# `AltText`

What an image shows, for someone who can't see it.

Use it beside each image a person might read about. An image with nothing to say has `none`, not empty text. For a long caption, use `Text`.

## Shape

One value, held as text in one set form, with no parts: `Logo`.

## Example

```jadpo
AltText("A red bicycle leaning against a brick wall")
```

`AltText(raw)` checks the text, and text that isn't one breaks the `format` rule.

`text.parse(raw, as: AltText)` reads one from text that comes from outside. Text that isn't one at all fails `malformed`, such as ` Logo` or `Logo `.

## Good to know

- It is one line of up to 1,000 characters.
- `==` tells you whether two are the same. `<` and `list.sort_by` don't take it.

## In JSON

A string, in a request, a response or `json.write`:

```json
"A red bicycle leaning against a brick wall"
"Logo"
```

## Details

<details>
<summary>Text form, storage, how it is shown, and operations</summary>

`AltText` is in the group Media and visual, and has been in Jadpo since 0.1.0.

### Text form

`text.from` writes one standard text form, the same form `text.parse` reads back: `A red bicycle leaning against a brick wall` and `Logo`.

### How it is stored

It is stored in one column named for the field, of type `text`. `Logo` is stored as `'Logo'`.

### How it is shown to people

`text.format(value, locale:)` shows it to people in their locale.

With `locale: Locale.en_gb`:

| Value | Shown |
|---|---|
| `A red bicycle leaning against a brick wall` | `A red bicycle leaning against a brick wall` |
| `Logo` | `Logo` |

### Operations

It also takes `text.parse`, `text.from`, `text.format`, `json.read`, `json.write` and `==`. [How every standard type behaves](/docs/every-standard-type-meets-one-contract.md) says how they work.

</details>