refactor: prepare for parrelel loading with MaybeImage

src/app/maybe_image.rs

@@ -0,0 +1,30 @@
+use iced::{task, widget};
+use image::DynamicImage;
+
+#[derive(Clone, Debug, Default)]
+pub enum MaybeImage {
+    #[default]
+    Unloaded,
+    Loading(task::Handle),
+    Loaded(widget::image::Handle),
+}
+impl MaybeImage {
+    pub fn handle(&self) -> Option<&widget::image::Handle> {
+        match self {
+            Self::Loaded(h) => Some(&h),
+            _ => None,
+        }
+    }
+
+    pub fn unload(&mut self) {
+        match self {
+            Self::Loading(task_handle) => task_handle.abort(),
+            _ => {}
+        }
+        *self = Self::Unloaded;
+    }
+}
+
+pub fn handle_from_image(image: DynamicImage) -> widget::image::Handle {
+    widget::image::Handle::from_rgba(image.width(), image.height(), image.into_rgba8().into_raw())
+}

src/app/mod.rs

@@ -14,7 +14,9 @@ use ignore::{WalkBuilder, types::TypesBuilder};
 use rayon::iter::{ParallelBridge, ParallelIterator};
 use rfd::AsyncFileDialog;
 
-use crate::SUPPORTED_TYPES;
+use crate::{SUPPORTED_TYPES, app::maybe_image::MaybeImage};
+
+mod maybe_image;
 
 #[derive(Clone, Debug)]
 enum Message {
@@ -30,7 +32,7 @@ enum Message {
 
 #[derive(Default)]
 struct State {
-    images: BTreeMap<PathBuf, Option<widget::image::Handle>>,
+    images: BTreeMap<PathBuf, MaybeImage>,
 
     columns: usize,
 
@@ -56,12 +58,12 @@ impl State {
     fn update(&mut self, message: Message) -> Task<Message> {
         match message {
             Message::LoadImage(path) => {
-                self.images
-                    .entry(path.clone())
-                    .and_modify(|e| *e = Some(widget::image::Handle::from_path(path)));
+                self.images.entry(path.clone()).and_modify(|e| {
+                    *e = MaybeImage::Loaded(widget::image::Handle::from_path(path))
+                });
             }
             Message::UnloadImage(path) => {
-                self.images.entry(path).and_modify(|e| *e = None);
+                self.images.entry(path).and_modify(MaybeImage::unload);
             }
 
             Message::OpenImage(path) => {
@@ -119,10 +121,10 @@ impl State {
     fn view(&self) -> Element<'_, Message, Theme, Renderer> {
         widget::column([
             widget::scrollable(
-                widget::grid(self.images.iter().map(|(path, opt_handle)| {
+                widget::grid(self.images.iter().map(|(path, maybe_image)| {
                     widget::button(widget::column([
                         widget::container(
-                            widget::sensor(opt_handle.as_ref().map_or_else(
+                            widget::sensor(maybe_image.handle().map_or_else(
                                 || Element::from(widget::space()),
                                 |handle| widget::image(handle).into(),
                             ))
@@ -184,7 +186,7 @@ impl State {
                     .map(|entry| entry.into_path())
             })
             .filter(|path| path.is_file())
-            .map(|path| (path, None))
+            .map(|path| (path, MaybeImage::Unloaded))
             .collect();
     }
 }