Support for getting raw input

[adsr]

Sometimes it may be useful to get at raw input data in addition to or instead of tb_event structs. For example, if one were writing a faithful readline clone, one would need to support key bindings specified as raw input, not as logical keys. There is a way to get around this presently¹ but it's a bit circuitous.

There are lot of ways to accomplish this. For example:

1. Add a tb_event.raw field. Would be annoying if we alloc-d for every tb_event, since the user would have to keep freeing it. If we didn't alloc, we could come up with a way that the raw data is valid until the next function call or something, which sounds complex.
2. Make separate functions tb_(poll|peek)_raw that return raw data instead of tb_event. Either make the _raw functions automatically append to the input buffer or add a tb_push_raw function so the caller could explicitly feed the input buffer. Unclear how this would handle resizes.
3. Keep a separate raw buffer alongside the input buffer. Make functions for consuming this buffer. Make an init flag for enabling this behavior.

Or maybe this is too niche. Feedback encouraged.

Footnotes

1. Initialize termbox to read from a pipe instead of the tty. Read the tty yourself (raw) then copy to termbox via the pipe. https://github.com/termbox/termbox2/blob/918369f9697dc8bb5927f69b3277a3ffbb920df4/demo/readline.c#L129 ↩

[AnErrupTion]

Would this allow for having more complex keybinds, like Ctrl+Alt+O, Shift+P and so on? If so, that'd be great! (Although it may already be possible to do as is, I'm not sure.) As for the implementation, I find the third option to be the cleanest, and sounds easier to implement than the other two options.

[adsr]

Those kind of inputs are already supported. You can test by running the keyboard demo. (Make sure you're in TB_INPUT_ALT mode first if you want to test any alt keys.)

Agree 3 seems the cleanest for implementation.

[TeddyRandby]

Would this allow for escape codes such as \x1b[14t, for querying the size of the terminal in pixels? This is a useful operation that I can't find a way to do otherwise. I'm imagining that I'd be able to:

tb_sendf("\x1b[14t");
struct tb_event ev;
int res = tb_poll_event(&ev);
// Read the raw bytes, and parse out the height/width

[adsr]

That could work but I think it would be a better use case for the proposed function tb_set_extract_func. This would be a way to set a callback to parse custom escape codes before or after termbox does its internal parsing. I have a branch for it somewhere. I'll aim to fix it up and post within the next week or two for review.