I would like a complete technical description of how controlnet works

[gitmesam]

1. How a layer is merged with a work path and a background image
2. How an image is generated along a working contour (if possible, I would like to see the internal stages of image generation in the form of slides)
3. how the contours of the generated layer are processed. This means cinematic quality and integrity of the entire resulting picture.
4. At this stage of controlnet development, what prevents you from achieving complete control over the result obtained?

So far, from the official information that is available on the network, I understand the work of the controlnet - only in general terms.

[gitmesam]

Almost a year and a half has passed and I still haven't received an answer...