From 2088e5d66117dd481e4c60ba6afe9ab8f3a2d4c1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 13:25:06 +0100
Subject: [PATCH 01/17] Try using closures for `Container::style`

`Box` should not allocate for zero-sized types; so
we should not be incurring much overhead. Just a
bit of indirection.
---
 widget/src/container.rs           | 41 +++++++++++++++++--------------
 widget/src/helpers.rs             |  4 +--
 widget/src/pane_grid/content.rs   | 12 ++++-----
 widget/src/pane_grid/title_bar.rs | 10 ++++----
 widget/src/tooltip.rs             | 15 +++++------
 5 files changed, 43 insertions(+), 39 deletions(-)

diff --git a/widget/src/container.rs b/widget/src/container.rs
index d606b0aaf7..f51ff8789d 100644
--- a/widget/src/container.rs
+++ b/widget/src/container.rs
@@ -36,7 +36,7 @@ pub struct Container<
     vertical_alignment: alignment::Vertical,
     clip: bool,
     content: Element<'a, Message, Theme, Renderer>,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 impl<'a, Message, Theme, Renderer> Container<'a, Message, Theme, Renderer>
@@ -48,15 +48,15 @@ where
         content: impl Into<Element<'a, Message, Theme, Renderer>>,
     ) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
-        Self::with_style(content, Theme::default_style())
+        Self::with_style(content, Theme::default_style)
     }
 
     /// Creates a [`Container`] with the given content and style.
     pub fn with_style(
         content: impl Into<Element<'a, Message, Theme, Renderer>>,
-        style: fn(&Theme, Status) -> Appearance,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
     ) -> Self {
         let content = content.into();
         let size = content.as_widget().size_hint();
@@ -71,8 +71,8 @@ where
             horizontal_alignment: alignment::Horizontal::Left,
             vertical_alignment: alignment::Vertical::Top,
             clip: false,
+            style: Box::new(style),
             content,
-            style,
         }
     }
 
@@ -137,8 +137,11 @@ where
     }
 
     /// Sets the style of the [`Container`].
-    pub fn style(mut self, style: fn(&Theme, Status) -> Appearance) -> Self {
-        self.style = style;
+    pub fn style(
+        mut self,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
+    ) -> Self {
+        self.style = Box::new(style);
         self
     }
 
@@ -546,41 +549,41 @@ pub enum Status {
 }
 
 /// The style of a [`Container`].
-pub type Style<Theme> = fn(&Theme, Status) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Appearance + 'a>;
 
 /// The default style of a [`Container`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`Container`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self, status: Status) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        transparent
+    fn default_style(&self, status: Status) -> Appearance {
+        transparent(self, status)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance, _status| *appearance
+    fn default_style(&self, _status: Status) -> Appearance {
+        *self
     }
 }
 
 impl DefaultStyle for Color {
-    fn default_style() -> Style<Self> {
-        |color, _status| Appearance::default().with_background(*color)
+    fn default_style(&self, _status: Status) -> Appearance {
+        Appearance::default().with_background(*self)
     }
 }
 
 impl DefaultStyle for Gradient {
-    fn default_style() -> Style<Self> {
-        |gradient, _status| Appearance::default().with_background(*gradient)
+    fn default_style(&self, _status: Status) -> Appearance {
+        Appearance::default().with_background(*self)
     }
 }
 
 impl DefaultStyle for gradient::Linear {
-    fn default_style() -> Style<Self> {
-        |gradient, _status| Appearance::default().with_background(*gradient)
+    fn default_style(&self, _status: Status) -> Appearance {
+        Appearance::default().with_background(*self)
     }
 }
 
diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index 75072d2e20..89d6ef622e 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -58,7 +58,7 @@ pub fn container<'a, Message, Theme, Renderer>(
     content: impl Into<Element<'a, Message, Theme, Renderer>>,
 ) -> Container<'a, Message, Theme, Renderer>
 where
-    Theme: container::DefaultStyle,
+    Theme: container::DefaultStyle + 'a,
     Renderer: core::Renderer,
 {
     Container::new(content)
@@ -134,7 +134,7 @@ pub fn tooltip<'a, Message, Theme, Renderer>(
     position: tooltip::Position,
 ) -> crate::Tooltip<'a, Message, Theme, Renderer>
 where
-    Theme: container::DefaultStyle,
+    Theme: container::DefaultStyle + 'a,
     Renderer: core::text::Renderer,
 {
     Tooltip::new(content, tooltip, position)
diff --git a/widget/src/pane_grid/content.rs b/widget/src/pane_grid/content.rs
index aecec77749..98f4f99af3 100644
--- a/widget/src/pane_grid/content.rs
+++ b/widget/src/pane_grid/content.rs
@@ -24,7 +24,7 @@ pub struct Content<
 {
     title_bar: Option<TitleBar<'a, Message, Theme, Renderer>>,
     body: Element<'a, Message, Theme, Renderer>,
-    style: container::Style<Theme>,
+    style: container::Style<'a, Theme>,
 }
 
 impl<'a, Message, Theme, Renderer> Content<'a, Message, Theme, Renderer>
@@ -34,12 +34,12 @@ where
     /// Creates a new [`Content`] with the provided body.
     pub fn new(body: impl Into<Element<'a, Message, Theme, Renderer>>) -> Self
     where
-        Theme: container::DefaultStyle,
+        Theme: container::DefaultStyle + 'a,
     {
         Self {
             title_bar: None,
             body: body.into(),
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -55,9 +55,9 @@ where
     /// Sets the style of the [`Content`].
     pub fn style(
         mut self,
-        style: fn(&Theme, container::Status) -> container::Appearance,
+        style: impl Fn(&Theme, container::Status) -> container::Appearance + 'a,
     ) -> Self {
-        self.style = style.into();
+        self.style = Box::new(style);
         self
     }
 }
@@ -403,7 +403,7 @@ impl<'a, T, Message, Theme, Renderer> From<T>
     for Content<'a, Message, Theme, Renderer>
 where
     T: Into<Element<'a, Message, Theme, Renderer>>,
-    Theme: container::DefaultStyle,
+    Theme: container::DefaultStyle + 'a,
     Renderer: crate::core::Renderer,
 {
     fn from(element: T) -> Self {
diff --git a/widget/src/pane_grid/title_bar.rs b/widget/src/pane_grid/title_bar.rs
index 37f0f16030..8dfea6e319 100644
--- a/widget/src/pane_grid/title_bar.rs
+++ b/widget/src/pane_grid/title_bar.rs
@@ -25,7 +25,7 @@ pub struct TitleBar<
     controls: Option<Element<'a, Message, Theme, Renderer>>,
     padding: Padding,
     always_show_controls: bool,
-    style: container::Style<Theme>,
+    style: container::Style<'a, Theme>,
 }
 
 impl<'a, Message, Theme, Renderer> TitleBar<'a, Message, Theme, Renderer>
@@ -37,14 +37,14 @@ where
         content: impl Into<Element<'a, Message, Theme, Renderer>>,
     ) -> Self
     where
-        Theme: container::DefaultStyle,
+        Theme: container::DefaultStyle + 'a,
     {
         Self {
             content: content.into(),
             controls: None,
             padding: Padding::ZERO,
             always_show_controls: false,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -66,9 +66,9 @@ where
     /// Sets the style of the [`TitleBar`].
     pub fn style(
         mut self,
-        style: fn(&Theme, container::Status) -> container::Appearance,
+        style: impl Fn(&Theme, container::Status) -> container::Appearance + 'a,
     ) -> Self {
-        self.style = style.into();
+        self.style = Box::new(style);
         self
     }
 
diff --git a/widget/src/tooltip.rs b/widget/src/tooltip.rs
index 8c8ee9831a..8e11ca986b 100644
--- a/widget/src/tooltip.rs
+++ b/widget/src/tooltip.rs
@@ -28,7 +28,7 @@ pub struct Tooltip<
     gap: f32,
     padding: f32,
     snap_within_viewport: bool,
-    style: container::Style<Theme>,
+    style: container::Style<'a, Theme>,
 }
 
 impl<'a, Message, Theme, Renderer> Tooltip<'a, Message, Theme, Renderer>
@@ -47,7 +47,7 @@ where
         position: Position,
     ) -> Self
     where
-        Theme: container::DefaultStyle,
+        Theme: container::DefaultStyle + 'a,
     {
         Tooltip {
             content: content.into(),
@@ -56,7 +56,7 @@ where
             gap: 0.0,
             padding: Self::DEFAULT_PADDING,
             snap_within_viewport: true,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -81,9 +81,9 @@ where
     /// Sets the style of the [`Tooltip`].
     pub fn style(
         mut self,
-        style: fn(&Theme, container::Status) -> container::Appearance,
+        style: impl Fn(&Theme, container::Status) -> container::Appearance + 'a,
     ) -> Self {
-        self.style = style.into();
+        self.style = Box::new(style);
         self
     }
 }
@@ -239,7 +239,7 @@ where
                 positioning: self.position,
                 gap: self.gap,
                 padding: self.padding,
-                style: self.style,
+                style: &self.style,
             })))
         } else {
             None
@@ -309,7 +309,8 @@ where
     positioning: Position,
     gap: f32,
     padding: f32,
-    style: container::Style<Theme>,
+    style:
+        &'b (dyn Fn(&Theme, container::Status) -> container::Appearance + 'a),
 }
 
 impl<'a, 'b, Message, Theme, Renderer>

From 60b5822b67e569e99efc9e4176c3e6d3f859d0bb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 13:30:47 +0100
Subject: [PATCH 02/17] Use closures for `Button::style`

