The Gesture class represents a recognized movement by the user. More...

Inherits com.leapmotion.leap.Interface.

Inherited by com.leapmotion.leap.CircleGesture, com.leapmotion.leap.KeyTapGesture, com.leapmotion.leap.ScreenTapGesture, and com.leapmotion.leap.SwipeGesture.

Classes
enum	State
	The possible gesture states. More...

enum	Type
	The supported types of gestures. More...

Public Member Functions
long	duration ()
	The elapsed duration of the recognized movement up to the frame containing this Gesture object, in microseconds.

float	durationSeconds ()
	The elapsed duration in seconds.

boolean	equals (Gesture rhs)
	Compare Gesture object equality.

Frame	frame ()
	The Frame containing this Gesture instance.

	Gesture ()
	Constructs a new Gesture object.

	Gesture (Gesture rhs)
	Constructs a new copy of an Gesture object.

HandList	hands ()
	The list of hands associated with this Gesture, if any.

int	id ()
	The gesture ID.

boolean	isValid ()
	Reports whether this Gesture instance represents a valid Gesture.

PointableList	pointables ()
	The list of fingers and tools associated with this Gesture, if any.

Gesture.State	state ()
	The gesture state.

String	toString ()
	A string containing a brief, human-readable description of this Gesture.

Gesture.Type	type ()
	The gesture type.

Static Public Member Functions
static Gesture	invalid ()
	Returns an invalid Gesture object.

Detailed Description

The Gesture class represents a recognized movement by the user.

The Leap Motion Controller watches the activity within its field of view for certain movement patterns typical of a user gesture or command. For example, a movement from side to side with the hand can indicate a swipe gesture, while a finger poking forward can indicate a screen tap gesture.

When the Leap Motion software recognizes a gesture, it assigns an ID and adds a Gesture object to the frame gesture list. For continuous gestures, which occur over many frames, the Leap Motion software updates the gesture by adding a Gesture object having the same ID and updated properties in each subsequent frame.

Important: Recognition for each type of gesture must be enabled using the Controller::enableGesture() function; otherwise no gestures are recognized or reported.

Subclasses of Gesture define the properties for the specific movement patterns recognized by the Leap Motion software.

The Gesture subclasses for include:

CircleGesture – A circular movement by a finger.
SwipeGesture – A straight line movement by the hand with fingers extended.
ScreenTapGesture – A forward tapping movement by a finger.
KeyTapGesture – A downward tapping movement by a finger.

Circle and swipe gestures are continuous and these objects can have a state of start, update, and stop.

The screen tap gesture is a discrete gesture. The Leap Motion software only creates a single ScreenTapGesture object for each tap and it always has a stop state.

Get valid Gesture instances from a Frame object. You can get a list of gestures with the Frame::gestures() method. You can get a list of gestures since a specified frame with the Frame::gestures(const Frame&) method. You can also use the Frame::gesture() method to find a gesture in the current frame using an ID value obtained in a previous frame.

Gesture objects can be invalid. For example, when you get a gesture by ID using Frame::gesture(), and there is no gesture with that ID in the current frame, then gesture() returns an Invalid Gesture object (rather than a null value). Always check object validity in situations where a gesture might be invalid.

The following keys can be used with the Config class to configure the gesture recognizer:

Key string	Value type	Default value	Units
Gesture.Circle.MinRadius	float	5.0	mm
Gesture.Circle.MinArc	float	1.5*pi	radians
Gesture.Swipe.MinLength	float	150	mm
Gesture.Swipe.MinVelocity	float	1000	mm/s
Gesture.KeyTap.MinDownVelocity	float	50	mm/s
Gesture.KeyTap.HistorySeconds	float	0.1	s
Gesture.KeyTap.MinDistance	float	5.0	mm
Gesture.ScreenTap.MinForwardVelocity	float	50	mm/s
Gesture.ScreenTap.HistorySeconds	float	0.1	s
Gesture.ScreenTap.MinDistance	float	3.0	mm

Since: 1.0

Constructor & Destructor Documentation

com.leapmotion.leap.Gesture.Gesture ( )

Constructs a new Gesture object.

An uninitialized Gesture object is considered invalid. Get valid instances of the Gesture class, which will be one of the Gesture subclasses, from a Frame object.

Since: 1.0

com.leapmotion.leap.Gesture.Gesture ( Gesture rhs )

Constructs a new copy of an Gesture object.

Gesture copy = new Gesture(gesture);

Since: 1.0

Member Function Documentation

long com.leapmotion.leap.Gesture.duration ( )

The elapsed duration of the recognized movement up to the frame containing this Gesture object, in microseconds.

float microseconds = gesture.duration();

The duration reported for the first Gesture in the sequence (with the STATE_START state) will typically be a small positive number since the movement must progress far enough for the Leap Motion software to recognize it as an intentional gesture.

