Leverage DefaultStyle traits instead of Default

winit/src/application.rs

@@ -38,7 +38,7 @@ use std::sync::Arc;
 /// can be toggled by pressing `F12`.
 pub trait Application: Program
 where
-    Style<Self::Theme>: Default,
+    Self::Theme: DefaultStyle,
 {
     /// The data needed to initialize your [`Application`].
     type Flags;
@@ -64,7 +64,7 @@ where
 
     /// Returns the `Style` variation of the `Theme`.
     fn style(&self, theme: &Self::Theme) -> Appearance {
-        Style::default().resolve(theme)
+        theme.default_style()
     }
 
     /// Returns the event `Subscription` for the current state of the
@@ -104,39 +104,19 @@ pub struct Appearance {
     pub text_color: Color,
 }
 
-/// The style of an [`Application`].
-#[derive(Debug, PartialEq, Eq)]
-pub struct Style<Theme>(pub fn(&Theme) -> Appearance);
-
-impl<Theme> Style<Theme> {
-    /// Resolves the [`Style`] with the given `Theme` to produce
-    /// an [`Appearance`].
-    pub fn resolve(self, theme: &Theme) -> Appearance {
-        (self.0)(theme)
-    }
-}
-
-impl<Theme> Clone for Style<Theme> {
-    fn clone(&self) -> Self {
-        *self
-    }
-}
-
-impl<Theme> Copy for Style<Theme> {}
-
-impl<Theme> From<fn(&Theme) -> Appearance> for Style<Theme> {
-    fn from(f: fn(&Theme) -> Appearance) -> Self {
-        Style(f)
-    }
-}
-
-impl Default for Style<Theme> {
-    fn default() -> Self {
-        Style(default)
-    }
-}
-
 /// The default style of an [`Application`].
+pub trait DefaultStyle {
+    /// Returns the default style of an [`Application`].
+    fn default_style(&self) -> Appearance;
+}
+
+impl DefaultStyle for Theme {
+    fn default_style(&self) -> Appearance {
+        default(self)
+    }
+}
+
+/// The default [`Appearance`] of an [`Application`] with the built-in [`Theme`].
 pub fn default(theme: &Theme) -> Appearance {
     let palette = theme.extended_palette();
 
@@ -156,7 +136,7 @@ where
     A: Application + 'static,
     E: Executor + 'static,
     C: Compositor<Renderer = A::Renderer> + 'static,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     use futures::task;
     use futures::Future;
@@ -340,7 +320,7 @@ async fn run_instance<A, E, C>(
     A: Application + 'static,
     E: Executor + 'static,
     C: Compositor<Renderer = A::Renderer> + 'static,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     use futures::stream::StreamExt;
     use winit::event;
@@ -663,7 +643,7 @@ pub fn build_user_interface<'a, A: Application>(
     debug: &mut Debug,
 ) -> UserInterface<'a, A::Message, A::Theme, A::Renderer>
 where
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     debug.view_started();
     let view = application.view();
@@ -694,7 +674,7 @@ pub fn update<A: Application, C, E: Executor>(
     window: &winit::window::Window,
 ) where
     C: Compositor<Renderer = A::Renderer> + 'static,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     for message in messages.drain(..) {
         debug.log_message(&message);
@@ -745,7 +725,7 @@ pub fn run_command<A, C, E>(
     A: Application,
     E: Executor,
     C: Compositor<Renderer = A::Renderer> + 'static,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     use crate::runtime::command;
     use crate::runtime::system;

winit/src/application/state.rs

@@ -14,7 +14,7 @@ use winit::window::Window;
 #[allow(missing_debug_implementations)]
 pub struct State<A: Application>
 where
-    application::Style<A::Theme>: Default,
+    A::Theme: application::DefaultStyle,
 {
     title: String,
     scale_factor: f64,
@@ -29,7 +29,7 @@ where
 
 impl<A: Application> State<A>
 where
-    application::Style<A::Theme>: Default,
+    A::Theme: application::DefaultStyle,
 {
     /// Creates a new [`State`] for the provided [`Application`] and window.
     pub fn new(application: &A, window: &Window) -> Self {

winit/src/multi_window.rs

@@ -22,7 +22,7 @@ use crate::runtime::user_interface::{self, UserInterface};
 use crate::runtime::Debug;
 use crate::{Clipboard, Error, Proxy, Settings};
 
-pub use crate::application::{default, Appearance, Style};
+pub use crate::application::{default, Appearance, DefaultStyle};
 
 use std::collections::HashMap;
 use std::mem::ManuallyDrop;
@@ -42,7 +42,7 @@ use std::time::Instant;
 /// can be toggled by pressing `F12`.
 pub trait Application: Program
 where
-    Style<Self::Theme>: Default,
+    Self::Theme: DefaultStyle,
 {
     /// The data needed to initialize your [`Application`].
     type Flags;
@@ -68,7 +68,7 @@ where
 