---
 widget/src/button.rs  | 29 ++++++++++++++++-------------
 widget/src/helpers.rs |  2 +-
 2 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/widget/src/button.rs b/widget/src/button.rs
index e265aa1f63..5790f811bd 100644
--- a/widget/src/button.rs
+++ b/widget/src/button.rs
@@ -56,7 +56,7 @@ where
     height: Length,
     padding: Padding,
     clip: bool,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 impl<'a, Message, Theme, Renderer> Button<'a, Message, Theme, Renderer>
@@ -68,7 +68,7 @@ where
         content: impl Into<Element<'a, Message, Theme, Renderer>>,
     ) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         let content = content.into();
         let size = content.as_widget().size_hint();
@@ -80,7 +80,7 @@ where
             height: size.height.fluid(),
             padding: DEFAULT_PADDING,
             clip: false,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -120,8 +120,11 @@ where
     }
 
     /// Sets the style variant of this [`Button`].
-    pub fn style(mut self, style: fn(&Theme, Status) -> Appearance) -> Self {
-        self.style = style;
+    pub fn style(
+        mut self,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
+    ) -> Self {
+        self.style = Box::new(style);
         self
     }
 
@@ -439,29 +442,29 @@ impl std::default::Default for Appearance {
 }
 
 /// The style of a [`Button`].
-pub type Style<Theme> = fn(&Theme, Status) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Appearance + 'a>;
 
 /// The default style of a [`Button`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`Button`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self, status: Status) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        primary
+    fn default_style(&self, status: Status) -> Appearance {
+        primary(self, status)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance, _status| *appearance
+    fn default_style(&self, _status: Status) -> Appearance {
+        *self
     }
 }
 
 impl DefaultStyle for Color {
-    fn default_style() -> Style<Self> {
-        |color, _status| Appearance::default().with_background(*color)
+    fn default_style(&self, _status: Status) -> Appearance {
+        Appearance::default().with_background(*self)
     }
 }
 
diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index 89d6ef622e..db21c8e97f 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -117,7 +117,7 @@ pub fn button<'a, Message, Theme, Renderer>(
     content: impl Into<Element<'a, Message, Theme, Renderer>>,
 ) -> Button<'a, Message, Theme, Renderer>
 where
-    Theme: button::DefaultStyle,
+    Theme: button::DefaultStyle + 'a,
     Renderer: core::Renderer,
 {
     Button::new(content)

From 66dce4865eb00f7cc7b75e64cd8a96a496916285 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 13:34:51 +0100
Subject: [PATCH 03/17] Use closures for `Scrollable::style`

---
 widget/src/helpers.rs    |  2 +-
 widget/src/scrollable.rs | 35 +++++++++++++++++------------------
 2 files changed, 18 insertions(+), 19 deletions(-)

diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index db21c8e97f..e30b282924 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -104,7 +104,7 @@ pub fn scrollable<'a, Message, Theme, Renderer>(
     content: impl Into<Element<'a, Message, Theme, Renderer>>,
 ) -> Scrollable<'a, Message, Theme, Renderer>
 where
-    Theme: scrollable::DefaultStyle,
+    Theme: scrollable::DefaultStyle + 'a,
     Renderer: core::Renderer,
 {
     Scrollable::new(content)
diff --git a/widget/src/scrollable.rs b/widget/src/scrollable.rs
index 3431275209..c03bbb7db1 100644
--- a/widget/src/scrollable.rs
+++ b/widget/src/scrollable.rs
@@ -36,7 +36,7 @@ pub struct Scrollable<
     direction: Direction,
     content: Element<'a, Message, Theme, Renderer>,
     on_scroll: Option<Box<dyn Fn(Viewport) -> Message + 'a>>,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 impl<'a, Message, Theme, Renderer> Scrollable<'a, Message, Theme, Renderer>
@@ -48,7 +48,7 @@ where
         content: impl Into<Element<'a, Message, Theme, Renderer>>,
     ) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         Self::with_direction(content, Direction::default())
     }
@@ -59,20 +59,16 @@ where
         direction: Direction,
     ) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
-        Self::with_direction_and_style(
-            content,
-            direction,
-            Theme::default_style(),
-        )
+        Self::with_direction_and_style(content, direction, Theme::default_style)
     }
 
     /// Creates a new [`Scrollable`] with the given [`Direction`] and style.
     pub fn with_direction_and_style(
         content: impl Into<Element<'a, Message, Theme, Renderer>>,
         direction: Direction,
-        style: fn(&Theme, Status) -> Appearance,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
     ) -> Self {
         let content = content.into();
 
@@ -95,7 +91,7 @@ where
             direction,
             content,
             on_scroll: None,
-            style: style.into(),
+            style: Box::new(style),
         }
     }
 
@@ -126,8 +122,11 @@ where
     }
 
     /// Sets the style of the [`Scrollable`] .
-    pub fn style(mut self, style: fn(&Theme, Status) -> Appearance) -> Self {
-        self.style = style.into();
+    pub fn style(
+        mut self,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
+    ) -> Self {
+        self.style = Box::new(style);
         self
     }
 }
@@ -1603,23 +1602,23 @@ pub struct Scroller {
 }
 
 /// The style of a [`Scrollable`].
-pub type Style<Theme> = fn(&Theme, Status) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Appearance + 'a>;
 
 /// The default style of a [`Scrollable`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`Scrollable`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self, status: Status) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        default
+    fn default_style(&self, status: Status) -> Appearance {
+        default(self, status)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance, _status| *appearance
+    fn default_style(&self, _status: Status) -> Appearance {
+        *self
     }
 }
 

From 71b9b3c3b1242dd571170fb0f8dd22760a1b4c53 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 13:41:14 +0100
Subject: [PATCH 04/17] Use closures for `Svg::style`

---
 examples/svg/src/main.rs | 12 ++++++------
 widget/src/helpers.rs    |  6 ++++--
 widget/src/svg.rs        | 38 +++++++++++++++++++++-----------------
 3 files changed, 31 insertions(+), 25 deletions(-)

diff --git a/examples/svg/src/main.rs b/examples/svg/src/main.rs
index 4e23804875..0870dce438 100644
--- a/examples/svg/src/main.rs
+++ b/examples/svg/src/main.rs
@@ -41,12 +41,12 @@ impl Sandbox for Tiger {
         ));
 
         let svg = svg(handle).width(Length::Fill).height(Length::Fill).style(
-            if self.apply_color_filter {
-                |_theme, _status| svg::Appearance {
-                    color: Some(color!(0x0000ff)),
-                }
-            } else {
-                |_theme, _status| svg::Appearance::default()
+            |_theme, _status| svg::Appearance {
+                color: if self.apply_color_filter {
+                    Some(color!(0x0000ff))
+                } else {
+                    None
+                },
             },
         );
 
diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index e30b282924..91d5ee80f3 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -362,9 +362,11 @@ pub fn image<Handle>(handle: impl Into<Handle>) -> crate::Image<Handle> {
 /// [`Svg`]: crate::Svg
 /// [`Handle`]: crate::svg::Handle
 #[cfg(feature = "svg")]
-pub fn svg<Theme>(handle: impl Into<core::svg::Handle>) -> crate::Svg<Theme>
+pub fn svg<'a, Theme>(
+    handle: impl Into<core::svg::Handle>,
+) -> crate::Svg<'a, Theme>
 where
-    Theme: crate::svg::DefaultStyle,
+    Theme: crate::svg::DefaultStyle + 'a,
 {
     crate::Svg::new(handle)
 }
diff --git a/widget/src/svg.rs b/widget/src/svg.rs
index 6e61d27a2a..1ac07ade3e 100644
--- a/widget/src/svg.rs
+++ b/widget/src/svg.rs
@@ -20,26 +20,26 @@ pub use crate::core::svg::Handle;
 /// [`Svg`] images can have a considerable rendering cost when resized,
 /// specially when they are complex.
 #[allow(missing_debug_implementations)]
-pub struct Svg<Theme = crate::Theme> {
+pub struct Svg<'a, Theme = crate::Theme> {
     handle: Handle,
     width: Length,
     height: Length,
     content_fit: ContentFit,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
-impl<Theme> Svg<Theme> {
+impl<'a, Theme> Svg<'a, Theme> {
     /// Creates a new [`Svg`] from the given [`Handle`].
     pub fn new(handle: impl Into<Handle>) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         Svg {
             handle: handle.into(),
             width: Length::Fill,
             height: Length::Shrink,
             content_fit: ContentFit::Contain,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -48,7 +48,7 @@ impl<Theme> Svg<Theme> {
     #[must_use]
     pub fn from_path(path: impl Into<PathBuf>) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         Self::new(Handle::from_path(path))
     }
@@ -80,13 +80,17 @@ impl<Theme> Svg<Theme> {
 
     /// Sets the style variant of this [`Svg`].
     #[must_use]
-    pub fn style(mut self, style: fn(&Theme, Status) -> Appearance) -> Self {
-        self.style = style;
+    pub fn style(
+        mut self,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
+    ) -> Self {
+        self.style = Box::new(style);
         self
     }
 }
 
-impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer> for Svg<Theme>
+impl<'a, Message, Theme, Renderer> Widget<Message, Theme, Renderer>
+    for Svg<'a, Theme>
 where
     Renderer: svg::Renderer,
 {
@@ -182,13 +186,13 @@ where
     }
 }
 
-impl<'a, Message, Theme, Renderer> From<Svg<Theme>>
+impl<'a, Message, Theme, Renderer> From<Svg<'a, Theme>>
     for Element<'a, Message, Theme, Renderer>
 where
     Theme: 'a,
     Renderer: svg::Renderer + 'a,
 {
-    fn from(icon: Svg<Theme>) -> Element<'a, Message, Theme, Renderer> {
+    fn from(icon: Svg<'a, Theme>) -> Element<'a, Message, Theme, Renderer> {
         Element::new(icon)
     }
 }
@@ -214,22 +218,22 @@ pub struct Appearance {
 }
 
 /// The style of an [`Svg`].
-pub type Style<Theme> = fn(&Theme, Status) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Appearance + 'a>;
 
 /// The default style of an [`Svg`].
 pub trait DefaultStyle {
     /// Returns the default style of an [`Svg`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self, status: Status) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        |_theme, _status| Appearance::default()
+    fn default_style(&self, _status: Status) -> Appearance {
+        Appearance::default()
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance, _status| *appearance
+    fn default_style(&self, _status: Status) -> Appearance {
+        *self
     }
 }

