Add menu code, adapted from iced_aw

src/theme/style/button.rs

@@ -32,6 +32,8 @@ pub enum Button {
     Transparent,
     AppletMenu,
     AppletIcon,
+    MenuRoot,
+    MenuItem,
 }
 
 pub fn appearance(
@@ -120,6 +122,19 @@ pub fn appearance(
             appearance.icon_color = Some(cosmic.background.on.into());
             appearance.text_color = Some(cosmic.background.on.into());
         }
+        Button::MenuRoot => {
+            appearance.background = None;
+            appearance.icon_color = Some(cosmic.accent.base.into());
+            appearance.text_color = Some(cosmic.accent.base.into());
+        }
+        Button::MenuItem => {
+            let (background, _, _) = color(&cosmic.background.component);
+            appearance.background = Some(Background::Color(background));
+
+            appearance.icon_color = Some(cosmic.background.on.into());
+            appearance.text_color = Some(cosmic.background.on.into());
+            corner_radii = &cosmic.corner_radii.radius_s;
+        }
     }
 
     appearance.border_radius = (*corner_radii).into();

src/theme/style/menu_bar.rs

@@ -0,0 +1,80 @@
+// From iced_aw, license MIT
+
+//! Change the appearance of menu bars and their menus.
+use iced_widget::core::Color;
+use crate::Theme;
+
+/// The appearance of a menu bar and its menus.
+#[derive(Debug, Clone, Copy)]
+pub struct Appearance {
+    /// The background color of the menu bar and its menus.
+    pub background: Color,
+    /// The border width of the menu bar and its menus.
+    pub border_width: f32,
+    /// The border radius of the menu bar.
+    pub bar_border_radius: [f32; 4],
+    /// The border radius of the menus.
+    pub menu_border_radius: [f32; 4],
+    /// The border [`Color`] of the menu bar and its menus.
+    pub border_color: Color,
+    /// The expand value of the menus' background
+    pub background_expand: [u16; 4],
+    /// The highlighted path [`Color`] of the the menu bar and its menus.
+    pub path: Color,
+}
+
+/// The style sheet of a menu bar and its menus.
+pub trait StyleSheet {
+    /// The supported style of the [`StyleSheet`].
+    type Style: Default;
+
+    /// Produces the [`Appearance`] of a menu bar and its menus.
+    fn appearance(&self, style: &Self::Style) -> Appearance;
+}
+
+/// The style of a menu bar and its menus
+#[derive(Default)]
+#[allow(missing_debug_implementations)]
+pub enum MenuBarStyle {
+    /// The default style.
+    #[default]
+    Default,
+    /// A [`Theme`] that uses a `Custom` palette.
+    Custom(Box<dyn StyleSheet<Style = Theme>>),
+}
+
+impl From<fn(&Theme) -> Appearance> for MenuBarStyle {
+    fn from(f: fn(&Theme) -> Appearance) -> Self {
+        Self::Custom(Box::new(f))
+    }
+}
+
+impl StyleSheet for fn(&Theme) -> Appearance {
+    type Style = Theme;
+
+    fn appearance(&self, style: &Self::Style) -> Appearance {
+        (self)(style)
+    }
+}
+
+impl StyleSheet for Theme {
+    type Style = MenuBarStyle;
+
+    fn appearance(&self, style: &Self::Style) -> Appearance {
+        let cosmic = self.cosmic();
+        let component = &cosmic.background.component;
+
+        match style {
+            MenuBarStyle::Default => Appearance {
+                background: component.base.into(),
+                border_width: 1.0,
+                bar_border_radius: cosmic.corner_radii.radius_xl,
+                menu_border_radius: cosmic.corner_radii.radius_s,
+                border_color: component.divider.into(),
+                background_expand: [1; 4],
+                path: component.hover.into(),
+            },
+            MenuBarStyle::Custom(c) => c.appearance(self),
+        }
+    }
+}

src/theme/style/mod.rs

@@ -17,6 +17,8 @@ pub use self::iced::Rule;
 pub use self::iced::Svg;
 pub use self::iced::Text;
 
+pub mod menu_bar;
+
 mod segmented_button;
 pub use self::segmented_button::SegmentedButton;