#include <Leap.h>

Inheritance diagram for Leap::Frame:

Detailed Description

The Frame class represents a set of hand and finger tracking data detected in a single frame.

The Leap detects hands, fingers and tools within the tracking area, reporting their positions, orientations and motions in frames at the Leap frame rate.

Access Frame objects through an instance of a Leap Controller. Implement a Listener subclass to receive a callback event when a new Frame is available.

Public Member Functions
	Frame (FrameImplementation *)

LEAP_EXPORT	Frame ()

LEAP_EXPORT int64_t	id () const

LEAP_EXPORT int64_t	timestamp () const

LEAP_EXPORT HandList	hands () const

LEAP_EXPORT Hand	hand (int32_t id) const

LEAP_EXPORT PointableList	pointables () const

LEAP_EXPORT Pointable	pointable (int32_t id) const

LEAP_EXPORT FingerList	fingers () const

LEAP_EXPORT Finger	finger (int32_t id) const

LEAP_EXPORT ToolList	tools () const

LEAP_EXPORT Tool	tool (int32_t id) const

LEAP_EXPORT Gesture	gesture (int32_t id) const

LEAP_EXPORT GestureList	gestures () const

LEAP_EXPORT GestureList	gestures (const Frame &sinceFrame) const

LEAP_EXPORT Vector	translation (const Frame &sinceFrame) const

LEAP_EXPORT float	translationProbability (const Frame &sinceFrame) const

LEAP_EXPORT Vector	rotationAxis (const Frame &sinceFrame) const

LEAP_EXPORT float	rotationAngle (const Frame &sinceFrame) const

LEAP_EXPORT float	rotationAngle (const Frame &sinceFrame, const Vector &axis) const

LEAP_EXPORT Matrix	rotationMatrix (const Frame &sinceFrame) const

LEAP_EXPORT float	rotationProbability (const Frame &sinceFrame) const

LEAP_EXPORT float	scaleFactor (const Frame &sinceFrame) const

LEAP_EXPORT float	scaleProbability (const Frame &sinceFrame) const

LEAP_EXPORT bool	isValid () const

LEAP_EXPORT bool	operator== (const Frame &) const

LEAP_EXPORT bool	operator!= (const Frame &) const

LEAP_EXPORT std::string	toString () const

Static Public Member Functions
static LEAP_EXPORT const Frame &	invalid ()

Friends
LEAP_EXPORT friend std::ostream &	operator<< (std::ostream &, const Frame &)

Additional Inherited Members
Protected Attributes inherited from Leap::Interface
class SharedObject *	m_object

Protected Member Functions inherited from Leap::Interface
LEAP_EXPORT	Interface (void *owner)

LEAP_EXPORT	Interface (Implementation reference, void owner)

LEAP_EXPORT	Interface (const Interface &rhs)

LEAP_EXPORT Interface &	operator= (const Interface &rhs)

virtual LEAP_EXPORT	~Interface ()

template<typename T >
T *	get () const

Constructor details

◆ Frame() [1/2]

Leap::Frame::Frame ( FrameImplementation * )

◆ Frame() [2/2]

LEAP_EXPORT Leap::Frame::Frame ( )

Constructs a Frame object.

Frame instances created with this constructor are invalid. Get valid Frame objects by calling the Controller::frame() function.

Function details

◆ finger()

LEAP_EXPORT Finger Leap::Frame::finger ( int32_t id ) const

The Finger object with the specified ID in this frame.

Use the Frame::finger() function to retrieve the Finger object from this frame using an ID value obtained from a previous frame. This function always returns a Finger object, but if no finger with the specified ID is present, an invalid Finger object is returned.

Note that ID values persist across frames, but only until tracking of a particular object is lost. If tracking of a finger is lost and subsequently regained, the new Finger object representing that physical finger may have a different ID than that representing the finger in an earlier frame.

Parameters

id	The ID value of a Finger object from a previous frame.

Returns: The Finger object with the matching ID if one exists in this frame; otherwise, an invalid Finger object is returned.

◆ fingers()

LEAP_EXPORT FingerList Leap::Frame::fingers ( ) const

The list of Finger objects detected in this frame, given in arbitrary order. The list can be empty if no fingers are detected.

Returns: The FingerList containing all Finger objects detected in this frame.

◆ gesture()

LEAP_EXPORT Gesture Leap::Frame::gesture ( int32_t id ) const

The Gesture object with the specified ID in this frame.

