Simplify theming for `Application`

3 files changed, 24 insertions, 26 deletions

diff --git a/winit/src/multi_window.rs b/winit/src/multi_window.rs
index 03066d6c..19951ed3 100644
--- a/winit/src/multi_window.rs
+++ b/winit/src/multi_window.rs
@@ -20,9 +20,10 @@ use crate::runtime::command::{self, Command};
 use crate::runtime::multi_window::Program;
 use crate::runtime::user_interface::{self, UserInterface};
 use crate::runtime::Debug;
-use crate::style::application::StyleSheet;
 use crate::{Clipboard, Error, Proxy, Settings};
 
+pub use crate::application::{default, Appearance, Style};
+
 use std::collections::HashMap;
 use std::mem::ManuallyDrop;
 use std::sync::Arc;
@@ -41,7 +42,7 @@ use std::time::Instant;
 /// can be toggled by pressing `F12`.
 pub trait Application: Program
 where
-    Self::Theme: StyleSheet,
+    Style<Self::Theme>: Default,
 {
     /// The data needed to initialize your [`Application`].
     type Flags;
@@ -66,8 +67,8 @@ where
     fn theme(&self, window: window::Id) -> Self::Theme;
 
     /// Returns the `Style` variation of the `Theme`.
-    fn style(&self) -> <Self::Theme as StyleSheet>::Style {
-        Default::default()
+    fn style(&self, theme: &Self::Theme) -> Appearance {
+        Style::default().resolve(theme)
     }
 
     /// Returns the event `Subscription` for the current state of the
@@ -108,7 +109,7 @@ where
     A: Application + 'static,
     E: Executor + 'static,
     C: Compositor<Renderer = A::Renderer> + 'static,
-    A::Theme: StyleSheet,
+    Style<A::Theme>: Default,
 {
     use winit::event_loop::EventLoopBuilder;
 
@@ -349,7 +350,7 @@ async fn run_instance<A, E, C>(
     A: Application + 'static,
     E: Executor + 'static,
     C: Compositor<Renderer = A::Renderer> + 'static,
-    A::Theme: StyleSheet,
+    Style<A::Theme>: Default,
 {
     use winit::event;
     use winit::event_loop::ControlFlow;
@@ -819,7 +820,7 @@ fn build_user_interface<'a, A: Application>(
     id: window::Id,
 ) -> UserInterface<'a, A::Message, A::Theme, A::Renderer>
 where
-    A::Theme: StyleSheet,
+    Style<A::Theme>: Default,
 {
     debug.view_started();
     let view = application.view(id);
@@ -847,7 +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,
-    A::Theme: StyleSheet,
+    Style<A::Theme>: Default,
 {
     for message in messages.drain(..) {
         debug.log_message(&message);
@@ -890,7 +891,7 @@ fn run_command<A, C, E>(
     A: Application,
     E: Executor,
     C: Compositor<Renderer = A::Renderer> + 'static,
-    A::Theme: StyleSheet,
+    Style<A::Theme>: Default,
 {
     use crate::runtime::clipboard;
     use crate::runtime::system;
@@ -1216,8 +1217,8 @@ pub fn build_user_interfaces<'a, A: Application, C: Compositor>(
     mut cached_user_interfaces: HashMap<window::Id, user_interface::Cache>,
 ) -> HashMap<window::Id, UserInterface<'a, A::Message, A::Theme, A::Renderer>>
 where
-    A::Theme: StyleSheet,
     C: Compositor<Renderer = A::Renderer>,
+    Style<A::Theme>: Default,
 {
     cached_user_interfaces
         .drain()
diff --git a/winit/src/multi_window/state.rs b/winit/src/multi_window/state.rs
index 2e97a13d..8a332176 100644
--- a/winit/src/multi_window/state.rs
+++ b/winit/src/multi_window/state.rs
@@ -2,18 +2,16 @@ use crate::conversion;
 use crate::core::{mouse, window};
 use crate::core::{Color, Size};
 use crate::graphics::Viewport;
-use crate::multi_window::Application;
-use crate::style::application;
+use crate::multi_window::{self, Application};
 use std::fmt::{Debug, Formatter};
 
