What's the difference between outline and ring in tailwind

Tailwindcss supports both outline utility and ring. While I understand that ring is implemented using shadows, I'm not sure what's the use case to use each of them.

Do you have an example when to use what and why? Is one of them more suitable for focus styles? Why?

3 Answers

By the question, i assume you know the general use case of both outline and ring. In a gist it can be used interchangeably, but ring is used when you want more customization and outline is used to produce simple effect.

To explain further,

1. outline

It can be applied to create a decorative effect, highlight a particular element, or serve as a focus indicator for keyboard navigation.

2. ring

It provides more customising choices, like size, colour, and opacity may all be changed using the several iterations of the ring utility class. It can be used to highlight a button or input field in a circle when it is the focus or to create a border-like effect around an element.

In summary, ring is used to create a customisable ring around an element, outline is often used to create a solid or dashed outline around an element. Use ring when you require additional customization choices or want to create a circular highlight effect, and use outline when you want a simpler, more basic effect.

Both of these answers here are not quite correct.

You can change the width, color, offset, and opacity using both ring and outline. The difference between the two is that ring uses the CSS box-shadow property, and outline uses the CSS outline property.

In the past, the main reason people preferred box-shadow was because outline wouldn't honor an element's border radius, but now it does.

Box shadow does offer more customization, but it is specifically via blur and the ability to support multiple colors -- not width, opacity, or a single color like the other answers suggest.

For most use cases, it doesn't matter which one you choose.

The main difference is that ring allows you to outline an element with different widths where outline allows you to do it with different styles. See these two pages from the tailwind docs :