Use the Frame::gesture() function to return a Gesture object in this frame using an ID obtained in an earlier frame. The function always returns a Gesture object, but if there was no update for the gesture in this frame, then an invalid Gesture object is returned.

All Gesture objects representing the same recognized movement share the same ID.

Parameters

id	The ID of an Gesture object from a previous frame.

Returns: The Gesture object in the frame with the specified ID if one exists; Otherwise, an Invalid Gesture object.

◆ gestures() [1/2]

LEAP_EXPORT GestureList Leap::Frame::gestures ( ) const

The gestures recognized or continuing in this frame.

Circle and swipe gestures are updated every frame. Tap gestures only appear in the list for a single frame.

Returns: GestureList the list of gestures.

◆ gestures() [2/2]

LEAP_EXPORT GestureList Leap::Frame::gestures ( const Frame & sinceFrame ) const

Returns a GestureList containing all gestures that have occurred since the specified frame.

Parameters

sinceFrame An earlier Frame object. The starting frame must still be in the frame history cache, which has a default length of 60 frames.

Returns: GestureList The list of the Gesture objects that have occurred since the specified frame.

◆ hand()

LEAP_EXPORT Hand Leap::Frame::hand ( int32_t id ) const

The Hand object with the specified ID in this frame.

Use the Frame::hand() function to retrieve the Hand object from this frame using an ID value obtained from a previous frame. This function always returns a Hand object, but if no hand with the specified ID is present, an invalid Hand object is returned.

Note that ID values persist across frames, but only until tracking of a particular object is lost. If tracking of a hand is lost and subsequently regained, the new Hand object representing that physical hand may have a different ID than that representing the physical hand in an earlier frame.

Parameters

id	The ID value of a Hand object from a previous frame.

Returns: The Hand object with the matching ID if one exists in this frame; otherwise, an invalid Hand object is returned.

◆ hands()

LEAP_EXPORT HandList Leap::Frame::hands ( ) const

The list of Hand objects detected in this frame, given in arbitrary order. The list can be empty if no hands are detected.

Returns: The HandList containing all Hand objects detected in this frame.

◆ id()

LEAP_EXPORT int64_t Leap::Frame::id ( ) const

A unique ID for this Frame. Consecutive frames processed by the Leap have consecutive increasing values.

Returns: The frame ID.

◆ invalid()

static LEAP_EXPORT const Frame& Leap::Frame::invalid ( )

static

Returns an invalid Frame object.

You can use the instance returned by this function in comparisons testing whether a given Frame instance is valid or invalid. (You can also use the Frame::isValid() function.)

Returns: The invalid Frame instance.

◆ isValid()

LEAP_EXPORT bool Leap::Frame::isValid ( ) const

Reports whether this Frame instance is valid.

A valid Frame is one generated by the Leap::Controller object that contains tracking data for all detected entities. An invalid Frame contains no actual tracking data, but you can call its functions without risk of a null pointer exception. The invalid Frame mechanism makes it more convenient to track individual data across the frame history. For example, you can invoke:

Finger finger = controller.frame(n).finger(fingerID);

Leap::Frame::finger

LEAP_EXPORT Finger finger(int32_t id) const

Leap::Pointable::frame

LEAP_EXPORT Frame frame() const

for an arbitrary Frame history value, "n", without first checking whether frame(n) returned a null object. (You should still check that the returned Finger instance is valid.)

Returns: True, if this is a valid Frame object; false otherwise.

◆ operator!=()

LEAP_EXPORT bool Leap::Frame::operator!= ( const Frame & ) const

Compare Frame object inequality. Two Frame objects are equal if and only if both Frame objects represent the exact same frame of tracking data and both Frame objects are valid.

◆ operator==()

LEAP_EXPORT bool Leap::Frame::operator== ( const Frame & ) const

Compare Frame object equality. Two Frame objects are equal if and only if both Frame objects represent the exact same frame of tracking data and both Frame objects are valid.

◆ pointable()

LEAP_EXPORT Pointable Leap::Frame::pointable ( int32_t id ) const

The Pointable object with the specified ID in this frame.

Use the Frame::pointable() function to retrieve the Pointable object from this frame using an ID value obtained from a previous frame. This function always returns a Pointable object, but if no finger or tool with the specified ID is present, an invalid Pointable object is returned.

