Implement styling for `ProgressBar`

10 files changed, 151 insertions, 67 deletions

diff --git a/examples/progress_bar.rs b/examples/progress_bar.rs
index 901428de..43b09928 100644
--- a/examples/progress_bar.rs
+++ b/examples/progress_bar.rs
@@ -1,7 +1,4 @@
-use iced::{
-    slider, Background, Color, Column, Element, Length, ProgressBar, Sandbox,
-    Settings, Slider,
-};
+use iced::{slider, Column, Element, ProgressBar, Sandbox, Settings, Slider};
 
 pub fn main() {
     Progress::run(Settings::default())
@@ -38,14 +35,7 @@ impl Sandbox for Progress {
     fn view(&mut self) -> Element<Message> {
         Column::new()
             .padding(20)
-            .push(
-                ProgressBar::new(0.0..=100.0, self.value)
-                    .background(Background::Color(Color::from_rgb(
-                        0.6, 0.6, 0.6,
-                    )))
-                    .active_color(Color::from_rgb(0.0, 0.95, 0.0))
-                    .height(Length::Units(30)),
-            )
+            .push(ProgressBar::new(0.0..=100.0, self.value))
             .push(Slider::new(
                 &mut self.progress_bar_slider,
                 0.0..=100.0,
diff --git a/examples/styling.rs b/examples/styling.rs
index 215185e3..426e0638 100644
--- a/examples/styling.rs
+++ b/examples/styling.rs
@@ -1,6 +1,7 @@
 use iced::{
     button, scrollable, slider, text_input, Button, Column, Container, Element,
-    Length, Radio, Row, Sandbox, Scrollable, Settings, Slider, Text, TextInput,
+    Length, ProgressBar, Radio, Row, Sandbox, Scrollable, Settings, Slider,
+    Text, TextInput,
 };
 
 pub fn main() {
@@ -82,13 +83,17 @@ impl Sandbox for Styling {
         )
         .style(self.theme);
 
+        let progress_bar =
+            ProgressBar::new(0.0..=100.0, self.slider_value).style(self.theme);
+
         let content = Column::new()
             .spacing(20)
             .padding(20)
             .max_width(600)
             .push(choose_theme)
             .push(Row::new().spacing(10).push(text_input).push(button))
-            .push(slider);
+            .push(slider)
+            .push(progress_bar);
 
         let scrollable = Scrollable::new(&mut self.scroll)
             .style(self.theme)
@@ -104,7 +109,9 @@ impl Sandbox for Styling {
 }
 
 mod style {
-    use iced::{button, container, scrollable, slider, text_input};
+    use iced::{
+        button, container, progress_bar, scrollable, slider, text_input,
+    };
 
     #[derive(Debug, Clone, Copy, PartialEq, Eq)]
     pub enum Theme {
@@ -167,6 +174,15 @@ mod style {
         }
     }
 
+    impl From<Theme> for Box<dyn progress_bar::StyleSheet> {
+        fn from(theme: Theme) -> Self {
+            match theme {
+                Theme::Light => Default::default(),
+                Theme::Dark => dark::ProgressBar.into(),
+            }
+        }
+    }
+
     mod light {
         use iced::{button, Background, Color, Vector};
 
@@ -197,8 +213,8 @@ mod style {
 
     mod dark {
         use iced::{
-            button, container, scrollable, slider, text_input, Background,
-            Color,
+            button, container, progress_bar, scrollable, slider, text_input,
+            Background, Color,
         };
 
         const SURFACE: Color = Color::from_rgb(
@@ -268,7 +284,7 @@ mod style {
             }
 
             fn placeholder_color(&self) -> Color {
-                Color::from_rgb(0.7, 0.7, 0.7)
+                Color::from_rgb(0.4, 0.4, 0.4)
             }
 