Returns: int64_t the elapsed duration in microseconds.

Since: 1.0

float com.leapmotion.leap.Gesture.durationSeconds ( )

The elapsed duration in seconds.

float seconds = gesture.durationSeconds();

See Also: duration()

Returns: float the elapsed duration in seconds.

Since: 1.0

boolean com.leapmotion.leap.Gesture.equals ( Gesture rhs )

Compare Gesture object equality.

Boolean gestureIsEqual = thisGesture.equals(thatGesture);

Two Gestures are equal if they represent the same snapshot of the same recognized movement.

Since: 1.0

Frame com.leapmotion.leap.Gesture.frame ( )

The Frame containing this Gesture instance.

Frame frameOfGesture = gesture.frame();

_

Returns: Frame The parent Frame object.

Since: 1.0

HandList com.leapmotion.leap.Gesture.hands ( )

The list of hands associated with this Gesture, if any.

HandList handsForGesture = gesture.hands();

If no hands are related to this gesture, the list is empty.

Returns: HandList the list of related Hand objects.

Since: 1.0

int com.leapmotion.leap.Gesture.id ( )

The gesture ID.

All Gesture objects belonging to the same recognized movement share the same ID value. Use the ID value with the Frame::gesture() method to find updates related to this Gesture object in subsequent frames.

int gestureToFind = gesture.id();
GestureList manyGestures = frame.gestures(olderFrame);

for(int g = 0; g < manyGestures.count(); g++)
{
    if (manyGestures.get(g).id() == gestureToFind) {
        //Process it...
    }
}

Returns: int32_t the ID of this Gesture.

Since: 1.0

static Gesture com.leapmotion.leap.Gesture.invalid ( )

static

Returns an invalid Gesture object.

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

Gesture trackedGesture = frame.gesture(gestureID);

if (!trackedGesture.equals(Gesture.invalid())) {
    //Process it...
}

Returns: The invalid Gesture instance.

Since: 1.0

boolean com.leapmotion.leap.Gesture.isValid ( )

Reports whether this Gesture instance represents a valid Gesture.

An invalid Gesture object does not represent a snapshot of a recognized movement. Invalid Gesture objects are returned when a valid object cannot be provided. For example, when you get an gesture by ID using Frame::gesture(), and there is no gesture with that ID in the current frame, then gesture() returns an Invalid Gesture object (rather than a null value). Always check object validity in situations where an gesture might be invalid.

if (gesture.isValid()) {
    // Process it...
}

Returns: bool True, if this is a valid Gesture instance; false, otherwise.

Since: 1.0

PointableList com.leapmotion.leap.Gesture.pointables ( )

The list of fingers and tools associated with this Gesture, if any.

If no Pointable objects are related to this gesture, the list is empty.

PointableList pointablesForGesture = gesture.pointables();

Returns: PointableList the list of related Pointable objects.

Since: 1.0

Gesture.State com.leapmotion.leap.Gesture.state ( )

The gesture state.

Recognized movements occur over time and have a beginning, a middle, and an end. The 'state()' attribute reports where in that sequence this Gesture object falls.

for(int g = 0; g < frame.gestures().count(); g++)
{
    switch (frame.gestures().get(g).state()) {
        case STATE_START:
            //Handle starting gestures
            break;
        case STATE_UPDATE:
            //Handle continuing gestures
            break;
        case STATE_STOP:
            //Handle ending gestures
            break;
        default:
            //Handle unrecognized states
            break;
    }
}

Returns: Gesture::State A value from the Gesture::State enumeration.

Since: 1.0

String com.leapmotion.leap.Gesture.toString ( )

A string containing a brief, human-readable description of this Gesture.

for(int g = 0; g < frame.gestures().count(); g++){
    System.out.println(frame.gestures().get(g).toString());
}

Since: 1.0

Gesture.Type com.leapmotion.leap.Gesture.type ( )

The gesture type.

for(int g = 0; g < frame.gestures().count(); g++)
{
    switch (frame.gestures().get(g).type()) {
        case TYPE_CIRCLE:
            //Handle circle gestures
            break;
        case TYPE_KEY_TAP:
            //Handle key tap gestures
            break;
        case TYPE_SCREEN_TAP:
            //Handle screen tap gestures
            break;
        case TYPE_SWIPE:
            //Handle swipe gestures
            break;
        default:
            //Handle unrecognized gestures
            break;
    }
}

Returns: Gesture::Type A value from the Gesture::Type enumeration.

Since: 1.0

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