import VTSequence from "@/components/VTSequence";

# Insert Character (ICH)

<VTSequence sequence={["CSI", "Pn", "@"]} />

Insert `n` blank characters at the current cursor position and shift
existing cell contents right.

The parameter `n` must be an integer greater than or equal to 1. If `n` is less than
or equal to 0, adjust `n` to be 1. If `n` is omitted, `n` defaults to 1.

This sequence always unsets the pending wrap state.

If the cursor position is outside of the [left and right margins](#TODO),
this sequence does not change the screen, but the pending wrap state is
still reset.

Existing cells shifted beyond the right margin are deleted. Inserted cells
are blank with the background color colored according to the current SGR state.

## Validation

### ICH V-1: No Scroll Region, Fits on Screen

```bash
printf "ABC"
printf "\033[1G"
printf "\033[2@"
```

```
|XcABC_____|
```

### ICH V-2: SGR State

```bash
printf "ABC"
printf "\033[1G"
printf "\033[41m"
printf "\033[2@"
printf "X"
```

```
|c_ABC_____|
```

The `c_` cells should both have a red background. The `ABC` cells should
remain unchanged in style.

### ICH V-3: Shifting Content Off the Screen

```bash
cols=$(tput cols)
printf "\033[${cols}G"
printf "\033[2D"
printf "ABC"
printf "\033[2D"
printf "\033[2@"
printf "X"
```

```
|_______XcA|
```

### ICH V-4: Inside Left/Right Scroll Region

```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "\033[?69h" # enable left/right margins
printf "\033[3;5s" # scroll region left/right
printf "\033[3G"
printf "ABC"
printf "\033[3G"
printf "\033[2@"
printf "X"
```

```
|__XcA_____|
```

### ICH V-5: Outside Left/Right Scroll Region

```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "\033[?69h" # enable left/right margins
printf "\033[3;5s" # scroll region left/right
printf "\033[3G"
printf "ABC"
printf "\033[1G"
printf "\033[2@"
printf "X"
```

```
|XcABC_____|
```