how can I retrieve the display resolution that RV uses for a source (I can see in the image info widget that sometimes the resolution and display resolution are not identical). As this value is necessary to apply cropping correctly I need to find it. (via python).
I tried to use commands.sources.rendered but this returns an emty array.
I think renderedImages is the command you are looking for:
images = rv.commands.renderedImages();
Is the images array empty? It should return the images that are rendered at the current frame.
So, for instance, if you are in layout mode, the array should contain all sources.
Is it possible you are running that within a source-setup? IIRC, commands.renderedImages() requires a first render to have happened.
No, it’s not in a source setup package. I found a workaround but strangely the command always returns empty.