A camera problem.

[J.Hilk]

@jenya7
do you call show() on your viewfinder instance ? It will probably never change its state, if the viewfinder is not "visible"

[JonB]

@jenya7
Yes, at least the code is right, but won't help if that never gets hit.
Bearing in mind I know nothing about cameras, why did you comment out the m_camera->isCaptureModeSupported(...) lines, what do these actually return? If they return false presumably that would explain why you never get QCameraImageCapture::readyForCaptureChanged ?

Oh I see @J-Hilk has chimed in with some knowledge of this camera stuff....

[jenya7]

@J-Hilk said in A camera problem.:

@jenya7
do you call show() on your viewfinder instance ? It will probably never change its state, if the viewfinder is not "visible"

It can be an issue.
Although I create an object in mainwindow.cpp

QCameraViewfinder *v_finder;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    v_finder= new QCameraViewfinder(this);

    ui->setupUi(this);
    ui->textEditTerminalTx->installEventFilter(this);
}

It's not physically allocated. The app wasn't suppose to have such widget.
So on v_finder->show() I get an exception.
Is it possible to emulate the viewfinder ?

[jenya7]

This post is deleted!

[jsulm]

@jenya7 said in A camera problem.:

It's not physically allocated

It is, see the first line in the constructor

[JonB]

@jenya7
What is "not physically allocated", and why do you get an exception on what?

There is a basic example at https://doc.qt.io/qt-5/qcameraviewfinder.html

camera = new QCamera;

viewfinder = new QCameraViewfinder();
viewfinder->show();

camera->setViewfinder(viewfinder);

imageCapture = new QCameraImageCapture(camera);

camera->setCaptureMode(QCamera::CaptureStillImage);
camera->start();

Did you test whether just this code might work for you?

You also ought check those m_camera->isCaptureModeSupported(...) I mentioned, else you are whistling in the wind....

[jenya7]

@JonB
viewfinder = new QCameraViewfinder(); is an empty object, not tied to any widget. in the original example viewfinder is tied to a StackedWidget panel.

[jenya7]

@jsulm said in A camera problem.:

@jenya7 said in A camera problem.:

It's not physically allocated

It is, see the first line in the constructor

It doesn't work

[jsulm]

@jenya7 said in A camera problem.:

viewfinder = new QCameraViewfinder(); is an empty object, not tied to any widget.

It's not "empty". And a widget does not have to be "tied" to another widget. If it is not and you call show() on it it will be shown in its own window, but it should not crash...

[jsulm]

@jenya7 said in A camera problem.:

It doesn't work

What doesn't work? I'm sure that line works. Do you call show() after that line or before?

[jenya7]

@jsulm said in A camera problem.:

@jenya7 said in A camera problem.:

viewfinder = new QCameraViewfinder(); is an empty object, not tied to any widget.

It's not "empty". And a widget does not have to be "tied" to another widget. If it is not and you call show() on it it will be shown in its own window, but it should not crash...

I see. I'll try to understand what causes the crash.

[JonB]

@jenya7 said in A camera problem.:

viewfinder = new QCameraViewfinder(); is an empty object, not tied to any widget

QCameraViewfinder is a QWidget, so don't know what this means. In your case you may need to give it a parent or add it somewhere. I have suggested code you might try before turning to your own code....

[jenya7]

@JonB said in A camera problem.:

@jenya7
What is "not physically allocated", and why do you get an exception on what?

There is a basic example at https://doc.qt.io/qt-5/qcameraviewfinder.html
Did you test whether just this code might work for you?

You also ought check those m_camera->isCaptureModeSupported(...) I mentioned, else you are whistling in the wind....

bool supported = m_camera->isCaptureModeSupported(QCamera::CaptureStillImage);

Yes. It's supported.
I see the Camera object is created before MainWindow::MainWindow(QWidget *parent) constructor.
Is it normal?

[jsulm]

@jenya7 said in A camera problem.:

I see the Camera object is created before MainWindow::MainWindow(QWidget *parent) constructor.

Where do you see it and where do you create camera object? Can you please post relevant code?

[JonB]

@jenya7
OK, but why not try the example from the docs, in a standalone test program? Not going to say it again.....

[jenya7]

@JonB said in A camera problem.:

@jenya7
OK, but why not try the example from the docs, in a standalone test program? Not going to say it again.....

It runs on Windows machine. Have to arrange some camera....

[JonB]

@jenya7
What runs on Windows machine? It's just sample code, does it not run on whatever platform you are on? You may know better than I, I'll keep quiet now.

[jenya7]

@jsulm said in A camera problem.:

@jenya7 said in A camera problem.:

I see the Camera object is created before MainWindow::MainWindow(QWidget *parent) constructor.

Where do you see it and where do you create camera object? Can you please post relevant code?

I put a break point in the MainWindow constructor and Camera constructor and see which hits the first.
This way it works without errors

QCameraViewfinder *v_finder;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    v_finder = new QCameraViewfinder(this);
    v_finder->show();

    ui->setupUi(this);
    ui->textEditTerminalTx->installEventFilter(this);
}

void Camera::setCamera(const QCameraInfo &cameraInfo)
{
       //........................

     m_camera->setViewfinder(v_finder);

      //............................
}

Is it OK?

[JonB]

@jenya7 said in A camera problem.:

I put a break point in the MainWindow constructor and Camera constructor and see which hits the first.

And what was the result?!

I see the Camera object is created before MainWindow::MainWindow(QWidget *parent) constructor.

At the time your Camera::setCamera() is called, has v_finder = new QCameraViewfinder(this); been executed yet? If not then v_finder in m_camera->setViewfinder(v_finder) will be nullptr....

[jenya7]

@JonB said in A camera problem.:

@jenya7 said in A camera problem.:

I put a break point in the MainWindow constructor and Camera constructor and see which hits the first.

And what was the result?!

I see the Camera object is created before MainWindow::MainWindow(QWidget *parent) constructor.

At the time your Camera::setCamera() is called, has v_finder = new QCameraViewfinder(this); been executed yet? If not then v_finder in m_camera->setViewfinder(v_finder) will be nullptr....

m_camera->setViewfinder(v_finder) is executed first