 
enum  MdgTimerMetric {
  kTimerMetric_callback, kTimerMetric_compute, kTimerMetric_dirty, kTimerMetric_draw,
  kTimerMetric_fetch, kTimerMetric_callbackViaAPI, kTimerMetric_callbackNotViaAPI, kTimerMetric_computeDuringCallback,
  kTimerMetric_computeNotDuringCallback, kTimerMetrics
}
 The different timer metrics which can be queried. More...
 
enum  MdgTimerType { kTimerType_self, kTimerType_inclusive, kTimerType_count, kTimerTypes }
 The types of timers which can be queried. More...
 

Public Member Functions

virtual MFn::Type type () const
 Function set type. More...
 
virtual ~MFnExpression ()
 Destructor.
 
 MFnExpression ()
 Default constructor.
 
 MFnExpression (MObject &object, MStatus *ReturnStatus=NULL)
 Constructor. More...
 
MObject create (const MString &expression, MObject &object=MObject::kNullObj, MStatus *ReturnStatus=NULL)
 This method creates and returns a dependency node for a given expression. More...
 
MString expression (MStatus *ReturnStatus=NULL)
 Gets the expression string for this expression node. More...
 
MStatus setExpression (const MString &expression)
 Sets the expression string for this expression node. More...
 
MStatus getDefaultObject (MObject &object)
 Gets the "default" object for the expression. More...
 
MStatus setDefaultObject (MObject &object)
 Sets the "default" object for the expression. More...
 
bool isAnimated (MStatus *ReturnStatus=NULL)
 If this is true, then the expression will be evaluated whenever time changes, regardless of whether the other inputs have changed. More...
 
MStatus setAnimated (bool value=false)
 Sets the way in which the expression is evaluated. More...
 
MStatus evaluate (MDoubleArray &result)
 Evaluate this expression and return the result. More...
 
UnitConversion unitConversion (MStatus *ReturnStatus=NULL) const
 Get the unit conversion status for the expression node. More...
 
MStatus setUnitConversion (UnitConversion conversion)
 Set the unit conversion options for the expression node. More...
 
 MFnExpression (const MObject &object, MStatus *ReturnStatus=NULL)
 Constructor. More...
 
MStatus getExpression (MString &expression)
 NO SCRIPT SUPPORT. More...
 
- Public Member Functions inherited from MFnDependencyNode
virtual ~MFnDependencyNode ()
 Destructor.
 
 MFnDependencyNode ()
 Default constructor.
 
 MFnDependencyNode (MObject &object, MStatus *ReturnStatus=NULL)
 Constructor. More...
 
MObject create (const MTypeId &typeId, MStatus *ReturnStatus=NULL)
 Creates a new dependency node with the given type tag. More...
 
MObject create (const MTypeId &typeId, const MString &name, MStatus *ReturnStatus=NULL)
 Creates a new dependency node with the given type tag. More...
 
MObject create (const MString &type, MStatus *ReturnStatus=NULL)
 Creates a new dependency node with the given type. More...
 
MObject create (const MString &type, const MString &name, MStatus *ReturnStatus=NULL)
 Creates a new dependency node with the given type. More...
 
MTypeId typeId (MStatus *ReturnStatus=NULL) const
 Returns the type id of this node. More...
 
MString typeName (MStatus *ReturnStatus=NULL) const
 Returns the type name of this node. More...
 
MString name (MStatus *ReturnStatus=NULL) const
 Returns the name of this node. More...
 
MString absoluteName (MStatus *ReturnStatus=NULL) const
 Returns the absolute name of this node. More...
 
MString uniqueName (MStatus *ReturnStatus=NULL) const
 Returns the unique name of this node. More...
 
MString pluginName (MStatus *ReturnStatus=NULL) const
 Returns the name of the plug-in this MFnDependendencyNode was defined in. More...
 
MString setName (const MString &name, bool createNamespace=false, MStatus *ReturnStatus=NULL)
 Sets the name of this node. More...
 
