feat: lazy load images

this keeps the images loaded, eventually causing an OOM

weird that dropping the handles doesn't clear memory

src/app/mod.rs

@@ -1,18 +1,16 @@
-use std::{
-    borrow::Cow,
-    collections::HashMap,
-    env,
-    path::{Path, PathBuf},
-};
+use std::{borrow::Cow, collections::HashMap, env, path::PathBuf};
 
-use iced::{Color, Element, Length, Renderer, Task, Theme, application, theme, widget};
+use iced::{Color, Element, Renderer, Task, Theme, application, theme, widget};
 use ignore::{WalkBuilder, types::TypesBuilder};
-use image::{DynamicImage, EncodableLayout, RgbaImage};
 use rayon::iter::{ParallelBridge, ParallelIterator};
 
 use crate::SUPPORTED_TYPES;
 
-enum Message {}
+#[derive(Clone, Debug)]
+enum Message {
+    LoadImage(PathBuf),
+    UnloadImage(PathBuf),
+}
 
 #[derive(Default)]
 enum Mode {
@@ -23,7 +21,7 @@ enum Mode {
 #[derive(Default)]
 struct State {
     mode: Mode,
-    images: HashMap<PathBuf, Option<(RgbaImage, widget::image::Handle)>>,
+    images: HashMap<PathBuf, Option<widget::image::Handle>>,
 }
 
 impl State {
@@ -54,32 +52,40 @@ impl State {
                     .map(|entry| entry.into_path())
             })
             .filter(|path| path.is_file())
-            .map(|path| {
-                let image = image::open(&path)
-                    .inspect_err(|e| eprintln!("{e}"))
-                    .ok()
-                    .map(DynamicImage::into_rgba8);
-                let handle = image.as_ref().map(|image| {
-                    widget::image::Handle::from_rgba(image.width(), image.height(), unsafe {
-                        std::mem::transmute::<&[u8], &'static [u8]>(image.as_bytes())
-                    })
-                });
-                (path, image.map(|image| (image, handle.unwrap())))
-            })
+            .map(|path| (path, None))
             .collect(),
         }
     }
     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)));
+            }
+            Message::UnloadImage(path) => {
+                self.images.entry(path).and_modify(|e| *e = None);
+            }
+        }
+
         Task::none()
     }
     fn view(&self) -> Element<'_, Message, Theme, Renderer> {
         widget::scrollable(
-            widget::grid(
-                self.images
-                    .iter()
-                    .filter_map(|(_k, v)| v.as_ref())
-                    .map(|(_image, handle)| widget::image(handle).into()),
-            )
+            widget::grid(self.images.iter().map(|(path, opt_handle)| {
+                opt_handle.as_ref().map_or_else(
+                    || {
+                        widget::sensor(widget::space())
+                            .on_show(|_size| Message::LoadImage(path.clone()))
+                            .into()
+                    },
+                    |handle| {
+                        widget::sensor(widget::image(handle))
+                            .on_hide(Message::UnloadImage(path.clone()))
+                            .into()
+                    },
+                )
+            }))
             .fluid(500)
             .spacing(0),
         )