Pass Camera preview from QML to C++

[kolegs]

Hey,

I got a problem with passing Camera preview from QML to C++, I need to process it there. Here is my code, anyone knows what I am doing wrong?
Test.cpp
@#include "test.h"

Test::Test(QObject *rootObject, QObject *parent) : QObject(parent)
{
QObject *camera = rootObject->findChild<QObject *>(QString("camera"));
setCamera(camera);
}

void Test::processPreview(int, const QImage& image)
{
qDebug() << "PROCESS IMAGE" << image;
}

void Test::setCamera(QObject *cameraObject)
{
QVariant cameraVariant = cameraObject->property("mediaObject");
QCamera camera = qvariant_cast<QCamera>(cameraVariant);
QCameraImageCapture *imageCapture = new QCameraImageCapture(camera);
connect(imageCapture, SIGNAL(imageCaptured(int, const QImage&)),
this, SLOT(processPreview(int, const QImage&)));
}

void Test::setCamera2(QObject *cameraObject)
{
QVariant cameraVariant = cameraObject->property("mediaObject");
QCamera camera = qvariant_cast<QCamera>(cameraVariant);
QMediaService *service = camera->service();
QMediaControl *control = service->requestControl(QCameraImageCaptureControl_iid);
QCameraImageCaptureControl captureControl = qobject_cast<QCameraImageCaptureControl>(control);
connect(captureControl, SIGNAL(imageCaptured(int, const QImage&)),
this, SLOT(processPreview(int, const QImage&)));
}

void Test::imageCapture(QString url)
{
qDebug() << url;
}

Test::~Test()
{

}@

and main.qml
@import QtQuick 2.4
import QtQuick.Controls 1.3
import QtQuick.Window 2.2
import QtQuick.Dialogs 1.2
import QtMultimedia 5.4

ApplicationWindow {
title: qsTr("Hello World")
width: 640
height: 480
visible: true

Item {
    anchors.fill: parent

    Camera {
        objectName: "camera"
        id: camera



        imageProcessing.whiteBalanceMode: CameraImageProcessing.WhiteBalanceFlash

        exposure {
            exposureCompensation: -1.0
            exposureMode: Camera.ExposurePortrait
        }

        flash.mode: Camera.FlashRedEyeReduction

        imageCapture {
            onImageCaptured: {
                photoPreview.source = preview  // Show the preview in an Image
            }
        }
    }

    VideoOutput {
        source: camera
        anchors.fill: parent
        focus : visible // to receive focus and capture key events when visible
    }

    Image {
        id: photoPreview
        onSourceChanged: imageChanged(source)
    }
}

}
@

I tried both setCamera and setCamera2 but they doesnt work.
I can see the preview on Android tablet, which I am using for testing.

Thanks in advance

[cincirin]

Hi,
what exactly went wrong ?
I used C++ QCamera(and all related) from QML and everything is working properly, but I didn't try to find camera object from qml root.
Instead I create a property in C++ class, expose it to qml, and from qml assign the camera object to that C++ property.