Type Alias usvg::FontSelectionFn

pub type FontSelectionFn<'a> = Box<dyn Fn(&Font, &mut Arc<Database>) -> Option<ID> + Send + Sync + 'a>;

A shorthand for FontResolver’s font selection function.

This function receives a font specification (families + a style, weight, stretch triple) and a font database and should return the ID of the font that shall be used (if any).

In the basic case, the function will search the existing fonts in the database to find a good match, e.g. via Database::query. This is what the default implementation does.

Users with more complex requirements can mutate the database to load additional fonts dynamically. To perform mutation, it is recommended to call Arc::make_mut on the provided database. (This call is not done outside of the callback to not needless clone an underlying shared database if no mutation will be performed.) It is important that the database is only mutated additively. Removing fonts or replacing the entire database will break things.

Aliased Type

struct FontSelectionFn<'a>(/* private fields */);