Add Ui::close and Response::should_close (#5729)

This adds a generic way of telling containers to close from their child
`Ui`s.

* Part of #5727 
* [x] I have followed the instructions in the PR template

---------

Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>

crates/egui_demo_lib/src/demo/context_menu.rs

@@ -59,25 +59,25 @@ impl ContextMenus {
         ui.set_max_width(200.0); // To make sure we wrap long text
 
         if ui.button("Open…").clicked() {
-            ui.close_menu();
+            ui.close();
         }
         ui.menu_button("SubMenu", |ui| {
             ui.menu_button("SubMenu", |ui| {
                 if ui.button("Open…").clicked() {
-                    ui.close_menu();
+                    ui.close();
                 }
                 let _ = ui.button("Item");
                 ui.menu_button("Recursive", Self::nested_menus)
             });
             ui.menu_button("SubMenu", |ui| {
                 if ui.button("Open…").clicked() {
-                    ui.close_menu();
+                    ui.close();
                 }
                 let _ = ui.button("Item");
             });
             let _ = ui.button("Item");
             if ui.button("Open…").clicked() {
-                ui.close_menu();
+                ui.close();
             }
         });
         ui.menu_button("SubMenu", |ui| {
@@ -86,7 +86,7 @@ impl ContextMenus {
             let _ = ui.button("Item3");
             let _ = ui.button("Item4");
             if ui.button("Open…").clicked() {
-                ui.close_menu();
+                ui.close();
             }
         });
         let _ = ui.button("Very long text for this item that should be wrapped");

crates/egui_demo_lib/src/demo/demo_app_windows.rs

@@ -234,7 +234,7 @@ impl DemoWindows {
                     ui.set_style(ui.ctx().style()); // ignore the "menu" style set by `menu_button`.
                     self.demo_list_ui(ui);
                     if ui.ui_contains_pointer() && ui.input(|i| i.pointer.any_click()) {
-                        ui.close_menu();
+                        ui.close();
                     }
                 });
 
@@ -345,7 +345,7 @@ fn file_menu_button(ui: &mut Ui) {
             .clicked()
         {
             ui.ctx().memory_mut(|mem| mem.reset_areas());
-            ui.close_menu();
+            ui.close();
         }
 
         if ui
@@ -357,7 +357,7 @@ fn file_menu_button(ui: &mut Ui) {
             .clicked()
         {
             ui.ctx().memory_mut(|mem| *mem = Default::default());
-            ui.close_menu();
+            ui.close();
         }
     });
 }

crates/egui_demo_lib/src/demo/modals.rs

@@ -96,7 +96,9 @@ impl crate::View for Modals {
                             *save_modal_open = true;
                         }
                         if ui.button("Cancel").clicked() {
-                            *user_modal_open = false;
+                            // You can call `ui.close()` to close the modal.
+                            // (This causes the current modals `should_close` to return true)
+                            ui.close();
                         }
                     },
                 );
@@ -123,7 +125,7 @@ impl crate::View for Modals {
                         }
 
                         if ui.button("No Thanks").clicked() {
-                            *save_modal_open = false;
+                            ui.close();
                         }
                     },
                 );

crates/egui_demo_lib/src/demo/popups.rs

@@ -153,6 +153,10 @@ impl crate::View for PopupsDemo {
             .show(|ui| {
                 _ = ui.button("Menu item 1");
                 _ = ui.button("Menu item 2");
+
+                if ui.button("I always close the menu").clicked() {
+                    ui.close();
+                }
             });
 
         self.apply_options(Popup::context_menu(&response).id(Id::new("context_menu")))

crates/egui_demo_lib/src/demo/window_options.rs

@@ -1,4 +1,4 @@
-use egui::Vec2b;
+use egui::{UiKind, Vec2b};
 
 #[derive(Clone, PartialEq)]
 #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
@@ -149,6 +149,16 @@ impl crate::View for WindowOptions {
                 self.disabled_time = ui.input(|i| i.time);
             }
             egui::reset_button(ui, self, "Reset");
+            if ui
+                .button("Close")
+                .on_hover_text("You can collapse / close Windows via Ui::close")
+                .clicked()
+            {
+                // Calling close would close the collapsible within the window
+                // ui.close();
+                // Instead, we close the window itself
+                ui.close_kind(UiKind::Window);
+            }
             ui.add(crate::egui_github_link_file!());
         });
     }

crates/egui_demo_lib/tests/snapshots/demos/Window Options.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:3411a4a8939b7e731c9c1a6331921b0ac905f4e3e86a51af70bdb38d9446f5e1
-size 35193
+oid sha256:e67b1e676ff994cb9557939db3dca5ddd15c69d167afd96c0957a2a3b75c0fd8
+size 36007