import VTSequence from "@/components/VTSequence";

# Erase Display (ED)

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

Erase display contents with behavior depending on the command `n`.

If `n` is unset, the value of `n` is 0. The only valid values for `n` are
0, 1, 2, or 3. If any other value of `n` is given, do not execute this sequence.
The remainder of the sequence documentation assumes a valid value of `n`.

For all valid values of `n` except 3, this sequence unsets the pending wrap state.
The cursor position will remain unchanged under all circumstances throughout
this sequence.

If [Select Character Selection Attribute (DECSCA)](#TODO) is enabled
or was the most recently enabled protection mode on the currently active screen,
protected attributes are ignored. Otherwise, protected attributes will be
respected. For more details on this specific logic for protected attribute
handling, see [Erase Character (ECH)](/vt/ech).

For all operations, if a multi-cell character would be split, erase the full multi-cell
character. For example, if "橋" is printed and the erase would only erase the
first or second cell of the two-cell character, both cells should be erased.

This sequence does not respect any scroll regions (top, bottom, left, or
right). The boundaries of the operation are the full visible screen.

If `n` is `0`, perform an **erase display below** operation. Erase all
cells to the right and below the cursor. The background color of erased cells
is colored according to the current SGR state.

If `n` is `1`, perform an **erase display above** operation. Erase all
cells to the left and above the cursor. The background color of erased cells
is colored according to the current SGR state.

If `n` is `2`, **erase the entire display**. This is the equivalent of
erase above (`n = 1`) and erase below (`n = 0`) both being executed.

If `n` is `3`, **erase only the scrollback region**. This does not affect
the visible display of the screen and does not move the cursor. The scrollback
region is the region of the terminal that is currently above the visible
area of the screen when the screen is scrolled completely to the bottom.

## Validation

### ED V-1: Simple Erase Below

```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "ABC\n"
printf "DEF\n"
printf "GHI\n"
printf "\033[2;2H"
printf "\033[0J"
```

```
|ABC_____|
|Dc______|
|________|
```

### ED V-2: Erase Below SGR State

```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "ABC\n"
printf "DEF\n"
printf "GHI\n"
printf "\033[2;2H"
printf "\033[41m"
printf "\033[0J"
```

```
|ABC_____|
|Dc______|
|________|
```

All the cells right and below of the cursor should be colored red.

### ED V-3: Erase Below Multi-Cell Character

```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "AB橋C\n"
printf "DE橋F\n"
printf "GH橋I\n"
printf "\033[2;4H"
printf "\033[0J"
```

```
|AB橋C___|
|DE_c____|
|________|
```

### ED V-4: Simple Erase Above

```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "ABC\n"
printf "DEF\n"
printf "GHI\n"
printf "\033[2;2H"
printf "\033[1J"
```

```
|________|
|_cF_____|
|GHI_____|
```

### ED V-5: Simple Erase Complete

```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "ABC\n"
printf "DEF\n"
printf "GHI\n"
printf "\033[2;2H"
printf "\033[2J"
```

```
|________|
|_c______|
|________|
```