From 66f81c3429c736c5ca17d022ed1d6cdcc15e4f94 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 13:44:03 +0100
Subject: [PATCH 05/17] Use closures for `Rule::style`

---
 widget/src/helpers.rs |  8 ++++----
 widget/src/rule.rs    | 37 +++++++++++++++++++------------------
 2 files changed, 23 insertions(+), 22 deletions(-)

diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index 91d5ee80f3..4bff0f169a 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -315,9 +315,9 @@ pub fn vertical_space() -> Space {
 /// Creates a horizontal [`Rule`] with the given height.
 ///
 /// [`Rule`]: crate::Rule
-pub fn horizontal_rule<Theme>(height: impl Into<Pixels>) -> Rule<Theme>
+pub fn horizontal_rule<'a, Theme>(height: impl Into<Pixels>) -> Rule<'a, Theme>
 where
-    Theme: rule::DefaultStyle,
+    Theme: rule::DefaultStyle + 'a,
 {
     Rule::horizontal(height)
 }
@@ -325,9 +325,9 @@ where
 /// Creates a vertical [`Rule`] with the given width.
 ///
 /// [`Rule`]: crate::Rule
-pub fn vertical_rule<Theme>(width: impl Into<Pixels>) -> Rule<Theme>
+pub fn vertical_rule<'a, Theme>(width: impl Into<Pixels>) -> Rule<'a, Theme>
 where
-    Theme: rule::DefaultStyle,
+    Theme: rule::DefaultStyle + 'a,
 {
     Rule::vertical(width)
 }
diff --git a/widget/src/rule.rs b/widget/src/rule.rs
index 8580d4c7a6..9fa5f74fb1 100644
--- a/widget/src/rule.rs
+++ b/widget/src/rule.rs
@@ -10,48 +10,49 @@ use crate::core::{
 
 /// Display a horizontal or vertical rule for dividing content.
 #[allow(missing_debug_implementations)]
-pub struct Rule<Theme = crate::Theme> {
+pub struct Rule<'a, Theme = crate::Theme> {
     width: Length,
     height: Length,
     is_horizontal: bool,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
-impl<Theme> Rule<Theme> {
+impl<'a, Theme> Rule<'a, Theme> {
     /// Creates a horizontal [`Rule`] with the given height.
     pub fn horizontal(height: impl Into<Pixels>) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         Rule {
             width: Length::Fill,
             height: Length::Fixed(height.into().0),
             is_horizontal: true,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
     /// Creates a vertical [`Rule`] with the given width.
     pub fn vertical(width: impl Into<Pixels>) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         Rule {
             width: Length::Fixed(width.into().0),
             height: Length::Fill,
             is_horizontal: false,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
     /// Sets the style of the [`Rule`].
-    pub fn style(mut self, style: fn(&Theme) -> Appearance) -> Self {
-        self.style = style;
+    pub fn style(mut self, style: impl Fn(&Theme) -> Appearance + 'a) -> Self {
+        self.style = Box::new(style);
         self
     }
 }
 
-impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer> for Rule<Theme>
+impl<'a, Message, Theme, Renderer> Widget<Message, Theme, Renderer>
+    for Rule<'a, Theme>
 where
     Renderer: crate::core::Renderer,
 {
@@ -126,14 +127,14 @@ where
     }
 }
 
-impl<'a, Message, Theme, Renderer> From<Rule<Theme>>
+impl<'a, Message, Theme, Renderer> From<Rule<'a, Theme>>
     for Element<'a, Message, Theme, Renderer>
 where
     Message: 'a,
     Theme: 'a,
     Renderer: 'a + crate::core::Renderer,
 {
-    fn from(rule: Rule<Theme>) -> Element<'a, Message, Theme, Renderer> {
+    fn from(rule: Rule<'a, Theme>) -> Element<'a, Message, Theme, Renderer> {
         Element::new(rule)
     }
 }
@@ -216,23 +217,23 @@ impl FillMode {
 }
 
 /// The style of a [`Rule`].
-pub type Style<Theme> = fn(&Theme) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme) -> Appearance + 'a>;
 
 /// The default style of a [`Rule`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`Rule`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        default
+    fn default_style(&self) -> Appearance {
+        default(self)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance| *appearance
+    fn default_style(&self) -> Appearance {
+        *self
     }
 }
 

From aeb72d528fce58ac94df3c015c10d6fe05f81a01 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 14:35:55 +0100
Subject: [PATCH 06/17] Use closures for `Text::style`

---
 core/src/widget/text.rs        | 83 ++++++++++++----------------------
 examples/component/src/main.rs | 10 +++-
 widget/src/helpers.rs          |  3 +-
 3 files changed, 40 insertions(+), 56 deletions(-)

diff --git a/core/src/widget/text.rs b/core/src/widget/text.rs
index 0305972bbc..66e2d066c6 100644
--- a/core/src/widget/text.rs
+++ b/core/src/widget/text.rs
@@ -6,7 +6,8 @@ use crate::renderer;
 use crate::text::{self, Paragraph};
 use crate::widget::tree::{self, Tree};
 use crate::{
-    Color, Element, Layout, Length, Pixels, Point, Rectangle, Size, Widget,
+    Color, Element, Layout, Length, Pixels, Point, Rectangle, Size, Theme,
+    Widget,
 };
 
 use std::borrow::Cow;
@@ -28,7 +29,7 @@ where
     vertical_alignment: alignment::Vertical,
     font: Option<Renderer::Font>,
     shaping: Shaping,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 impl<'a, Theme, Renderer> Text<'a, Theme, Renderer>
@@ -36,7 +37,10 @@ where
     Renderer: text::Renderer,
 {
     /// Create a new fragment of [`Text`] with the given contents.
-    pub fn new(content: impl Into<Cow<'a, str>>) -> Self {
+    pub fn new(content: impl Into<Cow<'a, str>>) -> Self
+    where
+        Theme: DefaultStyle + 'a,
+    {
         Text {
             content: content.into(),
             size: None,
@@ -47,7 +51,7 @@ where
             horizontal_alignment: alignment::Horizontal::Left,
             vertical_alignment: alignment::Vertical::Top,
             shaping: Shaping::Basic,
-            style: Style::default(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -72,20 +76,21 @@ where
     }
 
     /// Sets the style of the [`Text`].
-    pub fn style(mut self, style: fn(&Theme) -> Appearance) -> Self {
-        self.style = Style::Themed(style);
+    pub fn style(mut self, style: impl Fn(&Theme) -> Appearance + 'a) -> Self {
+        self.style = Box::new(style);
         self
     }
 
     /// Sets the [`Color`] of the [`Text`].
-    pub fn color(mut self, color: impl Into<Color>) -> Self {
-        self.style = Style::Colored(Some(color.into()));
-        self
+    pub fn color(self, color: impl Into<Color>) -> Self {
+        self.color_maybe(Some(color))
     }
 
     /// Sets the [`Color`] of the [`Text`], if `Some`.
     pub fn color_maybe(mut self, color: Option<impl Into<Color>>) -> Self {
-        self.style = Style::Colored(color.map(Into::into));
+        let color = color.map(Into::into);
+
+        self.style = Box::new(move |_theme| Appearance { color });
         self
     }
 
@@ -183,11 +188,7 @@ where
         viewport: &Rectangle,
     ) {
         let state = tree.state.downcast_ref::<State<Renderer::Paragraph>>();
-
-        let appearance = match self.style {
-            Style::Themed(f) => f(theme),
-            Style::Colored(color) => Appearance { color },
-        };
+        let appearance = (self.style)(theme);
 
         draw(renderer, style, layout, state, appearance, viewport);
     }
@@ -290,28 +291,9 @@ where
     }
 }
 
-impl<'a, Theme, Renderer> Clone for Text<'a, Theme, Renderer>
-where
-    Renderer: text::Renderer,
-{
-    fn clone(&self) -> Self {
-        Self {
-            content: self.content.clone(),
-            size: self.size,
-            line_height: self.line_height,
-            width: self.width,
-            height: self.height,
-            horizontal_alignment: self.horizontal_alignment,
-            vertical_alignment: self.vertical_alignment,
-            font: self.font,
-            style: self.style,
-            shaping: self.shaping,
-        }
-    }
-}
-
 impl<'a, Theme, Renderer> From<&'a str> for Text<'a, Theme, Renderer>
 where
+    Theme: DefaultStyle + 'a,
     Renderer: text::Renderer,
 {
     fn from(content: &'a str) -> Self {
@@ -322,7 +304,7 @@ where
 impl<'a, Message, Theme, Renderer> From<&'a str>
     for Element<'a, Message, Theme, Renderer>
 where
-    Theme: 'a,
+    Theme: DefaultStyle + 'a,
     Renderer: text::Renderer + 'a,
 {
     fn from(content: &'a str) -> Self {
@@ -339,28 +321,23 @@ pub struct Appearance {
     pub color: Option<Color>,
 }
 
-#[derive(Debug)]
-enum Style<Theme> {
-    Themed(fn(&Theme) -> Appearance),
-    Colored(Option<Color>),
-}
+/// The style of some [`Text`].
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme) -> Appearance + 'a>;
 
-impl<Theme> Clone for Style<Theme> {
-    fn clone(&self) -> Self {
-        *self
-    }
+/// The default style of some [`Text`].
+pub trait DefaultStyle {
+    /// Returns the default style of some [`Text`].
+    fn default_style(&self) -> Appearance;
 }
 
-impl<Theme> Copy for Style<Theme> {}
-
-impl<Theme> Default for Style<Theme> {
-    fn default() -> Self {
-        Style::Colored(None)
+impl DefaultStyle for Theme {
+    fn default_style(&self) -> Appearance {
+        Appearance::default()
     }
 }
 
