Add support for libsixel

[HalosGhost]

libsixel is an ANSI-compatible library for SIXEL/DEC graphics painting in a terminal. This allows for richer interface design and better integration between the text-based and graphical environments.

There is at least one person who has already started work on wrapping libsixel for use in Rust, though a different wrapper may be preferrable.

xterm whose terminfo alacritty defaults to already supports libsixel (through a compile-time option).

[aslpavel]

Sixel support would be really nice to have. By the way it would not require any binding for libsixel format is pretty simple to implement directly.

[crocket]

sixel doesn't support 24-bit colors yet, but it is still good.

[aslpavel]

Sixel does support 24-bit, it is just palette based. It is just not very efficient if you have too many distinct colors.

[aurelg]

Extra motivation: it seems lsix relies on sixel.

[vifino]

Hey. I would love sixel support in alacritty as well.
Have there been any attempts yet?
Sounds like something I could try to implement, but unfortunately I'm pretty busy.
Might get around to it in a few weeks?

[chrisduerr]

Have there been any attempts yet?

There have not.

Sounds like something I could try to implement, but unfortunately I'm pretty busy.
Might get around to it in a few weeks?

If you want to give it a shot, feel free and let me know if you need any help.

[Aaron1011]

I'd be interested in working on this.

[chrisduerr]

@Aaron1011 If you have any specific questions, please let me know either here or on the Alacritty IRC on freenode.

[vifino]

If anything, implementing both is a good idea. Sixel has quite a few nice uses.
It is not just displaying images. Plots for example: Sixel backend for Python's Matplotlib.

[mbaz]

Sevaral scientific plotting packages support sixels (example), which is nice because you don't need a browser or additional windows to see the plots. However, very few terminals, and no modern terminals, support it. It'd be nice to have a modern, fast terminal support this.

[mbaz]

@leotaku You're right that most of those programs generate a PNG and then translate it to sixels, and that the kitty protocol is likely to be a better, more modern solution. To me as a user, the important feature is to get images on the terminal, in a way that is as standard, well-documented and widely supported as possible.

[chrisduerr]

Sixel is a standardized and accepted protocol. Kitty's own protocol is not.

[crocket]

You better create a new issue about kitty protocol.

[HalosGhost]

@leotaku, I line up with @chrisduerr. Sixel has been a standard for an incredibly long time; more than that, it is wholly backwards-compatible. Every other format I've seen for images-on-terminal (including kitty, iTerm2, terminology, and others) is propretary, is not interoperable and/or is not backwards compatible.

Sixel is the only reasonable option. It also has the benefit of having several high-quality implementations out there already.

[crocket]

Is sixel going to support 24bit color space? The current color space is 8bit.