Highlight: Add possibility to select (block) styles

[hanneslsm]

What problem does this address?

Currently, it's possible to change with the highlight features text or background color. Because the possibilities to customize this are very limited, it'd be great if we would add styles as we know it from block styles.

What is your proposed solution?

Add the option to add (block) styles for highlight / the <mark> tag, which are then selectable in the UI.

Example for a custom style:

.is-style-highlight-yellow {
/** just a example class name **/
    background: 0 0;
    background-image: linear-gradient(90deg, rgba(255, 225, 0, .1), rgba(255, 225, 0, .7) 4%, rgba(255, 225, 0, .3));
    border-radius: .8rem .3rem;
}

Example taken from: https://www.commercegurus.com/product/shoptimizer/

[t-hamano]

Thanks for the suggestion.

Is what you're proposing equivalent to Formatting Toolbar API?

[hanneslsm]

Thanks @t-hamano, I didn't know this existed.
It looks like it is a possibility to solve the issue but also looks much like plugin territory. What I'm suggesting is more straight forward for theme developers and integrated in the UI, much like registering block styles:

[justintadlock]

Using block styles for inline text would break for all kinds of styles. This is definitely a Formatting Toolbar API thing.

What would be cool is if there was an easy way to register RichText formats via theme JSON-like objects or files. It'd limit what you want to do with the API, but it'd be a simple way to associate a class with some inline text and style it.