-impl<Theme> From<fn(&Theme) -> Appearance> for Style<Theme> {
-    fn from(f: fn(&Theme) -> Appearance) -> Self {
-        Style::Themed(f)
+impl DefaultStyle for Color {
+    fn default_style(&self) -> Appearance {
+        Appearance { color: Some(*self) }
     }
 }
diff --git a/examples/component/src/main.rs b/examples/component/src/main.rs
index a1572b1ddf..d4f99798ca 100644
--- a/examples/component/src/main.rs
+++ b/examples/component/src/main.rs
@@ -83,7 +83,10 @@ mod numeric_input {
 
     impl<Message, Theme> Component<Message, Theme> for NumericInput<Message>
     where
-        Theme: button::DefaultStyle + text_input::DefaultStyle + 'static,
+        Theme: text::DefaultStyle
+            + button::DefaultStyle
+            + text_input::DefaultStyle
+            + 'static,
     {
         type State = ();
         type Event = Event;
@@ -158,7 +161,10 @@ mod numeric_input {
     impl<'a, Message, Theme> From<NumericInput<Message>>
         for Element<'a, Message, Theme>
     where
-        Theme: button::DefaultStyle + text_input::DefaultStyle + 'static,
+        Theme: text::DefaultStyle
+            + button::DefaultStyle
+            + text_input::DefaultStyle
+            + 'static,
         Message: 'a,
     {
         fn from(numeric_input: NumericInput<Message>) -> Self {
diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index 4bff0f169a..cc9bfeef59 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -14,7 +14,7 @@ use crate::rule::{self, Rule};
 use crate::runtime::Command;
 use crate::scrollable::{self, Scrollable};
 use crate::slider::{self, Slider};
-use crate::text::Text;
+use crate::text::{self, Text};
 use crate::text_editor::{self, TextEditor};
 use crate::text_input::{self, TextInput};
 use crate::toggler::{self, Toggler};
@@ -147,6 +147,7 @@ pub fn text<'a, Theme, Renderer>(
     text: impl ToString,
 ) -> Text<'a, Theme, Renderer>
 where
+    Theme: text::DefaultStyle + 'a,
     Renderer: core::text::Renderer,
 {
     Text::new(text.to_string())

From 58a0d5b7fff3000c46f5f2c468fce9442c78ef20 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 14:45:28 +0100
Subject: [PATCH 07/17] Use closures for `Radio::style`

---
 widget/src/helpers.rs |  6 +++---
 widget/src/radio.rs   | 41 ++++++++++++++++++++++-------------------
 2 files changed, 25 insertions(+), 22 deletions(-)

diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index cc9bfeef59..896e2c1372 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -170,15 +170,15 @@ where
 /// Creates a new [`Radio`].
 ///
 /// [`Radio`]: crate::Radio
-pub fn radio<Message, Theme, Renderer, V>(
+pub fn radio<'a, Message, Theme, Renderer, V>(
     label: impl Into<String>,
     value: V,
     selected: Option<V>,
     on_click: impl FnOnce(V) -> Message,
-) -> Radio<Message, Theme, Renderer>
+) -> Radio<'a, Message, Theme, Renderer>
 where
     Message: Clone,
-    Theme: radio::DefaultStyle,
+    Theme: radio::DefaultStyle + 'a,
     Renderer: core::text::Renderer,
     V: Copy + Eq,
 {
diff --git a/widget/src/radio.rs b/widget/src/radio.rs
index 5e4a3c1fb7..a7b7dd036a 100644
--- a/widget/src/radio.rs
+++ b/widget/src/radio.rs
@@ -17,8 +17,8 @@ use crate::core::{
 ///
 /// # Example
 /// ```no_run
-/// # type Radio<Message> =
-/// #     iced_widget::Radio<Message, iced_widget::Theme, iced_widget::renderer::Renderer>;
+/// # type Radio<'a, Message> =
+/// #     iced_widget::Radio<'a, Message, iced_widget::Theme, iced_widget::renderer::Renderer>;
 /// #
 /// # use iced_widget::column;
 /// #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -67,7 +67,7 @@ use crate::core::{
 /// let content = column![a, b, c, all];
 /// ```
 #[allow(missing_debug_implementations)]
-pub struct Radio<Message, Theme = crate::Theme, Renderer = crate::Renderer>
+pub struct Radio<'a, Message, Theme = crate::Theme, Renderer = crate::Renderer>
 where
     Renderer: text::Renderer,
 {
@@ -81,10 +81,10 @@ where
     text_line_height: text::LineHeight,
     text_shaping: text::Shaping,
     font: Option<Renderer::Font>,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
-impl<Message, Theme, Renderer> Radio<Message, Theme, Renderer>
+impl<'a, Message, Theme, Renderer> Radio<'a, Message, Theme, Renderer>
 where
     Message: Clone,
     Renderer: text::Renderer,
@@ -110,7 +110,7 @@ where
         f: F,
     ) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
         V: Eq + Copy,
         F: FnOnce(V) -> Message,
     {
@@ -125,7 +125,7 @@ where
             text_line_height: text::LineHeight::default(),
             text_shaping: text::Shaping::Basic,
             font: None,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -175,14 +175,17 @@ where
     }
 
     /// Sets the style of the [`Radio`] button.
-    pub fn style(mut self, style: fn(&Theme, Status) -> Appearance) -> Self {
-        self.style = style;
+    pub fn style(
+        mut self,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
+    ) -> Self {
+        self.style = Box::new(style);
         self
     }
 }
 
-impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer>
-    for Radio<Message, Theme, Renderer>
+impl<'a, Message, Theme, Renderer> Widget<Message, Theme, Renderer>
+    for Radio<'a, Message, Theme, Renderer>
 where
     Message: Clone,
     Renderer: text::Renderer,
@@ -353,7 +356,7 @@ where
     }
 }
 
-impl<'a, Message, Theme, Renderer> From<Radio<Message, Theme, Renderer>>
+impl<'a, Message, Theme, Renderer> From<Radio<'a, Message, Theme, Renderer>>
     for Element<'a, Message, Theme, Renderer>
 where
     Message: 'a + Clone,
@@ -361,7 +364,7 @@ where
     Renderer: 'a + text::Renderer,
 {
     fn from(
-        radio: Radio<Message, Theme, Renderer>,
+        radio: Radio<'a, Message, Theme, Renderer>,
     ) -> Element<'a, Message, Theme, Renderer> {
         Element::new(radio)
     }
@@ -398,23 +401,23 @@ pub struct Appearance {
 }
 
 /// The style of a [`Radio`] button.
-pub type Style<Theme> = fn(&Theme, Status) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Appearance + 'a>;
 
 /// The default style of a [`Radio`] button.
 pub trait DefaultStyle {
     /// Returns the default style of a [`Radio`] button.
-    fn default_style() -> Style<Self>;
+    fn default_style(&self, status: Status) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        default
+    fn default_style(&self, status: Status) -> Appearance {
+        default(self, status)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance, _status| *appearance
+    fn default_style(&self, _status: Status) -> Appearance {
+        *self
     }
 }
 

From afd138dba697976f61e335555b69417c4c84f7f2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 14:47:36 +0100
Subject: [PATCH 08/17] Use closures for `Slider::style` and
 `VerticalSlider::style`

---
 widget/src/helpers.rs         |  4 ++--
 widget/src/slider.rs          | 25 ++++++++++++++-----------
 widget/src/vertical_slider.rs | 13 ++++++++-----
 3 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index 896e2c1372..c3801b0971 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -240,7 +240,7 @@ pub fn slider<'a, T, Message, Theme>(
 where
     T: Copy + From<u8> + std::cmp::PartialOrd,
     Message: Clone,
-    Theme: slider::DefaultStyle,
+    Theme: slider::DefaultStyle + 'a,
 {
     Slider::new(range, value, on_change)
 }
@@ -256,7 +256,7 @@ pub fn vertical_slider<'a, T, Message, Theme>(
 where
     T: Copy + From<u8> + std::cmp::PartialOrd,
     Message: Clone,
-    Theme: vertical_slider::DefaultStyle,
+    Theme: vertical_slider::DefaultStyle + 'a,
 {
     VerticalSlider::new(range, value, on_change)
 }
diff --git a/widget/src/slider.rs b/widget/src/slider.rs
index f3ea9bfdbc..d3b46a98c1 100644
--- a/widget/src/slider.rs
+++ b/widget/src/slider.rs
@@ -49,7 +49,7 @@ pub struct Slider<'a, T, Message, Theme = crate::Theme> {
     on_release: Option<Message>,
     width: Length,
     height: f32,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 impl<'a, T, Message, Theme> Slider<'a, T, Message, Theme>
@@ -70,7 +70,7 @@ where
     ///   `Message`.
     pub fn new<F>(range: RangeInclusive<T>, value: T, on_change: F) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
         F: 'a + Fn(T) -> Message,
     {
         let value = if value >= *range.start() {
@@ -95,7 +95,7 @@ where
             on_release: None,
             width: Length::Fill,
             height: Self::DEFAULT_HEIGHT,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -131,8 +131,11 @@ where
     }
 
     /// Sets the style of the [`Slider`].
-    pub fn style(mut self, style: fn(&Theme, Status) -> Appearance) -> Self {
-        self.style = style.into();
+    pub fn style(
+        mut self,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
+    ) -> Self {
+        self.style = Box::new(style);
         self
     }
 
@@ -547,23 +550,23 @@ pub enum HandleShape {
 }
 
 /// The style of a [`Slider`].
-pub type Style<Theme> = fn(&Theme, Status) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Appearance + 'a>;
 
