Font Fallback not working for at least `汉` on Windows

[CryZe]

The font family returned by fontique for the Hani script is Yu Gothic UI on Windows, which does not have the character 汉. The character is in Microsoft YaHei UI, which is not returned at all.

Reproduction:

use fontique::{Collection, FallbackKey, Script, SourceCache};

let mut collection = Collection::default();
let mut source_cache = SourceCache::default();
let family_ids: Vec<_> = collection
    .fallback_families(FallbackKey::new(Script::from_bytes(*b"Hani"), None))
    .collect();
let family_names: Vec<_> = family_ids
    .iter()
    .map(|&id| collection.family_name(id).unwrap().to_owned())
    .collect();

println!("fallback families: {family_names:?}");

let family_id = family_ids[0];
let family_name = collection.family_name(family_id).unwrap().to_owned();
let family = collection.family(family_id).unwrap();
let font = family.default_font().unwrap();
let data = font.load(Some(&mut source_cache)).unwrap();
let charmap = font.charmap_index().charmap(data.as_ref()).unwrap();

println!("{family_name}: 汉 -> {:?}", charmap.map('汉'));

The problematic line seems to be here, which doesn't contain enough characters for more coverage:

parley/fontique/src/script.rs

Line 112 in 8294d3e

(Script::from_str_unchecked("Hani"), "今"),

though apparently for DirectWrite only a single font is queried anyway, so it wouldn't be the only thing that needs to be fixed.

parley/fontique/src/backend/dwrite.rs

Line 200 in 8294d3e

fn family_name_for_text(&mut self, text: &str, locale: Option<&str>) -> Option<String> {

[nicoburns]

Am I understanding correctly that there is a fundamental issue with Fontique that it assumes that a given (script, locale) pair can be covered by a single fallback font, but that this isn't true for the Hani script on Windows where you actually need two fallback fonts?

[CryZe]

That is my understanding of it, yes. Though it could of course be even more than two for other cases. I don't have enough of a deep understanding of how correct fallback would work.