-use iced_style::application::StyleSheet;
 use winit::event::{Touch, WindowEvent};
 use winit::window::Window;
 
 /// The state of a multi-windowed [`Application`].
 pub struct State<A: Application>
 where
-    A::Theme: application::StyleSheet,
+    multi_window::Style<A::Theme>: Default,
 {
     title: String,
     scale_factor: f64,
@@ -22,12 +20,12 @@ where
     cursor_position: Option<winit::dpi::PhysicalPosition<f64>>,
     modifiers: winit::keyboard::ModifiersState,
     theme: A::Theme,
-    appearance: application::Appearance,
+    appearance: multi_window::Appearance,
 }
 
 impl<A: Application> Debug for State<A>
 where
-    A::Theme: application::StyleSheet,
+    multi_window::Style<A::Theme>: Default,
 {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         f.debug_struct("multi_window::State")
@@ -43,7 +41,7 @@ where
 
 impl<A: Application> State<A>
 where
-    A::Theme: application::StyleSheet,
+    multi_window::Style<A::Theme>: Default,
 {
     /// Creates a new [`State`] for the provided [`Application`]'s `window`.
     pub fn new(
@@ -54,7 +52,7 @@ where
         let title = application.title(window_id);
         let scale_factor = application.scale_factor(window_id);
         let theme = application.theme(window_id);
-        let appearance = theme.appearance(&application.style());
+        let appearance = application.style(&theme);
 
         let viewport = {
             let physical_size = window.inner_size();
@@ -236,6 +234,6 @@ where
 
         // Update theme and appearance
         self.theme = application.theme(window_id);
-        self.appearance = self.theme.appearance(&application.style());
+        self.appearance = application.style(&self.theme);
     }
 }
diff --git a/winit/src/multi_window/window_manager.rs b/winit/src/multi_window/window_manager.rs
index 23f3c0ba..2800e923 100644
--- a/winit/src/multi_window/window_manager.rs
+++ b/winit/src/multi_window/window_manager.rs
@@ -2,8 +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};
-use crate::style::application::StyleSheet;
+use crate::multi_window::{Application, State, Style};
 
 use std::collections::BTreeMap;
 use std::sync::Arc;
@@ -12,8 +11,8 @@ use winit::monitor::MonitorHandle;
 #[allow(missing_debug_implementations)]
 pub struct WindowManager<A: Application, C: Compositor>
 where
-    A::Theme: StyleSheet,
     C: Compositor<Renderer = A::Renderer>,
+    Style<A::Theme>: Default,
 {
     aliases: BTreeMap<winit::window::WindowId, Id>,
     entries: BTreeMap<Id, Window<A, C>>,
@@ -23,7 +22,7 @@ impl<A, C> WindowManager<A, C>
 where
     A: Application,
     C: Compositor<Renderer = A::Renderer>,
-    A::Theme: StyleSheet,
+    Style<A::Theme>: Default,
 {
     pub fn new() -> Self {
         Self {
@@ -109,7 +108,7 @@ impl<A, C> Default for WindowManager<A, C>
 where
     A: Application,
     C: Compositor<Renderer = A::Renderer>,
-    A::Theme: StyleSheet,
+    Style<A::Theme>: Default,
 {
     fn default() -> Self {
         Self::new()
@@ -121,7 +120,7 @@ pub struct Window<A, C>
 where
     A: Application,
     C: Compositor<Renderer = A::Renderer>,
-    A::Theme: StyleSheet,
+    Style<A::Theme>: Default,
 {
     pub raw: Arc<winit::window::Window>,
     pub state: State<A>,
@@ -136,7 +135,7 @@ impl<A, C> Window<A, C>
 where
     A: Application,
     C: Compositor<Renderer = A::Renderer>,
-    A::Theme: StyleSheet,
+    Style<A::Theme>: Default,
 {
     pub fn position(&self) -> Option<Point> {
         self.raw