> If all you care about is GTK, then you could have just done a native port of GTK. That would actually be a lot easier than trying to reimplement every X client library.

LOL! Do you really think I woke up one day and said "hmm, I need a GTK port. I know, I'll reimplement Xlib!" without even taking a look at the GTK codebase? Of course I looked at the GTK codebase, and so did a number of other Haiku developers, and we came to the conclusion that writing a native Haiku backend would be a ridiculously unpleasant task (as one other Haiku developer pointed out, GDK backends are typically > 1 MB of source code, and in a dialect of C that I am, uh, if I put it politely, not a fan of.)

It turns out that writing an Xlib compatibility layer was, in the final analysis, a far more expedient and efficient way to port GTK. If I went the long way around, I would have had to write probably over 100k lines of code across GTK, Cairo, and who knows how many other projects (I stopped counting how many dependent libraries I built in the first stages of this attempt.)

Meanwhile, Xlibe does the job with only ~7000 SLOC. That's compared to ~23000 SLOC in the "gdk/x11" folder alone, not to mention all the other X11-related files scattered around the GDK and GTK source trees, or all the ifdefs throughout the codebase, and all the other projects that GTK depends on which interact with the X11 layers in GDK. There is a reason it took literal years to get GTK on Wayland natively...

> With GTK4 it should be even easier because the backends were simplified and a lot of the weird X idiosyncrasies were removed

I find that hard to believe given how deeply some of those X idiosyncrasies are embedded.

But anyway, supposing you're correct: Why should I care about GTK4? Even GIMP of all projects, the (more or less) flagship GTK application and one of the primary reasons a GTK port is generally desirable, has decided that for now, a GTK4 port is "out of scope" (no, really [1]) at least for the immediate future. So even if a GTK4 port was more technically feasible, why exactly would I care if none of the software I want runs on GTK4?

Oh, and let's not forget: with an Xlib compatibility layer, I can also get GTK2 and then whatever applications are still stuck on that; plus plenty of other X11-only things which otherwise I wouldn't be able to get.

[1]: https://gitlab.gnome.org/GNOME/gimp/-/issues/6440

> you might actually have a chance to get hardware acceleration to work without having to go through the pain of dealing with GLX

I didn't yet try to implement GLX but it looks more than feasible. Sure, it's not the most pleasant of APIs to deal with, but implementing it doesn't look so bad.

> The problem with Xlib is that's is not just the one library, it's actually about 30 libraries.

If you mean libraries like Xt, Xaw, Xmu, Xpm, etc., those just run on top of Xlib itself, they don't interact with the X11 protocol directly, and so I can and did build and use those unmodified directly from X.org. For all they know they are running with a strange X11 server that provides an odd but completely valid featureset. Xeyes, which you can see a screenshot of in the README, uses Xt and Xaw, so clearly those work already in this environment.

> Nobody has gotten that far, and if you do get that far

I think I have gotten "that far." I can run Xt/Xaw applications (albeit with a few font rendering glitches, though I just didn't bother to patch that), I can run GTK, and sure, I didn't implement every single drawing mode or every quirky feature, but I don't really care about running Motif, so why does that matter so much?

> So the goal here can't really be reached in any practical terms, unless you just want to stop here.

How about this: You tell me some X11 application you think I can't run under this, and we'll just see if you're wrong (or why nobody cares.)