Create a BigRedButton struct, like CloseButton

The `BigRedButton` should be a real struct and component so that I can
query for it later.

I'm following the same API pattern as the `CloseButton` struct, in that
there is a spawner using the `Commands` (or `ChildSpawnerCommands`) and
the observer functions are static methods.

src/widgets/machines.rs

@@ -3,7 +3,7 @@ use bevy::{color::palettes::css::*, prelude::*, ui::Val::*};
 use crate::{
   game::machines::*,
   resources::UiTheme,
-  widgets::{machine_ui_base, spawn_big_red_button},
+  widgets::{BigRedButton, machine_ui_base},
 };
 
 impl CuttingMachine {
@@ -42,7 +42,7 @@ impl CuttingMachine {
           BackgroundColor(DARK_GRAY.into()),
           Pickable::default(),
         ))
-        .with_children(|cmds| spawn_big_red_button(cmds, "CUT"));
+        .with_children(|cmds| BigRedButton::spawn_big_red_button(cmds, "CUT"));
     });
   }
 }
@@ -82,7 +82,7 @@ impl RotatingMachine {
           BackgroundColor(DARK_GRAY.into()),
           Pickable::default(),
         ))
-        .with_children(|cmds| spawn_big_red_button(cmds, "TURN"));
+        .with_children(|cmds| BigRedButton::spawn_big_red_button(cmds, "TURN"));
     });
   }
 }

src/widgets/mod.rs

@@ -82,8 +82,13 @@ fn machine_ui_base(commands: &mut Commands, header: impl Into<String>, theme: &U
   root_pane
 }
 
-// TODO: Hook up action handling (callback? Observer? Some other weird component?)
-fn spawn_big_red_button(commands: &mut ChildSpawnerCommands, text: impl Into<String>) {
+/// The "Big Red Button" that makes a machine perform it's action.
+#[derive(Component)]
+pub struct BigRedButton;
+
+impl BigRedButton {
+  // TODO: Hook up action handling (callback? Observer? Some other weird component?)
+  fn spawn_big_red_button(commands: &mut ChildSpawnerCommands, text: impl Into<String>) {
     let mut builder = commands.spawn((
       Button,
       Node {
@@ -108,61 +113,62 @@ fn spawn_big_red_button(commands: &mut ChildSpawnerCommands, text: impl Into<Str
         TextShadow::default(),
       ],
     ));
-  builder.observe(button_hover_start);
-  builder.observe(button_hover_stop);
-  builder.observe(button_press_start);
-  builder.observe(button_press_stop);
-}
+    builder.observe(BigRedButton::button_hover_start);
+    builder.observe(BigRedButton::button_hover_stop);
+    builder.observe(BigRedButton::button_press_start);
+    builder.observe(BigRedButton::button_press_stop);
+  }
 
-/// Re-color the button when a pointer passes over it
-fn button_hover_start(
+  /// Re-color the button when a pointer passes over it
+  fn button_hover_start(
     event: Trigger<Pointer<Over>>,
     // Get button background and border colors so we can change them.
     // Filter for *changed* interactions, and only entities with a [`Button`]
     mut button_colors: Query<(&mut BackgroundColor, &mut BorderColor), With<Button>>,
     ui_theme: Res<UiTheme>,
-) {
+  ) {
     // Get the components for only the Trigger's target entity
     if let Ok((mut bg, mut border)) = button_colors.get_mut(event.target()) {
       bg.0 = ui_theme.brb_hover_bg;
       border.0 = ui_theme.brb_hover_border;
     }
-}
+  }
 
-// TODO: Consolidate these with the help of a NewType enum and `trigger_map()`
-// see: https://github.com/bevyengine/bevy/issues/14649
+  // TODO: Consolidate these with the help of a NewType enum and `trigger_map()`
+  // see: https://github.com/bevyengine/bevy/issues/14649
 
-fn button_hover_stop(
+  fn button_hover_stop(
     event: Trigger<Pointer<Out>>,
     mut button_colors: Query<(&mut BackgroundColor, &mut BorderColor), With<Button>>,
     ui_theme: Res<UiTheme>,
-) {
+  ) {
     if let Ok((mut bg, mut border)) = button_colors.get_mut(event.target()) {
       bg.0 = ui_theme.brb_bg;
       border.0 = ui_theme.brb_border;
     }
-}
+  }
 
-fn button_press_start(
+  fn button_press_start(
     event: Trigger<Pointer<Pressed>>,
     mut button_colors: Query<(&mut BackgroundColor, &mut BorderColor), With<Button>>,
     ui_theme: Res<UiTheme>,
-) {
+  ) {
     if let Ok((mut bg, mut border)) = button_colors.get_mut(event.target()) {
       bg.0 = ui_theme.brb_pressed_bg;
       border.0 = ui_theme.brb_pressed_border;
     }
-}
+  }
 
-fn button_press_stop(
+  fn button_press_stop(
     event: Trigger<Pointer<Released>>,
     mut button_colors: Query<(&mut BackgroundColor, &mut BorderColor), With<Button>>,
     ui_theme: Res<UiTheme>,
-) {
+  ) {
     if let Ok((mut bg, mut border)) = button_colors.get_mut(event.target()) {
       bg.0 = ui_theme.brb_bg;
       border.0 = ui_theme.brb_border;
     }
+  }
 }
 
 /// Button marker for closing (despawning) an in-game menu entity.