In Qt5 the palette was introduced in the Control object (part of Qt-
Quick-Controls-2).
In Qt6 this property was moved to the superclass 'Item'.
This means that we no longer need to refer to a control when using a
palette, every single thing in QtQuick is an Item, afterall.
This adds a prettty cutout screen and better feedback on the camera view
popping up.
We also make visible the scan overlay instantly, hiding out any other UI
that is hidden beneath it.
We correctly handle various odd issues with Qt / Android.
- the permissions request (QFuture) returned in a different thread, we
now move back to the main thread before doing any calls on the
multimedia objects.
- The popping up of the android permissions requestor actually makes the
app think its being made inactive. Now we no longer cancel the QR scan
request in such cases.
After working on android and the qtmultimedia library for a week,
I have a much better understanding of what works and what doesn't.
The resulting design is thus presented. We will have one
CameraController class which refers to one overlay panel in QML
and in different places in the GUI objects based on QRScanner
can be created to initiate a scan.
This additionally moves the actual scanning out of the GUI thread
since blocking that is a no-no.
Now to move towards actually supporting scanning usecases.
tomFlowee