add(widget): primitive progressbar widget

9 files changed, 239 insertions, 5 deletions

diff --git a/core/src/background.rs b/core/src/background.rs
index 2f75e45c..e1a37ddc 100644
--- a/core/src/background.rs
+++ b/core/src/background.rs
@@ -12,4 +12,4 @@ impl From<Color> for Background {
     fn from(color: Color) -> Self {
         Background::Color(color)
     }
-}
\ No newline at end of file
+}
diff --git a/examples/progressbar.rs b/examples/progressbar.rs
new file mode 100644
index 00000000..4663f8df
--- /dev/null
+++ b/examples/progressbar.rs
@@ -0,0 +1,51 @@
+use iced::{slider, Column, Element, Sandbox, Settings, Slider};
+use iced_winit::Progressbar;
+
+pub fn main() {
+    Progress::run(Settings::default())
+}
+
+#[derive(Default)]
+struct Progress {
+    value: f32,
+    progressbar_slider: slider::State,
+}
+
+#[derive(Debug, Clone, Copy)]
+enum Message {
+    SliderChanged(f32),
+}
+
+impl Sandbox for Progress {
+    type Message = Message;
+
+    fn new() -> Self {
+        Self::default()
+    }
+
+    fn title(&self) -> String {
+        String::from("A simple Progressbar")
+    }
+
+    fn update(&mut self, message: Message) {
+        match message {
+            Message::SliderChanged(x) => {
+                self.value = x;
+            }
+        }
+    }
+
+    fn view(&mut self) -> Element<Message> {
+        Column::new()
+            .padding(20)
+            .push(Progressbar::new(0.0..=100.0, self.value))
+            .padding(20)
+            .push(Slider::new(
+                &mut self.progressbar_slider,
+                0.0..=100.0,
+                self.value,
+                Message::SliderChanged,
+            ))
+            .into()
+    }
+}
diff --git a/native/src/widget.rs b/native/src/widget.rs
index dcc99645..d899da58 100644
--- a/native/src/widget.rs
+++ b/native/src/widget.rs
@@ -25,6 +25,7 @@ pub mod checkbox;
 pub mod column;
 pub mod container;
 pub mod image;
+pub mod progressbar;
 pub mod radio;
 pub mod row;
 pub mod scrollable;
@@ -45,6 +46,8 @@ pub use container::Container;
 #[doc(no_inline)]
 pub use image::Image;
 #[doc(no_inline)]
+pub use progressbar::Progressbar;
+#[doc(no_inline)]
 pub use radio::Radio;
 #[doc(no_inline)]
 pub use row::Row;
diff --git a/native/src/widget/progressbar.rs b/native/src/widget/progressbar.rs
new file mode 100644
index 00000000..a6725f2c
--- /dev/null
+++ b/native/src/widget/progressbar.rs
@@ -0,0 +1,135 @@
+//! Display a progressbar
+//!
+//!
+//! [`Progressbar`]: struct.Progressbar.html
+use crate::{
+    layout, Element, Hasher, Layout, Length, Point, Rectangle, Size, Widget,
+};
+
+use std::{hash::Hash, ops::RangeInclusive};
+
+/// A progressbar
+///
+/// # Example
+///
+/// ```
+/// # use iced_native::Progressbar;
+///
+/// Progressbar::new(0.0..=100.0, value);
+/// ```
+///
+/// TODO: Get a progressbar render
+/// ![Slider drawn by Coffee's renderer](https://github.com/hecrj/coffee/blob/bda9818f823dfcb8a7ad0ff4940b4d4b387b5208/images/ui/slider.png?raw=true)
+#[allow(missing_debug_implementations)]
+pub struct Progressbar {
+    range: RangeInclusive<f32>,
+    value: f32,
+    width: Length,
+}
+
+impl Progressbar {
+    /// Creates a new [`Progressbar`].
+    ///
+    /// It expects:
+    ///   * an inclusive range of possible values
+    ///   * the current value of the [`Progressbar`]
+    ///
+    /// [`Progressbar`]: struct.Progressbar.html
+    pub fn new(range: RangeInclusive<f32>, value: f32) -> Self {
+        Progressbar {
+            value: value.max(*range.start()).min(*range.end()),
+            range,
+            width: Length::Fill,
+        }
+    }
+
+    /// Sets the width of the [`Progressbar`].
+    ///
+    /// [`Progressbar`]: struct.Progressbar.html
+    pub fn width(mut self, width: Length) -> Self {
+        self.width = width;
+        self
+    }
+}
+
+impl<Message, Renderer> Widget<Message, Renderer> for Progressbar
+where
+    Renderer: self::Renderer,
+{
+    fn width(&self) -> Length {
+        self.width
+    }
+
+    fn height(&self) -> Length {
+        Length::Shrink
+    }
+
+    fn layout(
+        &self,
+        renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        let limits = limits
+            .width(self.width)
+            .height(Length::Units(renderer.height() as u16));
+
+        let size = limits.resolve(Size::ZERO);
+
+        layout::Node::new(size)
+    }
+
+    fn draw(
+        &self,
+        renderer: &mut Renderer,
+        layout: Layout<'_>,
+        _cursor_position: Point,
+    ) -> Renderer::Output {
+        renderer.draw(layout.bounds(), self.range.clone(), self.value)
+    }
+
+    fn hash_layout(&self, state: &mut Hasher) {
+        self.width.hash(state);
+    }
+}
+
+/// The renderer of a [`Progressbar`].
+///
+/// Your [renderer] will need to implement this trait before being
+/// able to use a [`Progressbar`] in your user interface.
+///
+/// [`Progressbar`]: struct.Progressbar.html
+/// [renderer]: ../../renderer/index.html
+pub trait Renderer: crate::Renderer {
+    /// Returns the height of the [`Progressbar`].
+    ///
+    /// [`Progressbar`]: struct.Progressbar.html
+    fn height(&self) -> u32;
+
+    /// Draws a [`Progressbar`].
+    ///
+    /// It receives:
+    ///   * the local state of the [`Progressbar`]
+    ///   * the bounds of the [`Progressbar`]
+    ///   * the range of values of the [`Progressbar`]
+    ///   * the current value of the [`Progressbar`]
+    ///
+    /// [`Progressbar`]: struct.Progressbar.html
+    /// [`State`]: struct.State.html
+    /// [`Class`]: enum.Class.html
+    fn draw(
+        &self,
+        bounds: Rectangle,
+        range: RangeInclusive<f32>,
+        value: f32,
+    ) -> Self::Output;
+}
+
+impl<'a, Message, Renderer> From<Progressbar> for Element<'a, Message, Renderer>
+where
+    Renderer: self::Renderer,
+    Message: 'static,
+{
+    fn from(progressbar: Progressbar) -> Element<'a, Message, Renderer> {
+        Element::new(progressbar)
+    }
+}
diff --git a/native/src/widget/text_input.rs b/native/src/widget/text_input.rs
index 1d1c32a2..c994b7ba 100644
--- a/native/src/widget/text_input.rs
+++ b/native/src/widget/text_input.rs
@@ -633,7 +633,8 @@ impl Value {
             .unwrap_or(self.len())
     }
 
