Type Alias SpanHighlighter 

pub type SpanHighlighter = Box<dyn Fn(&str, &Theme) -> Vec<(Range<usize>, AlphaColor<Srgb>)>>;

Colours spans of a field’s text from the theme: each (range, colour) is a byte range of the text and the ink it takes (a reference in a formula, in the colour of the cells it outlines).

Aliased Type

pub struct SpanHighlighter(/* private fields */);