MUuid uuid (MStatus *ReturnStatus=NULL) const
 Returns the node's UUID. More...
 
void setUuid (const MUuid &uuid, MStatus *ReturnStatus=NULL)
 Sets the node's UUID. More...
 
MStatus getConnections (MPlugArray &array) const
 Get all of the current connections to this node as an array of plugs. More...
 
unsigned int attributeCount (MStatus *ReturnStatus=NULL) const
 Returns the number of attributes that this node has. More...
 
MObject attribute (unsigned int index, MStatus *ReturnStatus=NULL) const
 Finds the attribute of this node at the given index. More...
 
MObject reorderedAttribute (unsigned int index, MStatus *ReturnStatus=NULL) const
 Some nodes, such as the various animCurve nodes, require that their attributes be set in a specific order for proper operation. More...
 
MObject attribute (const MString &attrName, MStatus *ReturnStatus=NULL) const
 Finds the attribute of this node that has the given name. More...
 
MAttrClass attributeClass (const MObject &attr, MStatus *ReturnStatus=NULL) const
 Returns the class (normal, dynamic, extension) of the specified attribute. More...
 
MStatus getAffectedAttributes (const MObject &attr, MObjectArray &affectedAttributes) const
 Returns an array of attributes that are affected by the attribute passed in. More...
 
MStatus getAffectedByAttributes (const MObject &attr, MObjectArray &affectedByAttributes) const
 Returns an array of attributes that affect the attribute passed in, attr. More...
 
MPlug findPlug (const MObject &attr, bool wantNetworkedPlug, MStatus *ReturnStatus=NULL) const
 Attempt to find a plug for the given attribute. More...
 
MPlug findPlug (const MString &attrName, bool wantNetworkedPlug, MStatus *ReturnStatus=NULL) const
 Attempt to find a plug for the given attribute. More...
 
MPlug findPlug (const MObject &attr, MStatus *ReturnStatus=NULL) const
 This method is obsolete. More...
 
MPlug findPlug (const MString &attrName, MStatus *ReturnStatus=NULL) const
 This method is obsolete. More...
 
MStatus addAttribute (const MObject &attr)
 Add a new dynamic attibute to this node. More...
 
MStatus removeAttribute (const MObject &attr)
 Remove a dynamic attribute from a node. More...
 
MPxNodeuserNode (MStatus *ReturnStatus=NULL) const
 If the function set's node is a plug-in node, then this method will extract the MPxNode pointer from it. More...
 
bool isFromReferencedFile (MStatus *ReturnStatus=NULL) const
 Indicates whether or not this node came from a referenced file. More...
 
bool isShared (MStatus *ReturnStatus=NULL) const
 Indicates whether or not this node is shared. More...
 
bool isTrackingEdits (MStatus *ReturnStatus=NULL) const
 Returns whether or not edits on the given node are being tracked by the generalized edit system. More...
 
bool hasUniqueName (MStatus *ReturnStatus=NULL) const
 Indicates whether or not this node's name is unique within the scene. More...
 
MString parentNamespace (MStatus *ReturnStatus=NULL) const
 Returns the name of the namespace in which this node resides. More...
 
bool isLocked (MStatus *ReturnStatus=NULL) const
 Indicates whether or not this node is locked. More...
 
MStatus setLocked (bool locked)
 Locks or unlocks this node. More...
 
bool isNewAttribute (const MObject &attr, MStatus *ReturnStatus=NULL) const
 Indicates whether or not the specified attribute was added to this node within the current scene. More...
 
MStatus setFlag (unsigned int flag, bool state)
 Sets the state of the specified flag for the node. More...
 
bool isFlagSet (unsigned int flag, MStatus *ReturnStatus=NULL) const
 Retrieves the current state of the specified flag for a node. More...
 
bool isDefaultNode (MStatus *ReturnStatus=NULL) const
 Returns true if the node is a default node. More...
 
