class MPxContext

Jump to documentation

Inheritance:

MPxContext

public members:

	MPxContext ()
virtual	~MPxContext ()
virtual void	toolOnSetup ( MEvent & event )
virtual void	toolOffCleanup ()
virtual MStatus	doPress ( MEvent & event )
virtual MStatus	doRelease ( MEvent & event )
virtual MStatus	doDrag ( MEvent & event )
virtual MStatus	doHold ( MEvent & event )
virtual MStatus	doEnterRegion ( MEvent & event )
virtual MStatus	helpStateHasChanged ( MEvent & event )
virtual void	deleteAction ()
virtual void	completeAction ()
virtual MStatus	addManipulator ( const MObject & manipulator )
virtual MStatus	deleteManipulators ()
MStatus	setImage ( const MString & image , ImageIndex index )
MString	image ( ImageIndex index, MStatus * ReturnStatus = NULL ) const
virtual void	abortAction ()
virtual bool	processNumericalInput ( const MDoubleArray &values, const MIntArray &flags, bool isAbsolute )
virtual bool	feedbackNumericalInput () const
virtual MSyntax::MArgType	argTypeNumericalInput ( unsigned int index ) const
virtual MString	stringClassName () const
virtual void	getClassName ( MString & name ) const NO SCRIPT SUPPORT
MStatus	getImage ( MString & image , ImageIndex index ) const NO SCRIPT SUPPORT

protected members:

MStatus	setHelpString ( const MString & str ) USE _setHelpString() IN SCRIPT
MStatus	setTitleString ( const MString & str ) USE _setTitleString() IN SCRIPT
MStatus	setCursor ( const MCursor & cursor ) USE _setCursor() IN SCRIPT
MStatus	beginMarquee ( MEvent & event ) USE _beginMarquee() IN SCRIPT
MStatus	dragMarquee ( MEvent & event ) USE _dragMarquee() IN SCRIPT
MStatus	releaseMarquee ( MEvent & event, short& top, short& left, short& bottom, short& right ) USE _releaseMarquee() IN SCRIPT
virtual MPxToolCommand *	newToolCommand () CALL _newToolCommand() IN SCRIPT
static bool	ignoreEntry ( const MIntArray &flags, unsigned int entry ) USE _ignoreEntry() IN SCRIPT

Documentation

Description

This is the base class for user defined contexts.

Contexts provide a way to create interactive tools in Maya. A context class defines what happens when interactive events, such as mouse events, occur within an interactive panel in Maya.

Since there are default actions for all tools in Maya, such as the right mouse button event which brings up an options menu, only as subset of the events that occur in a view can be overridden.
The events that can be overridden are:

• doPress - mouse button press event (left & middle only)
• doRelease - mouse buttons release event (left & middle only)
• doDrag - mouse button drag event (left & middle only)
• doHold - mouse button hold event (left & middle only)
• deleteAction - delete/backspace key event
• completeAction - complete key event
• abortAction - abort/escape key event

A context is activated by pressing the toolButton for that context. Once the context is activated, it will handle the events that occur within 3d panel.

A context is deactivated when some other tool button is pressed.

There can be more than one instance of a context in Maya, for example, dragging a tool icon into the shelf creates another instance of that context. Since there can be multiple instances of the same context there is a command class, MPxContextCommand, which is responsible for the creation of contexts. See MPxContextCommand for more information.

Functions

MPxContext:: MPxContext ()

Description

Class contstructor.
This constructor will only be called from MPxContextCommand::makeObj.
Users must override this method.

MPxContext:: ~MPxContext ()

Description

Default destructor.
Users can override this method to free any user instantiated data when the context is destroyed.

MStatus MPxContext:: helpStateHasChanged ( MEvent & )

Description

This method is called whenever the help state may need to be updated. The base method does nothing and should be overriden if the user needs to change the help information based on events.

The event can be used to get more explicit information about the event. See MEvent for more information.

Arguments

• event The event information.

Return Value

• Status code

Status Codes

• MS::kSuccess

void MPxContext:: toolOnSetup ( MEvent & event )

Description

This method is called when the context is activated, i.e when the toolButton for the context is pressed. Users can override this method and use it to set up any user defined data that needs to be initialized on each activation.

Arguments

• event The button press event information.

Return Value

• None

void MPxContext:: toolOffCleanup ()

Description

This method is called when the context is deactivated, i.e when another context is activated. Users can override this method and use it to reset any user defined data to a specific state.

Return Value

• None

MStatus MPxContext:: doPress ( MEvent & event)

Description

This method is called when any mouse button is pressed. The base method does nothing and should be overriden if the user needs to do anything on a button press.

The event can be used to get more explicit information about the press such as the button number. See MEvent for more information.

Arguments

• event The button press event information.

