Implement theme styling for Canvas

examples/bezier_tool/src/main.rs

@@ -71,7 +71,7 @@ mod bezier {
     use iced::{
         canvas::event::{self, Event},
         canvas::{self, Canvas, Cursor, Frame, Geometry, Path, Stroke},
-        mouse, Element, Length, Point, Rectangle,
+        mouse, Element, Length, Point, Rectangle, Theme,
     };
 
     #[derive(Default)]
@@ -158,7 +158,12 @@ mod bezier {
             }
         }
 
-        fn draw(&self, bounds: Rectangle, cursor: Cursor) -> Vec<Geometry> {
+        fn draw(
+            &self,
+            _theme: &Theme,
+            bounds: Rectangle,
+            cursor: Cursor,
+        ) -> Vec<Geometry> {
             let content =
                 self.state.cache.draw(bounds.size(), |frame: &mut Frame| {
                     Curve::draw_all(self.curves, frame);

examples/clock/src/main.rs

@@ -81,7 +81,12 @@ impl Application for Clock {
 }
 
 impl<Message> canvas::Program<Message> for Clock {
-    fn draw(&self, bounds: Rectangle, _cursor: Cursor) -> Vec<Geometry> {
+    fn draw(
+        &self,
+        _theme: &Theme,
+        bounds: Rectangle,
+        _cursor: Cursor,
+    ) -> Vec<Geometry> {
         let clock = self.clock.draw(bounds.size(), |frame| {
             let center = frame.center();
             let radius = frame.width().min(frame.height()) / 2.0;

examples/color_palette/src/main.rs

@@ -236,7 +236,12 @@ impl Theme {
 }
 
 impl<Message> canvas::Program<Message> for Theme {
-    fn draw(&self, bounds: Rectangle, _cursor: Cursor) -> Vec<Geometry> {
+    fn draw(
+        &self,
+        _theme: &iced::Theme,
+        bounds: Rectangle,
+        _cursor: Cursor,
+    ) -> Vec<Geometry> {
         let theme = self.canvas_cache.draw(bounds.size(), |frame| {
             self.draw(frame);
         });

examples/game_of_life/src/main.rs

@@ -163,7 +163,7 @@ mod grid {
         alignment,
         canvas::event::{self, Event},
         canvas::{self, Cache, Canvas, Cursor, Frame, Geometry, Path, Text},
-        mouse, Color, Element, Length, Point, Rectangle, Size, Vector,
+        mouse, Color, Element, Length, Point, Rectangle, Size, Theme, Vector,
     };
     use rustc_hash::{FxHashMap, FxHashSet};
     use std::future::Future;
@@ -445,7 +445,12 @@ mod grid {
             }
         }
 
-        fn draw(&self, bounds: Rectangle, cursor: Cursor) -> Vec<Geometry> {
+        fn draw(
+            &self,
+            _theme: &Theme,
+            bounds: Rectangle,
+            cursor: Cursor,
+        ) -> Vec<Geometry> {
             let center = Vector::new(bounds.width / 2.0, bounds.height / 2.0);
 
             let life = self.life_cache.draw(bounds.size(), |frame| {

examples/pure/game_of_life/src/main.rs

@@ -3,6 +3,8 @@
 mod preset;
 
 use grid::Grid;
+use preset::Preset;
+
 use iced::executor;
 use iced::pure::{
     button, checkbox, column, container, pick_list, row, slider, text,
@@ -12,7 +14,6 @@ use iced::theme::{self, Theme};
 use iced::time;
 use iced::window;
 use iced::{Alignment, Command, Length, Settings, Subscription};
-use preset::Preset;
 use std::time::{Duration, Instant};
 
