Add Style variant support to application::StyleSheet

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());
     }
 }