Return Value

• Status code

Status Codes

• MS::kSuccess

MStatus MPxContext:: doDrag ( MEvent & event)

Description

This method is called when a mouse drag event occurs. The base method does nothing and should be overriden if the user needs to do anything during a mouse drag.

The event can be used to get more explicit information about the drag such as the cursor location. See MEvent for more information.

Arguments

• event The mouse drag event information.

Return Value

• Status code

Status Codes

• MS::kSuccess

MStatus MPxContext:: doRelease ( MEvent & event)

Description

This method is called when any mouse button is released. The base method does nothing and should be overriden if the user needs to do anything on a button release.

The event can be used to get more explicit information about the release such as the button number. See MEvent for more information.

Arguments

• event The mouse button release information.

Return Value

• Status code

Status Codes

• MS::kSuccess

MStatus MPxContext:: doHold ( MEvent & event)

Description

This method is called when a mouse button is pressed but before the mouse is dragged.
The base method does nothing and should be overriden if the user needs to do anything on a button hold.

The event can be used to get more explicit information about the hold such as the button number. See MEvent for more information.

Arguments

• event The mouse button hold event information.

Return Value

• Status code

Status Codes

• MS::kSuccess

MStatus MPxContext:: doEnterRegion ( MEvent & event)

Description

This method is called when the mouse pointer enters a screen panel region.
The base method sets the help string and the cursor which may have been set via setHelpString and setCursor respectively.

The event can be used to get more explicit information about the event. See MEvent for more information.

Arguments

• event The enter region event information.

Return Value

• Status code

Status Codes

• MS::kSuccess

void MPxContext:: deleteAction ()

Description

This method is called when the delete or backspace key is pressed.
The default behaviour for this method is to delete the items on the current selection list.
Users can override this method if they wish to do anything else when this event occurs.

Return Value

• None

void MPxContext:: completeAction ()

Description

This method is called when the complete key is pressed. The default complete key in Maya is the enter key. Users can override this method if a tool has several steps. For example, a tool may have several steps where the user must select objects and then press the completion key before proceeding.

Return Value

• None

MStatus MPxContext:: addManipulator (const MObject &manipulator)

Description

This method adds a manipulator to the context.

Arguments

• manipulator the manipulator to be added to the context

Return Value

• MS::kSuccess operation successful
• MS::kFailure operation failed

MStatus MPxContext:: deleteManipulators ()

Description

This method deletes all the manipulators that belong to the context.

Return Value

• MS::kSuccess operation successful
• MS::kFailure operation failed

MStatus MPxContext:: setImage (const MString & image , ImageIndex index)

Description

This method is used to set an XPM icon image that is to be used to represent this tool context in various places including the tool bar and can be queried from mel using the contextInfo command.

Arguments

• image the name of an XPM file to be used as the icon
• index the index of the image being set; three image representations are permitted: kImage1, kImage2, kImage3

Return Value

• MS::kSuccess operation successful
• MS::kFailure operation failed

MStatus MPxContext:: getImage ( MString & image , ImageIndex index) const

Description

This method is used to retrieve an XPM icon image that has previously been set for this tool context. This icon image will be used to represent this tool context in various places including the tool bar and can be queried from mel using the contextInfo command.

Python Notes

This method is not supported in Python. See the version which returns a string.

Arguments

• image the returned name of an XPM Icon file
• index the index for the image being retrieved; three image representations are permitted: kImage1, kImage2, kImage3

Return Value

• MS::kSuccess operation successful
• MS::kFailure operation failed

MString MPxContext:: image (ImageIndex index, MStatus * ReturnStatus) const

Description

This method is used to retrieve an XPM icon image that has previously been set for this tool context. This icon image will be used to represent this tool context in various places including the tool bar and can be queried from mel using the contextInfo command.

Arguments

• index the index for the image being retrieved; three image representations are permitted: kImage1, kImage2, kImage3
• ReturnStatus Status code (see below)

Return Value

• string name

Status Codes

• MS::kSuccess operation successful
• MS::kFailure operation failed

void MPxContext:: abortAction ()

Description

This method is called when the abort key is pressed. The default abort key in Maya is the escape key. Users can override this method if they wish to perform certain operations when the abort key is pressed.

Return Value

• none

bool MPxContext:: processNumericalInput ( const MDoubleArray &values, const MIntArray &flags, bool isAbsolute )

Description

This method processes the input from the numerical input field. Users can override this method if they wish to process numerical input. For a given entry in the numeric input field, if the user types a dot ".", this indicates that the entry should not be modified. The overridden version of this method should take this into account using the ignoreEntry method with the flags that are passed in. The overridden version of this method should also process the numeric input as an absolute input or relative input depending on whether the isAbsolute flag is true or not. The return value should indicate whether or not the numerical input has been processed.

