Files
DarkRoom/third_party/i-slint-renderer-skia-1.17.1/font_cache.rs
T
dtourolle dc1add9dbb Vendor wgpu-hal 29.0.4 and i-slint-renderer-skia 1.17.1, unmodified
The Android develop view reads its frame back through memory (TD-1)
because wgpu's Vulkan swapchain never pre-rotates, and a portrait window
on this tablet's landscape panel then tears. The fix is a small patch to
each of these two crates, and this commit is only the ground it lands on:
both are byte-for-byte the crates.io sources the lockfile already
resolved, so the commits that follow are the patch and nothing else.

third_party/ is excluded from the workspace, or every path dependency
under the root would become a member and `--workspace` would test and
lint upstream code as ours. The README says how to carry the patches
across a Slint or wgpu bump, which matters because a stale version here
does not fail the build — cargo just warns and uses the unpatched crate.
2026-09-25 04:18:39 -04:00

107 lines
4.0 KiB
Rust

// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
use clru::CLruCache;
use i_slint_common::sharedfontique::HashedBlob;
use i_slint_core::textlayout::sharedparley::{fontique, parley};
use std::cell::RefCell;
use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};
use std::num::NonZeroUsize;
const FONT_CACHE_CAPACITY: NonZeroUsize = NonZeroUsize::new(64).unwrap();
pub struct FontCache {
font_mgr: skia_safe::FontMgr,
// Use HashedBlob in key to keep strong reference to font data blob,
// preventing eviction from fontique's shared cache (see commit 30a03cf).
// The u64 is a hash of variation settings (0 for base typefaces).
fonts: CLruCache<(HashedBlob, u32, u64), Option<skia_safe::Typeface>>,
}
impl Default for FontCache {
fn default() -> Self {
Self { font_mgr: skia_safe::FontMgr::new(), fonts: CLruCache::new(FONT_CACHE_CAPACITY) }
}
}
impl FontCache {
pub fn font_with_variations(
&mut self,
font: &parley::FontData,
synthesis: &fontique::Synthesis,
) -> Option<skia_safe::Typeface> {
let variation_settings = synthesis.variation_settings();
let mut variations_hash = 0u64;
if !variation_settings.is_empty() {
let mut hasher = DefaultHasher::new();
for &(tag, value) in variation_settings {
tag.to_be_bytes().hash(&mut hasher);
value.to_bits().hash(&mut hasher);
}
variations_hash = hasher.finish();
}
let key = (font.data.clone().into(), font.index, variations_hash);
if let Some(cached) = self.fonts.get(&key) {
return cached.clone();
}
let mut typeface = self.load_typeface_internal(font);
if !variation_settings.is_empty() {
typeface = typeface.and_then(|base| {
let coords: Vec<skia_safe::font_arguments::variation_position::Coordinate> =
variation_settings
.iter()
.map(|&(tag, value)| {
skia_safe::font_arguments::variation_position::Coordinate {
axis: skia_safe::FourByteTag::new(u32::from_be_bytes(
tag.to_be_bytes(),
)),
value,
}
})
.collect();
let position =
skia_safe::font_arguments::VariationPosition { coordinates: &coords };
let args = skia_safe::FontArguments::new().set_variation_design_position(position);
base.clone_with_arguments(&args).or(Some(base))
});
}
self.fonts.put(key, typeface.clone());
typeface
}
fn load_typeface_internal(&self, font: &parley::FontData) -> Option<skia_safe::Typeface> {
let typeface = self.font_mgr.new_from_data(
font.data.as_ref(),
if font.index > 0 { Some(font.index as _) } else { None },
);
// Due to https://issues.skia.org/issues/310510989, fonts from true type collections
// with an index > 0 fail to load on macOS. As a workaround, we manually extract the font from the
// collection and load it as a single font.
#[cfg(target_vendor = "apple")]
if font.index > 0
&& typeface.is_none()
&& let Some(typeface) = read_fonts::CollectionRef::new(font.data.as_ref())
.ok()
.and_then(|ttc| ttc.get(font.index).ok())
.map(|ttf| write_fonts::FontBuilder::new().copy_missing_tables(ttf).build())
.and_then(|new_ttf| self.font_mgr.new_from_data(&new_ttf, None))
{
return Some(typeface);
}
typeface
}
}
thread_local! {
pub static FONT_CACHE: RefCell<FontCache> = RefCell::new(Default::default())
}