Add styling support for `ComboBox` and `Menu`

11 files changed, 206 insertions, 41 deletions

diff --git a/glow/src/widget/combo_box.rs b/glow/src/widget/combo_box.rs
index bb3931ef..bfface29 100644
--- a/glow/src/widget/combo_box.rs
+++ b/glow/src/widget/combo_box.rs
@@ -1,3 +1,8 @@
 pub use iced_native::combo_box::State;
 
-pub type ComboBox<'a, T, Message> = iced_native::ComboBox<'a, T, Message>;
+pub use iced_graphics::combo_box::{Style, StyleSheet};
+pub use iced_graphics::overlay::menu::Style as Menu;
+
+/// A widget allowing the selection of a single value from a list of options.
+pub type ComboBox<'a, T, Message> =
+    iced_native::ComboBox<'a, T, Message, crate::Renderer>;
diff --git a/graphics/src/lib.rs b/graphics/src/lib.rs
index 92e8432e..0c427634 100644
--- a/graphics/src/lib.rs
+++ b/graphics/src/lib.rs
@@ -9,18 +9,18 @@
 #![forbid(rust_2018_idioms)]
 #![cfg_attr(docsrs, feature(doc_cfg))]
 mod antialiasing;
-mod overlay;
 mod primitive;
 mod renderer;
 mod transformation;
 mod viewport;
-mod widget;
 
 pub mod backend;
 pub mod defaults;
 pub mod font;
 pub mod layer;
+pub mod overlay;
 pub mod triangle;
+pub mod widget;
 pub mod window;
 
 #[doc(no_inline)]
diff --git a/graphics/src/overlay.rs b/graphics/src/overlay.rs
index c57668d4..b9a0e3e0 100644
--- a/graphics/src/overlay.rs
+++ b/graphics/src/overlay.rs
@@ -1 +1 @@
-mod menu;
+pub mod menu;
diff --git a/graphics/src/overlay/menu.rs b/graphics/src/overlay/menu.rs
index f4204f25..13065645 100644
--- a/graphics/src/overlay/menu.rs
+++ b/graphics/src/overlay/menu.rs
@@ -1,18 +1,23 @@
 use crate::backend::Backend;
 use crate::{Primitive, Renderer};
 use iced_native::{
-    mouse, overlay, Background, Color, Font, HorizontalAlignment, Point,
-    Rectangle, VerticalAlignment,
+    mouse, overlay, Color, Font, HorizontalAlignment, Point, Rectangle,
+    VerticalAlignment,
 };
 
+pub use iced_style::menu::Style;
+
 impl<B> overlay::menu::Renderer for Renderer<B>
 where
     B: Backend,
 {
+    type Style = Style;
+
     fn decorate(
         &mut self,
         bounds: Rectangle,
         _cursor_position: Point,
+        style: &Style,
         (primitives, mouse_cursor): Self::Output,
     ) -> Self::Output {
         (
@@ -20,11 +25,9 @@ where
                 primitives: vec![
                     Primitive::Quad {
                         bounds,
-                        background: Background::Color(
-                            [0.87, 0.87, 0.87].into(),
-                        ),
-                        border_color: [0.7, 0.7, 0.7].into(),
-                        border_width: 1,
+                        background: style.background,
+                        border_color: style.border_color,
+                        border_width: style.border_width,
                         border_radius: 0,
                     },
                     primitives,
@@ -42,6 +45,7 @@ where
         hovered_option: Option<usize>,
         text_size: u16,
         padding: u16,
+        style: &Style,
     ) -> Self::Output {
         use std::f32;
 
@@ -63,7 +67,7 @@ where
             if is_selected {
                 primitives.push(Primitive::Quad {
                     bounds,
-                    background: Background::Color([0.4, 0.4, 1.0].into()),
+                    background: style.selected_background,
                     border_color: Color::TRANSPARENT,
                     border_width: 0,
                     border_radius: 0,
@@ -81,9 +85,9 @@ where
                 size: f32::from(text_size),
                 font: Font::Default,
                 color: if is_selected {
-                    Color::WHITE
+                    style.selected_text_color
                 } else {
-                    Color::BLACK
+                    style.text_color
                 },
                 horizontal_alignment: HorizontalAlignment::Left,
                 vertical_alignment: VerticalAlignment::Center,
diff --git a/graphics/src/widget/combo_box.rs b/graphics/src/widget/combo_box.rs
index 92024c6c..078b5def 100644
--- a/graphics/src/widget/combo_box.rs
+++ b/graphics/src/widget/combo_box.rs
@@ -1,18 +1,29 @@
 use crate::backend::{self, Backend};
 use crate::{Primitive, Renderer};
 use iced_native::{
-    mouse, Background, Color, Font, HorizontalAlignment, Point, Rectangle,
-    VerticalAlignment,
+    mouse, Font, HorizontalAlignment, Point, Rectangle, VerticalAlignment,
 };
+use iced_style::menu;
 