MStatus setDoNotWrite (bool flag)
 Use this method to mark the "do not write" state of this node. More...
 
bool canBeWritten (MStatus *ReturnStatus=NULL) const
 Returns the do not write state of the node. More...
 
bool hasAttribute (const MString &name, MStatus *ReturnStatus=NULL) const
 Returns true if the node already has an attribute with the given name. More...
 
MObject getAliasAttr (bool force, MStatus *ReturnStatus=NULL)
 Returns the node's alias attribute, which is a special attribute used to store information about the node's attribute aliases. More...
 
bool setAlias (const MString &alias, const MString &name, const MPlug &plug, bool add=true, MStatus *ReturnStatus=NULL)
 Sets or removes an alias (i.e. More...
 
bool findAlias (const MString &alias, MObject &attrObj, MStatus *ReturnStatus=NULL) const
 Retrieves the attribute with the given alias. More...
 
bool getAliasList (MStringArray &strArray, MStatus *ReturnStatus=NULL)
 Returns a list of all attribute aliases for this node. More...
 
MString plugsAlias (const MPlug &plug, MStatus *ReturnStatus=NULL)
 Returns the alias for the plug's attribute or the empty string if that attribute has no alias. More...
 
MStatus setIcon (const MString &filename)
 Associates a custom icon with the node for display in the Maya UI. More...
 
MString icon (MStatus *ReturnStatus=NULL) const
 Returns the custom icon filename associated with the node. More...
 
MStatus getExternalContent (MExternalContentInfoTable &table) const
 Returns the external content (files) that this node depends on. More...
 
MStatus addExternalContentForFileAttr (MExternalContentInfoTable &table, const MObject &attr) const
 Adds content info to the specified table from a file path attribute. More...
 
MStatus setExternalContentForFileAttr (const MObject &attr, const MExternalContentLocationTable &table)
 Sets content info in the specified attribute from the table. More...
 
MStatus setExternalContent (const MExternalContentLocationTable &table)
 Changes the location of external content. More...
 
bool affectsAnimation (MStatus *ReturnStatus=NULL) const
 Indicates whether or not this node is allowed to animate. More...
 
MStatus setAffectsAnimation ()
 Define a node can affect animation. More...
 
MString setName (const MString &name, MStatus *ReturnStatus)
 This method is obsolete. More...
 
 MFnDependencyNode (const MObject &object, MStatus *ReturnStatus=NULL)
 This method is not available in Python. More...
 
bool getPlugsAlias (const MPlug &plug, MString &aliasName, MStatus *ReturnStatus=NULL)
 This method is not available in Python. More...
 
virtual const adsk::Data::Associationsmetadata (MStatus *ReturnStatus=NULL) const
 This method is not available in Python. More...
 
virtual MStatus setMetadata (const adsk::Data::Associations &)
 This method is not available in Python. More...
 
virtual MStatus deleteMetadata ()
 This method is not available in Python. More...
 
virtual MStatus validateMetadata (MString &errors) const
 This method is not available in Python. More...
 
MStatus dgTimerOn ()
 Indicates that this node should collect DG timing data whenever DG timing is enabled. More...
 
MStatus dgTimerOff ()
 Indicates that this node should no longer collect DG timing data when DG timing is enabled. More...
 
MdgTimerState dgTimerQueryState (MStatus *ReturnStatus=NULL)
 The function returns the current on/off state of the node's timer. More...
 
MStatus dgTimerReset ()
 The function resets the dependency graph timers and counters for this node to zero. More...
 
double dgTimer (const MdgTimerMetric timerMetric, const MdgTimerType timerType, MStatus *ReturnStatus=NULL) const
 The function returns the specified timer value for the current node. More...
 
MStatus dgCallbacks (const MdgTimerType type, MStringArray &callbackName, MDoubleArray &value)
 Node callbacks that occur when timing is enabled get logged with the node and can be queried via this method. More...
 
MStatus dgCallbackIds (const MdgTimerType type, const MString &callbackName, MCallbackIdArray &callbackId, MDoubleArray &value)
 This method provides a further breakdown of the per-callback time returned via dgCallbacks() by returning the data on a per-callbackId basis. More...
 
