pinch

pinch is a pinch gesture detection for leap motion websocket API written in Go.

This program uses https://github.com/whoisjake/gomotion/ for parsing frames into Go structs and reading frames from the default LeapMotion websocket.

This project was originally an idea by [@lemonzi](https://github.com/lemonzi)
The HandPinchRouter reads frames and emits Pinch object pointers which contain the point at which the pinch event occurred and the hand id that created it.

A pinch event is sent under the following conditions:

- there are only 2 extended fingers per hand AND
- one or more of them disappear- which happens, according to the LeapMotion when 2 fingers converge; AND
- the distance between them at the moment they disappear is less than a constant AND
- the last several frames for each finger show that they are each converging on each other.

There is a demo here: https://github.com/stuntgoat/leap-motion-pinch-gesture Usage taken from the demo above:

func main() {
	// from [https://github.com/whoisjake/gomotion/
	runtime.GOMAXPROCS(runtime.NumCPU())

	device, err := gomotion.GetDevice("ws://127.0.0.1:6437/v3.json")
	if err != nil {
		panic(err.Error())
	}
	defer device.Close()
	device.Listen()

    // create a router object that will keep track and update the finger
	// positions per hand.
    var router = pinch.HandPinchRouter{
		FrameChan: make(chan *gomotion.Frame), // send gomotion.Frame pointers here
		PinchChecks: make(map[int]pinch.HandPinchCheck), // holds fingers per hand
		PinchChan: make(chan *pinch.Pinch), // will emit Pinch pointers as the occur
	}

    go router.RouteHand()
	for {
		select {
		case frame := <- device.Pipe:
			router.FrameChan <- frame
		case pinch := <- router.PinchChan:
			fmt.Printf("PINCH DETECTED: %+v\n", pinch)
		}
	}
}