so there is a library of tutorials for beginners,intermediate, advanced and experts. Would be very helpful
GUI tutorial as well
I have recently added my nimbook to the wiki page, seems the entry has been renamed, but at least survived. And Google generally finds it when you type in "Nimprogramming". And when you have found the html document, you can replace the "nim" with "gtk" and get the gtk4 book, but that one has not many pages yet.
When you are interested in GTK for Nim at all the you better start with the GTK3 examples in the the github README, or the more fancy copy at http://ssalewski.de/gintroreadme.html. Because not all Linux distros ship GTK4 already, and because the examples in http://ssalewski.de/gtkprogramming.html for GTK4 needs latest gintro v0.8.3 on which we are still working. You can install it with nimble install gintro@#head but you may get a duplicated entry for
g_thread_new ~/.nimble/pkgs/gintro-#head/gintro/glib.nim
proc g_thread_new(name: cstring; fn: ThreadFunc; data:pointer): ptr Thread00 {.importc, libprag.}
result.impl = g_thread_new(name, fn, data)
If you have two entries, just delete one with a text editor and it should work. I will try to fix that in the next days and then release v0.8.3.
And note that I have listed many other Nim GUI toolkits in http://ssalewski.de/gtkprogramming.html, maybe you like them better.