MStatus addAttribute (const MObject &attr, MAttrClass type)
 This method is obsolete. More...
 
MStatus removeAttribute (const MObject &attr, MAttrClass type)
 This method is obsolete. More...
 
- Public Member Functions inherited from MFnBase
virtual ~MFnBase ()
 Class Destructor. More...
 
bool hasObj (MFn::Type) const
 Determines whether or not the Function Set is compatible with the specified Maya Object within the API RTTI system. More...
 
bool hasObj (const MObject &) const
 Determines whether or not the Function Set is compatible with the specified Maya Object within the API RTTI system. More...
 
MObject object (MStatus *ReturnStatus=nullptr) const
 Returns the MObject that is attached to the Function Set. More...
 
virtual MStatus setObject (MObject &object)
 Attaches the Function Set to the specified Maya Object. More...
 
virtual MStatus setObject (const MObject &object)
 NO SCRIPT SUPPORT. More...
 

Static Public Member Functions

static const char * className ()
 Returns the name of this class. More...
 
- Static Public Member Functions inherited from MFnDependencyNode
static const char * className ()
 Returns the name of this class. More...
 
static MString classification (const MString &nodeTypeName)
 Retrieves the classification string for a node type. More...
 
static unsigned int allocateFlag (const MString pluginName, MStatus *ReturnStatus=NULL)
 Allocates a node flag for sole use by the caller. More...
 
static MStatus deallocateFlag (const MString pluginName, unsigned int flag)
 Deallocates a node flag which was previously allocated by a call to allocateFlag. More...
 
static MStatus deallocateAllFlags (const MString pluginName)
 Deallocates all of the node flags which are currently allocated to the specified plugin. More...
 
static void enableDGTiming (bool enable)
 Globally enables or disables the DG node timing mechanism. More...
 
- Static Public Member Functions inherited from MFnBase
static const char * className ()
 Returns the name of this class. More...
 
static const char * typeString (MFn::Type)
 Returns the type string for a given type. More...
 
static bool isValid (MFn::Type)
 Returns true if type is in the range of valid types. More...
 

Detailed Description

Expression function set.

This class is used to create, edit, and query expression nodes.

Examples:
AbcBullet/MayaUtility.cpp, and AbcExport/MayaUtility.cpp.

Member Enumeration Documentation

Unit conversion modes.

Enumerator
kAll 

Convert all units.

kNone 

Do not do any unit conversion.

kAngularOnly 

Only convert angular units.

Constructor & Destructor Documentation

MFnExpression ( MObject object,
MStatus ReturnStatus = NULL 
)

Constructor.

Class constructor that initializes the function set to the given MObject.

Parameters
[in]objectThe MObject to attach the function set to
[out]ReturnStatusthe return status
Status Codes:
  • MS::kSuccess if the function set is successfully attached
  • MS::kInvalidParameter if the MObject does not represent a valid Maya object or if the function set is not allowed to attach to this MObject
MFnExpression ( const MObject object,
MStatus ReturnStatus = NULL 
)

Constructor.

Class constructor that initializes the function set to the given MObject.

Parameters
[in]objectThe MObject to attach the function set to
[out]ReturnStatusthe return status
Status Codes:
  • MS::kSuccess if the function set is successfully attached
  • MS::kInvalidParameter if the MObject does not represent a valid Maya object or if the function set is not allowed to attach to this MObject

Member Function Documentation

MFn::Type type ( ) const
virtual

Function set type.

Return the class type : MFn::kExpression.

Returns
the class type.

Reimplemented from MFnDependencyNode.

OPENMAYA_MAJOR_NAMESPACE_OPEN const char * className ( )
static

Returns the name of this class.

Return the class name : "MFnExpression".

Returns
Name of this class.
MObject create ( const MString expression,
MObject object = MObject::kNullObj,
MStatus ReturnStatus = NULL 
)

This method creates and returns a dependency node for a given expression.