Note that ID values persist across frames, but only until tracking of a particular object is lost. If tracking of a finger or tool is lost and subsequently regained, the new Pointable object representing that finger or tool may have a different ID than that representing the finger or tool in an earlier frame.

Parameters

id	The ID value of a Pointable object from a previous frame.

Returns: The Pointable object with the matching ID if one exists in this frame; otherwise, an invalid Pointable object is returned.

◆ pointables()

LEAP_EXPORT PointableList Leap::Frame::pointables ( ) const

The list of Pointable objects (fingers and tools) detected in this frame, given in arbitrary order. The list can be empty if no fingers or tools are detected.

Returns: The PointableList containing all Pointable objects detected in this frame.

◆ rotationAngle() [1/2]

LEAP_EXPORT float Leap::Frame::rotationAngle ( const Frame & sinceFrame ) const

The angle of rotation around the rotation axis derived from the overall rotational motion between the current frame and the specified frame.

The returned angle is expressed in radians measured clockwise around the rotation axis (using the right-hand rule) between the start and end frames. The value is always between 0 and pi radians (0 and 180 degrees).

The Leap derives frame rotation from the relative change in position and orientation of all objects detected in the field of view.

If either this frame or sinceFrame is an invalid Frame object, then the angle of rotation is zero.

Parameters

sinceFrame The starting frame for computing the relative rotation.

Returns: A positive value containing the heuristically determined rotational change between the current frame and that specified in the sinceFrame parameter.

◆ rotationAngle() [2/2]

LEAP_EXPORT float Leap::Frame::rotationAngle	(	const Frame &	sinceFrame,
		const Vector &	axis
	)		const

The angle of rotation around the specified axis derived from the overall rotational motion between the current frame and the specified frame.

The returned angle is expressed in radians measured clockwise around the rotation axis (using the right-hand rule) between the start and end frames. The value is always between -pi and pi radians (-180 and 180 degrees).

The Leap derives frame rotation from the relative change in position and orientation of all objects detected in the field of view.

If either this frame or sinceFrame is an invalid Frame object, then the angle of rotation is zero.

Parameters

sinceFrame	The starting frame for computing the relative rotation.
axis	The axis to measure rotation around.

Returns: A value containing the heuristically determined rotational change between the current frame and that specified in the sinceFrame parameter around the given axis.

◆ rotationAxis()

LEAP_EXPORT Vector Leap::Frame::rotationAxis ( const Frame & sinceFrame ) const

The axis of rotation derived from the overall rotational motion between the current frame and the specified frame.

The returned direction vector is normalized.

The Leap derives frame rotation from the relative change in position and orientation of all objects detected in the field of view.

If either this frame or sinceFrame is an invalid Frame object, or if no rotation is detected between the two frames, a zero vector is returned.

Parameters

sinceFrame The starting frame for computing the relative rotation.

Returns: A normalized direction Vector representing the axis of the heuristically determined rotational change between the current frame and that specified in the sinceFrame parameter.

◆ rotationMatrix()

LEAP_EXPORT Matrix Leap::Frame::rotationMatrix ( const Frame & sinceFrame ) const

The transform matrix expressing the rotation derived from the overall rotational motion between the current frame and the specified frame.

The Leap derives frame rotation from the relative change in position and orientation of all objects detected in the field of view.

If either this frame or sinceFrame is an invalid Frame object, then this method returns an identity matrix.

Parameters

sinceFrame The starting frame for computing the relative rotation.

Returns: A transformation Matrix containing the heuristically determined rotational change between the current frame and that specified in the sinceFrame parameter.

◆ rotationProbability()

LEAP_EXPORT float Leap::Frame::rotationProbability ( const Frame & sinceFrame ) const

The estimated probability that the overall motion between the current frame and the specified frame is intended to be a rotating motion.

If either this frame or sinceFrame is an invalid Frame object, then this method returns zero.

Parameters

sinceFrame The starting frame for computing the relative rotation.

Returns: A value between 0 and 1 representing the estimated probability that the overall motion between the current frame and the specified frame is intended to be a rotating motion.

◆ scaleFactor()

LEAP_EXPORT float Leap::Frame::scaleFactor ( const Frame & sinceFrame ) const

The scale factor derived from the overall motion between the current frame and the specified frame.

The scale factor is always positive. A value of 1.0 indicates no scaling took place. Values between 0.0 and 1.0 indicate contraction and values greater than 1.0 indicate expansion.