             fn value_color(&self) -> Color {
@@ -372,5 +388,17 @@ mod style {
                 }
             }
         }
+
+        pub struct ProgressBar;
+
+        impl progress_bar::StyleSheet for ProgressBar {
+            fn style(&self) -> progress_bar::Style {
+                progress_bar::Style {
+                    background: Background::Color(SURFACE),
+                    bar: Background::Color(ACTIVE),
+                    border_radius: 10,
+                }
+            }
+        }
     }
 }
diff --git a/native/src/renderer/null.rs b/native/src/renderer/null.rs
index 72f06a87..b721e29e 100644
--- a/native/src/renderer/null.rs
+++ b/native/src/renderer/null.rs
@@ -1,7 +1,7 @@
 use crate::{
-    button, checkbox, column, radio, row, scrollable, slider, text, text_input,
-    Color, Element, Font, HorizontalAlignment, Layout, Point, Rectangle,
-    Renderer, Size, VerticalAlignment,
+    button, checkbox, column, progress_bar, radio, row, scrollable, slider,
+    text, text_input, Color, Element, Font, HorizontalAlignment, Layout, Point,
+    Rectangle, Renderer, Size, VerticalAlignment,
 };
 
 /// A renderer that does nothing.
@@ -196,6 +196,21 @@ impl slider::Renderer for Null {
         _value: f32,
         _is_dragging: bool,
         _style_sheet: &Self::Style,
-    ) -> Self::Output {
+    ) {
+    }
+}
+
+impl progress_bar::Renderer for Null {
+    type Style = ();
+
+    const DEFAULT_HEIGHT: u16 = 30;
+
+    fn draw(
+        &self,
+        _bounds: Rectangle,
+        _range: std::ops::RangeInclusive<f32>,
+        _value: f32,
+        _style: &Self::Style,
+    ) {
     }
 }
diff --git a/native/src/widget/progress_bar.rs b/native/src/widget/progress_bar.rs
index fe517404..0bc860dd 100644
--- a/native/src/widget/progress_bar.rs
+++ b/native/src/widget/progress_bar.rs
@@ -1,7 +1,6 @@
 //! Provide progress feedback to your users.
 use crate::{
-    layout, Background, Color, Element, Hasher, Layout, Length, Point,
-    Rectangle, Size, Widget,
+    layout, Element, Hasher, Layout, Length, Point, Rectangle, Size, Widget,
 };
 
 use std::{hash::Hash, ops::RangeInclusive};
@@ -10,8 +9,9 @@ use std::{hash::Hash, ops::RangeInclusive};
 ///
 /// # Example
 /// ```
-/// # use iced_native::ProgressBar;
+/// # use iced_native::renderer::Null;
 /// #
+/// # pub type ProgressBar = iced_native::ProgressBar<Null>;
 /// let value = 50.0;
 ///
 /// ProgressBar::new(0.0..=100.0, value);
@@ -19,16 +19,15 @@ use std::{hash::Hash, 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 {
+pub struct ProgressBar<Renderer: self::Renderer> {
     range: RangeInclusive<f32>,
     value: f32,
     width: Length,
     height: Option<Length>,
-    background: Option<Background>,
-    active_color: Option<Color>,
+    style: Renderer::Style,
 }
 
-impl ProgressBar {
+impl<Renderer: self::Renderer> ProgressBar<Renderer> {
     /// Creates a new [`ProgressBar`].
     ///
     /// It expects:
@@ -42,8 +41,7 @@ impl ProgressBar {
             range,
             width: Length::Fill,
             height: None,
-            background: None,
-            active_color: None,
+            style: Renderer::Style::default(),
         }
     }
 
@@ -63,24 +61,16 @@ impl ProgressBar {
         self
     }
 
-    /// Sets the background of the [`ProgressBar`].
+    /// Sets the style of the [`ProgressBar`].
     ///
     /// [`ProgressBar`]: struct.ProgressBar.html
-    pub fn background(mut self, background: Background) -> Self {
-        self.background = Some(background);
-        self
-    }
-
-    /// Sets the active color of the [`ProgressBar`].
-    ///
-    /// [`ProgressBar`]: struct.ProgressBar.html
-    pub fn active_color(mut self, active_color: Color) -> Self {
-        self.active_color = Some(active_color);
+    pub fn style(mut self, style: impl Into<Renderer::Style>) -> Self {
+        self.style = style.into();
         self
     }
 }
 
