I have recently a good experience creating a GUI using the GLMakie.jl infrastructure. The up side is that the result is cross-platform (Windows, Mac, Linux), and that the Julia infrastructure to distribute binaries (such as the underlying Fortran code) is great (in summary, you’ll have your binary code stored as a Julia package in Yggdrasil and have it as a dependency of the interface package) - the Julia built in package manager takes care of all dependencies. I currently use that just to distribute a Fortran code, with a very thin Julia package wrapping it, and I have less issues with user installations than ever.
The downside is that, currently, it is easy to distribute the interface if the user does not have a barrier towards installing Julia and running a few commands in the Julia REPL. The alternative is to distribute an app pack, but which will be quite heavy, to carry the Julia runtime and the dependencies.
Personally I use Python with PyQt or PySide and pyqtgraph (https://www.pyqtgraph.org/) for the graphics.
I use Fortran for speeding some critical part of the applications. Consider that I’m mostly displaying and analyzing experimental data, and a fast graphic is essential (matplotlib is too slow).
One feature that I found quite interesting in pyqtgraph is that I can plot a vertical line that can be moved on a graph and act like a slider (actually every graphic object can react to an action on them).
I had a look at GLMakie and I found it interesting, the problem that I still have is that in order to zoom differently along the x or the y of a plot I need to use the keyboard, while in pyqtgraoh there is the same convention of matpltolib: you can “pan” with the left mouse button and zoom with the right mouse button.
I attempted to use fortran with gtk recently. Chatgpt turned to be extremely useful and time-saving in providing a template for the problem I was trying to solve. It also spelled out all dependencies. The solution wasn’t perfect, but it took me one hour instead of days fighting with gtk.
You can find a list of GTK tutorials here: Tutorials · vmagnin/gtk-fortran Wiki · GitHub
The two first are in C. A moderate knowledge of that language is of course an advantage to dive into the GTK world.
