There’s The Craft of Text Editing by Craig A. Finseth:

https://www.finseth.com/craft/

This book got me started on my journey of creating a text editor for Android 10 or so years ago. It mainly focuses on data structures for efficiently storing and editing text. I can't recall any GUI-related topics being in there.

My initial implementation was based on this book and used one rich TextView with Spans to do the rendering. After that turned out way too slow I switched to drawing everything myself using the Android 2D drawing API's. It was a fun side project and I learned a lot from it.

That seems to be about a non-graphical (monospace text) editor, though.

2nded.

I would love to hear about a "first line to last line" tutorial for a simple GTK app in C, python or preferable rust.

To me there seems to be a huge diffuse overhead to GUI programming, which is discouraging for my kind of brain. I thrive building tree houses, but despise puzzles.

Anyone got a link?

That book would probably be very similar to a book about writing your own web browser (since any part of a webpage can be edited by a javascript routine, and modern documents come close to webpages in complexity).

same here, that would be so much fun!