-impl<Message, Renderer> Widget<Message, Renderer> for ProgressBar
+impl<Message, Renderer> Widget<Message, Renderer> for ProgressBar<Renderer>
 where
     Renderer: self::Renderer,
 {
@@ -119,8 +109,7 @@ where
             layout.bounds(),
             self.range.clone(),
             self.value,
-            self.background,
-            self.active_color,
+            &self.style,
         )
     }
 
@@ -138,6 +127,8 @@ where
 /// [`ProgressBar`]: struct.ProgressBar.html
 /// [renderer]: ../../renderer/index.html
 pub trait Renderer: crate::Renderer {
+    type Style: Default;
+
     /// The default height of a [`ProgressBar`].
     ///
     /// [`ProgressBar`]: struct.ProgressBar.html
@@ -158,17 +149,19 @@ pub trait Renderer: crate::Renderer {
         bounds: Rectangle,
         range: RangeInclusive<f32>,
         value: f32,
-        background: Option<Background>,
-        active_color: Option<Color>,
+        style: &Self::Style,
     ) -> Self::Output;
 }
 
-impl<'a, Message, Renderer> From<ProgressBar> for Element<'a, Message, Renderer>
+impl<'a, Message, Renderer> From<ProgressBar<Renderer>>
+    for Element<'a, Message, Renderer>
 where
-    Renderer: self::Renderer,
+    Renderer: 'static + self::Renderer,
     Message: 'static,
 {
-    fn from(progress_bar: ProgressBar) -> Element<'a, Message, Renderer> {
+    fn from(
+        progress_bar: ProgressBar<Renderer>,
+    ) -> Element<'a, Message, Renderer> {
         Element::new(progress_bar)
     }
 }
diff --git a/src/native.rs b/src/native.rs
index c2584fdd..5a4db8f6 100644
--- a/src/native.rs
+++ b/src/native.rs
@@ -34,13 +34,13 @@ pub mod widget {
         pub use iced_winit::svg::{Handle, Svg};
     }
 
-    pub use iced_winit::{Checkbox, ProgressBar, Radio, Text};
+    pub use iced_winit::{Checkbox, Radio, Text};
 
     #[doc(no_inline)]
     pub use {
         button::Button, container::Container, image::Image,
-        scrollable::Scrollable, slider::Slider, svg::Svg,
-        text_input::TextInput,
+        progress_bar::ProgressBar, scrollable::Scrollable, slider::Slider,
+        svg::Svg, text_input::TextInput,
     };
 
     /// A container that distributes its contents vertically.
diff --git a/style/src/lib.rs b/style/src/lib.rs
index 4b8d339e..3f3dc0b0 100644
--- a/style/src/lib.rs
+++ b/style/src/lib.rs
@@ -1,5 +1,6 @@
 pub mod button;
 pub mod container;
+pub mod progress_bar;
 pub mod scrollable;
 pub mod slider;
 pub mod text_input;
diff --git a/style/src/progress_bar.rs b/style/src/progress_bar.rs
new file mode 100644
index 00000000..73503fa8
--- /dev/null
+++ b/style/src/progress_bar.rs
@@ -0,0 +1,42 @@
+//! Provide progress feedback to your users.
+use iced_core::{Background, Color};
+
+/// The appearance of a progress bar.
+#[derive(Debug)]
+pub struct Style {
+    pub background: Background,
+    pub bar: Background,
+    pub border_radius: u16,
+}
+
+/// A set of rules that dictate the style of a progress bar.
+pub trait StyleSheet {
+    fn style(&self) -> Style;
+}
+
+struct Default;
+
+impl StyleSheet for Default {
+    fn style(&self) -> Style {
+        Style {
+            background: Background::Color(Color::from_rgb(0.6, 0.6, 0.6)),
+            bar: Background::Color(Color::from_rgb(0.3, 0.9, 0.3)),
+            border_radius: 5,
+        }
+    }
+}
+
+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/wgpu/src/renderer/widget/progress_bar.rs b/wgpu/src/renderer/widget/progress_bar.rs
index e9346fda..8bb9db03 100644
--- a/wgpu/src/renderer/widget/progress_bar.rs
+++ b/wgpu/src/renderer/widget/progress_bar.rs
@@ -1,7 +1,9 @@
-use crate::{Primitive, Renderer};
-use iced_native::{progress_bar, Background, Color, MouseCursor, Rectangle};
+use crate::{progress_bar::StyleSheet, Primitive, Renderer};
+use iced_native::{progress_bar, Color, MouseCursor, Rectangle};
 
