# Shadcn Standard

> 4:3 standard aspect ratio

- Type: example, free and open source (MIT)
- Component: [Aspect Ratio](https://reui.io/components/aspect-ratio.md)
- Page: https://reui.io/components/aspect-ratio/c-aspect-ratio-2
- Docs (Base UI): https://ui.shadcn.com/docs/components/base/aspect-ratio.md
- Docs (Radix UI): https://ui.shadcn.com/docs/components/radix/aspect-ratio.md
- MCP: `get_example("c-aspect-ratio-2")`
- Registry item: https://reui.io/r/styles/base-nova/c-aspect-ratio-2.json
- Uses: Aspect Ratio

## Best for

The 4:3 shape of phone camera photos and classic TV footage, in a landscape box up to 28rem wide

## When not to use

- Photos from most DSLR and 35mm film cameras, which come out at 3:2: use [Classic Photo](https://reui.io/components/aspect-ratio/c-aspect-ratio-6.md) (`get_example("c-aspect-ratio-6")`)

## Install

```bash
npx shadcn@latest add @reui/c-aspect-ratio-2
```

## About Shadcn Aspect Ratio

### When to use

- Video, banner and screenshot slots in widescreen shapes such as 16:9, 21:9 and 16:10
- Photo and thumbnail slots in square, landscape or portrait shapes, cropped to fill the box
- Media boxes whose height follows their width, so the space is held before the image arrives

### When not to use

- A sign in page split between the form and a full height image panel: use the [Auth blocks](https://reui.io/blocks/application/auth.md)
- Several images the user swipes or steps through one at a time: use [Carousel](https://reui.io/components/carousel.md) (`get_component("carousel")`)
- A choice of exactly one option from a short visible list: use [Radio Group](https://reui.io/components/radio-group.md) (`get_component("radio-group")`)

### Agent notes

- Pass `ratio` as width divided by height, as in 16 / 9; the base twin requires it and the radix twin falls back to 1 when it is missing
- Every `img` is a random grayscale `picsum.photos` placeholder whose `alt` is only the ratio label; swap `src` and write a real `alt`
- Set width on a parent, as the `max-w-md` or `max-w-xs` wrapper does; radix puts `className` on an absolute inner layer, where a width class breaks the ratio

Every ReUI item has a twin like this one; the index is https://reui.io/llms.txt. Agents with the ReUI MCP (https://reui.io/docs/mcp) get the same guidance from the getters named above.