1 files changed, 43 insertions, 22 deletions

diff --git a/src/application.rs b/src/application.rs
index 11735b93..e8d8e982 100644
--- a/src/application.rs
+++ b/src/application.rs
@@ -1,5 +1,8 @@
+//! Build interactive cross-platform applications.
 use crate::window;
-use crate::{Color, Command, Element, Executor, Settings, Subscription};
+use crate::{Command, Element, Executor, Settings, Subscription};
+
+pub use iced_native::application::{Appearance, StyleSheet};
 
 /// An interactive cross-platform application.
 ///
@@ -57,7 +60,7 @@ use crate::{Color, Command, Element, Executor, Settings, Subscription};
 /// says "Hello, world!":
 ///
 /// ```no_run
-/// use iced::{executor, Application, Command, Element, Settings, Text};
+/// use iced::{executor, Application, Command, Element, Settings, Text, Theme};
 ///
 /// pub fn main() -> iced::Result {
 ///     Hello::run(Settings::default())
@@ -67,8 +70,9 @@ use crate::{Color, Command, Element, Executor, Settings, Subscription};
 ///
 /// impl Application for Hello {
 ///     type Executor = executor::Default;
-///     type Message = ();
 ///     type Flags = ();
+///     type Message = ();
+///     type Theme = Theme;
 ///
 ///     fn new(_flags: ()) -> (Hello, Command<Self::Message>) {
 ///         (Hello, Command::none())
@@ -99,6 +103,9 @@ pub trait Application: Sized {
     /// The type of __messages__ your [`Application`] will produce.
     type Message: std::fmt::Debug + Send;
 
+    /// The theme of your [`Application`].
+    type Theme: Default + StyleSheet;
+
     /// The data needed to initialize your [`Application`].
     type Flags;
 
@@ -129,6 +136,28 @@ pub trait Application: Sized {
     /// Any [`Command`] returned will be executed immediately in the background.
     fn update(&mut self, message: Self::Message) -> Command<Self::Message>;
 
+    /// Returns the widgets to display in the [`Application`].
+    ///
+    /// These widgets can produce __messages__ based on user interaction.
+    fn view(
+        &mut self,
+    ) -> Element<'_, Self::Message, crate::Renderer<Self::Theme>>;
+
+    /// Returns the current [`Theme`] of the [`Application`].
+    ///
+    /// [`Theme`]: Self::Theme
+    fn theme(&self) -> Self::Theme {
+        Self::Theme::default()
+    }
+
+    /// Returns the current [`Style`] of the [`Theme`].
+    ///
+    /// [`Style`]: <Self::Theme as StyleSheet>::Style
+    /// [`Theme`]: Self::Theme
+    fn style(&self) -> <Self::Theme as StyleSheet>::Style {
+        <Self::Theme as StyleSheet>::Style::default()
+    }
+
     /// Returns the event [`Subscription`] for the current state of the
     /// application.
     ///
@@ -141,11 +170,6 @@ pub trait Application: Sized {
         Subscription::none()
     }
 
-    /// Returns the widgets to display in the [`Application`].
-    ///
-    /// These widgets can produce __messages__ based on user interaction.
-    fn view(&mut self) -> Element<'_, Self::Message>;
-
     /// Returns the current [`Application`] mode.
     ///
     /// The runtime will automatically transition your application if a new mode
@@ -158,13 +182,6 @@ pub trait Application: Sized {
         window::Mode::Windowed
     }
 
-    /// Returns the background color of the [`Application`].
-    ///
-    /// By default, it returns [`Color::WHITE`].
-    fn background_color(&self) -> Color {
-        Color::WHITE
-    }
-
     /// Returns the scale factor of the [`Application`].
     ///
     /// It can be used to dynamically control the size of the UI at runtime
@@ -213,7 +230,7 @@ pub trait Application: Sized {
         Ok(crate::runtime::application::run::<
             Instance<Self>,
             Self::Executor,
-            crate::renderer::window::Compositor,
+            crate::renderer::window::Compositor<Self::Theme>,
         >(settings.into(), renderer_settings)?)
     }
 }
@@ -224,14 +241,14 @@ impl<A> iced_winit::Program for Instance<A>
 where
     A: Application,
 {
-    type Renderer = crate::renderer::Renderer;
+    type Renderer = crate::Renderer<A::Theme>;
     type Message = A::Message;
 
     fn update(&mut self, message: Self::Message) -> Command<Self::Message> {
         self.0.update(message)
     }
 
-    fn view(&mut self) -> Element<'_, Self::Message> {
+    fn view(&mut self) -> Element<'_, Self::Message, Self::Renderer> {
         self.0.view()
     }
 }
@@ -252,6 +269,14 @@ where
         self.0.title()
     }
 
+    fn theme(&self) -> A::Theme {
+        self.0.theme()
+    }
+
+    fn style(&self) -> <A::Theme as StyleSheet>::Style {
+        self.0.style()
+    }
+
     fn mode(&self) -> iced_winit::Mode {
         match self.0.mode() {
             window::Mode::Windowed => iced_winit::Mode::Windowed,
@@ -264,10 +289,6 @@ where
         self.0.subscription()
     }
 
-    fn background_color(&self) -> Color {
-        self.0.background_color()
-    }
-
     fn scale_factor(&self) -> f64 {
         self.0.scale_factor()
     }