You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: gocv.go
    path of file: ./repos/qt/internal/examples/qml/gocv
    
    the code of the file until where you have to start completion: package main

import (
	"github.com/therecipe/qt/core"
	"github.com/therecipe/qt/gui"
	"github.com/therecipe/qt/quick"

	"fmt"
	"gocv.io/x/gocv"
	"image"
	"image/color"
	"sync"
)

func init() {
	GoCV_QmlRegisterType2("CustomModule", 1, 0, "GoCV")
}

type GoCV struct {
	quick.QQuickPaintedItem

	_ func() `constructor:"init"`
	_ bool   `property:"detect"`

	image *gui.QImage
	data  []byte
	mutex *sync.Mutex
}

func (p *GoCV) init() {
	p.SetDetect(false)

    
func (p *GoCV) init() {
	p.SetDetect(false)

	xmlFile := "./facedetect.xml"

	//setup gocv
	webcam, _ := gocv.OpenVideoCapture(0)
	// prepare image matrix
	img := gocv.NewMat()

	//setup painting
	p.image = gui.NewQImage()
	p.mutex = new(sync.Mutex)
	p.SetRenderTarget(quick.QQuickPaintedItem__FramebufferObject)
	p.ConnectPaint(p.paint)

	// color for the rect when faces detected
	blue := color.RGBA{0, 0, 255, 0}

	// load classifier to recognize faces
	classifier := gocv.NewCascadeClassifier()

	if !classifier.Load(xmlFile) {
		fmt.Printf("Error reading cascade file: %v\n", xmlFile)
		return
	}

	go func() {
		for {
			webcam.Read(&img)
			if img.Empty() {
				fmt.Println("empty, continuing")
				continue
			}
			p.mutex.Lock()

			if p.IsDetect() {
				// detect faces
				rects := classifier.DetectMultiScale(img)
				fmt.Printf("found %d faces\n", len(rects))

				// draw a rectangle around each face on the original image,
				// along with text identifing as "Human"
				for _, r := range rects {
					gocv.Rectangle(&img, r, blue, 3)

					size := gocv.GetTextSize("Human", gocv.FontHersheyPlain, 1.2, 2)
					pt := image.Pt(r.Min.X+(r.Min.X/2)-(size.X/2), r.Min.Y-2)
					gocv.PutText(&img, "Human", pt, gocv.FontHersheyPlain, 1.2, blue, 2)
				}
			}

			p.data, _ = gocv.IMEncode(".jpg", img)

			p.mutex.Unlock()
			p.Update()
		}
	}()
}