QtQuick PDF viewer example(s) showing how to zoom and rotate

One way to handle zoom is to provide toolbar buttons and/or keyboard shortcuts. Another way is to use PinchHandler, and then re-render the page at a new zoom level when the pinch is complete. The ideal viewer should have both.

Rotation could also be done by pinching, but maybe it's not necessary to do it that way since 90-degree increments are enough.

Of course rotating a Qt Quick Image by any increment is trivial. It remains to be seen if there is a use case that requires asking PDFium to re-render the page with a different rotation; it can be done if we need to.