 pub fn main() -> iced::Result {
@@ -216,7 +217,7 @@ mod grid {
     };
     use iced::pure::Element;
     use iced::{
-        alignment, mouse, Color, Length, Point, Rectangle, Size, Vector,
+        alignment, mouse, Color, Length, Point, Rectangle, Size, Theme, Vector,
     };
     use rustc_hash::{FxHashMap, FxHashSet};
     use std::future::Future;
@@ -525,6 +526,7 @@ mod grid {
         fn draw(
             &self,
             _interaction: &Interaction,
+            _theme: &Theme,
             bounds: Rectangle,
             cursor: Cursor,
         ) -> Vec<Geometry> {

examples/solar_system/src/main.rs

@@ -135,6 +135,7 @@ impl State {
 impl<Message> canvas::Program<Message> for State {
     fn draw(
         &self,
+        _theme: &Theme,
         bounds: Rectangle,
         _cursor: Cursor,
     ) -> Vec<canvas::Geometry> {

graphics/src/widget/canvas.rs

@@ -62,10 +62,10 @@ use std::marker::PhantomData;
 /// ```no_run
 /// # mod iced {
 /// #     pub use iced_graphics::canvas;
-/// #     pub use iced_native::{Color, Rectangle};
+/// #     pub use iced_native::{Color, Rectangle, Theme};
 /// # }
 /// use iced::canvas::{self, Canvas, Cursor, Fill, Frame, Geometry, Path, Program};
-/// use iced::{Color, Rectangle};
+/// use iced::{Color, Rectangle, Theme};
 ///
 /// // First, we define the data we need for drawing
 /// #[derive(Debug)]
@@ -75,7 +75,7 @@ use std::marker::PhantomData;
 ///
 /// // Then, we implement the `Program` trait
 /// impl Program<()> for Circle {
-///     fn draw(&self, bounds: Rectangle, _cursor: Cursor) -> Vec<Geometry>{
+///     fn draw(&self, _theme: &Theme, bounds: Rectangle, _cursor: Cursor) -> Vec<Geometry>{
 ///         // We prepare a new `Frame`
 ///         let mut frame = Frame::new(bounds.size());
 ///
@@ -94,14 +94,21 @@ use std::marker::PhantomData;
 /// let canvas = Canvas::new(Circle { radius: 50.0 });
 /// ```
 #[derive(Debug)]
-pub struct Canvas<Message, P: Program<Message>> {
+pub struct Canvas<Message, Theme, P>
+where
+    P: Program<Message, Theme>,
+{
     width: Length,
     height: Length,
     program: P,
     message_: PhantomData<Message>,
+    theme_: PhantomData<Theme>,
 }
 
-impl<Message, P: Program<Message>> Canvas<Message, P> {
+impl<Message, Theme, P> Canvas<Message, Theme, P>
+where
+    P: Program<Message, Theme>,
+{
     const DEFAULT_SIZE: u16 = 100;
 
     /// Creates a new [`Canvas`].
@@ -111,6 +118,7 @@ impl<Message, P: Program<Message>> Canvas<Message, P> {
             height: Length::Units(Self::DEFAULT_SIZE),
             program,
             message_: PhantomData,
+            theme_: PhantomData,
         }
     }
 
@@ -127,9 +135,9 @@ impl<Message, P: Program<Message>> Canvas<Message, P> {
     }
 }
 
-impl<Message, P, B, T> Widget<Message, Renderer<B, T>> for Canvas<Message, P>
+impl<Message, P, B, T> Widget<Message, Renderer<B, T>> for Canvas<Message, T, P>
 where
-    P: Program<Message>,
+    P: Program<Message, T>,
     B: Backend,
 {
     fn width(&self) -> Length {
@@ -204,7 +212,7 @@ where
     fn draw(
         &self,
         renderer: &mut Renderer<B, T>,
-        _theme: &T,
+        theme: &T,
         _style: &renderer::Style,
         layout: Layout<'_>,
         cursor_position: Point,
@@ -225,7 +233,7 @@ where
             renderer.draw_primitive(Primitive::Group {
                 primitives: self
                     .program
-                    .draw(bounds, cursor)
+                    .draw(theme, bounds, cursor)
                     .into_iter()
                     .map(Geometry::into_primitive)
                     .collect(),
@@ -234,15 +242,16 @@ where
     }
 }
 
