Objective C

1. Link your target with the framework (/System/Library/PrivateFrameworks/MultitouchSupport.framework/MultitouchSupport)
2. Add MTDeviceDeclarations.h to your project.
3. Query list of available devices:

NSMutableArray* deviceList = (NSMutableArray*)MTDeviceCreateList(); 

1. Register callback:

MTRegisterContactFrameCallback(deviceList objectAtIndex:i, touchCallback);

1. Starts receiving events:

MTDeviceStart(deviceList objectAtIndex:i, 0); //start sending events

1. The callback function should have this signature (maximum number of fingers can be detected is 11):

int touchCallback(int device, Touch *data, int nFingers, double timestamp, int frame)

1. Touch struct has this structure:

typedef struct


{


	int frame; //the current frame


	double timestamp; //event timestamp


	int identifier; //identifier guaranteed unique for life of touch per device


	int state; //the current state (not sure what the values mean)


	int unknown1; //no idea what this does


	int unknown2; //no idea what this does either


	mtVector normalized; //the normalized position and vector of the touch (0,0 to 1,1)


	float size; //the size of the touch (the area of your finger being tracked)


	int unknown3; //no idea what this does


	float angle; //the angle of the touch in radian  -|


	float majorAxis; //the major axis of the touch   -|-- an ellipsoid. you can track the angle of each finger!


	float minorAxis; //the minor axis of the touch   -|


	mtVector unknown4; //not sure what this is for


	int unknown52; //no clue


	float unknown6; //no clue


}Touch;

Example projects:

• Objective-C (source)
• Python (source)

Utility

• Finger visualization (source)