The Finger class represents a tracked finger. More...

Inherits Pointable.

Public Types
enum	Joint
	Deprecated as of version 2.0. More...

enum	Type
	Enumerates the names of the fingers. More...

enum	Zone
	Defines the values for reporting the state of a Pointable object in relation to an adaptive touch plane. More...

Public Member Functions
Bone	bone (Bone::Type boneIx) const
	The bone at a given bone index on this finger. More...

Vector	direction () const
	The direction in which this finger is pointing. More...

	Finger (FingerImplementation *)

	Finger ()
	Constructs a Finger object. More...

	Finger (const Pointable &)
	If the specified Pointable object represents a finger, creates a copy of it as a Finger object; otherwise, creates an invalid Finger object. More...

Frame	frame () const
	The Frame associated with this Pointable object. More...

Hand	hand () const
	The Hand associated with a finger. More...

int32_t	id () const
	A unique ID assigned to this Pointable object, whose value remains the same across consecutive frames while the tracked finger remains visible. More...

bool	isExtended () const
	Whether or not this Pointable is in an extended posture. More...

bool	isFinger () const
	Whether or not this Pointable is classified as a finger. More...

bool	isTool () const
	Whether or not this Pointable is classified as a tool. More...

bool	isValid () const
	Reports whether this is a valid Pointable object. More...

Vector	jointPosition (Joint jointIx) const
	Deprecated as of version 2.0 Use 'bone' method instead. More...

float	length () const
	The estimated length of the finger in millimeters. More...

bool	operator!= (const Pointable &) const
	Compare Pointable object inequality. More...

bool	operator== (const Pointable &) const
	Compare Pointable object equality. More...

Vector	stabilizedTipPosition () const
	The stabilized tip position of this Pointable. More...

float	timeVisible () const
	The duration of time this Pointable has been visible to the Leap Motion Controller. More...

Vector	tipPosition () const
	The tip position in millimeters from the Leap Motion origin. More...

Vector	tipVelocity () const
	The rate of change of the tip position in millimeters/second. More...

std::string	toString () const
	A string containing a brief, human readable description of the Finger object. More...

float	touchDistance () const
	A value proportional to the distance between this Pointable object and the adaptive touch plane. More...

Zone	touchZone () const
	The current touch zone of this Pointable object. More...

Type	type () const
	The name of this finger. More...

float	width () const
	The estimated width of the finger in millimeters. More...

Static Public Member Functions
static const Finger &	invalid ()
	Returns an invalid Finger object. More...

Detailed Description

The Finger class represents a tracked finger.

Fingers are Pointable objects that the Leap Motion software has classified as a finger. Get valid Finger objects from a Frame or a Hand object.

Fingers may be permanently associated to a hand. In this case the angular order of the finger IDs will be invariant. As fingers move in and out of view it is possible for the guessed ID of a finger to be incorrect. Consequently, it may be necessary for finger IDs to be exchanged. All tracked properties, such as velocity, will remain continuous in the API. However, quantities that are derived from the API output (such as a history of positions) will be discontinuous unless they have a corresponding ID exchange.

Note that Finger objects can be invalid, which means that they do not contain valid tracking data and do not correspond to a physical finger. Invalid Finger objects can be the result of asking for a Finger object using an ID from an earlier frame when no Finger objects with that ID exist in the current frame. A Finger object created from the Finger constructor is also invalid. Test for validity with the Finger::isValid() function.

Since: 1.0

Member Enumeration Documentation

enum Joint

Deprecated as of version 2.0.

Enumerator
JOINT_MCP
JOINT_PIP
JOINT_DIP
JOINT_TIP

enum Type

Enumerates the names of the fingers.

Members of this enumeration are returned by Finger::type() to identify a Finger object.

Since: 2.0

Enumerator
TYPE_THUMB	The thumb.
TYPE_INDEX	The index or fore-finger.
TYPE_MIDDLE	The middle finger.
TYPE_RING	The ring finger.
TYPE_PINKY	The pinky or little finger.

enum Zone

inherited

Defines the values for reporting the state of a Pointable object in relation to an adaptive touch plane.

