LeapInteractionBox Class Reference

The LeapInteractionBox class represents a box-shaped region completely within the field of view of the Leap Motion controller. More...

Inherits NSObject.

Instance Methods
(LeapVector *)	- denormalizePoint:
	Converts a position defined by normalized LeapInteractionBox coordinates into device coordinates in millimeters. More...
(BOOL)	- equals:
	Reports whether this is a valid LeapInteractionBox object. More...
(LeapVector *)	- normalizePoint:clamp:
	Normalizes the coordinates of a point using the interaction box. More...

Class Methods
(LeapInteractionBox *)	+ invalid
	Returns an invalid LeapInteractionBox object. More...

Properties
LeapVector *	center
	The center of the LeapInteractionBox in device coordinates (millimeters). More...
float	depth
	The depth of the LeapInteractionBox in millimeters, measured along the z-axis. More...
float	height
	The height of the LeapInteractionBox in millimeters, measured along the y-axis. More...
BOOL	isValid
	Reports whether this is a valid LeapInteractionBox object. More...
float	width
	The width of the LeapInteractionBox in millimeters, measured along the x-axis. More...

Detailed Description

The LeapInteractionBox class represents a box-shaped region completely within the field of view of the Leap Motion controller.

The interaction box is an axis-aligned rectangular prism and provides normalized coordinates for hands, fingers, and tools within this box. The InteractionBox class can make it easier to map positions in the Leap Motion coordinate system to 2D or 3D coordinate systems used for application drawing.

The LeapInteractionBox region is defined by a center and dimensions along the x, y, and z axes.

LeapInteractionBox *interactionBox = frame.interactionBox;

Since 1.0

Method Documentation

- (LeapVector *) denormalizePoint:

(const LeapVector *)

position

Converts a position defined by normalized LeapInteractionBox coordinates into device coordinates in millimeters.

LeapVector *normalizedPoint =
        [[LeapVector alloc] initWithX:.23 y:.87 z:.67];
LeapVector *leapCoordinates =
        [frame.interactionBox denormalizePoint:normalizedPoint];

This function performs the inverse of [LeapInteractionBox normalizePoint:].

Parameters

position

A normalized position in LeapInteractionBox coordinates.

Returns

The corresponding denormalized position in device coordinates.

Since 1.0

- (BOOL) equals:

(const LeapInteractionBox *)

other

Reports whether this is a valid LeapInteractionBox object.

[thisBox equals:thatBox];

Returns

True, if this LeapInteractionBox object contains valid data.

Since 1.0

+ (LeapInteractionBox *) invalid

Returns an invalid LeapInteractionBox object.

LeapInteractionBox *invalidBox = LeapInteractionBox.invalid;

Returns

The invalid InteractionBox instance.

Since 1.0

- (LeapVector *) normalizePoint:		(const LeapVector *)	position
clamp:		(BOOL)	clamp

Normalizes the coordinates of a point using the interaction box.

Coordinates from the Leap frame of reference (millimeters) are converted to a range of [0..1] such that the minimum value of the LeapInteractionBox maps to 0 and the maximum value of the LeapInteractionBox maps to 1.

int displayWidth = 680;
int displayHeight = 400;
LeapVector *point =
        [[LeapVector alloc] initWithX:-75 y:234 z:0];

LeapVector *normalized =
        [frame.interactionBox normalizePoint:point clamp:YES];

int displayX = normalized.x * displayWidth;
int displayY = (1 - normalized.y) * displayHeight;

Parameters

position	The input position in device coordinates.
clamp	Whether or not to limit the output value to the range [0,1] when the input position is outside the LeapInteractionBox. Defaults to true.

Returns

The normalized position.

Since 1.0

Property Documentation

- (LeapVector*) center

readnonatomicassign

The center of the LeapInteractionBox in device coordinates (millimeters).

This point is equidistant from all sides of the box.

LeapVector *center = interactionBox.center;

Returns

The LeapInteractionBox center in device coordinates.

Since 1.0

- (float) depth

readnonatomicassign

The depth of the LeapInteractionBox in millimeters, measured along the z-axis.

float depth = interactionBox.depth;

Returns

The LeapInteractionBox depth in millimeters.

Since 1.0

- (float) height

readnonatomicassign

The height of the LeapInteractionBox in millimeters, measured along the y-axis.

float height = interactionBox.height;

Returns

The LeapInteractionBox height in millimeters.

Since 1.0

- (BOOL) isValid

readnonatomicassign

Reports whether this is a valid LeapInteractionBox object.

if(interactionBox.isValid){
    //Use the data...
}

Returns

True, if this LeapInteractionBox object contains valid data.

Since 1.0

- (float) width

readnonatomicassign

The width of the LeapInteractionBox in millimeters, measured along the x-axis.

float width = interactionBox.width;

Returns

The LeapInteractionBox width in millimeters.

Since 1.0