-impl<'a, Message, P, B, T> From<Canvas<Message, P>>
+impl<'a, Message, P, B, T> From<Canvas<Message, T, P>>
     for Element<'a, Message, Renderer<B, T>>
 where
     Message: 'static,
-    P: Program<Message> + 'a,
+    P: Program<Message, T> + 'a,
     B: Backend,
+    T: 'a,
 {
     fn from(
-        canvas: Canvas<Message, P>,
+        canvas: Canvas<Message, T, P>,
     ) -> Element<'a, Message, Renderer<B, T>> {
         Element::new(canvas)
     }

graphics/src/widget/canvas/program.rs

@@ -1,6 +1,8 @@
 use crate::canvas::event::{self, Event};
 use crate::canvas::{Cursor, Geometry};
-use iced_native::{mouse, Rectangle};
+
+use iced_native::mouse;
+use iced_native::Rectangle;
 
 /// The state and logic of a [`Canvas`].
 ///
@@ -8,7 +10,7 @@ use iced_native::{mouse, Rectangle};
 /// application.
 ///
 /// [`Canvas`]: crate::widget::Canvas
-pub trait Program<Message> {
+pub trait Program<Message, Theme = iced_native::Theme> {
     /// Updates the state of the [`Program`].
     ///
     /// When a [`Program`] is used in a [`Canvas`], the runtime will call this
@@ -36,7 +38,12 @@ pub trait Program<Message> {
     ///
     /// [`Frame`]: crate::widget::canvas::Frame
     /// [`Cache`]: crate::widget::canvas::Cache
-    fn draw(&self, bounds: Rectangle, cursor: Cursor) -> Vec<Geometry>;
+    fn draw(
+        &self,
+        theme: &Theme,
+        bounds: Rectangle,
+        cursor: Cursor,
+    ) -> Vec<Geometry>;
 
     /// Returns the current mouse interaction of the [`Program`].
     ///
@@ -53,9 +60,9 @@ pub trait Program<Message> {
     }
 }
 
-impl<T, Message> Program<Message> for &mut T
+impl<T, Message, Theme> Program<Message, Theme> for &mut T
 where
-    T: Program<Message>,
+    T: Program<Message, Theme>,
 {
     fn update(
         &mut self,
@@ -66,8 +73,13 @@ where
         T::update(self, event, bounds, cursor)
     }
 
-    fn draw(&self, bounds: Rectangle, cursor: Cursor) -> Vec<Geometry> {
-        T::draw(self, bounds, cursor)
+    fn draw(
+        &self,
+        theme: &Theme,
+        bounds: Rectangle,
+        cursor: Cursor,
+    ) -> Vec<Geometry> {
+        T::draw(self, theme, bounds, cursor)
     }
 
     fn mouse_interaction(

graphics/src/widget/pure/canvas.rs

@@ -30,10 +30,10 @@ use std::marker::PhantomData;
 /// #     pub mod pure {
 /// #         pub use iced_graphics::pure::canvas;
 /// #     }
-/// #     pub use iced_native::{Color, Rectangle};
+/// #     pub use iced_native::{Color, Rectangle, Theme};
 /// # }
 /// use iced::pure::canvas::{self, Canvas, Cursor, Fill, Frame, Geometry, Path, Program};
-/// use iced::{Color, Rectangle};
+/// use iced::{Color, Rectangle, Theme};
 ///
 /// // First, we define the data we need for drawing
 /// #[derive(Debug)]
@@ -45,7 +45,7 @@ use std::marker::PhantomData;
 /// impl Program<()> for Circle {
 ///     type State = ();
 ///
-///     fn draw(&self, _state: &(), bounds: Rectangle, _cursor: Cursor) -> Vec<Geometry>{
+///     fn draw(&self, _state: &(), _theme: &Theme, bounds: Rectangle, _cursor: Cursor) -> Vec<Geometry>{
 ///         // We prepare a new `Frame`
 ///         let mut frame = Frame::new(bounds.size());
 ///
@@ -64,19 +64,20 @@ use std::marker::PhantomData;
 /// let canvas = Canvas::new(Circle { radius: 50.0 });
 /// ```
 #[derive(Debug)]
-pub struct Canvas<Message, P>
+pub struct Canvas<Message, Theme, P>
 where
-    P: Program<Message>,
+    P: Program<Message, Theme>,
 {
     width: Length,
     height: Length,
     program: P,
     message_: PhantomData<Message>,
+    theme_: PhantomData<Theme>,
 }
 
