QML Image: Invalid image provider with modified declarative camera example

[Martin Burchell]

I'm updating our application to Qt6.2.

We have a CameraQml widget, which is based on the declarative camera example and has the ability to save the captured image. The images are being saved OK but the preview window only displays the first captured photo. For subsequent photos the preview window shows a black screen and there is the error message:

qrc:/resources/camera_qml/PhotoPreview.qml:59:5: QML Image: Invalid image provider: image://camera/preview_1

This is on Ubuntu 20.04, though I don't think this is a platform-related issue.

The declarative camera example runs fine and does not display this message so I'm pretty sure the problem is in my code. It seems like something isn't getting tidied up properly.

I've extracted the relevant code into an example at https://github.com/martinburchell/qml-camera-example .

The main application is at:
https://github.com/martinburchell/qml-camera-example/blob/main/main.cpp

The widget containing the QML is at:
https://github.com/martinburchell/qml-camera-example/blob/main/cameraqml.cpp

The QML is different from the example in the following ways:

https://github.com/martinburchell/qml-camera-example/blob/main/resources/camera_qml/camera.qml

We've added:

• handlers for onImageCaptured and onImageSaved to ImageCapture.
• a custom handler for onImageSavedToFile to PhotoPreview
• a custom fileNoLongerNeeded signal to tidy up saved images

https://github.com/martinburchell/qml-camera-example/blob/main/resources/camera_qml/PhotoCaptureControls.qml

The CameraButton onClicked handler sends the fileNoLongerNeeded signal mentioned above.

https://github.com/martinburchell/qml-camera-example/blob/main/resources/camera_qml/PhotoPreview.qml

We've added a Save button, which sends the imageSavedToFile signal.

Any suggestions as to what the problem might be?

[Martin Burchell]

https://bugreports.qt.io/browse/QTBUG-111460