Experiment with calculating an Ui's "intrinsic size" by remembering the widget's size

crates/egui/src/containers/area.rs

@@ -613,7 +613,9 @@ impl Prepared {
             ..
         } = self;
 
-        state.size = Some(content_ui.min_size());
+        state.size = Some(content_ui.placer().min_item_size());
+
+        dbg!(state.size);
 
         // Make sure we report back the correct size.
         // Very important after the initial sizing pass, when the initial estimate of the size is way off.

crates/egui/src/containers/popup.rs

@@ -568,7 +568,8 @@ impl<'a> Popup<'a> {
 
         let mut response = area.show(&ctx, |ui| {
             style.apply(ui.style_mut());
-            frame.show(ui, content).inner
+            // frame.show(ui, content).inner
+            content(ui)
         });
 
         let closed_by_click = match close_behavior {

crates/egui/src/layout.rs

@@ -45,6 +45,8 @@ pub(crate) struct Region {
     /// If something has already been added, this will point to `style.spacing.item_spacing` beyond the latest child.
     /// The cursor can thus be `style.spacing.item_spacing` pixels outside of the `min_rect`.
     pub(crate) cursor: Rect,
+
+    pub min_item_size: Vec2,
 }
 
 impl Region {
@@ -426,6 +428,7 @@ impl Layout {
             min_rect: Rect::NOTHING, // temporary
             max_rect,
             cursor: self.initial_cursor(max_rect),
+            min_item_size: Vec2::default(),
         };
         let seed = self.next_widget_position(&region);
         region.min_rect = Rect::from_center_size(seed, Vec2::ZERO);
@@ -529,6 +532,7 @@ impl Layout {
                 mut cursor,
                 mut max_rect,
                 min_rect,
+                min_item_size,
             } = *region;
 
             match self.main_dir {
@@ -590,6 +594,7 @@ impl Layout {
                 min_rect,
                 max_rect,
                 cursor,
+                min_item_size,
             };
 
             self.next_frame_ignore_wrap(&region, child_size)

crates/egui/src/placer.rs

@@ -163,6 +163,7 @@ impl Placer {
         frame_rect: Rect,
         widget_rect: Rect,
         item_spacing: Vec2,
+        desired_size: Vec2,
     ) {
         debug_assert!(!frame_rect.any_nan());
         debug_assert!(!widget_rect.any_nan());
@@ -179,11 +180,17 @@ impl Placer {
             );
         }
 
+        self.region.min_item_size = self.region.min_item_size.max(desired_size);
+
         self.expand_to_include_rect(frame_rect); // e.g. for centered layouts: pretend we used whole frame
 
         self.region.sanity_check();
     }
 
+    pub(crate) fn min_item_size(&self) -> Vec2 {
+        self.region.min_item_size
+    }
+
     /// Move to the next row in a grid layout or wrapping layout.
     /// Otherwise does nothing.
     pub(crate) fn end_row(&mut self, item_spacing: Vec2, painter: &Painter) {

crates/egui/src/ui.rs

@@ -1403,7 +1403,7 @@ impl Ui {
         let widget_rect = self.placer.justify_and_align(frame_rect, desired_size);
 
         self.placer
-            .advance_after_rects(frame_rect, widget_rect, item_spacing);
+            .advance_after_rects(frame_rect, widget_rect, item_spacing, desired_size);
 
         register_rect(self, widget_rect);
 
@@ -1426,7 +1426,8 @@ impl Ui {
         let rect = rect.round_ui();
 
         let item_spacing = self.spacing().item_spacing;
-        self.placer.advance_after_rects(rect, rect, item_spacing);
+        self.placer
+            .advance_after_rects(rect, rect, item_spacing, rect.size());
         register_rect(self, rect);
 
