import VTSequence from "@/components/VTSequence";

# Delete Character (DCH)

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

Deletes `n` characters at the current cursor position and shifts existing
cell contents left.

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.

If the current cursor position is outside of the current scroll region,
this sequence does nothing. The cursor is outside of the current scroll
region if it is left of the [left margin](#TODO), or right of the
[right margin](#TODO).

This sequence unsets the pending wrap state. This sequence does _not_ unset
the pending wrap state if the cursor position is outside of the current
scroll region. This has to be called out explicitly because this behavior
differs from [Insert Character (ICH)](/vt/ich).

Only cells within the scroll region are deleted or shifted. Cells to the
right of the right margin are unmodified.
The blank cells inserted from the right margin are blank with the backgroud
color colored according to the current SGR state.

If a multi-cell character (such as "橋") is shifted so that the cell is split
in half, the multi-cell character can either be clipped or erased. Typical
behavior is to clip at the right edge of the screen and erase at a right
margin, but either behavior is acceptable.

## Validation

### DCH V-1: Simple Delete Character

```bash
printf "ABC123"
printf "\033[3G"
printf "\033[2P"
```

```
|AB23____|
```

### DCH V-2: SGR State

```bash
printf "ABC123"
printf "\033[3G"
printf "\033[41m"
printf "\033[2P"
```

```
|AB23____|
```

The two rightmost cells should have a red background color.

### DCH V-3: Outside Left/Right Scroll Region

```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "ABC123"
printf "\033[?69h" # enable left/right margins
printf "\033[3;5s" # scroll region left/right
printf "\033[2G"
printf "\033[P"
```

```
|ABC123__|
```

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

```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "ABC123"
printf "\033[?69h" # enable left/right margins
printf "\033[3;5s" # scroll region left/right
printf "\033[4G"
printf "\033[P"
```

```
|ABC2_3__|
```

### DCH V-5: Split Wide Character

```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "A橋123"
printf "\033[3G"
printf "\033[P"
```

```
|A_123_____|
```
