TextStyle::default() ask system for known existing font family

Rather than assuming a specific family exists, try a set of specific
names and if they fail, just grab any old font that the system reports
as existing

Co-Authored-By: Nathan Sobo <nathan@zed.dev>
This commit is contained in:
Julia 2023-05-30 14:46:27 -04:00
parent 1fc9103b61
commit 31516b7863
4 changed files with 56 additions and 16 deletions

View file

@ -25,8 +25,9 @@ struct Family {
pub struct FontCache(RwLock<FontCacheState>);
pub struct FontCacheState {
fonts: Arc<dyn platform::FontSystem>,
font_system: Arc<dyn platform::FontSystem>,
families: Vec<Family>,
default_family: Option<FamilyId>,
font_selections: HashMap<FamilyId, HashMap<Properties, FontId>>,
metrics: HashMap<FontId, Metrics>,
wrapper_pool: HashMap<(FontId, OrderedFloat<f32>), Vec<LineWrapper>>,
@ -42,8 +43,9 @@ unsafe impl Send for FontCache {}
impl FontCache {
pub fn new(fonts: Arc<dyn platform::FontSystem>) -> Self {
Self(RwLock::new(FontCacheState {
fonts,
font_system: fonts,
families: Default::default(),
default_family: None,
font_selections: Default::default(),
metrics: Default::default(),
wrapper_pool: Default::default(),
@ -73,14 +75,14 @@ impl FontCache {
let mut state = RwLockUpgradableReadGuard::upgrade(state);
if let Ok(font_ids) = state.fonts.load_family(name, features) {
if let Ok(font_ids) = state.font_system.load_family(name, features) {
if font_ids.is_empty() {
continue;
}
let family_id = FamilyId(state.families.len());
for font_id in &font_ids {
if state.fonts.glyph_for_char(*font_id, 'm').is_none() {
if state.font_system.glyph_for_char(*font_id, 'm').is_none() {
return Err(anyhow!("font must contain a glyph for the 'm' character"));
}
}
@ -99,6 +101,31 @@ impl FontCache {
))
}
/// Returns an arbitrary font family that is available on the system.
pub fn known_existing_family(&self) -> FamilyId {
if let Some(family_id) = self.0.read().default_family {
return family_id;
}
let default_family = self
.load_family(
&["Courier", "Helvetica", "Arial", "Verdana"],
&Default::default(),
)
.unwrap_or_else(|_| {
let all_family_names = self.0.read().font_system.all_families();
let all_family_names: Vec<_> = all_family_names
.iter()
.map(|string| string.as_str())
.collect();
self.load_family(&all_family_names, &Default::default())
.expect("could not load any default font family")
});
self.0.write().default_family = Some(default_family);
default_family
}
pub fn default_font(&self, family_id: FamilyId) -> FontId {
self.select_font(family_id, &Properties::default()).unwrap()
}
@ -115,7 +142,7 @@ impl FontCache {
let mut inner = RwLockUpgradableReadGuard::upgrade(inner);
let family = &inner.families[family_id.0];
let font_id = inner
.fonts
.font_system
.select_font(&family.font_ids, properties)
.unwrap_or(family.font_ids[0]);
@ -137,7 +164,7 @@ impl FontCache {
if let Some(metrics) = state.metrics.get(&font_id) {
f(metrics)
} else {
let metrics = state.fonts.font_metrics(font_id);
let metrics = state.font_system.font_metrics(font_id);
let metric = f(&metrics);
let mut state = RwLockUpgradableReadGuard::upgrade(state);
state.metrics.insert(font_id, metrics);
@ -157,8 +184,11 @@ impl FontCache {
let bounds;
{
let state = self.0.read();
glyph_id = state.fonts.glyph_for_char(font_id, 'm').unwrap();
bounds = state.fonts.typographic_bounds(font_id, glyph_id).unwrap();
glyph_id = state.font_system.glyph_for_char(font_id, 'm').unwrap();
bounds = state
.font_system
.typographic_bounds(font_id, glyph_id)
.unwrap();
}
bounds.width() * self.em_scale(font_id, font_size)
}
@ -168,8 +198,8 @@ impl FontCache {
let advance;
{
let state = self.0.read();
glyph_id = state.fonts.glyph_for_char(font_id, 'm').unwrap();
advance = state.fonts.advance(font_id, glyph_id).unwrap();
glyph_id = state.font_system.glyph_for_char(font_id, 'm').unwrap();
advance = state.font_system.advance(font_id, glyph_id).unwrap();
}
advance.x() * self.em_scale(font_id, font_size)
}
@ -214,7 +244,7 @@ impl FontCache {
.or_default();
let wrapper = wrappers
.pop()
.unwrap_or_else(|| LineWrapper::new(font_id, font_size, state.fonts.clone()));
.unwrap_or_else(|| LineWrapper::new(font_id, font_size, state.font_system.clone()));
LineWrapperHandle {
wrapper: Some(wrapper),
font_cache: self.clone(),

View file

@ -295,13 +295,14 @@ impl Default for TextStyle {
.as_ref()
.expect("TextStyle::default can only be called within a call to with_font_cache");
let font_family_name = Arc::from("Courier");
let font_family_id = font_cache
.load_family(&[&font_family_name], &Default::default())
.unwrap();
let font_family_id = font_cache.known_existing_family();
let font_id = font_cache
.select_font(font_family_id, &Default::default())
.unwrap();
.expect("did not have any font in system-provided family");
let font_family_name = font_cache
.family_name(font_family_id)
.expect("we loaded this family from the font cache, so this should work");
Self {
color: Default::default(),
font_family_name,

View file

@ -343,6 +343,7 @@ pub enum RasterizationOptions {
pub trait FontSystem: Send + Sync {
fn add_fonts(&self, fonts: &[Arc<Vec<u8>>]) -> anyhow::Result<()>;
fn all_families(&self) -> Vec<String>;
fn load_family(&self, name: &str, features: &FontFeatures) -> anyhow::Result<Vec<FontId>>;
fn select_font(
&self,

View file

@ -66,6 +66,14 @@ impl platform::FontSystem for FontSystem {
self.0.write().add_fonts(fonts)
}
fn all_families(&self) -> Vec<String> {
self.0
.read()
.system_source
.all_families()
.expect("core text should never return an error")
}
fn load_family(&self, name: &str, features: &Features) -> anyhow::Result<Vec<FontId>> {
self.0.write().load_family(name, features)
}