SDL GUI backend

[mmuman]

The idea is to be able to run Conky on ancient OSes and hardware (thinking about MiNT (not the GNU/Linux distro, the Atari OS) or AmigaOS), in a regular window but with minimal coding required, and also to allow testing the GUI backend without X11. I used SDL 1.2 because SDL2 only runs on Windows, OSX and Linux, which limits the interest for old platforms.

For now it only draws text with a hardcoded font. It also still needs to be compiled with X11 due to some variables here and there.

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[mmuman]

I added some way to locate and load TTF files by the font name, it kinda works.

[mmuman]

Just rebased, had to change some #ifdef info #if defined(BUILD_WAYLAND) || defined(BUILD_SDL) so maybe we'd need some BUILD_NONX11 define around to avoid these lists everywhere?

[brndnmtthws]

Just rebased, had to change some #ifdef info #if defined(BUILD_WAYLAND) || defined(BUILD_SDL) so maybe we'd need some BUILD_NONX11 define around to avoid these lists everywhere?

That could work, though it seems messy. There's also BUILD_GUI, but it sounds like that won't help here.

[mmuman]

The recent changes on color stuff just got rid of the #ifdef thing.

[mmuman]

And we have colors :-)

[Caellian]

Hi, I changed how registration of output displays works to avoid linker magic, you can check out how other backends are registered on main branch for reference.

Main differences are:

• sdl-output.cc should be guarded by build flag in CMakeLists.txt
• You need to provide a log message template fallback in display-output.cc for feature gated outputs

[mmuman]

Rebased, updated to last renaming, and should be up to @Caellian 's changes too.
Still not finished.

[mmuman]

(of course, pushing from wrong machine…)

[mmuman]

Default config now renders just fine.

[brndnmtthws]

I fixed the font loading on macOS, and added some basic font caching.

However, I get a blank window on macOS with the default config:

[brndnmtthws]

Not sure why the Nix build is failing, but it's fine to ignore it for now.

[mmuman]

Hmm probably something similar with how we accept GUI settings or not.

Btw, it fails to build on Haiku because ::map is not in <unordered_map>.

[mmuman]

Just to make sure, you might want to trace calls to set_foreground_color to see if it actually gets proper colors or just black.

[brndnmtthws]

Is there any reason we can't use SDL2 rather than 1.2? It seems like SDL 1.2 isn't as well supported by the distros.

Ubuntu doesn't appear to have SDL_ttf 1.2: https://packages.ubuntu.com/search?suite=noble&arch=any&searchon=names&keywords=libsdl-ttf

[brndnmtthws]

FWIW there's a decent migration guide here: https://wiki.libsdl.org/SDL2/MigrationGuide

[mmuman]

Yes, the idea is to run on very old OSes like Atari MiNT.

[brndnmtthws]

Yes, the idea is to run on very old OSes like Atari MiNT.

Ah, right, I see now that's in your original comment, but I had forgotten about it.

The SDL_ttf library is pretty tiny, I think we could just bundle it as a 3rd party source. It's literally just 2 source files (SDL_ttf.c and SDL_ttf.h). Then it can be used with the SDL 1.2 compat layer, which is widely available. What do you think of that?

[brndnmtthws]

One more thought: maybe we should make it more clear that we intentionally only support SDL 1.2, so that in the future we can support newer versions as well.

[brndnmtthws]

The SDL_ttf library is pretty tiny, I think we could just bundle it as a 3rd party source. It's literally just 2 source files (SDL_ttf.c and SDL_ttf.h). Then it can be used with the SDL 1.2 compat layer, which is widely available. What do you think of that?

Actually, this isn't as easy as I thought. SDL_ttf 1.2 depends on freetype 1, which is also somewhat deprecated.

At this point, I think it's better to just not support distros that don't ship with SDL1.2, or people can compile SDL1.2 (and its dependencies) themselves if they really want it in a modern distro that doesn't include all the SDL1.2 deps.

[mmuman]

I suppose we could support both with some #ifdef spaghetti.

[brndnmtthws]

I suppose we could support both with some #ifdef spaghetti.

This is less than ideal. It becomes really hard to maintain, and there are already a million different build options as it is.

I'd prefer to keep it simple, and since GitHub actions uses Ubuntu by default for the Linux CI, it would be good to make it compile on Ubuntu (and macOS too if possible). At least that way we can catch compiler errors.

Getting it to compile with Nix and macOS is pretty easy, but Ubuntu is a pain. Doing it in Docker would work, but I don't love that.

I guess we could use the ExternalProject feature of CMake, then it wouldn't be too hard to include both freetype 1 and SDL_ttf 1.2 as 3rdparty dependencies. While I don't like including 3rdparty code this way, in this case it makes some sense.

[mmuman]

Or just have a separate sdl2 display.