A default object can be specified, but if it is not specified in the expression string then the expression string values will be used.

If the expression string is of the form "objectName.attribute = ... " then the default object parameter is not needed. If you supply a default object in this case, then it will be ignored.

If the expression has no default object then you must supply one. For example, if the expression is of the form "attribute = ...", then you must supply a default object.

Parameters
[in]expressionThe expression string
[in]objectThe default object (optional - see above)
[out]ReturnStatusStatus code
Returns
The expression node
Status Codes:
  • MS::kSuccess
  • MS::kLicenseFailure application not licensed for attempted operation
  • MS::kFailure
MString expression ( MStatus ReturnStatus = NULL)

Gets the expression string for this expression node.

Parameters
[out]ReturnStatusStatus code. See below.
Returns
The expression string
Status Codes:
  • MS::kSuccess
  • MS::kFailure
MStatus setExpression ( const MString expression)

Sets the expression string for this expression node.

Parameters
[in]expressionThe expression string
Returns
Status Code
Status Codes:
  • MS::kSuccess
  • MS::kFailure
MStatus getDefaultObject ( MObject object)

Gets the "default" object for the expression.

Not all expressions have a default object. If there is no default object for the expression, the object will be set to MObject::kNullObject and the return status will indicate success. This is a completely legal case that the calling code should check for before blindly using the returned object.

Parameters
[out]objectstorage for the default object
Returns
Status Code
Status Codes:
  • MS::kSuccess
  • MS::kFailure
MStatus setDefaultObject ( MObject object)

Sets the "default" object for the expression.

This allows the expression writer to not type the object name for frequently-used objects.

This method will only work for expression strings in which the object name is not specified.

Parameters
[in]objectthe object to be set
Returns
Status Code
Status Codes:
  • MS::kSuccess
  • MS::kFailure
bool isAnimated ( MStatus ReturnStatus = NULL)

If this is true, then the expression will be evaluated whenever time changes, regardless of whether the other inputs have changed.

If it is false (the default) , then the expression will only be evaluated if one or more of the inputs change.

Note, if 'time' or 'frame' are inputs, then the expression will act as if this was set to true.

Parameters
[out]ReturnStatusStatus code
Returns
  • true expression will be evaluated whenever time changes
  • false
Status Codes:
  • MS::kSuccess
  • MS::kFailure
MStatus setAnimated ( bool  value = false)

Sets the way in which the expression is evaluated.

If this is true, then the expression will be evaluated whenever time changes, regardless of whether the other inputs have changed.

If it is false (the default) , then the expression will only be evaluated if one or more of the inputs change.

Note, if 'time' or 'frame' are inputs, then the expression will act as if this was set to true.

Parameters
[in]valuesets the objects evaluation type
Returns
Status Code
Status Codes:
  • MS::kSuccess
  • MS::kFailure
MStatus evaluate ( MDoubleArray result)

Evaluate this expression and return the result.

Parameters
[out]resultthe value of the expression
Returns
Status code
Status Codes:
  • MS::kSuccess
  • MS::kFailure
MFnExpression::UnitConversion unitConversion ( MStatus ReturnStatus = NULL) const

Get the unit conversion status for the expression node.

Parameters
[out]ReturnStatusStatus code
Returns
The unit conversion state for this node
Status Codes:
  • MS::kSuccess operation successful
  • MS::kFailure function set does not have a valid object
MStatus setUnitConversion ( UnitConversion  conversion)

Set the unit conversion options for the expression node.

Parameters
[in]conversionunit conversion state for this node
Returns
Status code
Status Codes:
  • MS::kSuccess operation successful
  • MS::kFailure function set does not have a valid object
MStatus getExpression ( MString expression)

NO SCRIPT SUPPORT.

Gets the expression string for this expression node.

Python Notes

This method is not supported in Python. Please see the one which returns a string

Parameters
[in]expressionThe expression string
Returns
Status code
Status Codes:
  • MS::kSuccess
  • MS::kFailure

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