egui/crates/egui_extras/src/loaders/svg_loader.rs

110 lines
3.3 KiB
Rust

use std::{mem::size_of, path::Path, sync::Arc};
use egui::{
ahash::HashMap,
load::{BytesPoll, ImageLoadResult, ImageLoader, ImagePoll, LoadError, SizeHint},
mutex::Mutex,
ColorImage,
};
use resvg::usvg;
type Entry = Result<Arc<ColorImage>, String>;
#[derive(Default)]
pub struct SvgLoader {
cache: Mutex<HashMap<(String, SizeHint), Entry>>,
}
impl SvgLoader {
pub const ID: &'static str = egui::generate_loader_id!(SvgLoader);
}
fn is_supported(uri: &str) -> bool {
let Some(ext) = Path::new(uri).extension().and_then(|ext| ext.to_str()) else {
return false;
};
ext == "svg"
}
impl ImageLoader for SvgLoader {
fn id(&self) -> &str {
Self::ID
}
fn load(&self, ctx: &egui::Context, uri: &str, size_hint: SizeHint) -> ImageLoadResult {
if !is_supported(uri) {
return Err(LoadError::NotSupported);
}
let uri = uri.to_owned();
let mut cache = self.cache.lock();
// We can't avoid the `uri` clone here without unsafe code.
if let Some(entry) = cache.get(&(uri.clone(), size_hint)).cloned() {
match entry {
Ok(image) => Ok(ImagePoll::Ready { image }),
Err(err) => Err(LoadError::Loading(err)),
}
} else {
match ctx.try_load_bytes(&uri) {
Ok(BytesPoll::Ready { bytes, .. }) => {
log::trace!("started loading {uri:?}");
let fit_to = match size_hint {
SizeHint::Scale(factor) => usvg::FitTo::Zoom(factor.into_inner()),
SizeHint::Width(w) => usvg::FitTo::Width(w),
SizeHint::Height(h) => usvg::FitTo::Height(h),
SizeHint::Size(w, h) => usvg::FitTo::Size(w, h),
};
let result =
crate::image::load_svg_bytes_with_size(&bytes, fit_to).map(Arc::new);
log::trace!("finished loading {uri:?}");
cache.insert((uri, size_hint), result.clone());
match result {
Ok(image) => Ok(ImagePoll::Ready { image }),
Err(err) => Err(LoadError::Loading(err)),
}
}
Ok(BytesPoll::Pending { size }) => Ok(ImagePoll::Pending { size }),
Err(err) => Err(err),
}
}
}
fn forget(&self, uri: &str) {
self.cache.lock().retain(|(u, _), _| u != uri);
}
fn forget_all(&self) {
self.cache.lock().clear();
}
fn byte_size(&self) -> usize {
self.cache
.lock()
.values()
.map(|result| match result {
Ok(image) => image.pixels.len() * size_of::<egui::Color32>(),
Err(err) => err.len(),
})
.sum()
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn check_support() {
// inverse of same test in `image_loader.rs`
assert!(!is_supported("https://test.png"));
assert!(!is_supported("test.jpeg"));
assert!(!is_supported("http://test.gif"));
assert!(!is_supported("test.webp"));
assert!(!is_supported("file://test"));
assert!(is_supported("test.svg"));
}
}