# `Atui.Terminal`
[🔗](https://github.com/iboard/atui/blob/v0.3.0/lib/atui/terminal.ex#L1)

Terminal setup, teardown and the handful of ANSI sequences the runtime needs.

## Getting keys one at a time

Putting the *terminal* in raw mode is not enough. When the BEAM finds a usable
terminal it starts its own line editor (`prim_tty`), which reads stdin, echoes
what you type and hands the reader a whole line once you press Enter — no
matter what `stty` says. So raw mode is asked for the way OTP intends:
`:shell.start_interactive({:noshell, :raw})`, which switches that driver into
raw mode and delivers each character as it is typed.

That path needs a VM started with `-noshell`, which is how `mix run` and
release start scripts run. Where it is not available — inside IEx, or on OTP
older than 26.2 — we fall back to `stty` against `/dev/tty`, which is enough
when the BEAM has not claimed the terminal (no `TERM`, output redirected).

## Ctrl-C

In raw mode `prim_tty` still treats byte 3 as the emulator break, popping the
BREAK menu over the UI. The VM flag `+Bc` makes it a normal byte instead, so
the runtime can act on it. Pass it however the application starts:

    elixir --erl "+Bc" -S mix run --no-halt
    ELIXIR_ERL_OPTIONS="+Bc" mix run --no-halt

In a release, put `+Bc` on a line of its own in `rel/vm.args.eex`.

# `draw`

Draws a frame, homing the cursor first so rows land where they belong.

# `enter`

Switches to the alternate screen buffer and hides the cursor.

# `leave`

Shows the cursor and returns to the normal screen buffer.

# `raw_mode`

Puts the terminal into raw mode with echo off.

Returns `{:ok, saved}` where `saved` is the previous `stty` state to hand back
to `restore/1` (`nil` if there was no terminal to ask), or `:error` if raw
mode could not be established at all — tests and CI, where the runtime falls
back to rendering blind.

# `restore`

Restores a `stty` state captured by `raw_mode/0`.

# `size`

The terminal size as `{columns, rows}`, falling back to 80x24.

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*Consult [api-reference.md](api-reference.md) for complete listing*