Add `Renderer::Defaults` and style inheritance

18 files changed, 69 insertions, 70 deletions

diff --git a/native/src/element.rs b/native/src/element.rs
index 63d2de0c..9b5adb9c 100644
--- a/native/src/element.rs
+++ b/native/src/element.rs
@@ -235,10 +235,12 @@ where
     pub fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {
-        self.widget.draw(renderer, layout, cursor_position)
+        self.widget
+            .draw(renderer, defaults, layout, cursor_position)
     }
 
     pub(crate) fn hash_layout(&self, state: &mut Hasher) {
@@ -316,10 +318,12 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {
-        self.widget.draw(renderer, layout, cursor_position)
+        self.widget
+            .draw(renderer, defaults, layout, cursor_position)
     }
 
     fn hash_layout(&self, state: &mut Hasher) {
@@ -384,10 +388,12 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {
         renderer.explain(
+            defaults,
             self.element.widget.as_ref(),
             layout,
             cursor_position,
diff --git a/native/src/renderer.rs b/native/src/renderer.rs
index 023dd42b..90cec6c8 100644
--- a/native/src/renderer.rs
+++ b/native/src/renderer.rs
@@ -44,6 +44,8 @@ pub trait Renderer: Sized {
     /// [`Renderer`]: trait.Renderer.html
     type Output;
 
+    type Defaults: Default;
+
     /// Lays out the elements of a user interface.
     ///
     /// You should override this if you need to perform any operations before or
diff --git a/native/src/renderer/debugger.rs b/native/src/renderer/debugger.rs
index 4cc50661..30f3d9a0 100644
--- a/native/src/renderer/debugger.rs
+++ b/native/src/renderer/debugger.rs
@@ -17,6 +17,7 @@ pub trait Debugger: super::Renderer {
     /// [`Element::explain`]: struct.Element.html#method.explain
     fn explain<Message>(
         &mut self,
+        defaults: &Self::Defaults,
         widget: &dyn Widget<Message, Self>,
         layout: Layout<'_>,
         cursor_position: Point,
diff --git a/native/src/renderer/null.rs b/native/src/renderer/null.rs
index 1be669c2..56d7e472 100644
--- a/native/src/renderer/null.rs
+++ b/native/src/renderer/null.rs
@@ -5,16 +5,26 @@ use crate::{
 };
 
 /// A renderer that does nothing.
+///
+/// It can be useful if you are writing tests!
 #[derive(Debug, Clone, Copy)]
 pub struct Null;
 
+impl Null {
+    pub fn new() -> Null {
+        Null
+    }
+}
+
 impl Renderer for Null {
     type Output = ();
+    type Defaults = ();
 }
 
 impl column::Renderer for Null {
     fn draw<Message>(
         &mut self,
+        _defaults: &Self::Defaults,
         _content: &[Element<'_, Message, Self>],
         _layout: Layout<'_>,
         _cursor_position: Point,
@@ -25,6 +35,7 @@ impl column::Renderer for Null {
 impl row::Renderer for Null {
     fn draw<Message>(
         &mut self,
+        _defaults: &Self::Defaults,
         _content: &[Element<'_, Message, Self>],
         _layout: Layout<'_>,
         _cursor_position: Point,
@@ -49,6 +60,7 @@ impl text::Renderer for Null {
 
     fn draw(
         &mut self,
+        _defaults: &Self::Defaults,
         _bounds: Rectangle,
         _content: &str,
         _size: u16,
@@ -119,13 +131,16 @@ impl text_input::Renderer for Null {
 impl button::Renderer for Null {
     type Style = ();
 
