:term should forward unknown sequences to host

[chemzqm]

iTerm2 version 3 beta support show image inside terminal with command like imgcat, but the image could not be seen with that command inside terminal of neovim.
That would also be cool if neovim support show image in buffer with an api .

[justinmk]

Some people are already doing this, see #4056

[chemzqm]

@justinmk I'm using latest neovim, but I can't get any image ouput with command imgcat inside the terminal of neovim

[justinmk]

It looks like imgcat is using a custom DCS 1337. I am guessing that is not a code that is recognized by libvterm (@leonerd can you confirm), but on the other hand we should forward it to iTerm2, but maybe we aren't?

Clearly there is some seequence that is recognized by libvterm to display images as demonstrated by #4056. imgcat could be modified to emit those codes instead?

[DarkDefender]

@justinmk IIRC the method in #4056 does not use terminal codes. It instead calls a image display program that displays the image at the requested location.

That's probably why it doesn't output the image at the correct location when inside neovim. Because it assumes that it is using the full terminal window. So it will not work with splits and so on.

I guess that the iTerm2 codes will eliminate this problem because the terminal will then know where to put the image depending on where it reads the DCS 1337 code