Since: 1.0

Enumerator

ZONE_NONE

The Pointable object is too far from the plane to be considered hovering or touching.

Since: 1.0

ZONE_HOVERING

The Pointable object is close to, but not touching the plane.

Since: 1.0

ZONE_TOUCHING

The Pointable has penetrated the plane.

Since: 1.0

Constructor & Destructor Documentation

Finger ( FingerImplementation * )

Finger ( )

Constructs a Finger object.

An uninitialized finger is considered invalid. Get valid Finger objects from a Frame or a Hand object.

Since: 1.0

Finger ( const Pointable & )

explicit

If the specified Pointable object represents a finger, creates a copy of it as a Finger object; otherwise, creates an invalid Finger object.

Leap::Finger finger = Leap::Finger(pointable);

Since: 1.0

Member Function Documentation

Bone bone ( Bone::Type boneIx ) const

The bone at a given bone index on this finger.

Leap::FingerList fingers = frame.hands()[0].fingers();
for(Leap::FingerList::const_iterator fl = fingers.begin(); fl != fingers.end(); fl++){
    Leap::Bone bone;
    Leap::Bone::Type boneType;
    for(int b = 0; b < 4; b++)
    {
        boneType = static_cast<Leap::Bone::Type>(b);
        bone = (*fl).bone(boneType);
        std::cout << "Finger index: " << (*fl).type() << " " << bone << std::endl;
    }
}

Parameters

boneIx An index value from the Bone::Type enumeration identifying the bone of interest.

Returns: The Bone that has the specified bone type.

Since: 2.0

Vector direction ( ) const

inherited

The direction in which this finger is pointing.

Leap::Vector pointingToward = pointable.direction();

The direction is expressed as a unit vector pointing in the same direction as the tip.

Returns: The Vector pointing in the same direction as the tip of this Pointable object.

Since: 1.0

Frame frame ( ) const

inherited

The Frame associated with this Pointable object.

Leap::Frame frameOfThisPointableObject = pointable.frame();

Returns: The associated Frame object, if available; otherwise, an invalid Frame object is returned.

Since: 1.0

Hand hand ( ) const

inherited

The Hand associated with a finger.

Leap::Hand attachedHand = pointable.hand();

This function always returns an invalid Hand object.

Returns: The associated Hand object, if available; otherwise, an invalid Hand object is returned.

Since: 1.0

int32_t id ( ) const

inherited

A unique ID assigned to this Pointable object, whose value remains the same across consecutive frames while the tracked finger remains visible.

If tracking is lost (for example, when a finger is occluded by another finger or when it is withdrawn from the Leap Motion Controller field of view), the Leap Motion software may assign a new ID when it detects the entity in a future frame.

int32_t theID = pointable.id();

Use the ID value with the Frame::pointable() function to find this Pointable object in future frames.

IDs should be from 1 to 100 (inclusive). If more than 100 objects are tracked an IDs of -1 will be used until an ID in the defined range is available.

Returns: The ID assigned to this Pointable object.

Since: 1.0

static const Finger& invalid ( )

static

Returns an invalid Finger object.

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

Leap::Finger invalidFinger = Leap::Finger::invalid();

Returns: The invalid Finger instance.

Since: 1.0

bool isExtended ( ) const

inherited

Whether or not this Pointable is in an extended posture.

A finger is considered extended if it is extended straight from the hand as if pointing. A finger is not extended when it is bent down and curled towards the palm.

int extendedFingers = 0;
for (int f = 0; f < hand.fingers().count(); f++)
{
    Leap::Finger finger = hand.fingers()[f];
    if(finger.isExtended()) extendedFingers++;
}

Returns: True, if the pointable is extended.

Since: 2.0

bool isFinger ( ) const

inherited

Whether or not this Pointable is classified as a finger.

if (pointable.isTool()) {
    Leap::Tool tool = Leap::Tool(pointable);
} else {
    Leap::Finger finger = Leap::Finger(pointable);
}

Returns: True, if this Pointable is classified as a finger.