 impl progress_bar::Renderer for Renderer {
+    type Style = Box<dyn StyleSheet>;
+
     const DEFAULT_HEIGHT: u16 = 30;
 
     fn draw(
@@ -9,9 +11,10 @@ impl progress_bar::Renderer for Renderer {
         bounds: Rectangle,
         range: std::ops::RangeInclusive<f32>,
         value: f32,
-        background: Option<Background>,
-        active_color: Option<Color>,
+        style_sheet: &Self::Style,
     ) -> Self::Output {
+        let style = style_sheet.style();
+
         let (range_start, range_end) = range.into_inner();
         let active_progress_width = bounds.width
             * ((value - range_start) / (range_end - range_start).max(1.0));
@@ -19,31 +22,27 @@ impl progress_bar::Renderer for Renderer {
         let background = Primitive::Group {
             primitives: vec![Primitive::Quad {
                 bounds: Rectangle { ..bounds },
-                background: background
-                    .unwrap_or(Background::Color([0.6, 0.6, 0.6].into()))
-                    .into(),
-                border_radius: 5,
+                background: style.background,
+                border_radius: style.border_radius,
                 border_width: 0,
                 border_color: Color::TRANSPARENT,
             }],
         };
 
-        let active_progress = Primitive::Quad {
+        let bar = Primitive::Quad {
             bounds: Rectangle {
                 width: active_progress_width,
                 ..bounds
             },
-            background: Background::Color(
-                active_color.unwrap_or([0.0, 0.95, 0.0].into()),
-            ),
-            border_radius: 5,
+            background: style.bar,
+            border_radius: style.border_radius,
             border_width: 0,
             border_color: Color::TRANSPARENT,
         };
 
         (
             Primitive::Group {
-                primitives: vec![background, active_progress],
+                primitives: vec![background, bar],
             },
             MouseCursor::OutOfBounds,
         )
diff --git a/wgpu/src/widget.rs b/wgpu/src/widget.rs
index 4b8d339e..3f3dc0b0 100644
--- a/wgpu/src/widget.rs
+++ b/wgpu/src/widget.rs
@@ -1,5 +1,6 @@
 pub mod button;
 pub mod container;
+pub mod progress_bar;
 pub mod scrollable;
 pub mod slider;
 pub mod text_input;
diff --git a/wgpu/src/widget/progress_bar.rs b/wgpu/src/widget/progress_bar.rs
new file mode 100644
index 00000000..34450b5e
--- /dev/null
+++ b/wgpu/src/widget/progress_bar.rs
@@ -0,0 +1,15 @@
+//! Allow your users to perform actions by pressing a button.
+//!
+//! A [`Button`] has some local [`State`].
+//!
+//! [`Button`]: type.Button.html
+//! [`State`]: struct.State.html
+use crate::Renderer;
+
+pub use iced_style::progress_bar::{Style, StyleSheet};
+
+/// A bar that displays progress.
+///
+/// This is an alias of an `iced_native` progress bar with an
+/// `iced_wgpu::Renderer`.
+pub type ProgressBar = iced_native::ProgressBar<Renderer>;