 /// The default style of a [`Slider`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`Slider`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self, status: Status) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        default
+    fn default_style(&self, status: Status) -> Appearance {
+        default(self, status)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance, _status| *appearance
+    fn default_style(&self, _status: Status) -> Appearance {
+        *self
     }
 }
 
diff --git a/widget/src/vertical_slider.rs b/widget/src/vertical_slider.rs
index f7030584ec..2aa8f4d1f0 100644
--- a/widget/src/vertical_slider.rs
+++ b/widget/src/vertical_slider.rs
@@ -51,7 +51,7 @@ pub struct VerticalSlider<'a, T, Message, Theme = crate::Theme> {
     on_release: Option<Message>,
     width: f32,
     height: Length,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 impl<'a, T, Message, Theme> VerticalSlider<'a, T, Message, Theme>
@@ -72,7 +72,7 @@ where
     ///   `Message`.
     pub fn new<F>(range: RangeInclusive<T>, value: T, on_change: F) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
         F: 'a + Fn(T) -> Message,
     {
         let value = if value >= *range.start() {
@@ -97,7 +97,7 @@ where
             on_release: None,
             width: Self::DEFAULT_WIDTH,
             height: Length::Fill,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -133,8 +133,11 @@ where
     }
 
     /// Sets the style of the [`VerticalSlider`].
-    pub fn style(mut self, style: fn(&Theme, Status) -> Appearance) -> Self {
-        self.style = style.into();
+    pub fn style(
+        mut self,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
+    ) -> Self {
+        self.style = Box::new(style);
         self
     }
 

From 67416302180ce27c81418b71798d02b52c44e625 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 14:51:30 +0100
Subject: [PATCH 09/17] Use closures for `QRCode::style`

---
 widget/src/helpers.rs |  6 ++++--
 widget/src/qr_code.rs | 24 ++++++++++++------------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index c3801b0971..b26736076f 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -391,9 +391,11 @@ where
 /// [`QRCode`]: crate::QRCode
 /// [`Data`]: crate::qr_code::Data
 #[cfg(feature = "qr_code")]
-pub fn qr_code<Theme>(data: &crate::qr_code::Data) -> crate::QRCode<'_, Theme>
+pub fn qr_code<'a, Theme>(
+    data: &'a crate::qr_code::Data,
+) -> crate::QRCode<'a, Theme>
 where
-    Theme: crate::qr_code::DefaultStyle,
+    Theme: crate::qr_code::DefaultStyle + 'a,
 {
     crate::QRCode::new(data)
 }
diff --git a/widget/src/qr_code.rs b/widget/src/qr_code.rs
index 41bcb83eae..90c0c97044 100644
--- a/widget/src/qr_code.rs
+++ b/widget/src/qr_code.rs
@@ -19,23 +19,23 @@ const QUIET_ZONE: usize = 2;
 
 /// A type of matrix barcode consisting of squares arranged in a grid which
 /// can be read by an imaging device, such as a camera.
-#[derive(Debug)]
+#[allow(missing_debug_implementations)]
 pub struct QRCode<'a, Theme = crate::Theme> {
     data: &'a Data,
     cell_size: u16,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 impl<'a, Theme> QRCode<'a, Theme> {
     /// Creates a new [`QRCode`] with the provided [`Data`].
     pub fn new(data: &'a Data) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         Self {
             data,
             cell_size: DEFAULT_CELL_SIZE,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -46,8 +46,8 @@ impl<'a, Theme> QRCode<'a, Theme> {
     }
 
     /// Sets the style of the [`QRCode`].
-    pub fn style(mut self, style: fn(&Theme) -> Appearance) -> Self {
-        self.style = style.into();
+    pub fn style(mut self, style: impl Fn(&Theme) -> Appearance + 'a) -> Self {
+        self.style = Box::new(style);
         self
     }
 }
@@ -336,23 +336,23 @@ pub struct Appearance {
 }
 
 /// The style of a [`QRCode`].
-pub type Style<Theme> = fn(&Theme) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme) -> Appearance + 'a>;
 
 /// The default style of a [`QRCode`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`QRCode`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        default
+    fn default_style(&self) -> Appearance {
+        default(self)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance| *appearance
+    fn default_style(&self) -> Appearance {
+        *self
     }
 }
 

From d0a1da194a7311d599bda0884c973e8eed6c15d8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 14:54:28 +0100
Subject: [PATCH 10/17] Use closures for `Toggler::style`

---
 widget/src/helpers.rs |  2 +-
 widget/src/toggler.rs | 25 ++++++++++++++-----------
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index b26736076f..dde6a20753 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -194,7 +194,7 @@ pub fn toggler<'a, Message, Theme, Renderer>(
     f: impl Fn(bool) -> Message + 'a,
 ) -> Toggler<'a, Message, Theme, Renderer>
 where
-    Theme: toggler::DefaultStyle,
+    Theme: toggler::DefaultStyle + 'a,
     Renderer: core::text::Renderer,
 {
     Toggler::new(label, is_checked, f)
diff --git a/widget/src/toggler.rs b/widget/src/toggler.rs
index 9e81ba332e..fc9e06e1d4 100644
--- a/widget/src/toggler.rs
+++ b/widget/src/toggler.rs
@@ -48,7 +48,7 @@ pub struct Toggler<
     text_shaping: text::Shaping,
     spacing: f32,
     font: Option<Renderer::Font>,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 impl<'a, Message, Theme, Renderer> Toggler<'a, Message, Theme, Renderer>
@@ -72,7 +72,7 @@ where
         f: F,
     ) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: 'a + DefaultStyle,
         F: 'a + Fn(bool) -> Message,
     {
         Toggler {
@@ -87,7 +87,7 @@ where
             text_shaping: text::Shaping::Basic,
             spacing: Self::DEFAULT_SIZE / 2.0,
             font: None,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -145,8 +145,11 @@ where
     }
 
     /// Sets the style of the [`Toggler`].
-    pub fn style(mut self, style: fn(&Theme, Status) -> Appearance) -> Self {
-        self.style = style.into();
+    pub fn style(
+        mut self,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
+    ) -> Self {
+        self.style = Box::new(style);
         self
     }
 }
@@ -398,23 +401,23 @@ pub struct Appearance {
 }
 
 /// The style of a [`Toggler`].
-pub type Style<Theme> = fn(&Theme, Status) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Appearance + 'a>;
 
 /// The default style of a [`Toggler`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`Toggler`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self, status: Status) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        default
+    fn default_style(&self, status: Status) -> Appearance {
+        default(self, status)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance, _status| *appearance
+    fn default_style(&self, _status: Status) -> Appearance {
+        *self
     }
 }
 

From 252eb88703196dd1d373fb45cbbb7ee7b85f3726 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 14:58:06 +0100
Subject: [PATCH 11/17] Use closures for `Checkbox::style`

---
 examples/checkbox/src/main.rs | 11 +++++------
 widget/src/checkbox.rs        | 25 ++++++++++++++-----------
 widget/src/helpers.rs         |  2 +-
 3 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/examples/checkbox/src/main.rs b/examples/checkbox/src/main.rs
index 121c99ea5a..ee745c0339 100644
--- a/examples/checkbox/src/main.rs
+++ b/examples/checkbox/src/main.rs
@@ -63,17 +63,16 @@ impl Application for Example {
         let default_checkbox = checkbox("Default", self.default)
             .on_toggle(Message::DefaultToggled);
 
-        let styled_checkbox = |label, style| {
+        let styled_checkbox = |label| {
             checkbox(label, self.styled)
                 .on_toggle_maybe(self.default.then_some(Message::StyledToggled))
-                .style(style)
         };
 
         let checkboxes = row![
-            styled_checkbox("Primary", checkbox::primary),
-            styled_checkbox("Secondary", checkbox::secondary),
-            styled_checkbox("Success", checkbox::success),
-            styled_checkbox("Danger", checkbox::danger),
+            styled_checkbox("Primary").style(checkbox::primary),
+            styled_checkbox("Secondary").style(checkbox::secondary),
+            styled_checkbox("Success").style(checkbox::success),
+            styled_checkbox("Danger").style(checkbox::danger),
         ]
         .spacing(20);
 
diff --git a/widget/src/checkbox.rs b/widget/src/checkbox.rs
index f0c7357bbe..15fb8f5844 100644
--- a/widget/src/checkbox.rs
+++ b/widget/src/checkbox.rs
@@ -51,7 +51,7 @@ pub struct Checkbox<
     text_shaping: text::Shaping,
     font: Option<Renderer::Font>,
     icon: Icon<Renderer::Font>,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 impl<'a, Message, Theme, Renderer> Checkbox<'a, Message, Theme, Renderer>
@@ -71,7 +71,7 @@ where
     ///   * a boolean describing whether the [`Checkbox`] is checked or not
     pub fn new(label: impl Into<String>, is_checked: bool) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         Checkbox {
             is_checked,
@@ -91,7 +91,7 @@ where
                 line_height: text::LineHeight::default(),
                 shaping: text::Shaping::Basic,
             },
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -174,8 +174,11 @@ where
     }
 
     /// Sets the style of the [`Checkbox`].
-    pub fn style(mut self, style: fn(&Theme, Status) -> Appearance) -> Self {
-        self.style = style;
+    pub fn style(
+        mut self,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
+    ) -> Self {
+        self.style = Box::new(style);
         self
     }
 }
@@ -424,23 +427,23 @@ pub struct Appearance {
 }
 
 /// The style of a [`Checkbox`].
-pub type Style<Theme> = fn(&Theme, Status) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Appearance + 'a>;
 
 /// The default style of a [`Checkbox`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`Checkbox`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self, status: Status) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        primary
+    fn default_style(&self, status: Status) -> Appearance {
+        primary(self, status)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance, _status| *appearance
+    fn default_style(&self, _status: Status) -> Appearance {
+        *self
     }
 }
 
diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index dde6a20753..7912d7b818 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -161,7 +161,7 @@ pub fn checkbox<'a, Message, Theme, Renderer>(
     is_checked: bool,
 ) -> Checkbox<'a, Message, Theme, Renderer>
 where
-    Theme: checkbox::DefaultStyle,
+    Theme: checkbox::DefaultStyle + 'a,
     Renderer: core::text::Renderer,
 {
     Checkbox::new(label, is_checked)