         let id = Id::new(self.next_auto_id_salt);
@@ -2412,8 +2413,22 @@ impl Ui {
         let mut child_ui = self.new_child(ui_builder);
         self.next_auto_id_salt = next_auto_id_salt; // HACK: we want `scope` to only increment this once, so that `ui.scope` is equivalent to `ui.allocate_space`.
         let ret = add_contents(&mut child_ui);
-        let response = child_ui.remember_min_rect();
+        let mut response = child_ui.remember_min_rect();
         self.advance_cursor_after_rect(child_ui.min_rect());
+        match self.layout().is_horizontal() {
+            true => {
+                response.intrinsic_size = Some(Vec2::new(
+                    response.rect.width(),
+                    self.placer.min_item_size().y,
+                ));
+            }
+            false => {
+                response.intrinsic_size = Some(Vec2::new(
+                    self.placer.min_item_size().x,
+                    response.rect.height(),
+                ));
+            }
+        }
         InnerResponse::new(ret, response)
     }
 

crates/egui/src/widgets/checkbox.rs

@@ -75,6 +75,7 @@ impl Widget for Checkbox<'_> {
 
         desired_size = desired_size.at_least(Vec2::splat(spacing.interact_size.y));
         desired_size.y = desired_size.y.max(icon_width);
+        dbg!(desired_size);
         let (rect, mut response) = ui.allocate_exact_size(desired_size, Sense::click());
 
         if response.clicked() {

crates/egui_demo_lib/src/demo/popups.rs

@@ -70,6 +70,18 @@ fn nested_menus(ui: &mut egui::Ui, checked: &mut bool) {
             }
             let _ = ui.button("Item");
             ui.menu_button("Recursive", |ui| nested_menus(ui, checked));
+
+            // if ui.button(if *checked { "short" } else { "Very long text for this item that should be wrapped" }).clicked() {
+            //     *checked = !*checked;
+            // }
+            ui.checkbox(
+                checked,
+                if *checked {
+                    "short"
+                } else {
+                    "Very long text for this item that should be wrapped"
+                },
+            );
         });
         ui.menu_button("SubMenu", |ui| {
             if ui.button("Open…").clicked() {

examples/hello_world_simple/src/main.rs

@@ -2,6 +2,7 @@
 #![allow(rustdoc::missing_crate_level_docs)] // it's an example
 
 use eframe::egui;
+use eframe::egui::{Align, Button, Layout, Popup, TextWrapMode, Widget};
 
 fn main() -> eframe::Result {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
@@ -15,19 +16,46 @@ fn main() -> eframe::Result {
     let mut name = "Arthur".to_owned();
     let mut age = 42;
 
+    let mut checked = true;
+
     eframe::run_simple_native("My egui App", options, move |ctx, _frame| {
         egui::CentralPanel::default().show(ctx, |ui| {
-            ui.heading("My egui Application");
+            // ui.heading("My egui Application");
-            ui.horizontal(|ui| {
+            // ui.horizontal(|ui| {
-                let name_label = ui.label("Your name: ");
+            //     let name_label = ui.label("Your name: ");
-                ui.text_edit_singleline(&mut name)
+            //     ui.text_edit_singleline(&mut name)
-                    .labelled_by(name_label.id);
+            //         .labelled_by(name_label.id);
-            });
+            // });
-            ui.add(egui::Slider::new(&mut age, 0..=120).text("age"));
+            // ui.add(egui::Slider::new(&mut age, 0..=120).text("age"));
-            if ui.button("Increment").clicked() {
+            // if ui.button("Increment").clicked() {
-                age += 1;
+            //     age += 1;
-            }
+            // }
-            ui.label(format!("Hello '{name}', age {age}"));
+            // ui.label(format!("Hello '{name}', age {age}"));
+
+            let response = ui.button("Hiiii");
+
+            let text = if checked {
+                "short"
+            } else {
+                "Very long text for this item that should be wrapped"
+            };
+            Popup::from_response(&response)
+                .layout(Layout::top_down_justified(Align::Min))
+                .show(|ui| {
+                    // ui.checkbox(&mut checked, text);
+
+                    ui.button("Hiiii");
+
+                    if Button::new(text)
+                        .wrap_mode(TextWrapMode::Extend)
+                        .ui(ui)
+                        .clicked()
+                    {
+                        checked = !checked;
+                    }
+
+                    ui.button("Some other button");
+                });
         });
     })
 }