Add Style variant support to application::StyleSheet

winit/src/application.rs

@@ -6,6 +6,7 @@ pub use state::State;
 use crate::clipboard::{self, Clipboard};
 use crate::conversion;
 use crate::mouse;
+use crate::renderer;
 use crate::{
     Command, Debug, Error, Executor, Mode, Proxy, Runtime, Settings, Size,
     Subscription,
@@ -18,7 +19,7 @@ use iced_graphics::window;
 use iced_native::program::Program;
 use iced_native::user_interface::{self, UserInterface};
 
-pub use iced_native::application::StyleSheet;
+pub use iced_native::application::{Appearance, StyleSheet};
 
 use std::mem::ManuallyDrop;
 
@@ -33,7 +34,10 @@ use std::mem::ManuallyDrop;
 ///
 /// When using an [`Application`] with the `debug` feature enabled, a debug view
 /// can be toggled by pressing `F12`.
-pub trait Application: Program {
+pub trait Application: Program
+where
+    <Self::Renderer as crate::Renderer>::Theme: StyleSheet,
+{
     /// The data needed to initialize your [`Application`].
     type Flags;
 
@@ -54,7 +58,14 @@ pub trait Application: Program {
     fn title(&self) -> String;
 
     /// Returns the current [`Theme`] of the [`Application`].
-    fn theme(&self) -> <Self::Renderer as iced_native::Renderer>::Theme;
+    fn theme(&self) -> <Self::Renderer as crate::Renderer>::Theme;
+
+    /// Returns the [`Style`] variation of the [`Theme`].
+    fn style(
+        &self,
+    ) -> <<Self::Renderer as crate::Renderer>::Theme as StyleSheet>::Style {
+        Default::default()
+    }
 
     /// Returns the event `Subscription` for the current state of the
     /// application.
@@ -110,7 +121,7 @@ where
     A: Application + 'static,
     E: Executor + 'static,
     C: window::Compositor<Renderer = A::Renderer> + 'static,
-    <A::Renderer as iced_native::Renderer>::Theme: StyleSheet,
+    <A::Renderer as crate::Renderer>::Theme: StyleSheet,
 {
     use futures::task;
     use futures::Future;
@@ -246,7 +257,7 @@ async fn run_instance<A, E, C>(
     A: Application + 'static,
     E: Executor + 'static,
     C: window::Compositor<Renderer = A::Renderer> + 'static,
-    <A::Renderer as iced_native::Renderer>::Theme: StyleSheet,
+    <A::Renderer as crate::Renderer>::Theme: StyleSheet,
 {
     use iced_futures::futures::stream::StreamExt;
     use winit::event;
@@ -255,7 +266,6 @@ async fn run_instance<A, E, C>(
 
     let mut state = State::new(&application, &window);
     let mut viewport_version = state.viewport_version();
-    let mut theme = application.theme();
 
     let physical_size = state.physical_size();
 
@@ -328,7 +338,6 @@ async fn run_instance<A, E, C>(
 
                     let should_exit = application.should_exit();
 
-                    theme = application.theme();
                     user_interface = ManuallyDrop::new(build_user_interface(
                         &mut application,
                         cache,
@@ -345,7 +354,10 @@ async fn run_instance<A, E, C>(
                 debug.draw_started();
                 let new_mouse_interaction = user_interface.draw(
                     &mut renderer,
-                    &theme,
+                    state.theme(),
+                    &renderer::Style {
+                        text_color: state.text_color(),
+                    },
                     state.cursor_position(),
                 );
                 debug.draw_finished();
@@ -396,7 +408,10 @@ async fn run_instance<A, E, C>(
                     debug.draw_started();
                     let new_mouse_interaction = user_interface.draw(
                         &mut renderer,
-                        &theme,
+                        state.theme(),
+                        &renderer::Style {
+                            text_color: state.text_color(),
+                        },
                         state.cursor_position(),
                     );
 
@@ -422,7 +437,7 @@ async fn run_instance<A, E, C>(
                     &mut renderer,
                     &mut surface,
                     state.viewport(),
-                    theme.background_color(),
+                    state.background_color(),
                     &debug.overlay(),
                 ) {
                     Ok(()) => {
@@ -531,7 +546,9 @@ pub fn update<A: Application, E: Executor>(
     messages: &mut Vec<A::Message>,
     window: &winit::window::Window,
     graphics_info: impl FnOnce() -> compositor::Information + Copy,
-) {
+) where
+    <A::Renderer as crate::Renderer>::Theme: StyleSheet,
+{
     for message in messages.drain(..) {
         debug.log_message(&message);
 

winit/src/application/state.rs

@@ -1,13 +1,17 @@
+use crate::application::{self, StyleSheet as _};
 use crate::conversion;
-use crate::{Application, Debug, Mode, Point, Size, Viewport};
+use crate::{Application, Color, Debug, Mode, Point, Size, Viewport};
 
 use std::marker::PhantomData;
 use winit::event::{Touch, WindowEvent};
 use winit::window::Window;
 
 /// The state of a windowed [`Application`].
-#[derive(Debug, Clone)]
-pub struct State<A: Application> {
+#[allow(missing_debug_implementations)]
+pub struct State<A: Application>
+where
+    <A::Renderer as crate::Renderer>::Theme: application::StyleSheet,
+{
     title: String,
     mode: Mode,
     scale_factor: f64,
@@ -15,15 +19,22 @@ pub struct State<A: Application> {
     viewport_version: usize,
     cursor_position: winit::dpi::PhysicalPosition<f64>,
     modifiers: winit::event::ModifiersState,
+    theme: <A::Renderer as crate::Renderer>::Theme,
+    appearance: application::Appearance,
     application: PhantomData<A>,
 }
 
-impl<A: Application> State<A> {
+impl<A: Application> State<A>
+where
+    <A::Renderer as crate::Renderer>::Theme: application::StyleSheet,
+{
     /// Creates a new [`State`] for the provided [`Application`] and window.
     pub fn new(application: &A, window: &Window) -> Self {
         let title = application.title();
         let mode = application.mode();
         let scale_factor = application.scale_factor();
+        let theme = application.theme();
+        let appearance = theme.appearance(application.style());
 
         let viewport = {
             let physical_size = window.inner_size();
@@ -43,6 +54,8 @@ impl<A: Application> State<A> {
             // TODO: Encode cursor availability in the type-system
             cursor_position: winit::dpi::PhysicalPosition::new(-1.0, -1.0),
             modifiers: winit::event::ModifiersState::default(),
+            theme,
+            appearance,
             application: PhantomData,
         }
     }
@@ -87,6 +100,21 @@ impl<A: Application> State<A> {
         self.modifiers
     }
 
+    /// Returns the current theme of the [`State`].
+    pub fn theme(&self) -> &<A::Renderer as crate::Renderer>::Theme {
+        &self.theme
+    }
+
+    /// Returns the current background [`Color`] of the [`State`].
+    pub fn background_color(&self) -> Color {
+        self.appearance.background_color
+    }
+
+    /// Returns the current text [`Color`] of the [`State`].
+    pub fn text_color(&self) -> Color {
+        self.appearance.text_color
+    }
+
     /// Processes the provided window event and updates the [`State`]
     /// accordingly.
     pub fn update(
@@ -192,5 +220,9 @@ impl<A: Application> State<A> {
 
             self.scale_factor = new_scale_factor;
         }
+
+        // Update theme and appearance
+        self.theme = application.theme();
+        self.appearance = self.theme.appearance(application.style());
     }
 }