From d1e40495410049aedb6756be1febd83bae5eee1e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 15:35:48 +0100
Subject: [PATCH 12/17] Use closures for `TextInput::style`

---
 widget/src/combo_box.rs  | 32 +++++++++++---------------------
 widget/src/helpers.rs    |  4 ++--
 widget/src/text_input.rs | 29 ++++++++++++++++-------------
 3 files changed, 29 insertions(+), 36 deletions(-)

diff --git a/widget/src/combo_box.rs b/widget/src/combo_box.rs
index bddf278925..956678824f 100644
--- a/widget/src/combo_box.rs
+++ b/widget/src/combo_box.rs
@@ -62,7 +62,7 @@ where
         on_selected: impl Fn(T) -> Message + 'static,
     ) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         let style = Theme::default_style();
 
@@ -125,7 +125,10 @@ where
     }
 
     /// Sets the style of the [`ComboBox`].
-    pub fn style(mut self, style: impl Into<Style<Theme>>) -> Self {
+    pub fn style(mut self, style: impl Into<Style<Theme>>) -> Self
+    where
+        Theme: 'a,
+    {
         let style = style.into();
 
         self.text_input = self.text_input.style(style.text_input);
@@ -761,10 +764,10 @@ where
 }
 
 /// The style of a [`ComboBox`].
-#[derive(Debug, PartialEq, Eq)]
+#[allow(missing_debug_implementations)]
 pub struct Style<Theme> {
     /// The style of the [`TextInput`] of the [`ComboBox`].
-    pub text_input: fn(&Theme, text_input::Status) -> text_input::Appearance,
+    pub text_input: text_input::Style<'static, Theme>,
 
     /// The style of the [`Menu`] of the [`ComboBox`].
     ///
@@ -772,22 +775,6 @@ pub struct Style<Theme> {
     pub menu: menu::Style<Theme>,
 }
 
-impl Style<Theme> {
-    /// The default style of a [`ComboBox`].
-    pub const DEFAULT: Self = Self {
-        text_input: text_input::default,
-        menu: menu::Style::<Theme>::DEFAULT,
-    };
-}
-
-impl<Theme> Clone for Style<Theme> {
-    fn clone(&self) -> Self {
-        *self
-    }
-}
-
-impl<Theme> Copy for Style<Theme> {}
-
 /// The default style of a [`ComboBox`].
 pub trait DefaultStyle: Sized {
     /// Returns the default style of a [`ComboBox`].
@@ -796,6 +783,9 @@ pub trait DefaultStyle: Sized {
 
 impl DefaultStyle for Theme {
     fn default_style() -> Style<Self> {
-        Style::<Self>::DEFAULT
+        Style {
+            text_input: Box::new(text_input::default),
+            menu: menu::Style::DEFAULT,
+        }
     }
 }
diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index 7912d7b818..2606826ddc 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -209,7 +209,7 @@ pub fn text_input<'a, Message, Theme, Renderer>(
 ) -> TextInput<'a, Message, Theme, Renderer>
 where
     Message: Clone,
-    Theme: text_input::DefaultStyle,
+    Theme: text_input::DefaultStyle + 'a,
     Renderer: core::text::Renderer,
 {
     TextInput::new(placeholder, value)
@@ -291,7 +291,7 @@ pub fn combo_box<'a, T, Message, Theme, Renderer>(
 ) -> ComboBox<'a, T, Message, Theme, Renderer>
 where
     T: std::fmt::Display + Clone,
-    Theme: combo_box::DefaultStyle,
+    Theme: combo_box::DefaultStyle + 'a,
     Renderer: core::text::Renderer,
 {
     ComboBox::new(state, placeholder, selection, on_selected)
diff --git a/widget/src/text_input.rs b/widget/src/text_input.rs
index 9ed8480a7e..b161ec74f9 100644
--- a/widget/src/text_input.rs
+++ b/widget/src/text_input.rs
@@ -75,7 +75,7 @@ pub struct TextInput<
     on_paste: Option<Box<dyn Fn(String) -> Message + 'a>>,
     on_submit: Option<Message>,
     icon: Option<Icon<Renderer::Font>>,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 /// The default [`Padding`] of a [`TextInput`].
@@ -90,9 +90,9 @@ where
     /// its current value.
     pub fn new(placeholder: &str, value: &str) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
-        Self::with_style(placeholder, value, Theme::default_style())
+        Self::with_style(placeholder, value, Theme::default_style)
     }
 
     /// Creates a new [`TextInput`] with the given placeholder,
@@ -100,7 +100,7 @@ where
     pub fn with_style(
         placeholder: &str,
         value: &str,
-        style: fn(&Theme, Status) -> Appearance,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
     ) -> Self {
         TextInput {
             id: None,
@@ -116,7 +116,7 @@ where
             on_paste: None,
             on_submit: None,
             icon: None,
-            style: style.into(),
+            style: Box::new(style),
         }
     }
 
@@ -203,8 +203,11 @@ where
     }
 
     /// Sets the style of the [`TextInput`].
-    pub fn style(mut self, style: fn(&Theme, Status) -> Appearance) -> Self {
-        self.style = style.into();
+    pub fn style(
+        mut self,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
+    ) -> Self {
+        self.style = Box::new(style);
         self
     }
 
@@ -1413,23 +1416,23 @@ pub struct Appearance {
 }
 
 /// The style of a [`TextInput`].
-pub type Style<Theme> = fn(&Theme, Status) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Appearance + 'a>;
 
 /// The default style of a [`TextInput`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`TextInput`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self, status: Status) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        default
+    fn default_style(&self, status: Status) -> Appearance {
+        default(self, status)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance, _status| *appearance
+    fn default_style(&self, _status: Status) -> Appearance {
+        *self
     }
 }
 

From fd7a23ca47b556ad82f2a8a9e3f849deb9f72f1b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 15:42:41 +0100
Subject: [PATCH 13/17] Use closures for `PaneGrid::style`

---
 widget/src/pane_grid.rs | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/widget/src/pane_grid.rs b/widget/src/pane_grid.rs
index bdeb42507d..beac0bd8a2 100644
--- a/widget/src/pane_grid.rs
+++ b/widget/src/pane_grid.rs
@@ -110,7 +110,7 @@ pub struct PaneGrid<
     on_click: Option<Box<dyn Fn(Pane) -> Message + 'a>>,
     on_drag: Option<Box<dyn Fn(DragEvent) -> Message + 'a>>,
     on_resize: Option<(f32, Box<dyn Fn(ResizeEvent) -> Message + 'a>)>,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 impl<'a, Message, Theme, Renderer> PaneGrid<'a, Message, Theme, Renderer>
@@ -126,7 +126,7 @@ where
         view: impl Fn(Pane, &'a T, bool) -> Content<'a, Message, Theme, Renderer>,
     ) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         let contents = if let Some((pane, pane_state)) =
             state.maximized.and_then(|pane| {
@@ -158,7 +158,7 @@ where
             on_click: None,
             on_drag: None,
             on_resize: None,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -218,8 +218,8 @@ where
     }
 
     /// Sets the style of the [`PaneGrid`].
-    pub fn style(mut self, style: fn(&Theme) -> Appearance) -> Self {
-        self.style = style;
+    pub fn style(mut self, style: impl Fn(&Theme) -> Appearance + 'a) -> Self {
+        self.style = Box::new(style);
         self
     }
 
@@ -1146,23 +1146,23 @@ pub struct Line {
 }
 
 /// The style of a [`PaneGrid`].
-pub type Style<Theme> = fn(&Theme) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme) -> Appearance + 'a>;
 
 /// The default style of a [`PaneGrid`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`PaneGrid`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        default
+    fn default_style(&self) -> Appearance {
+        default(self)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance| *appearance
+    fn default_style(&self) -> Appearance {
+        *self
     }
 }
 

From 7a5f5b0be779e5128de05fa779693fe65e81c1e6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 15:45:21 +0100
Subject: [PATCH 14/17] Use closures for `ProgressBar::style`

---
 widget/src/helpers.rs      |  6 +++---
 widget/src/progress_bar.rs | 36 ++++++++++++++++++------------------
 2 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index 2606826ddc..b23e3cb9c9 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -340,12 +340,12 @@ where
 ///   * the current value of the [`ProgressBar`].
 ///
 /// [`ProgressBar`]: crate::ProgressBar
-pub fn progress_bar<Theme>(
+pub fn progress_bar<'a, Theme>(
     range: RangeInclusive<f32>,
     value: f32,
-) -> ProgressBar<Theme>
+) -> ProgressBar<'a, Theme>
 where
-    Theme: progress_bar::DefaultStyle,
+    Theme: progress_bar::DefaultStyle + 'a,
 {
     ProgressBar::new(range, value)
 }
diff --git a/widget/src/progress_bar.rs b/widget/src/progress_bar.rs
index 7b0ea63f97..38d8da85b7 100644
--- a/widget/src/progress_bar.rs
+++ b/widget/src/progress_bar.rs
@@ -13,7 +13,7 @@ use std::ops::RangeInclusive;
 ///
 /// # Example
 /// ```no_run
-/// # type ProgressBar = iced_widget::ProgressBar;
+/// # type ProgressBar<'a> = iced_widget::ProgressBar<'a>;
 /// #
 /// let value = 50.0;
 ///
@@ -22,15 +22,15 @@ use std::ops::RangeInclusive;
 ///
 /// ![Progress bar drawn with `iced_wgpu`](https://user-images.githubusercontent.com/18618951/71662391-a316c200-2d51-11ea-9cef-52758cab85e3.png)
 #[allow(missing_debug_implementations)]
-pub struct ProgressBar<Theme = crate::Theme> {
+pub struct ProgressBar<'a, Theme = crate::Theme> {
     range: RangeInclusive<f32>,
     value: f32,
     width: Length,
     height: Option<Length>,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
-impl<Theme> ProgressBar<Theme> {
+impl<'a, Theme> ProgressBar<'a, Theme> {
     /// The default height of a [`ProgressBar`].
     pub const DEFAULT_HEIGHT: f32 = 30.0;
 