The Leap derives scaling from the relative inward or outward motion of all objects detected in the field of view (independent of translation and rotation).

If either this frame or sinceFrame is an invalid Frame object, then this method returns 1.0.

Parameters

sinceFrame The starting frame for computing the relative scaling.

Returns: A positive value representing the heuristically determined scaling change ratio between the current frame and that specified in the sinceFrame parameter.

◆ scaleProbability()

LEAP_EXPORT float Leap::Frame::scaleProbability ( const Frame & sinceFrame ) const

The estimated probability that the overall motion between the current frame and the specified frame is intended to be a scaling motion.

If either this frame or sinceFrame is an invalid Frame object, then this method returns zero.

Parameters

sinceFrame The starting frame for computing the relative scaling.

Returns: A value between 0 and 1 representing the estimated probability that the overall motion between the current frame and the specified frame is intended to be a scaling motion.

◆ timestamp()

LEAP_EXPORT int64_t Leap::Frame::timestamp ( ) const

The frame capture time in microseconds elapsed since the Leap started.

Returns: The timestamp in microseconds.

◆ tool()

LEAP_EXPORT Tool Leap::Frame::tool ( int32_t id ) const

The Tool object with the specified ID in this frame.

Use the Frame::tool() function to retrieve the Tool object from this frame using an ID value obtained from a previous frame. This function always returns a Tool object, but if no tool with the specified ID is present, an invalid Tool object is returned.

Note that ID values persist across frames, but only until tracking of a particular object is lost. If tracking of a tool is lost and subsequently regained, the new Tool object representing that tool may have a different ID than that representing the tool in an earlier frame.

Parameters

id	The ID value of a Tool object from a previous frame.

Returns: The Tool object with the matching ID if one exists in this frame; otherwise, an invalid Tool object is returned.

◆ tools()

LEAP_EXPORT ToolList Leap::Frame::tools ( ) const

The list of Tool objects detected in this frame, given in arbitrary order. The list can be empty if no tools are detected.

Returns: The ToolList containing all Tool objects detected in this frame.

◆ toString()

LEAP_EXPORT std::string Leap::Frame::toString ( ) const

A string containing a brief, human readable description of the Frame object.

Returns: A description of the Frame as a string.

◆ translation()

LEAP_EXPORT Vector Leap::Frame::translation ( const Frame & sinceFrame ) const

The change of position derived from the overall linear motion between the current frame and the specified frame.

The returned translation vector provides the magnitude and direction of the movement in millimeters.

The Leap derives frame translation from the linear motion of all objects detected in the field of view.

If either this frame or sinceFrame is an invalid Frame object, then this method returns a zero vector.

Parameters

sinceFrame The starting frame for computing the relative translation.

Returns: A Vector representing the heuristically determined change in position of all objects between the current frame and that specified in the sinceFrame parameter.

◆ translationProbability()

LEAP_EXPORT float Leap::Frame::translationProbability ( const Frame & sinceFrame ) const

The estimated probability that the overall motion between the current frame and the specified frame is intended to be a translating motion.

If either this frame or sinceFrame is an invalid Frame object, then this method returns zero.

Parameters

sinceFrame The starting frame for computing the translation.

Returns: A value between 0 and 1 representing the estimated probability that the overall motion between the current frame and the specified frame is intended to be a translating motion.

Related details

◆ operator<<

LEAP_EXPORT friend std::ostream& operator<<	(	std::ostream &	,
		const Frame &
	)

friend

Writes a brief, human readable description of the Frame object to an output stream.

Detailed Description

Public Member Functions

Static Public Member Functions

Friends

Additional Inherited Members

Constructor details

◆ Frame() [1/2]

◆ Frame() [2/2]

Function details

◆ finger()

◆ fingers()

◆ gesture()

◆ gestures() [1/2]

◆ gestures() [2/2]

◆ hand()

◆ hands()

◆ id()

◆ invalid()

◆ isValid()

◆ operator!=()

◆ operator==()

◆ pointable()

◆ pointables()

◆ rotationAngle() [1/2]

◆ rotationAngle() [2/2]

◆ rotationAxis()

◆ rotationMatrix()

◆ rotationProbability()

◆ scaleFactor()

◆ scaleProbability()

◆ timestamp()

◆ tool()

◆ tools()

◆ toString()

◆ translation()

◆ translationProbability()

Related details

◆ operator<<