-pub use iced_native::ComboBox;
+pub use iced_native::combo_box::State;
+pub use iced_style::combo_box::{Style, StyleSheet};
+
+/// A widget allowing the selection of a single value from a list of options.
+pub type ComboBox<'a, T, Message, Backend> =
+    iced_native::ComboBox<'a, T, Message, Renderer<Backend>>;
 
 impl<B> iced_native::combo_box::Renderer for Renderer<B>
 where
     B: Backend + backend::Text,
 {
+    type Style = Box<dyn StyleSheet>;
+
     const DEFAULT_PADDING: u16 = 5;
 
+    fn menu_style(style: &Box<dyn StyleSheet>) -> menu::Style {
+        style.menu()
+    }
+
     fn draw(
         &mut self,
         bounds: Rectangle,
@@ -20,31 +31,34 @@ where
         selected: Option<String>,
         text_size: u16,
         padding: u16,
+        style: &Box<dyn StyleSheet>,
     ) -> Self::Output {
         let is_mouse_over = bounds.contains(cursor_position);
 
+        let style = if is_mouse_over {
+            style.hovered()
+        } else {
+            style.active()
+        };
+
         let background = Primitive::Quad {
             bounds,
-            background: Background::Color([0.87, 0.87, 0.87].into()),
-            border_color: if is_mouse_over {
-                Color::BLACK
-            } else {
-                [0.7, 0.7, 0.7].into()
-            },
-            border_width: 1,
-            border_radius: 0,
+            background: style.background,
+            border_color: style.border_color,
+            border_width: style.border_width,
+            border_radius: style.border_radius,
         };
 
         let arrow_down = Primitive::Text {
             content: B::ARROW_DOWN_ICON.to_string(),
             font: B::ICON_FONT,
-            size: bounds.height * 0.7,
+            size: bounds.height * style.icon_size,
             bounds: Rectangle {
                 x: bounds.x + bounds.width - f32::from(padding) * 2.0,
                 y: bounds.center_y(),
                 ..bounds
             },
-            color: Color::BLACK,
+            color: style.text_color,
             horizontal_alignment: HorizontalAlignment::Right,
             vertical_alignment: VerticalAlignment::Center,
         };
@@ -56,7 +70,7 @@ where
                         content: label,
                         size: f32::from(text_size),
                         font: Font::Default,
-                        color: Color::BLACK,
+                        color: style.text_color,
                         bounds: Rectangle {
                             x: bounds.x + f32::from(padding),
                             y: bounds.center_y(),
diff --git a/native/src/overlay/menu.rs b/native/src/overlay/menu.rs
index 05c41181..9c180671 100644
--- a/native/src/overlay/menu.rs
+++ b/native/src/overlay/menu.rs
@@ -10,6 +10,7 @@ pub struct Menu<'a, Message, Renderer: self::Renderer> {
     is_open: &'a mut bool,
     width: u16,
     target_height: f32,
+    style: <Renderer as self::Renderer>::Style,
 }
 
 #[derive(Default)]
@@ -43,6 +44,7 @@ where
         target_height: f32,
         text_size: u16,
         padding: u16,
+        style: <Renderer as self::Renderer>::Style,
     ) -> Self
     where
         T: Clone + ToString,
@@ -55,6 +57,7 @@ where
                 on_selected,
                 text_size,
                 padding,
+                style.clone(),
             )),
         )
         .padding(1);
@@ -64,6 +67,7 @@ where
             is_open: &mut state.is_open,
             width,
             target_height,
+            style,
         }
     }
 }
@@ -156,11 +160,16 @@ where
             self.container
                 .draw(renderer, defaults, layout, cursor_position);
 
-        renderer.decorate(layout.bounds(), cursor_position, primitives)
+        renderer.decorate(
+            layout.bounds(),
+            cursor_position,
+            &self.style,
+            primitives,
+        )
     }
 }
 
-struct List<'a, T, Message>
+struct List<'a, T, Message, Renderer: self::Renderer>
 where
     [T]: ToOwned,
 {
@@ -169,9 +178,10 @@ where
     on_selected: Box<dyn Fn(T) -> Message>,
     text_size: u16,
     padding: u16,
+    style: <Renderer as self::Renderer>::Style,
 }
 
-impl<'a, T, Message> List<'a, T, Message>
+impl<'a, T, Message, Renderer: self::Renderer> List<'a, T, Message, Renderer>
 where
     [T]: ToOwned,
 {
@@ -181,6 +191,7 @@ where
         on_selected: Box<dyn Fn(T) -> Message>,
         text_size: u16,
         padding: u16,
+        style: <Renderer as self::Renderer>::Style,
     ) -> Self {
         List {
             hovered_option,
@@ -188,12 +199,13 @@ where
             on_selected,
             text_size,
             padding,
+            style,
         }
     }
 }
 