Since: 1.0

bool isTool ( ) const

inherited

Whether or not this Pointable is classified as a tool.

if (pointable.isTool()) {
    Leap::Tool tool = Leap::Tool(pointable);
} else {
    Leap::Finger finger = Leap::Finger(pointable);
}

Returns: false

Deprecated:: 3.0

bool isValid ( ) const

inherited

Reports whether this is a valid Pointable object.

if( pointable.isValid()) {
    //Use it...
}

Returns: True, if this Pointable object contains valid tracking data.

Since: 1.0

Vector jointPosition ( Joint jointIx ) const

Deprecated as of version 2.0 Use 'bone' method instead.

float length ( ) const

inherited

The estimated length of the finger in millimeters.

float apparentlength = pointable.length();

Returns: The estimated length of this Pointable object.

Since: 1.0

bool operator!= ( const Pointable & ) const

inherited

Compare Pointable object inequality.

thisPointable != thatPointable;

Two Pointable objects are equal if and only if both Pointable objects represent the exact same physical entities in the same frame and both Pointable objects are valid.

Since: 1.0

bool operator== ( const Pointable & ) const

inherited

Compare Pointable object equality.

thisPointable == thatPointable;

Two Pointable objects are equal if and only if both Pointable objects represent the exact same physical entities in the same frame and both Pointable objects are valid.

Since: 1.0

Vector stabilizedTipPosition ( ) const

inherited

The stabilized tip position of this Pointable.

Smoothing and stabilization is performed in order to make this value more suitable for interaction with 2D content. The stabilized position lags behind the tip position by a variable amount, depending primarily on the speed of movement.

Leap::Vector stabilizedPosition = pointable.stabilizedTipPosition();

Returns: A modified tip position of this Pointable object with some additional smoothing and stabilization applied.

Since: 1.0

float timeVisible ( ) const

inherited

The duration of time this Pointable has been visible to the Leap Motion Controller.

float lifetime = pointable.timeVisible();

Returns: The duration (in seconds) that this Pointable has been tracked.

Since: 1.0

Vector tipPosition ( ) const

inherited

The tip position in millimeters from the Leap Motion origin.

Leap::Vector currentPosition = pointable.tipPosition();

Returns: The Vector containing the coordinates of the tip position.

Since: 1.0

Vector tipVelocity ( ) const

inherited

The rate of change of the tip position in millimeters/second.

Leap::Vector currentSpeed = pointable.tipVelocity();

Returns: The Vector containing the coordinates of the tip velocity.

Since: 1.0

std::string toString ( ) const

inline

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

std::string description = finger.toString();

Returns: A description of the Finger object as a string.

Since: 1.0

float touchDistance ( ) const

inherited

A value proportional to the distance between this Pointable object and the adaptive touch plane.

float distance = pointable.touchDistance();
if (distance > 0) {
    //Handle hovering ...
} else {
    //Handle touching ...
}

Returns: The normalized touch distance of this Pointable object.

Deprecated:: 3.0

Zone touchZone ( ) const

inherited

The current touch zone of this Pointable object.

switch (pointable.touchZone()) {
    case Leap::Pointable::ZONE_NONE:
        //Handle distant pointable
        break;
    case Leap::Pointable::ZONE_HOVERING:
        //Handle pointable near touch plane
        break;
    case Leap::Pointable::ZONE_TOUCHING:
        //Handle pointable penetrating touch plane
        break;
    default:
        //Handle error cases...
        break;
}

Returns: The touch zone of this Pointable

Deprecated:: 3.0

Type type ( ) const

The name of this finger.

Leap::Finger::Type fingerType = finger.type();

Returns: The anatomical type of this finger as a member of the Finger::Type enumeration.

Since: 2.0

float width ( ) const

inherited

The estimated width of the finger in millimeters.

float averageThickness = pointable.width();

Returns: The estimated width of this Pointable object.

Since: 1.0

Finger¶

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation