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// Copyright 2024 the Parley Authors
// SPDX-License-Identifier: Apache-2.0 OR MIT
use alloc::{
boxed::Box,
str::FromStr,
string::{String, ToString},
sync::Arc,
vec,
vec::Vec,
};
use std::path::Path;
use hashbrown::HashMap;
use roxmltree::{Document, Node};
use super::{
FallbackKey, FamilyId, FamilyInfo, FamilyNameMap, GenericFamily, GenericFamilyMap, Language,
Script, scan,
};
// TODO: Use actual generic families here, where available, when fonts.xml is properly parsed.
// system-ui should map to `variant="compact"` in some scripts during fallback resolution.
const DEFAULT_GENERIC_FAMILIES: &[(GenericFamily, &[&str])] = &[
(
GenericFamily::SansSerif,
&["Roboto Flex", "Roboto", "Noto Sans"],
),
(GenericFamily::Serif, &["Noto Serif"]),
(GenericFamily::Monospace, &["monospace"]),
(GenericFamily::Cursive, &["Dancing Script"]),
(GenericFamily::Fantasy, &["Noto Serif"]),
(
GenericFamily::SystemUi,
&["Roboto Flex", "Roboto", "Noto Sans"],
),
(GenericFamily::Emoji, &["Noto Color Emoji"]),
(GenericFamily::Math, &["Noto Sans Math", "Noto Sans"]),
];
pub(crate) struct SystemFonts {
pub(crate) name_map: Arc<FamilyNameMap>,
pub(crate) generic_families: Arc<GenericFamilyMap>,
family_map: HashMap<FamilyId, FamilyInfo>,
locale_fallback: Box<[(Language, FamilyId)]>,
script_fallback: Box<[(Script, FamilyId)]>,
}
impl SystemFonts {
pub(crate) fn new() -> Self {
let android_root: String = std::env::var("ANDROID_ROOT").unwrap_or("/system".to_string());
let scan::ScannedCollection {
family_names: mut name_map,
families: family_map,
postscript_names,
..
} = scan::ScannedCollection::from_paths(Path::new(&android_root).join("fonts").to_str(), 8);
let mut generic_families = GenericFamilyMap::default();
for (family, names) in DEFAULT_GENERIC_FAMILIES {
generic_families.set(
*family,
names
.iter()
.filter_map(|name| name_map.get(name))
.map(|name| name.id()),
);
}
let mut locale_fallback = vec![];
let mut script_fallback = vec![];
// Try to get generic info from fonts.xml
if let Ok(s) = std::fs::read_to_string(Path::new(&android_root).join("etc/fonts.xml")) {
if let Ok(doc) = Document::parse(s.clone().as_str()) {
let root = doc.root_element();
if root.tag_name().name() == "familyset"
|| root
.attribute("version")
.is_some_and(|v| usize::from_str(v).is_ok_and(|x| x >= 21))
{
for child in root.children() {
match child.tag_name().name() {
"alias" => {
if let Some((name, to)) =
child.attribute("name").zip(child.attribute("to"))
{
if child.attribute("weight").is_some() {
// weight aliases are an Android quirk and are not in
// teresting for use cases other than Android legacy.
continue;
}
let to_n = name_map.get_or_insert(to);
name_map.add_alias(to_n.id(), name);
}
}
"family" => {
if let Some(name) = child.attribute("name") {
let f = name_map.get_or_insert(name);
let _id = f.id();
for _child in child.children() {
// TODO: map using postScriptName when available other
// wise use the file name, and perhaps if necess
// ary (e.g. if it's a collection), do something
// smarter, or something dumb that meets expecta
// tions on Android.
}
} else if let Some(langs) = child
.attribute("lang")
.map(|s| s.split(',').collect::<Vec<&str>>())
{
let (_has_for, hasnt_for): (
Vec<Node<'_, '_>>,
Vec<Node<'_, '_>>,
) = child
.children()
.partition(|c| c.attribute("fallbackFor").is_some());
{
// general fallback families
let (ps_named, _ps_unnamed): (
Vec<Node<'_, '_>>,
Vec<Node<'_, '_>>,
) = hasnt_for
.iter()
.partition(|c| c.attribute("postScriptName").is_some());
if let Some(family) = ps_named.iter().find_map(|x| {
postscript_names
.get(x.attribute("postScriptName").unwrap())
}) {
for lang in langs {
if let Some(scr) = lang.strip_prefix("und-") {
// Undefined lang for script-only fallbacks
script_fallback.push((
scr.parse().unwrap_or(Script::UNKNOWN),
*family,
));
} else if let Ok(locale) = Language::parse(lang) {
if let Some(scr) = locale
.script()
.and_then(|s| s.parse::<Script>().ok())
{
// Also fallback for the script on its own
script_fallback.push((scr, *family));
if Script::from_bytes(*b"Hant") == scr {
// This works around ambiguous han char
// acters going unmapped with current
// fallback code. This should be done in
// a locale-dependent manner, since that
// is the norm.
script_fallback.push((
Script::from_bytes(*b"Hani"),
*family,
));
}
}
locale_fallback.push((locale, *family));
}
}
}
// TODO: handle mapping to family names from file names
// when postScriptName is unavailable.
}
// family-specific fallback families, currently unimplemented
// because it requires a GenericFamily to be plumbed through
// the `RangedStyle` `font_stack` from `resolve` where it is
// currently thrown away.
{}
}
// TODO: interpret variant="compact" without fallbackFor as a
// fallback for system-ui, as falling back to a
// variant="elegant" for system-ui can mess up a layout
// in some scripts.
}
_ => {}
}
}
}
}
}
Self {
name_map: Arc::new(name_map),
generic_families: Arc::new(generic_families),
family_map,
locale_fallback: locale_fallback.into(),
script_fallback: script_fallback.into(),
}
}
pub(crate) fn family(&self, id: FamilyId) -> Option<FamilyInfo> {
self.family_map.get(&id).cloned()
}
pub(crate) fn fallback(&self, key: impl Into<FallbackKey>) -> Option<FamilyId> {
let key: FallbackKey = key.into();
let script = key.script();
key.locale()
.and_then(|locale| {
self.locale_fallback
.iter()
.find(|(other, _)| locale == *other)
.map(|(_, fid)| *fid)
})
.or_else(|| {
self.script_fallback
.iter()
.find(|(s, _)| script == *s)
.map(|(_, fid)| *fid)
})
.or_else(|| {
self.generic_families
.get(GenericFamily::SansSerif)
.first()
.copied()
})
}
}