typst/src/font.rs

50 lines
1.3 KiB
Rust

//! Font handling.
use fontdock::{ContainsChar, FaceFromVec, FontSource};
use ttf_parser::Face;
/// A font loader that is backed by a dynamic source.
pub type FontLoader = fontdock::FontLoader<Box<dyn FontSource<Face = FaceBuf>>>;
/// An owned font face.
pub struct FaceBuf {
data: Box<[u8]>,
face: Face<'static>,
}
impl FaceBuf {
/// Get a reference to the underlying face.
pub fn get(&self) -> &Face<'_> {
// We can't implement Deref because that would leak the internal 'static
// lifetime.
&self.face
}
/// The raw face data.
pub fn data(&self) -> &[u8] {
&self.data
}
}
impl FaceFromVec for FaceBuf {
fn from_vec(vec: Vec<u8>, i: u32) -> Option<Self> {
let data = vec.into_boxed_slice();
// SAFETY: The slices's location is stable in memory since we don't
// touch it and it can't be touched from outside this type.
let slice: &'static [u8] =
unsafe { std::slice::from_raw_parts(data.as_ptr(), data.len()) };
Some(Self {
data,
face: Face::from_slice(slice, i).ok()?,
})
}
}
impl ContainsChar for FaceBuf {
fn contains_char(&self, c: char) -> bool {
self.get().glyph_index(c).is_some()
}
}