Add ThemeChanged variant to Event in iced_sentinel

style/src/application.rs

@@ -1,5 +1,6 @@
 //! Change the appearance of an application.
-use iced_core::Color;
+use crate::core::Color;
+use crate::theme;
 
 /// A set of rules that dictate the style of an application.
 pub trait StyleSheet {
@@ -10,6 +11,17 @@ pub trait StyleSheet {
     ///
     /// [`Style`]: Self::Style
     fn appearance(&self, style: &Self::Style) -> Appearance;
+
+    /// Returns the [`theme::Palette`] of the application, if any.
+    ///
+    /// This may be used by other parts of the `iced` runtime to
+    /// try to match the style of your application.
+    ///
+    /// For instance, the Iced Axe uses this [`theme::Palette`] to
+    /// automatically style itself using your application's colors.
+    fn palette(&self) -> Option<theme::Palette> {
+        None
+    }
 }
 
 /// The appearance of an application.

style/src/lib.rs

@@ -7,11 +7,12 @@
 #![doc(
     html_logo_url = "https://raw.githubusercontent.com/iced-rs/iced/9ab6923e943f784985e9ef9ca28b10278297225d/docs/logo.svg"
 )]
-#![forbid(unsafe_code, rust_2018_idioms)]
+#![forbid(unsafe_code)]
 #![deny(
     unused_results,
     missing_docs,
     unused_results,
+    rust_2018_idioms,
     rustdoc::broken_intra_doc_links
 )]
 pub use iced_core as core;

style/src/theme/palette.rs

@@ -8,6 +8,7 @@ use palette::{FromColor, Hsl, Mix};
 
 /// A color palette.
 #[derive(Debug, Clone, Copy, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct Palette {
     /// The background [`Color`] of the [`Palette`].
     pub background: Color,