-    fn draw(
+    fn draw<Message>(
         &mut self,
+        _defaults: &Self::Defaults,
         _bounds: Rectangle,
         _cursor_position: Point,
+        _is_disabled: bool,
         _is_pressed: bool,
         _style: &Self::Style,
-        _content: Self::Output,
+        _content: &Element<'_, Message, Self>,
+        _content_layout: Layout<'_>,
     ) -> Self::Output {
     }
 }
diff --git a/native/src/user_interface.rs b/native/src/user_interface.rs
index 07b936a9..970bf0c1 100644
--- a/native/src/user_interface.rs
+++ b/native/src/user_interface.rs
@@ -43,24 +43,7 @@ where
     /// use iced_wgpu::Renderer;
     ///
     /// # mod iced_wgpu {
-    /// #     pub struct Renderer;
-    /// #
-    /// #     impl Renderer {
-    /// #         pub fn new() -> Self { Renderer }
-    /// #     }
-    /// #
-    /// #     impl iced_native::Renderer for Renderer { type Output = (); }
-    /// #
-    /// #     impl iced_native::column::Renderer for Renderer {
-    /// #         fn draw<Message>(
-    /// #             &mut self,
-    /// #             _children: &[iced_native::Element<'_, Message, Self>],
-    /// #             _layout: iced_native::Layout<'_>,
-    /// #             _cursor_position: iced_native::Point,
-    /// #         ) -> Self::Output {
-    /// #             ()
-    /// #         }
-    /// #     }
+    /// #     pub use iced_native::renderer::Null as Renderer;
     /// # }
     /// #
     /// # use iced_native::Column;
@@ -139,24 +122,7 @@ where
     /// use iced_wgpu::Renderer;
     ///
     /// # mod iced_wgpu {
-    /// #     pub struct Renderer;
-    /// #
-    /// #     impl Renderer {
-    /// #         pub fn new() -> Self { Renderer }
-    /// #     }
-    /// #
-    /// #     impl iced_native::Renderer for Renderer { type Output = (); }
-    /// #
-    /// #     impl iced_native::column::Renderer for Renderer {
-    /// #         fn draw<Message>(
-    /// #             &mut self,
-    /// #             _children: &[iced_native::Element<'_, Message, Self>],
-    /// #             _layout: iced_native::Layout<'_>,
-    /// #             _cursor_position: iced_native::Point,
-    /// #         ) -> Self::Output {
-    /// #             ()
-    /// #         }
-    /// #     }
+    /// #     pub use iced_native::renderer::Null as Renderer;
     /// # }
     /// #
     /// # use iced_native::Column;
@@ -241,24 +207,7 @@ where
     /// use iced_wgpu::Renderer;
     ///
     /// # mod iced_wgpu {
-    /// #     pub struct Renderer;
-    /// #
-    /// #     impl Renderer {
-    /// #         pub fn new() -> Self { Renderer }
-    /// #     }
-    /// #
-    /// #     impl iced_native::Renderer for Renderer { type Output = (); }
-    /// #
-    /// #     impl iced_native::column::Renderer for Renderer {
-    /// #         fn draw<Message>(
-    /// #             &mut self,
-    /// #             _children: &[iced_native::Element<'_, Message, Self>],
-    /// #             _layout: iced_native::Layout<'_>,
-    /// #             _cursor_position: iced_native::Point,
-    /// #         ) -> Self::Output {
-    /// #             ()
-    /// #         }
-    /// #     }
+    /// #     pub use iced_native::renderer::Null as Renderer;
     /// # }
     /// #
     /// # use iced_native::Column;
@@ -304,6 +253,7 @@ where
     pub fn draw(&self, renderer: &mut Renderer) -> Renderer::Output {
         self.root.widget.draw(
             renderer,
+            &Renderer::Defaults::default(),
             Layout::new(&self.layout),
             self.cursor_position,
         )
diff --git a/native/src/widget.rs b/native/src/widget.rs
index 26889280..4aa7e7f0 100644
--- a/native/src/widget.rs
+++ b/native/src/widget.rs
@@ -101,6 +101,7 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output;
diff --git a/native/src/widget/button.rs b/native/src/widget/button.rs
index 4a7187da..75ef2693 100644
--- a/native/src/widget/button.rs
+++ b/native/src/widget/button.rs
@@ -216,21 +216,19 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {
-        let content = self.content.draw(
-            renderer,
-            layout.children().next().unwrap(),
-            cursor_position,
-        );
-
         renderer.draw(
+            defaults,
             layout.bounds(),
             cursor_position,
+            self.on_press.is_none(),
             self.state.is_pressed,
             &self.style,
-            content,
+            &self.content,
+            layout.children().next().unwrap(),
         )
     }
 
@@ -253,13 +251,16 @@ pub trait Renderer: crate::Renderer + Sized {
     /// Draws a [`Button`].
     ///
     /// [`Button`]: struct.Button.html
-    fn draw(
+    fn draw<Message>(
         &mut self,
+        defaults: &Self::Defaults,
         bounds: Rectangle,
         cursor_position: Point,
+        is_disabled: bool,
         is_pressed: bool,
         style: &Self::Style,
-        content: Self::Output,
+        content: &Element<'_, Message, Self>,
+        content_layout: Layout<'_>,
     ) -> Self::Output;
 }
 
diff --git a/native/src/widget/checkbox.rs b/native/src/widget/checkbox.rs
index 0dcac712..87a7f629 100644
--- a/native/src/widget/checkbox.rs
+++ b/native/src/widget/checkbox.rs
@@ -134,6 +134,7 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {
@@ -146,6 +147,7 @@ where
 
         let label = text::Renderer::draw(
             renderer,
+            defaults,
             label_layout.bounds(),
             &self.label,
             text::Renderer::default_size(renderer),
diff --git a/native/src/widget/column.rs b/native/src/widget/column.rs
index 4b5d631c..3418d4b0 100644
--- a/native/src/widget/column.rs
+++ b/native/src/widget/column.rs
@@ -173,10 +173,11 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {
-        renderer.draw(&self.children, layout, cursor_position)
+        renderer.draw(defaults, &self.children, layout, cursor_position)
     }
 
