Add Resize::id_source and ScrollArea::id_source

CHANGELOG.md

@@ -9,6 +9,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Added ⭐
 
 * `SelectableLabel` (`ui.selectable_label` and `ui.selectable_value`): a text-button that can be selected
+* Add `Resize::id_source` and `ScrollArea::id_source` to let the user avoid Id clashes.
+
+### Changed 🔧
 
 * Changed default font to [Ubuntu-Light](https://fonts.google.com/specimen/Ubuntu).
 

egui/src/containers/resize.rs

@@ -20,6 +20,7 @@ pub(crate) struct State {
 #[derive(Clone, Copy, Debug)]
 pub struct Resize {
     id: Option<Id>,
+    id_source: Option<Id>,
 
     /// If false, we are no enabled
     resizable: bool,
@@ -36,6 +37,7 @@ impl Default for Resize {
     fn default() -> Self {
         Self {
             id: None,
+            id_source: None,
             resizable: true,
             min_size: Vec2::splat(16.0),
             max_size: Vec2::splat(f32::INFINITY),
@@ -52,6 +54,12 @@ impl Resize {
         self
     }
 
+    /// A source for the unique `Id`, e.g. `.id_source("second_resize_area")` or `.id_source(loop_index)`.
+    pub fn id_source(mut self, id_source: impl std::hash::Hash) -> Self {
+        self.id_source = Some(Id::new(id_source));
+        self
+    }
+
     /// Preferred / suggested width. Actual width will depend on contents.
     ///
     /// Examples:
@@ -146,7 +154,10 @@ struct Prepared {
 impl Resize {
     fn begin(&mut self, ui: &mut Ui) -> Prepared {
         let position = ui.available().min;
-        let id = self.id.unwrap_or_else(|| ui.make_persistent_id("resize"));
+        let id = self.id.unwrap_or_else(|| {
+            let id_source = self.id_source.unwrap_or_else(|| Id::new("resize"));
+            ui.make_persistent_id(id_source)
+        });
 
         let mut state = ui.memory().resize.get(&id).cloned().unwrap_or_else(|| {
             ui.ctx().request_repaint(); // counter frame delay

egui/src/containers/scroll_area.rs

@@ -30,6 +30,7 @@ impl Default for State {
 pub struct ScrollArea {
     max_height: f32,
     always_show_scroll: bool,
+    id_source: Option<Id>,
 }
 
 impl ScrollArea {
@@ -43,6 +44,7 @@ impl ScrollArea {
         Self {
             max_height,
             always_show_scroll: false,
+            id_source: None,
         }
     }
 
@@ -52,6 +54,12 @@ impl ScrollArea {
         self.always_show_scroll = always_show_scroll;
         self
     }
+
+    /// A source for the unique `Id`, e.g. `.id_source("second_scroll_area")` or `.id_source(loop_index)`.
+    pub fn id_source(mut self, id_source: impl std::hash::Hash) -> Self {
+        self.id_source = Some(Id::new(id_source));
+        self
+    }
 }
 
 struct Prepared {
@@ -68,11 +76,13 @@ impl ScrollArea {
         let Self {
             max_height,
             always_show_scroll,
+            id_source,
         } = self;
 
         let ctx = ui.ctx().clone();
 
-        let id = ui.make_persistent_id("scroll_area");
+        let id_source = id_source.unwrap_or_else(|| Id::new("scroll_area"));
+        let id = ui.make_persistent_id(id_source);
         let state = ctx
             .memory()
             .scroll_areas

egui/src/widgets/text_edit.rs

@@ -169,6 +169,7 @@ impl<'t> TextEdit<'t> {
         self
     }
 
+    /// A source for the unique `Id`, e.g. `.id_source("second_text_edit_field")` or `.id_source(loop_index)`.
     pub fn id_source(mut self, id_source: impl std::hash::Hash) -> Self {
         self.id_source = Some(Id::new(id_source));
         self