-impl<'a, T, Message, Renderer> Widget<'a, Message, Renderer>
-    for List<'a, T, Message>
+impl<'a, T, Message, Renderer: self::Renderer> Widget<'a, Message, Renderer>
+    for List<'a, T, Message, Renderer>
 where
     T: ToString + Clone,
     [T]: ToOwned,
@@ -286,15 +298,19 @@ where
             *self.hovered_option,
             self.text_size,
             self.padding,
+            &self.style,
         )
     }
 }
 
 pub trait Renderer: scrollable::Renderer + container::Renderer {
+    type Style: Default + Clone;
+
     fn decorate(
         &mut self,
         bounds: Rectangle,
         cursor_position: Point,
+        style: &<Self as Renderer>::Style,
         primitive: Self::Output,
     ) -> Self::Output;
 
@@ -306,16 +322,17 @@ pub trait Renderer: scrollable::Renderer + container::Renderer {
         hovered_option: Option<usize>,
         text_size: u16,
         padding: u16,
+        style: &<Self as Renderer>::Style,
     ) -> Self::Output;
 }
 
 impl<'a, T, Message, Renderer> Into<Element<'a, Message, Renderer>>
-    for List<'a, T, Message>
+    for List<'a, T, Message, Renderer>
 where
     T: ToString + Clone,
     [T]: ToOwned,
     Message: 'static,
-    Renderer: self::Renderer,
+    Renderer: 'a + self::Renderer,
 {
     fn into(self) -> Element<'a, Message, Renderer> {
         Element::new(self)
diff --git a/native/src/widget/combo_box.rs b/native/src/widget/combo_box.rs
index 2adee884..df2a530a 100644
--- a/native/src/widget/combo_box.rs
+++ b/native/src/widget/combo_box.rs
@@ -6,7 +6,7 @@ use crate::{
 };
 use std::borrow::Cow;
 
-pub struct ComboBox<'a, T, Message>
+pub struct ComboBox<'a, T, Message, Renderer: self::Renderer>
 where
     [T]: ToOwned<Owned = Vec<T>>,
 {
@@ -16,6 +16,7 @@ where
     width: Length,
     padding: u16,
     text_size: Option<u16>,
+    style: <Renderer as self::Renderer>::Style,
 }
 
 #[derive(Default)]
@@ -28,7 +29,8 @@ pub struct Internal<'a, T, Message> {
     on_selected: Box<dyn Fn(T) -> Message>,
 }
 
-impl<'a, T: 'a, Message> ComboBox<'a, T, Message>
+impl<'a, T: 'a, Message, Renderer: self::Renderer>
+    ComboBox<'a, T, Message, Renderer>
 where
     T: ToString,
     [T]: ToOwned<Owned = Vec<T>>,
@@ -48,7 +50,8 @@ where
             selected,
             width: Length::Shrink,
             text_size: None,
-            padding: 5,
+            padding: Renderer::DEFAULT_PADDING,
+            style: <Renderer as self::Renderer>::Style::default(),
         }
     }
 
@@ -72,10 +75,21 @@ where
         self.text_size = Some(size);
         self
     }
+
+    /// Sets the style of the [`ComboBox`].
+    ///
+    /// [`ComboBox`]: struct.ComboBox.html
+    pub fn style(
+        mut self,
+        style: impl Into<<Renderer as self::Renderer>::Style>,
+    ) -> Self {
+        self.style = style.into();
+        self
+    }
 }
 
 impl<'a, T: 'a, Message, Renderer> Widget<'a, Message, Renderer>
-    for ComboBox<'a, T, Message>
+    for ComboBox<'a, T, Message, Renderer>
 where
     T: Clone + ToString + Eq,
     [T]: ToOwned<Owned = Vec<T>>,
@@ -196,6 +210,7 @@ where
             self.selected.as_ref().map(ToString::to_string),
             self.text_size.unwrap_or(renderer.default_size()),
             self.padding,
+            &self.style,
         )
     }
 
@@ -223,6 +238,7 @@ where
                         bounds.height,
                         self.text_size.unwrap_or(20),
                         self.padding,
+                        Renderer::menu_style(&self.style),
                     )),
                 ))
             } else {
@@ -235,8 +251,14 @@ where
 }
 
 pub trait Renderer: text::Renderer + menu::Renderer {
+    type Style: Default;
+
     const DEFAULT_PADDING: u16;
 