     fn hash_layout(&self, state: &mut Hasher) {
@@ -213,6 +214,7 @@ pub trait Renderer: crate::Renderer + Sized {
     /// [`Layout`]: ../layout/struct.Layout.html
     fn draw<Message>(
         &mut self,
+        defaults: &Self::Defaults,
         content: &[Element<'_, Message, Self>],
         layout: Layout<'_>,
         cursor_position: Point,
diff --git a/native/src/widget/container.rs b/native/src/widget/container.rs
index 74f0e0ef..93804c99 100644
--- a/native/src/widget/container.rs
+++ b/native/src/widget/container.rs
@@ -147,11 +147,13 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {
         self.content.draw(
             renderer,
+            defaults,
             layout.children().next().unwrap(),
             cursor_position,
         )
diff --git a/native/src/widget/image.rs b/native/src/widget/image.rs
index 20375822..1efe4570 100644
--- a/native/src/widget/image.rs
+++ b/native/src/widget/image.rs
@@ -95,6 +95,7 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        _defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         _cursor_position: Point,
     ) -> Renderer::Output {
diff --git a/native/src/widget/radio.rs b/native/src/widget/radio.rs
index a9995b86..6ac00770 100644
--- a/native/src/widget/radio.rs
+++ b/native/src/widget/radio.rs
@@ -131,6 +131,7 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {
@@ -143,6 +144,7 @@ where
 
         let label = text::Renderer::draw(
             renderer,
+            defaults,
             label_layout.bounds(),
             &self.label,
             text::Renderer::default_size(renderer),
diff --git a/native/src/widget/row.rs b/native/src/widget/row.rs
index 3de65deb..76cca3d0 100644
--- a/native/src/widget/row.rs
+++ b/native/src/widget/row.rs
@@ -174,10 +174,11 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {
-        renderer.draw(&self.children, layout, cursor_position)
+        renderer.draw(defaults, &self.children, layout, cursor_position)
     }
 
     fn hash_layout(&self, state: &mut Hasher) {
@@ -215,6 +216,7 @@ pub trait Renderer: crate::Renderer + Sized {
     /// [`Layout`]: ../layout/struct.Layout.html
     fn draw<Message>(
         &mut self,
+        defaults: &Self::Defaults,
         children: &[Element<'_, Message, Self>],
         layout: Layout<'_>,
         cursor_position: Point,
diff --git a/native/src/widget/scrollable.rs b/native/src/widget/scrollable.rs
index 9fa602d5..9df09b14 100644
--- a/native/src/widget/scrollable.rs
+++ b/native/src/widget/scrollable.rs
@@ -255,6 +255,7 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {
@@ -277,7 +278,12 @@ where
                 Point::new(cursor_position.x, -1.0)
             };
 
-            self.content.draw(renderer, content_layout, cursor_position)
+            self.content.draw(
+                renderer,
+                defaults,
+                content_layout,
+                cursor_position,
+            )
         };
 
         self::Renderer::draw(
diff --git a/native/src/widget/slider.rs b/native/src/widget/slider.rs
index f446f7e8..ea66a347 100644
--- a/native/src/widget/slider.rs
+++ b/native/src/widget/slider.rs
@@ -178,6 +178,7 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        _defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {
diff --git a/native/src/widget/svg.rs b/native/src/widget/svg.rs
index 9580f195..f6202f72 100644
--- a/native/src/widget/svg.rs
+++ b/native/src/widget/svg.rs
@@ -91,6 +91,7 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        _defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         _cursor_position: Point,
     ) -> Renderer::Output {
diff --git a/native/src/widget/text.rs b/native/src/widget/text.rs
index cf9c9565..3a3db3cd 100644
--- a/native/src/widget/text.rs
+++ b/native/src/widget/text.rs
@@ -146,10 +146,12 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         _cursor_position: Point,
     ) -> Renderer::Output {
         renderer.draw(
+            defaults,
             layout.bounds(),
             &self.content,
             self.size.unwrap_or(renderer.default_size()),
@@ -209,6 +211,7 @@ pub trait Renderer: crate::Renderer {
     /// [`VerticalAlignment`]: enum.VerticalAlignment.html
     fn draw(
         &mut self,
+        defaults: &Self::Defaults,
         bounds: Rectangle,
         content: &str,
         size: u16,
diff --git a/native/src/widget/text_input.rs b/native/src/widget/text_input.rs
index 1d1c32a2..e2114f00 100644
--- a/native/src/widget/text_input.rs
+++ b/native/src/widget/text_input.rs
@@ -343,6 +343,7 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer,
+        _defaults: &Renderer::Defaults,
         layout: Layout<'_>,
         cursor_position: Point,
     ) -> Renderer::Output {