     /// Returns the `Style` variation of the `Theme`.
     fn style(&self, theme: &Self::Theme) -> Appearance {
-        Style::default().resolve(theme)
+        theme.default_style()
     }
 
     /// Returns the event `Subscription` for the current state of the
@@ -109,7 +109,7 @@ where
     A: Application + 'static,
     E: Executor + 'static,
     C: Compositor<Renderer = A::Renderer> + 'static,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     use winit::event_loop::EventLoopBuilder;
 
@@ -350,7 +350,7 @@ async fn run_instance<A, E, C>(
     A: Application + 'static,
     E: Executor + 'static,
     C: Compositor<Renderer = A::Renderer> + 'static,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     use winit::event;
     use winit::event_loop::ControlFlow;
@@ -820,7 +820,7 @@ fn build_user_interface<'a, A: Application>(
     id: window::Id,
 ) -> UserInterface<'a, A::Message, A::Theme, A::Renderer>
 where
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     debug.view_started();
     let view = application.view(id);
@@ -848,7 +848,7 @@ fn update<A: Application, C, E: Executor>(
     ui_caches: &mut HashMap<window::Id, user_interface::Cache>,
 ) where
     C: Compositor<Renderer = A::Renderer> + 'static,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     for message in messages.drain(..) {
         debug.log_message(&message);
@@ -891,7 +891,7 @@ fn run_command<A, C, E>(
     A: Application,
     E: Executor,
     C: Compositor<Renderer = A::Renderer> + 'static,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     use crate::runtime::clipboard;
     use crate::runtime::system;
@@ -1218,7 +1218,7 @@ pub fn build_user_interfaces<'a, A: Application, C: Compositor>(
 ) -> HashMap<window::Id, UserInterface<'a, A::Message, A::Theme, A::Renderer>>
 where
     C: Compositor<Renderer = A::Renderer>,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     cached_user_interfaces
         .drain()

winit/src/multi_window/state.rs

@@ -11,7 +11,7 @@ use winit::window::Window;
 /// The state of a multi-windowed [`Application`].
 pub struct State<A: Application>
 where
-    multi_window::Style<A::Theme>: Default,
+    A::Theme: multi_window::DefaultStyle,
 {
     title: String,
     scale_factor: f64,
@@ -25,7 +25,7 @@ where
 
 impl<A: Application> Debug for State<A>
 where
-    multi_window::Style<A::Theme>: Default,
+    A::Theme: multi_window::DefaultStyle,
 {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         f.debug_struct("multi_window::State")
@@ -41,7 +41,7 @@ where
 
 impl<A: Application> State<A>
 where
-    multi_window::Style<A::Theme>: Default,
+    A::Theme: multi_window::DefaultStyle,
 {
     /// Creates a new [`State`] for the provided [`Application`]'s `window`.
     pub fn new(

winit/src/multi_window/window_manager.rs

@@ -2,7 +2,7 @@ use crate::core::mouse;
 use crate::core::window::Id;
 use crate::core::{Point, Size};
 use crate::graphics::Compositor;
-use crate::multi_window::{Application, State, Style};
+use crate::multi_window::{Application, DefaultStyle, State};
 
 use std::collections::BTreeMap;
 use std::sync::Arc;
@@ -12,7 +12,7 @@ use winit::monitor::MonitorHandle;
 pub struct WindowManager<A: Application, C: Compositor>
 where
     C: Compositor<Renderer = A::Renderer>,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     aliases: BTreeMap<winit::window::WindowId, Id>,
     entries: BTreeMap<Id, Window<A, C>>,
@@ -22,7 +22,7 @@ impl<A, C> WindowManager<A, C>
 where
     A: Application,
     C: Compositor<Renderer = A::Renderer>,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     pub fn new() -> Self {
         Self {
@@ -108,7 +108,7 @@ impl<A, C> Default for WindowManager<A, C>
 where
     A: Application,
     C: Compositor<Renderer = A::Renderer>,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     fn default() -> Self {
         Self::new()
@@ -120,7 +120,7 @@ pub struct Window<A, C>
 where
     A: Application,
     C: Compositor<Renderer = A::Renderer>,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     pub raw: Arc<winit::window::Window>,
     pub state: State<A>,
@@ -135,7 +135,7 @@ impl<A, C> Window<A, C>
 where
     A: Application,
     C: Compositor<Renderer = A::Renderer>,
-    Style<A::Theme>: Default,
+    A::Theme: DefaultStyle,
 {
     pub fn position(&self) -> Option<Point> {
         self.raw