@@ -41,14 +41,14 @@ impl<Theme> ProgressBar<Theme> {
     ///   * the current value of the [`ProgressBar`]
     pub fn new(range: RangeInclusive<f32>, value: f32) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         ProgressBar {
             value: value.clamp(*range.start(), *range.end()),
             range,
             width: Length::Fill,
             height: None,
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
         }
     }
 
@@ -65,14 +65,14 @@ impl<Theme> ProgressBar<Theme> {
     }
 
     /// Sets the style of the [`ProgressBar`].
-    pub fn style(mut self, style: fn(&Theme) -> Appearance) -> Self {
-        self.style = style.into();
+    pub fn style(mut self, style: impl Fn(&Theme) -> Appearance + 'a) -> Self {
+        self.style = Box::new(style);
         self
     }
 }
 
-impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer>
-    for ProgressBar<Theme>
+impl<'a, Message, Theme, Renderer> Widget<Message, Theme, Renderer>
+    for ProgressBar<'a, Theme>
 where
     Renderer: crate::core::Renderer,
 {
@@ -143,7 +143,7 @@ where
     }
 }
 
-impl<'a, Message, Theme, Renderer> From<ProgressBar<Theme>>
+impl<'a, Message, Theme, Renderer> From<ProgressBar<'a, Theme>>
     for Element<'a, Message, Theme, Renderer>
 where
     Message: 'a,
@@ -151,7 +151,7 @@ where
     Renderer: 'a + crate::core::Renderer,
 {
     fn from(
-        progress_bar: ProgressBar<Theme>,
+        progress_bar: ProgressBar<'a, Theme>,
     ) -> Element<'a, Message, Theme, Renderer> {
         Element::new(progress_bar)
     }
@@ -169,23 +169,23 @@ pub struct Appearance {
 }
 
 /// The style of a [`ProgressBar`].
-pub type Style<Theme> = fn(&Theme) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme) -> Appearance + 'a>;
 
 /// The default style of a [`ProgressBar`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`ProgressBar`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        primary
+    fn default_style(&self) -> Appearance {
+        primary(self)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance| *appearance
+    fn default_style(&self) -> Appearance {
+        *self
     }
 }
 

From 3e190b9ee0d95d73008dab23b18117e0a21223d8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 15:47:37 +0100
Subject: [PATCH 15/17] Use closures for `TextEditor::style`

---
 widget/src/helpers.rs     |  8 ++++----
 widget/src/text_editor.rs | 25 ++++++++++++++-----------
 2 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/widget/src/helpers.rs b/widget/src/helpers.rs
index b23e3cb9c9..4863e55066 100644
--- a/widget/src/helpers.rs
+++ b/widget/src/helpers.rs
@@ -218,12 +218,12 @@ where
 /// Creates a new [`TextEditor`].
 ///
 /// [`TextEditor`]: crate::TextEditor
-pub fn text_editor<Message, Theme, Renderer>(
-    content: &text_editor::Content<Renderer>,
-) -> TextEditor<'_, core::text::highlighter::PlainText, Message, Theme, Renderer>
+pub fn text_editor<'a, Message, Theme, Renderer>(
+    content: &'a text_editor::Content<Renderer>,
+) -> TextEditor<'a, core::text::highlighter::PlainText, Message, Theme, Renderer>
 where
     Message: Clone,
-    Theme: text_editor::DefaultStyle,
+    Theme: text_editor::DefaultStyle + 'a,
     Renderer: core::text::Renderer,
 {
     TextEditor::new(content)
diff --git a/widget/src/text_editor.rs b/widget/src/text_editor.rs
index c7d62d92a5..5b8f6a1b72 100644
--- a/widget/src/text_editor.rs
+++ b/widget/src/text_editor.rs
@@ -41,7 +41,7 @@ pub struct TextEditor<
     width: Length,
     height: Length,
     padding: Padding,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
     on_edit: Option<Box<dyn Fn(Action) -> Message + 'a>>,
     highlighter_settings: Highlighter::Settings,
     highlighter_format: fn(
@@ -58,7 +58,7 @@ where
     /// Creates new [`TextEditor`] with the given [`Content`].
     pub fn new(content: &'a Content<Renderer>) -> Self
     where
-        Theme: DefaultStyle,
+        Theme: DefaultStyle + 'a,
     {
         Self {
             content,
@@ -68,7 +68,7 @@ where
             width: Length::Fill,
             height: Length::Shrink,
             padding: Padding::new(5.0),
-            style: Theme::default_style(),
+            style: Box::new(Theme::default_style),
             on_edit: None,
             highlighter_settings: (),
             highlighter_format: |_highlight, _theme| {
@@ -142,8 +142,11 @@ where
     }
 
     /// Sets the style of the [`TextEditor`].
-    pub fn style(mut self, style: fn(&Theme, Status) -> Appearance) -> Self {
-        self.style = style.into();
+    pub fn style(
+        mut self,
+        style: impl Fn(&Theme, Status) -> Appearance + 'a,
+    ) -> Self {
+        self.style = Box::new(style);
         self
     }
 }
@@ -809,23 +812,23 @@ pub struct Appearance {
 }
 
 /// The style of a [`TextEditor`].
-pub type Style<Theme> = fn(&Theme, Status) -> Appearance;
+pub type Style<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Appearance + 'a>;
 
 /// The default style of a [`TextEditor`].
 pub trait DefaultStyle {
     /// Returns the default style of a [`TextEditor`].
-    fn default_style() -> Style<Self>;
+    fn default_style(&self, status: Status) -> Appearance;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        default
+    fn default_style(&self, status: Status) -> Appearance {
+        default(self, status)
     }
 }
 
 impl DefaultStyle for Appearance {
-    fn default_style() -> Style<Self> {
-        |appearance, _status| *appearance
+    fn default_style(&self, _status: Status) -> Appearance {
+        *self
     }
 }
 

From b721fd935c6b689b1365e21dfc864e43bf3a5895 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 16:40:56 +0100
Subject: [PATCH 16/17] Use closures for `PickList::style`

---
 widget/src/combo_box.rs    | 20 +++++-----
 widget/src/overlay/menu.rs | 75 +++++++++-----------------------------
 widget/src/pick_list.rs    | 41 +++++++--------------
 3 files changed, 41 insertions(+), 95 deletions(-)

diff --git a/widget/src/combo_box.rs b/widget/src/combo_box.rs
index 956678824f..ee24d7429a 100644
--- a/widget/src/combo_box.rs
+++ b/widget/src/combo_box.rs
@@ -42,7 +42,7 @@ pub struct ComboBox<
     on_option_hovered: Option<Box<dyn Fn(T) -> Message>>,
     on_close: Option<Message>,
     on_input: Option<Box<dyn Fn(String) -> Message>>,
-    menu_style: menu::Style<Theme>,
+    menu_style: menu::Style<'a, Theme>,
     padding: Padding,
     size: Option<f32>,
 }
@@ -125,7 +125,7 @@ where
     }
 
     /// Sets the style of the [`ComboBox`].
-    pub fn style(mut self, style: impl Into<Style<Theme>>) -> Self
+    pub fn style(mut self, style: impl Into<Style<'a, Theme>>) -> Self
     where
         Theme: 'a,
     {
@@ -672,7 +672,7 @@ where
 
             self.state.sync_filtered_options(filtered_options);
 
-            let mut menu = menu::Menu::with_style(
+            let mut menu = menu::Menu::new(
                 menu,
                 &filtered_options.options,
                 hovered_option,
@@ -686,7 +686,7 @@ where
                     (self.on_selected)(x)
                 },
                 self.on_option_hovered.as_deref(),
-                self.menu_style,
+                &self.menu_style,
             )
             .width(bounds.width)
             .padding(self.padding);
@@ -765,27 +765,27 @@ where
 
 /// The style of a [`ComboBox`].
 #[allow(missing_debug_implementations)]
-pub struct Style<Theme> {
+pub struct Style<'a, Theme> {
     /// The style of the [`TextInput`] of the [`ComboBox`].
-    pub text_input: text_input::Style<'static, Theme>,
+    pub text_input: text_input::Style<'a, Theme>,
 
     /// The style of the [`Menu`] of the [`ComboBox`].
     ///
     /// [`Menu`]: menu::Menu
-    pub menu: menu::Style<Theme>,
+    pub menu: menu::Style<'a, Theme>,
 }
 
 /// The default style of a [`ComboBox`].
 pub trait DefaultStyle: Sized {
     /// Returns the default style of a [`ComboBox`].
-    fn default_style() -> Style<Self>;
+    fn default_style() -> Style<'static, Self>;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
+    fn default_style() -> Style<'static, Self> {
         Style {
             text_input: Box::new(text_input::default),
-            menu: menu::Style::DEFAULT,
+            menu: menu::DefaultStyle::default_style(),
         }
     }
 }
diff --git a/widget/src/overlay/menu.rs b/widget/src/overlay/menu.rs
index 746407c645..0364f980d4 100644
--- a/widget/src/overlay/menu.rs
+++ b/widget/src/overlay/menu.rs
@@ -38,7 +38,7 @@ pub struct Menu<
     text_line_height: text::LineHeight,
     text_shaping: text::Shaping,
     font: Option<Renderer::Font>,
-    style: Style<Theme>,
+    style: &'a Style<'a, Theme>,
 }
 
 impl<'a, T, Message, Theme, Renderer> Menu<'a, T, Message, Theme, Renderer>
@@ -48,37 +48,15 @@ where
     Theme: 'a,
     Renderer: text::Renderer + 'a,
 {
-    /// Creates a new [`Menu`] with the given [`State`], a list of options, and
-    /// the message to produced when an option is selected.
-    pub fn new(
-        state: &'a mut State,
-        options: &'a [T],
-        hovered_option: &'a mut Option<usize>,
-        on_selected: impl FnMut(T) -> Message + 'a,
-        on_option_hovered: Option<&'a dyn Fn(T) -> Message>,
-    ) -> Self
-    where
-        Theme: DefaultStyle,
-    {
-        Self::with_style(
-            state,
-            options,
-            hovered_option,
-            on_selected,
-            on_option_hovered,
-            Theme::default_style(),
-        )
-    }
-
     /// Creates a new [`Menu`] with the given [`State`], a list of options,
     /// the message to produced when an option is selected, and its [`Style`].
-    pub fn with_style(
+    pub fn new(
         state: &'a mut State,
         options: &'a [T],
         hovered_option: &'a mut Option<usize>,
         on_selected: impl FnMut(T) -> Message + 'a,
         on_option_hovered: Option<&'a dyn Fn(T) -> Message>,
-        style: Style<Theme>,
+        style: &'a Style<'a, Theme>,
     ) -> Self {
         Menu {
             state,
@@ -135,12 +113,6 @@ where
         self
     }
 
