[Qgis-user] How QGIS handles on-the-fly projection?

[Ionut Ungurianu]

Hi!

I’m looking to understand  in a more advanced way how QGIS handles on-the-fly projection.
In my case I set the project crs in epsg:3857 and I have a raster layer in epsg:4326. In this case what is happening with the layer?

I know that it’s based on PROJ, but I’m wondering what is actually happening in the back-end, what is happening in the map canvas, how is the layer render, is being resampled every time you pan the map or do zoom in/out ...

So, if someone can help with a detailed explanation, I would really appreciate it.

Thanks in advance!

All the best!
Ionut