Managed texture loading (#3297)

* add types from proposal * add load methods on `egui::Context` * implement loaders from proposal in `egui_extras` * impl `From<Vec2>` for `SizeHint` * re-export `SizeHint` from `egui` root * rework `svg` example to use new managed `Image` * split loaders into separate files + add logging * add `log_trace` * clean up `RetainedImage` from `svg` example * refactor ehttp loader response to bytes mapping * remove spammy trace * load images even without extension * fix lints * remove unused imports * use `Image2` in `download_image` * use `visuals.error_fg_color` in `Image2` error state * update lockfile * use `Arc<ColorImage>` in `ImageData` + add `forget` API * add `ui.image2` * add byte size query api * use iterators to sum loader byte sizes * add static image loading * use static image in `svg` example * small refactor of `Image2::ui` texture loading code * add `ImageFit` to size images properly * remove println calls * add bad image load to `download_image` example * add loader file extension support tests * fix lint errors in `loaders` * remove unused `poll-promise` dependency * add some docs to `Image2` * add some docs to `egui_extras::loaders::install` * explain `loaders::install` in examples * fix lint * upgrade `ehttp` to `0.3` for some crates * Remove some unused dependencies * Remove unnecessary context clone * Turn on the `log` create feature of egui_extras in all examples * rename `forget` and document it * derive `Debug` on `SizeHint` Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com> * round when converting SizeHint from vec2 Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com> * add `load` module docs * docstring `add_loader` methods * expose + document `load_include_bytes` * cache texture handles in `DefaultTextureLoader` * add `image2` doctest + further document `Image2` * use `Default` for default `Image2` options * update `image2` doc comment * mention immediate-mode safety * more fit calculation into inherent impl * add hover text on spinner * add `all-loaders` feature * clarify `egui_extras::loaders::install` behavior * explain how to enable image formats * properly format `uri` * use `thread::Builder` instead of `spawn` * use eq op instead of `matches` * inline `From<Arc<ColorImage>>` for `ImageData` * allow non-`'static` bytes + `forget` in `DefaultTextureLoader` * sort features * change `ehttp` feature to `http` * update `Image2` docs * refactor loader cache type --------- Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
2026-09-01 14:20:04 -04:00 · 2023-09-06 10:51:51 +02:00
parent 82704bebbf
commit ec671e754f
24 changed files with 1343 additions and 79 deletions
--- a/crates/egui_extras/src/loaders/file_loader.rs
+++ b/crates/egui_extras/src/loaders/file_loader.rs
@@ -0,0 +1,84 @@
+use egui::{
+    ahash::HashMap,
+    load::{Bytes, BytesLoadResult, BytesLoader, BytesPoll, LoadError},
+    mutex::Mutex,
+};
+use std::{sync::Arc, task::Poll, thread};
+
+type Entry = Poll<Result<Arc<[u8]>, String>>;
+
+#[derive(Default)]
+pub struct FileLoader {
+    /// Cache for loaded files
+    cache: Arc<Mutex<HashMap<String, Entry>>>,
+}
+
+const PROTOCOL: &str = "file://";
+
+impl BytesLoader for FileLoader {
+    fn load(&self, ctx: &egui::Context, uri: &str) -> BytesLoadResult {
+        // File loader only supports the `file` protocol.
+        let Some(path) = uri.strip_prefix(PROTOCOL) else {
+            return Err(LoadError::NotSupported);
+        };
+
+        let mut cache = self.cache.lock();
+        if let Some(entry) = cache.get(path).cloned() {
+            // `path` has either begun loading, is loaded, or has failed to load.
+            match entry {
+                Poll::Ready(Ok(bytes)) => Ok(BytesPoll::Ready {
+                    size: None,
+                    bytes: Bytes::Shared(bytes),
+                }),
+                Poll::Ready(Err(err)) => Err(LoadError::Custom(err)),
+                Poll::Pending => Ok(BytesPoll::Pending { size: None }),
+            }
+        } else {
+            crate::log_trace!("started loading {uri:?}");
+            // We need to load the file at `path`.
+
+            // Set the file to `pending` until we finish loading it.
+            let path = path.to_owned();
+            cache.insert(path.clone(), Poll::Pending);
+            drop(cache);
+
+            // Spawn a thread to read the file, so that we don't block the render for too long.
+            thread::Builder::new()
+                .name(format!("egui_extras::FileLoader::load({uri:?})"))
+                .spawn({
+                    let ctx = ctx.clone();
+                    let cache = self.cache.clone();
+                    let uri = uri.to_owned();
+                    move || {
+                        let result = match std::fs::read(&path) {
+                            Ok(bytes) => Ok(bytes.into()),
+                            Err(err) => Err(err.to_string()),
+                        };
+                        let prev = cache.lock().insert(path, Poll::Ready(result));
+                        assert!(matches!(prev, Some(Poll::Pending)));
+                        ctx.request_repaint();
+                        crate::log_trace!("finished loading {uri:?}");
+                    }
+                })
+                .expect("failed to spawn thread");
+
+            Ok(BytesPoll::Pending { size: None })
+        }
+    }
+
+    fn forget(&self, uri: &str) {
+        let _ = self.cache.lock().remove(uri);
+    }
+
+    fn byte_size(&self) -> usize {
+        self.cache
+            .lock()
+            .values()
+            .map(|entry| match entry {
+                Poll::Ready(Ok(bytes)) => bytes.len(),
+                Poll::Ready(Err(err)) => err.len(),
+                _ => 0,
+            })
+            .sum()
+    }
+}