Leap Motion Java API Reference  0.8.0
com.leapmotion.leap.Pointable Class Reference

The Pointable class reports the physical characteristics of a detected finger or tool. More...

Inherits com.leapmotion.leap.Interface.

Inherited by com.leapmotion.leap.Finger, and com.leapmotion.leap.Tool.

Classes

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

Public Member Functions

Vector direction ()
 The direction in which this finger or tool is pointing.
 
boolean equals (Pointable arg0)
 Compare Pointable object equality.
 
Frame frame ()
 The Frame associated with this Pointable object.
 
Hand hand ()
 The Hand associated with this finger or tool.
 
int id ()
 A unique ID assigned to this Pointable object, whose value remains the same across consecutive frames while the tracked finger or tool remains visible.
 
boolean isFinger ()
 Whether or not the Pointable is believed to be a finger.
 
boolean isTool ()
 Whether or not the Pointable is believed to be a tool.
 
boolean isValid ()
 Reports whether this is a valid Pointable object.
 
float length ()
 The estimated length of the finger or tool in millimeters.
 
 Pointable ()
 Constructs a Pointable object.
 
Vector stabilizedTipPosition ()
 The stabilized tip position of this Pointable.
 
Vector tipPosition ()
 The tip position in millimeters from the Leap Motion origin.
 
Vector tipVelocity ()
 The rate of change of the tip position in millimeters/second.
 
String toString ()
 A string containing a brief, human readable description of the Pointable object.
 
float touchDistance ()
 A value proportional to the distance between this Pointable object and the adaptive touch plane.
 
Pointable.Zone touchZone ()
 The current touch zone of this Pointable object.
 
float width ()
 The estimated width of the finger or tool in millimeters.
 

Static Public Member Functions

static Pointable invalid ()
 Returns an invalid Pointable object.
 

Detailed Description

The Pointable class reports the physical characteristics of a detected finger or tool.

Both fingers and tools are classified as Pointable objects. Use the Pointable::isFinger() function to determine whether a Pointable object represents a finger. Use the Pointable::isTool() function to determine whether a Pointable object represents a tool. The Leap Motion software classifies a detected entity as a tool when it is thinner, straighter, and longer than a typical finger.

To provide touch emulation, the Leap Motion software associates a floating touch plane that adapts to the user's finger movement and hand posture. The Leap Motion interprets purposeful movements toward this plane as potential touch points. The Pointable class reports touch state with the touchZone and touchDistance values.

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

Constructor & Destructor Documentation

com.leapmotion.leap.Pointable.Pointable ( )

Constructs a Pointable object.

An uninitialized pointable is considered invalid. Get valid Pointable objects from a Frame or a Hand object.

Member Function Documentation

Vector com.leapmotion.leap.Pointable.direction ( )

The direction in which this finger or tool is pointing.

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

Leap_Finger_Model.png
Returns
The Vector pointing in the same direction as the tip of this Pointable object.
boolean com.leapmotion.leap.Pointable.equals ( Pointable  arg0)

Compare Pointable object equality.

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.

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

The Frame associated with this Pointable object.

Returns
The associated Frame object, if available; otherwise, an invalid Frame object is returned.
Hand com.leapmotion.leap.Pointable.hand ( )

The Hand associated with this finger or tool.

Returns
The associated Hand object, if available; otherwise, an invalid Hand object is returned.
int com.leapmotion.leap.Pointable.id ( )

A unique ID assigned to this Pointable object, whose value remains the same across consecutive frames while the tracked finger or tool 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 device field of view), the Leap Motion software may assign a new ID when it detects the entity in a future frame.

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

Returns
The ID assigned to this Pointable object.
static Pointable com.leapmotion.leap.Pointable.invalid ( )
static

Returns an invalid Pointable object.

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

Returns
The invalid Pointable instance.
boolean com.leapmotion.leap.Pointable.isFinger ( )

Whether or not the Pointable is believed to be a finger.

Fingers are generally shorter, thicker, and less straight than tools.

Returns
True, if this Pointable is classified as a finger.
boolean com.leapmotion.leap.Pointable.isTool ( )

Whether or not the Pointable is believed to be a tool.

Tools are generally longer, thinner, and straighter than fingers.

Returns
True, if this Pointable is classified as a tool.
boolean com.leapmotion.leap.Pointable.isValid ( )

Reports whether this is a valid Pointable object.

Returns
True, if this Pointable object contains valid tracking data.
float com.leapmotion.leap.Pointable.length ( )

The estimated length of the finger or tool in millimeters.

The reported length is the visible length of the finger or tool from the hand to tip. If the length isn't known, then a value of 0 is returned.

Returns
The estimated length of this Pointable object.
Vector com.leapmotion.leap.Pointable.stabilizedTipPosition ( )

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.

Returns
A modified tip position of this Pointable object with some additional smoothing and stabilization applied.
Vector com.leapmotion.leap.Pointable.tipPosition ( )

The tip position in millimeters from the Leap Motion origin.

Returns
The Vector containing the coordinates of the tip position.
Vector com.leapmotion.leap.Pointable.tipVelocity ( )

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

Returns
The Vector containing the coordinates of the tip velocity.
String com.leapmotion.leap.Pointable.toString ( )

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

Returns
A description of the Pointable object as a string.
float com.leapmotion.leap.Pointable.touchDistance ( )

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

The touch distance is a value in the range [-1, 1]. The value 1.0 indicates the Pointable is at the far edge of the hovering zone. The value 0 indicates the Pointable is just entering the touching zone. A value of -1.0 indicates the Pointable is firmly within the touching zone. Values in between are proportional to the distance from the plane. Thus, the touchDistance of 0.5 indicates that the Pointable is halfway into the hovering zone.

You can use the touchDistance value to modulate visual feedback given to the user as their fingers close in on a touch target, such as a button.

Returns
The normalized touch distance of this Pointable object.
Pointable.Zone com.leapmotion.leap.Pointable.touchZone ( )

The current touch zone of this Pointable object.

The Leap Motion software computes the touch zone based on a floating touch plane that adapts to the user's finger movement and hand posture. The Leap Motion software interprets purposeful movements toward this plane as potential touch points. When a Pointable moves close to the adaptive touch plane, it enters the "hovering" zone. When a Pointable reaches or passes through the plane, it enters the "touching" zone.

The possible states are present in the Zone enum of this class:

  • Zone.NONE – The Pointable is outside the hovering zone.
  • Zone.HOVERING – The Pointable is close to, but not touching the touch plane.
  • Zone.TOUCHING – The Pointable has penetrated the touch plane.

The touchDistance value provides a normalized indication of the distance to the touch plane when the Pointable is in the hovering or touching zones.

Returns
The touch zone of this Pointable
float com.leapmotion.leap.Pointable.width ( )

The estimated width of the finger or tool in millimeters.

The reported width is the average width of the visible portion of the finger or tool from the hand to the tip. If the width isn't known, then a value of 0 is returned.

Returns
The estimated width of this Pointable object.