-impl<Message, P> Canvas<Message, P>
+impl<Message, Theme, P> Canvas<Message, Theme, P>
 where
-    P: Program<Message>,
+    P: Program<Message, Theme>,
 {
     const DEFAULT_SIZE: u16 = 100;
 
@@ -87,6 +88,7 @@ where
             height: Length::Units(Self::DEFAULT_SIZE),
             program,
             message_: PhantomData,
+            theme_: PhantomData,
         }
     }
 
@@ -103,9 +105,9 @@ where
     }
 }
 
-impl<Message, P, B, T> Widget<Message, Renderer<B, T>> for Canvas<Message, P>
+impl<Message, P, B, T> Widget<Message, Renderer<B, T>> for Canvas<Message, T, P>
 where
-    P: Program<Message>,
+    P: Program<Message, T>,
     B: Backend,
 {
     fn tag(&self) -> tree::Tag {
@@ -194,7 +196,7 @@ where
         &self,
         tree: &Tree,
         renderer: &mut Renderer<B, T>,
-        _theme: &T,
+        theme: &T,
         _style: &renderer::Style,
         layout: Layout<'_>,
         cursor_position: Point,
@@ -216,7 +218,7 @@ where
             renderer.draw_primitive(Primitive::Group {
                 primitives: self
                     .program
-                    .draw(state, bounds, cursor)
+                    .draw(state, theme, bounds, cursor)
                     .into_iter()
                     .map(Geometry::into_primitive)
                     .collect(),
@@ -225,15 +227,16 @@ where
     }
 }
 
-impl<'a, Message, P, B, T> From<Canvas<Message, P>>
+impl<'a, Message, P, B, T> From<Canvas<Message, T, P>>
     for Element<'a, Message, Renderer<B, T>>
 where
     Message: 'a,
-    P: Program<Message> + 'a,
+    P: Program<Message, T> + 'a,
     B: Backend,
+    T: 'a,
 {
     fn from(
-        canvas: Canvas<Message, P>,
+        canvas: Canvas<Message, T, P>,
     ) -> Element<'a, Message, Renderer<B, T>> {
         Element::new(canvas)
     }

graphics/src/widget/pure/canvas/program.rs

@@ -9,7 +9,7 @@ use crate::Rectangle;
 /// application.
 ///
 /// [`Canvas`]: crate::widget::Canvas
-pub trait Program<Message> {
+pub trait Program<Message, Theme = iced_native::Theme> {
     /// The internal state mutated by the [`Program`].
     type State: Default + 'static;
 
@@ -44,6 +44,7 @@ pub trait Program<Message> {
     fn draw(
         &self,
         state: &Self::State,
+        theme: &Theme,
         bounds: Rectangle,
         cursor: Cursor,
     ) -> Vec<Geometry>;
@@ -64,9 +65,9 @@ pub trait Program<Message> {
     }
 }
 
-impl<Message, T> Program<Message> for &T
+impl<Message, Theme, T> Program<Message, Theme> for &T
 where
-    T: Program<Message>,
+    T: Program<Message, Theme>,
 {
     type State = T::State;
 
@@ -83,10 +84,11 @@ where
     fn draw(
         &self,
         state: &Self::State,
+        theme: &Theme,
         bounds: Rectangle,
         cursor: Cursor,
     ) -> Vec<Geometry> {
-        T::draw(self, state, bounds, cursor)
+        T::draw(self, state, theme, bounds, cursor)
     }
 
     fn mouse_interaction(