Arguments

• values the values from the numerical input field
• flags used in conjunction with the ignoreEntry method, determines whether or not a given entry should be ignored
• isAbsolute whether or not the input should be interpreted as absolute

Return Value

• false the default return value

bool MPxContext:: feedbackNumericalInput () const

Description

This method is called to update the numerical feedback. The format and values for the feedback line can be set through the methods in MFeedbackLine, specifically setFormat and setValue. The return value should indicate whether or not the numerical feedback has been provided.

Return Value

• false the default return value

MSyntax::MArgType MPxContext:: argTypeNumericalInput (unsigned int index) const

Description

This method is used by the feedback line to determine what units to display. Users should override this method to return the appropriate argument type for the given index of the numeric input field. Specifically, this method should be overridden to return one of the following:

• MSyntax::kNoArg for no argument
• MSyntax::kDistance for linear units
• MSyntax::kAngle for angular units

Arguments

• index the index of the numerical input whose argument type is requested

Return Value

• MSyntax::kNoArg the default return value

void MPxContext:: getClassName ( MString &name) const

Description

This method is called to determine the name that uniquely identifies the context. Either this method, or the stringClassName method which returns a string, should be overridden such that the name is set to the appropriate string. For example:

	void MPxExampleContext::getClassName(MString &name) const
	{ name.set("exampleTool"); }
	

This name is used by Maya to call the appropriate tool property sheet MEL scripts, specifically:

• <name>Properties.mel
• <name>Values.mel

If this method is not overriden, by default it will set the string to "defaultTool".

Python Notes

This method is not supported in Python. For contexts implemented in Python please see stringClassName() which returns a string.

Arguments

• name string that uniquely identifies the context

Return Value

• none

MString MPxContext:: stringClassName () const

Description

This method is called to determine the name that uniquely identifies the context. Either this method, or the getClassName method, should be overridden such that the name is set to the appropriate string. For example:

	MString MPxExampleContext::stringClassName() const
	{ return "exampleTool"; }
	

This name is used by Maya to call the appropriate tool property sheet MEL scripts, specifically:

• <name>Properties.mel
• <name>Values.mel

If this method is not overriden, by default it will set the string to "defaultTool".

Arguments

Return Value

• name string that uniquely identifies the context

MStatus MPxContext:: setHelpString ( const MString & str )

Description

Set the help string to the given MString.
This string will appear in the help line in Maya.

Arguments

• str The new help string.

Return Value

• Status code

Status Codes

• MS::kSuccess

MStatus MPxContext:: setTitleString ( const MString & str )

Description

Set the title of the context to the MString that is passed in.
This string will appear in the help line when this context is activated.

Arguments

• event The new title string.

Return Value

• Status code

Status Codes

• MS::kSuccess

MStatus MPxContext:: setCursor ( const MCursor & newCursor )

Description

Set the cursor used by the context to the MCursor that is passed in.

Arguments

• newCursor The new cursor.

Return Value

• Status code

Status Codes

• MS::kSuccess The method was successful.
• MS::kInsufficientMemory Out of memory.

MStatus MPxContext:: beginMarquee ( MEvent & event )

Description

Start drawing a dragged out marquee box.
A marquee box is a rectangular area of the screen specified by two points representing opposite corners of the rectangle.
Marquee's are commonly used in the selection of multiple items from a region of the screen. The marquee rectangle acts as a guideline for the region of the screen that will be effected.

Arguments

• event Current event information.

Return Value

• Status code

Status Codes

• MS::kSuccess

MStatus MPxContext:: dragMarquee ( MEvent & event )

Description

Draws a rectangle representing the dragged out area initiated with the beginMarquee method.

Arguments

• event Current event information.

Return Value

• Status code

Status Codes

• MS::kSuccess

MStatus MPxContext:: releaseMarquee ( MEvent & event, short& top, short& left, short& bottom, short& right )

Description

End the marquee drawing cycle and return the coordinates corresponding to the dragged out area.
The rectangular guideline representing the dragged area is cleared.

Arguments

• event Current event information.
• top highest value
• left left-most value
• bottom lowest value
• right right-most value

Return Value

• Status Code

Status Codes

• MS::kSuccess

MPxToolCommand * MPxContext:: newToolCommand ()

Description

Create a new instance of the tool command associated with this context. The tool command (derived from MPxToolCommand) is the command that was registered along with the context command in :

    MFnPlugin::registerContextCommand( contextCommand, contextCommandCreator,
                                       toolCommand, toolCommandCreator )
	

Return Value

• A new instance of the MPxToolCommand.

bool MPxContext:: ignoreEntry (const MIntArray &flags, unsigned int entry)

Description

This is a helper method which can be called from processNumericalInput to examine a flags array and return true if the requested (0-based) entry is to be ignored.

Arguments

• flags used in conjunction with the processNumericalInput method, determines whether or not a given entry should be ignored.
• entry the entry specified by a (0-based) index

Return Value

• true the given entry should be ignored
• false the given entry should not be ignored

Direct child classes:

- MPxSelectionContext