+    fn menu_style(
+        style: &<Self as Renderer>::Style,
+    ) -> <Self as menu::Renderer>::Style;
+
     fn draw(
         &mut self,
         bounds: Rectangle,
@@ -244,11 +266,12 @@ pub trait Renderer: text::Renderer + menu::Renderer {
         selected: Option<String>,
         text_size: u16,
         padding: u16,
+        style: &<Self as Renderer>::Style,
     ) -> Self::Output;
 }
 
 impl<'a, T: 'a, Message, Renderer> Into<Element<'a, Message, Renderer>>
-    for ComboBox<'a, T, Message>
+    for ComboBox<'a, T, Message, Renderer>
 where
     T: Clone + ToString + Eq,
     [T]: ToOwned<Owned = Vec<T>>,
diff --git a/style/src/combo_box.rs b/style/src/combo_box.rs
new file mode 100644
index 00000000..4d0c4e46
--- /dev/null
+++ b/style/src/combo_box.rs
@@ -0,0 +1,70 @@
+use crate::menu;
+use iced_core::{Background, Color};
+
+/// The appearance of a combo box.
+#[derive(Debug, Clone, Copy)]
+pub struct Style {
+    pub text_color: Color,
+    pub background: Background,
+    pub border_radius: u16,
+    pub border_width: u16,
+    pub border_color: Color,
+    pub icon_size: f32,
+}
+
+impl std::default::Default for Style {
+    fn default() -> Self {
+        Self {
+            text_color: Color::BLACK,
+            background: Background::Color([0.87, 0.87, 0.87].into()),
+            border_radius: 0,
+            border_width: 1,
+            border_color: [0.7, 0.7, 0.7].into(),
+            icon_size: 0.7,
+        }
+    }
+}
+
+/// A set of rules that dictate the style of a container.
+pub trait StyleSheet {
+    fn menu(&self) -> menu::Style;
+
+    fn active(&self) -> Style;
+
+    /// Produces the style of a container.
+    fn hovered(&self) -> Style;
+}
+
+struct Default;
+
+impl StyleSheet for Default {
+    fn menu(&self) -> menu::Style {
+        menu::Style::default()
+    }
+
+    fn active(&self) -> Style {
+        Style::default()
+    }
+
+    fn hovered(&self) -> Style {
+        Style {
+            border_color: Color::BLACK,
+            ..self.active()
+        }
+    }
+}
+
+impl std::default::Default for Box<dyn StyleSheet> {
+    fn default() -> Self {
+        Box::new(Default)
+    }
+}
+
+impl<T> From<T> for Box<dyn StyleSheet>
+where
+    T: 'static + StyleSheet,
+{
+    fn from(style: T) -> Self {
+        Box::new(style)
+    }
+}
diff --git a/style/src/lib.rs b/style/src/lib.rs
index 72d83aec..b19d6600 100644
--- a/style/src/lib.rs
+++ b/style/src/lib.rs
@@ -6,7 +6,9 @@ pub use iced_core::{Background, Color};
 
 pub mod button;
 pub mod checkbox;
+pub mod combo_box;
 pub mod container;
+pub mod menu;
 pub mod progress_bar;
 pub mod radio;
 pub mod scrollable;
diff --git a/style/src/menu.rs b/style/src/menu.rs
new file mode 100644
index 00000000..e8321dc7
--- /dev/null
+++ b/style/src/menu.rs
@@ -0,0 +1,25 @@
+use iced_core::{Background, Color};
+
+/// The appearance of a menu.
+#[derive(Debug, Clone, Copy)]
+pub struct Style {
+    pub text_color: Color,
+    pub background: Background,
+    pub border_width: u16,
+    pub border_color: Color,
+    pub selected_text_color: Color,
+    pub selected_background: Background,
+}
+
+impl std::default::Default for Style {
+    fn default() -> Self {
+        Self {
+            text_color: Color::BLACK,
+            background: Background::Color([0.87, 0.87, 0.87].into()),
+            border_width: 1,
+            border_color: [0.7, 0.7, 0.7].into(),
+            selected_text_color: Color::WHITE,
+            selected_background: Background::Color([0.4, 0.4, 1.0].into()),
+        }
+    }
+}
diff --git a/wgpu/src/widget/combo_box.rs b/wgpu/src/widget/combo_box.rs
index bb3931ef..bfface29 100644
--- a/wgpu/src/widget/combo_box.rs
+++ b/wgpu/src/widget/combo_box.rs
@@ -1,3 +1,8 @@
 pub use iced_native::combo_box::State;
 
-pub type ComboBox<'a, T, Message> = iced_native::ComboBox<'a, T, Message>;
+pub use iced_graphics::combo_box::{Style, StyleSheet};
+pub use iced_graphics::overlay::menu::Style as Menu;
+
+/// A widget allowing the selection of a single value from a list of options.
+pub type ComboBox<'a, T, Message> =
+    iced_native::ComboBox<'a, T, Message, crate::Renderer>;