Persist window state across runs

src/window/utils.rs

@@ -1,6 +1,6 @@
 use std::{
     fmt::{Display, UpperHex},
-    ops::{Bound, RangeBounds},
+    ops::{Bound, Deref, DerefMut, RangeBounds},
     str::FromStr,
 };
 
@@ -8,7 +8,7 @@ use atoi::FromRadix16;
 use egui::{
     Align, Color32, CornerRadius, CursorIcon, Event, Frame, Key, Layout, Margin, Rect, Response,
     RichText, Sense, Shape, Stroke, StrokeKind, TextEdit, Ui, UiBuilder, Vec2, Widget, WidgetText,
-    ecolor::HexColor,
+    ecolor::HexColor, util::id_type_map::SerializableAny,
 };
 use num_traits::{CheckedAdd, CheckedSub, One};
 
@@ -409,3 +409,51 @@ impl ResponseExt for Response {
         self.clicked() || self.dragged()
     }
 }
+
+pub struct UiData<T> {
+    current: T,
+    prev: T,
+    loaded: bool,
+}
+
+impl<T> UiData<T>
+where
+    T: Default + PartialEq + SerializableAny,
+{
+    pub fn new() -> Self {
+        Self {
+            current: T::default(),
+            prev: T::default(),
+            loaded: false,
+        }
+    }
+
+    pub fn load(&mut self, ui: &Ui) {
+        if !self.loaded {
+            self.current = ui
+                .data_mut(|d| d.get_persisted(ui.id()))
+                .unwrap_or_default();
+            self.loaded = true;
+        }
+    }
+
+    pub fn save(&mut self, ui: &Ui) {
+        if self.current != self.prev {
+            ui.data_mut(|d| d.insert_persisted(ui.id(), self.current.clone()));
+            self.prev = self.current.clone();
+        }
+    }
+}
+
+impl<T> Deref for UiData<T> {
+    type Target = T;
+    fn deref(&self) -> &Self::Target {
+        &self.current
+    }
+}
+
+impl<T> DerefMut for UiData<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.current
+    }
+}