-    /// Sets the style of the [`Menu`].
-    pub fn style(mut self, style: impl Into<Style<Theme>>) -> Self {
-        self.style = style.into();
-        self
-    }
-
     /// Turns the [`Menu`] into an overlay [`Element`] at the given target
     /// position.
     ///
@@ -190,7 +162,7 @@ where
     container: Container<'a, Message, Theme, Renderer>,
     width: f32,
     target_height: f32,
-    style: Style<Theme>,
+    style: &'a Style<'a, Theme>,
 }
 
 impl<'a, Message, Theme, Renderer> Overlay<'a, Message, Theme, Renderer>
@@ -234,10 +206,10 @@ where
                     text_line_height,
                     text_shaping,
                     padding,
-                    style: style.list,
+                    style: &style.list,
                 },
                 scrollable::Direction::default(),
-                style.scrollable,
+                &style.scrollable,
             ),
             container::transparent,
         );
@@ -356,7 +328,7 @@ where
     text_line_height: text::LineHeight,
     text_shaping: text::Shaping,
     font: Option<Renderer::Font>,
-    style: fn(&Theme) -> Appearance,
+    style: &'a dyn Fn(&Theme) -> Appearance,
 }
 
 impl<'a, T, Message, Theme, Renderer> Widget<Message, Theme, Renderer>
@@ -599,39 +571,26 @@ pub struct Appearance {
 }
 
 /// The style of the different parts of a [`Menu`].
-#[derive(Debug, PartialEq, Eq)]
-pub struct Style<Theme> {
+#[allow(missing_debug_implementations)]
+pub struct Style<'a, Theme> {
     /// The style of the list of the [`Menu`].
-    pub list: fn(&Theme) -> Appearance,
+    pub list: Box<dyn Fn(&Theme) -> Appearance + 'a>,
     /// The style of the [`Scrollable`] of the [`Menu`].
-    pub scrollable: fn(&Theme, scrollable::Status) -> scrollable::Appearance,
+    pub scrollable: scrollable::Style<'a, Theme>,
 }
 
-impl Style<Theme> {
-    /// The default style of a [`Menu`] with the built-in [`Theme`].
-    pub const DEFAULT: Self = Self {
-        list: default,
-        scrollable: scrollable::default,
-    };
-}
-
-impl<Theme> Clone for Style<Theme> {
-    fn clone(&self) -> Self {
-        *self
-    }
-}
-
-impl<Theme> Copy for Style<Theme> {}
-
 /// The default style of a [`Menu`].
 pub trait DefaultStyle: Sized {
     /// Returns the default style of a [`Menu`].
-    fn default_style() -> Style<Self>;
+    fn default_style() -> Style<'static, Self>;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        Style::<Theme>::DEFAULT
+    fn default_style() -> Style<'static, Self> {
+        Style {
+            list: Box::new(default),
+            scrollable: Box::new(scrollable::default),
+        }
     }
 }
 
diff --git a/widget/src/pick_list.rs b/widget/src/pick_list.rs
index beb4e0c1f2..52d5439705 100644
--- a/widget/src/pick_list.rs
+++ b/widget/src/pick_list.rs
@@ -47,7 +47,7 @@ pub struct PickList<
     text_shaping: text::Shaping,
     font: Option<Renderer::Font>,
     handle: Handle<Renderer::Font>,
-    style: Style<Theme>,
+    style: Style<'a, Theme>,
 }
 
 impl<'a, T, L, V, Message, Theme, Renderer>
@@ -151,7 +151,7 @@ where
     }
 
     /// Sets the style of the [`PickList`].
-    pub fn style(mut self, style: impl Into<Style<Theme>>) -> Self {
+    pub fn style(mut self, style: impl Into<Style<'a, Theme>>) -> Self {
         self.style = style.into();
         self
     }
@@ -529,7 +529,7 @@ where
 
             let on_select = &self.on_select;
 
-            let mut menu = Menu::with_style(
+            let mut menu = Menu::new(
                 &mut state.menu,
                 self.options.borrow(),
                 &mut state.hovered_option,
@@ -539,7 +539,7 @@ where
                     (on_select)(option)
                 },
                 None,
-                self.style.menu,
+                &self.style.menu,
             )
             .width(bounds.width)
             .padding(self.padding)
@@ -676,40 +676,27 @@ pub struct Appearance {
 }
 
 /// The styles of the different parts of a [`PickList`].
-#[derive(Debug, PartialEq, Eq)]
-pub struct Style<Theme> {
+#[allow(missing_debug_implementations)]
+pub struct Style<'a, Theme> {
     /// The style of the [`PickList`] itself.
-    pub field: fn(&Theme, Status) -> Appearance,
+    pub field: Box<dyn Fn(&Theme, Status) -> Appearance + 'a>,
 
     /// The style of the [`Menu`] of the pick list.
-    pub menu: menu::Style<Theme>,
+    pub menu: menu::Style<'a, Theme>,
 }
 
-impl Style<Theme> {
-    /// The default style of a [`PickList`] with the built-in [`Theme`].
-    pub const DEFAULT: Self = Self {
-        field: default,
-        menu: menu::Style::<Theme>::DEFAULT,
-    };
-}
-
-impl<Theme> Clone for Style<Theme> {
-    fn clone(&self) -> Self {
-        *self
-    }
-}
-
-impl<Theme> Copy for Style<Theme> {}
-
 /// The default style of a [`PickList`].
 pub trait DefaultStyle: Sized {
     /// Returns the default style of a [`PickList`].
-    fn default_style() -> Style<Self>;
+    fn default_style() -> Style<'static, Self>;
 }
 
 impl DefaultStyle for Theme {
-    fn default_style() -> Style<Self> {
-        Style::<Self>::DEFAULT
+    fn default_style() -> Style<'static, Self> {
+        Style {
+            field: Box::new(default),
+            menu: menu::DefaultStyle::default_style(),
+        }
     }
 }
 

From 98621aa344a7a0e1b23f320d21a4687af559998e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?= <hector@hecrj.dev>
Date: Tue, 12 Mar 2024 16:52:53 +0100
Subject: [PATCH 17/17] Remove `themer` use from `gradient` example :tada:

---
 examples/gradient/src/main.rs | 20 ++++++++++----------
 widget/src/container.rs       | 24 +++++++++++++++++++++---
 2 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/examples/gradient/src/main.rs b/examples/gradient/src/main.rs
index 4a8b2fa54e..8ed4c830cc 100644
--- a/examples/gradient/src/main.rs
+++ b/examples/gradient/src/main.rs
@@ -1,6 +1,6 @@
 use iced::application;
 use iced::widget::{
-    checkbox, column, container, horizontal_space, row, slider, text, themer,
+    checkbox, column, container, horizontal_space, row, slider, text,
 };
 use iced::{gradient, window};
 use iced::{
@@ -70,16 +70,16 @@ impl Sandbox for Gradient {
             transparent,
         } = *self;
 
-        let gradient = gradient::Linear::new(angle)
-            .add_stop(0.0, start)
-            .add_stop(1.0, end);
+        let gradient_box = container(horizontal_space())
+            .style(move |_theme, _status| {
+                let gradient = gradient::Linear::new(angle)
+                    .add_stop(0.0, start)
+                    .add_stop(1.0, end);
 
-        let gradient_box = themer(
-            gradient,
-            container(horizontal_space())
-                .width(Length::Fill)
-                .height(Length::Fill),
-        );
+                gradient.into()
+            })
+            .width(Length::Fill)
+            .height(Length::Fill);
 
         let angle_picker = row![
             text("Angle").width(64),
diff --git a/widget/src/container.rs b/widget/src/container.rs
index f51ff8789d..7c133588ed 100644
--- a/widget/src/container.rs
+++ b/widget/src/container.rs
@@ -539,6 +539,24 @@ impl Appearance {
     }
 }
 
+impl From<Color> for Appearance {
+    fn from(color: Color) -> Self {
+        Self::default().with_background(color)
+    }
+}
+
+impl From<Gradient> for Appearance {
+    fn from(gradient: Gradient) -> Self {
+        Self::default().with_background(gradient)
+    }
+}
+
+impl From<gradient::Linear> for Appearance {
+    fn from(gradient: gradient::Linear) -> Self {
+        Self::default().with_background(gradient)
+    }
+}
+
 /// The possible status of a [`Container`].
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum Status {
@@ -571,19 +589,19 @@ impl DefaultStyle for Appearance {
 
 impl DefaultStyle for Color {
     fn default_style(&self, _status: Status) -> Appearance {
-        Appearance::default().with_background(*self)
+        Appearance::from(*self)
     }
 }
 
 impl DefaultStyle for Gradient {
     fn default_style(&self, _status: Status) -> Appearance {
-        Appearance::default().with_background(*self)
+        Appearance::from(*self)
     }
 }
 
 impl DefaultStyle for gradient::Linear {
     fn default_style(&self, _status: Status) -> Appearance {
-        Appearance::default().with_background(*self)
+        Appearance::from(*self)
     }
 }