-    /// Returns a new [`Value`] containing the graphemes until the given `index`.
+    /// Returns a new [`Value`] containing the graphemes until the given
+    /// `index`.
     ///
     /// [`Value`]: struct.Value.html
     pub fn until(&self, index: usize) -> Self {
diff --git a/wgpu/src/renderer/widget.rs b/wgpu/src/renderer/widget.rs
index f82631d5..94ebd10e 100644
--- a/wgpu/src/renderer/widget.rs
+++ b/wgpu/src/renderer/widget.rs
@@ -2,6 +2,7 @@ mod button;
 mod checkbox;
 mod column;
 mod image;
+mod progressbar;
 mod radio;
 mod row;
 mod scrollable;
diff --git a/wgpu/src/renderer/widget/progressbar.rs b/wgpu/src/renderer/widget/progressbar.rs
new file mode 100644
index 00000000..3c62e54d
--- /dev/null
+++ b/wgpu/src/renderer/widget/progressbar.rs
@@ -0,0 +1,43 @@
+use crate::{Primitive, Renderer};
+use iced_native::{progressbar, Background, Color, MouseCursor, Rectangle};
+
+impl progressbar::Renderer for Renderer {
+    fn height(&self) -> u32 {
+        30
+    }
+
+    fn draw(
+        &self,
+        bounds: Rectangle,
+        range: std::ops::RangeInclusive<f32>,
+        value: f32,
+    ) -> Self::Output {
+        let (range_start, range_end) = range.into_inner();
+        let active_progress_width = bounds.width
+            * ((value - range_start) / (range_end - range_start).max(1.0));
+
+        let background = Primitive::Group {
+            primitives: vec![Primitive::Quad {
+                bounds: Rectangle { ..bounds },
+                background: Color::from_rgb(0.6, 0.6, 0.6).into(),
+                border_radius: 5,
+            }],
+        };
+
+        let active_progress = Primitive::Quad {
+            bounds: Rectangle {
+                width: active_progress_width,
+                ..bounds
+            },
+            background: Background::Color([0.0, 0.95, 0.0].into()),
+            border_radius: 4,
+        };
+
+        (
+            Primitive::Group {
+                primitives: vec![background, active_progress],
+            },
+            MouseCursor::OutOfBounds,
+        )
+    }
+}
diff --git a/winit/src/conversion.rs b/winit/src/conversion.rs
index 0537d853..279b975a 100644
--- a/winit/src/conversion.rs
+++ b/winit/src/conversion.rs
@@ -50,7 +50,8 @@ pub fn button_state(element_state: winit::event::ElementState) -> ButtonState {
     }
 }
 
-/// Convert some `ModifiersState` from [`winit`] to an [`iced_native`] modifiers state.
+/// Convert some `ModifiersState` from [`winit`] to an [`iced_native`] modifiers
+/// state.
 ///
 /// [`winit`]: https://github.com/rust-windowing/winit
 /// [`iced_native`]: https://github.com/hecrj/iced/tree/master/native
diff --git a/winit/src/debug/basic.rs b/winit/src/debug/basic.rs
index c9da392c..d46edba6 100644
--- a/winit/src/debug/basic.rs
+++ b/winit/src/debug/basic.rs
@@ -1,5 +1,4 @@
-use std::collections::VecDeque;
-use std::time;
+use std::{collections::VecDeque, time};
 
 #[derive(Debug)]
 pub struct Debug {