Camera element on N8

mascotti

Hello, I have created a simple QML app for exercising the Camera example taken from http://doc.qt.nokia.com/qtmobility/qml-multimedia.html

I have added all the relevant header files and Symbian capabilities but it seems the camera doesn't show any content when the application starts on the N8. I can see only a white background. Here is the main.qml file

@
import Qt 4.7
import QtMultimediaKit 1.1

Camera {
focus : visible // to receive focus and capture key events when visible

 flashMode: Camera.FlashRedEyeReduction
 whiteBalanceMode: Camera.WhiteBalanceFlash
 exposureCompensation: -1.0

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

}
@

Do you know please if I have missed any other parameters?
Thank you

Chuck Gao

Do you have right capability ?

mascotti

Yes , here is part of my .pro file

@
symbian {
TARGET.CAPABILITY += NetworkServices UserEnvironment NetworkServices Location ReadUserData WriteUserData
}
@

thank you

mascotti

In this example I can see the viewfinder with a black background but no camera images are displayed. However if I press the capture button then the preview image is filled with the camera's capture image. Also when taking a picture I can see the camera flash working. Any idea from this example why QML Camera element doesn't display the images when not taking a picture?
Thank you

@
import QtQuick 1.0
import QtMultimediaKit 1.1

Rectangle {
id: rotateCam
state: 'CameraStarted'
states: [
State {
name: "CameraStarted"
PropertyChanges { target: previewImage; z: -1 }
PropertyChanges { target: rotateCam; color: "black" }
PropertyChanges { target: takePhotoButton; buttonText: "Take Image" }
PropertyChanges { target: camera; captureResolution: Qt.size(camera.width,camera.height)}
},
State {
name: "CapturingPhoto"
PropertyChanges { target: previewImage; z: -1 }
PropertyChanges { target: rotateCam; color: "red" }
PropertyChanges { target: takePhotoButton; buttonText: "Cancel" }
},
State {
name: "ShowingPreview"
PropertyChanges { target: previewImage; z: 2 }
PropertyChanges { target: rotateCam; color: "black" }
PropertyChanges { target: takePhotoButton; buttonText: "Back" }
}
]

Camera {
    id: camera
    anchors.fill: parent
    anchors.margins: 4
    //focus : visible // to receive focus and capture key events when visible
    flashMode: Camera.FlashRedEyeReduction
    whiteBalanceMode: Camera.WhiteBalanceFlash
    exposureCompensation: -1.0
    onImageCaptured: {
        console.log("Image captured!")
        previewImage.source = preview
        rotateCam.state = 'ShowingPreview'
    }

    Image {
        id: previewImage
        anchors.fill: parent
        fillMode: Image.PreserveAspectFit
        smooth: true
    }
}

CameraButton {
    id: exitButton
    anchors.right: parent.right
    anchors.top: parent.top
    anchors.margins: 60
    buttonText: "Exit"
    onButtonPressed: Qt.quit()
}

CameraButton {
    id: takePhotoButton
    anchors.left: parent.left
    anchors.top: parent.top
    anchors.margins: 60
    buttonText: "Take Image"
    onButtonPressed: {
        if (rotateCam.state == 'CameraStarted') {
            camera.captureImage()
        } else if (rotateCam.state == 'ShowingPreview') {
            rotateCam.state = 'CameraStarted'
        }
    }
}

MouseArea {
    anchors.fill: parent
    onClicked: {
        console.log("Mouse pressed!")
        if (rotateCam.state == 'CameraStarted')
            camera.searchAndLock()
        else if (rotateCam.state == 'ShowingPreview')
            rotateCam.state = 'CameraStarted'
    }
}

}

// End of file

@

kibsoft

So, I have the same issue..When I use qml camera I see only black screen (Symbian^1, Nokia 5800).

http://www.developer.nokia.com/info/sw.nokia.com/id/cc9937ed-9f1f-44b4-981f-38245bf9cae5/Qt_QCamera_Example.html
This non-qml example works perfectly on my device.

mascotti, did you find a way to fix this behaviour?

mascotti

Hi,
the problem in my case was that I was using a QT's version on my device that was older then the one I was using for developing. I suggest you make sure that you are using the same QT mobility version both on the device and QT sdk.

Hope this help
Maurizio

simon-h

I have the same problem on a Symbian^1 phone (Nokia X6). Here is the minimal code for a Qt Quick Application generated from the wizard. I am using Qt 1.1.2 SDK downloaded yesterday (10/07/2011), which uses Qt Mobility 1.1.3 with Qt 4.7.3. I manually installed the two Qt /QtMobility library .sis files that are the SDK start menu group.

// .pro contains following extra lines
// symbian:TARGET.CAPABILITY += UserEnvironment
// CONFIG += mobility
// MOBILITY += multimedia

// main.qml contains:
import QtQuick 1.0
import QtMultimediaKit 1.1

Camera {
}

Result: viewfinder not appear. However the above works fine for a Symbian^3 build on Nokia N8 - viewfinder does turn on.

simon-h

Raised bug report http://bugreports.qt.nokia.com/browse/QTMOBILITY-1769
Please vote for it if you can repeat it yourself.