feat: use lyon for easing

1 files changed, 324 insertions, 0 deletions

diff --git a/examples/loading_spinners/src/linear.rs b/examples/loading_spinners/src/linear.rs
new file mode 100644
index 00000000..eb8a7408
--- /dev/null
+++ b/examples/loading_spinners/src/linear.rs
@@ -0,0 +1,324 @@
+//! Show a linear progress indicator.
+use iced::window;
+use iced_core::event::{self, Event};
+use iced_core::renderer;
+use iced_core::time::Instant;
+use iced_core::widget::tree::{self, Tree};
+use iced_core::window::RedrawRequest;
+use iced_core::{layout, Size};
+use iced_core::{
+    Background, Clipboard, Color, Element, Layout, Length, Point, Rectangle,
+    Shell, Widget,
+};
+
+use super::easing::{self, Easing};
+
+use std::time::Duration;
+
+#[allow(missing_debug_implementations)]
+pub struct Linear<'a, Renderer>
+where
+    Renderer: iced_core::Renderer,
+    Renderer::Theme: StyleSheet,
+{
+    width: Length,
+    height: Length,
+    style: <Renderer::Theme as StyleSheet>::Style,
+    easing: &'a Easing,
+    cycle_duration: Duration,
+}
+
+impl<'a, Renderer> Linear<'a, Renderer>
+where
+    Renderer: iced_widget::core::Renderer,
+    Renderer::Theme: StyleSheet,
+{
+    /// Creates a new [`Linear`] with the given content.
+    pub fn new() -> Self {
+        Linear {
+            width: Length::Fixed(100.0),
+            height: Length::Fixed(4.0),
+            style: <Renderer::Theme as StyleSheet>::Style::default(),
+            easing: &easing::STANDARD,
+            cycle_duration: Duration::from_millis(600),
+        }
+    }
+
+    /// Sets the width of the [`Linear`].
+    pub fn width(mut self, width: impl Into<Length>) -> Self {
+        self.width = width.into();
+        self
+    }
+
+    /// Sets the height of the [`Linear`].
+    pub fn height(mut self, height: impl Into<Length>) -> Self {
+        self.height = height.into();
+        self
+    }
+
+    /// Sets the style variant of this [`Linear`].
+    pub fn style(
+        mut self,
+        style: <Renderer::Theme as StyleSheet>::Style,
+    ) -> Self {
+        self.style = style;
+        self
+    }
+
+    /// Sets the motion easing of this [`Linear`].
+    pub fn easing(mut self, easing: &'a Easing) -> Self {
+        self.easing = easing;
+        self
+    }
+
+    /// Sets the cycle duration of this [`Linear`].
+    pub fn cycle_duration(mut self, duration: Duration) -> Self {
+        self.cycle_duration = duration / 2;
+        self
+    }
+}
+
+impl<'a, Renderer> Default for Linear<'a, Renderer>
+where
+    Renderer: iced_core::Renderer,
+    Renderer::Theme: StyleSheet,
+{
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[derive(Clone, Copy)]
+enum State {
+    Expanding { start: Instant, progress: f32 },
+    Contracting { start: Instant, progress: f32 },
+}
+
+impl Default for State {
+    fn default() -> Self {
+        Self::Expanding {
+            start: Instant::now(),
+            progress: 0.0,
+        }
+    }
+}
+
+impl State {
+    fn next(&self, now: Instant) -> Self {
+        match self {
+            Self::Expanding { .. } => Self::Contracting {
+                start: now,
+                progress: 0.0,
+            },
+            Self::Contracting { .. } => Self::Expanding {
+                start: now,
+                progress: 0.0,
+            },
+        }
+    }
+
+    fn start(&self) -> Instant {
+        match self {
+            Self::Expanding { start, .. } | Self::Contracting { start, .. } => {
+                *start
+            }
+        }
+    }
+
+    fn timed_transition(&self, cycle_duration: Duration, now: Instant) -> Self {
+        let elapsed = now.duration_since(self.start());
+
+        match elapsed {
+            elapsed if elapsed > cycle_duration => self.next(now),
+            _ => self.with_elapsed(cycle_duration, elapsed),
+        }
+    }
+
+    fn with_elapsed(
+        &self,
+        cycle_duration: Duration,
+        elapsed: Duration,
+    ) -> Self {
+        let progress = elapsed.as_secs_f32() / cycle_duration.as_secs_f32();
+        match self {
+            Self::Expanding { start, .. } => Self::Expanding {
+                start: *start,
+                progress,
+            },
+            Self::Contracting { start, .. } => Self::Contracting {
+                start: *start,
+                progress,
+            },
+        }
+    }
+}
+
+impl<'a, Message, Renderer> Widget<Message, Renderer> for Linear<'a, Renderer>
+where
+    Message: 'a + Clone,
+    Renderer: 'a + iced_core::Renderer,
+    Renderer::Theme: StyleSheet,
+{
+    fn tag(&self) -> tree::Tag {
+        tree::Tag::of::<State>()
+    }
+
+    fn state(&self) -> tree::State {
+        tree::State::new(State::default())
+    }
+
+    fn width(&self) -> Length {
+        self.width
+    }
+
+    fn height(&self) -> Length {
+        self.height
+    }
+
+    fn layout(
+        &self,
+        _renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        let limits = limits.width(self.width).height(self.height);
+        let size = limits.resolve(Size::ZERO);
+
+        layout::Node::new(size)
+    }
+
+    fn on_event(
+        &mut self,
+        tree: &mut Tree,
+        event: Event,
+        _layout: Layout<'_>,
+        _cursor_position: Point,
+        _renderer: &Renderer,
+        _clipboard: &mut dyn Clipboard,
+        shell: &mut Shell<'_, Message>,
+    ) -> event::Status {
+        let state = tree.state.downcast_mut::<State>();
+
+        if let Event::Window(window::Event::RedrawRequested(now)) = event {
+            *state = state.timed_transition(self.cycle_duration, now);
+
+            shell.request_redraw(RedrawRequest::NextFrame);
+        }
+
+        event::Status::Ignored
+    }
+
+    fn draw(
+        &self,
+        tree: &Tree,
+        renderer: &mut Renderer,
+        theme: &Renderer::Theme,
+        _style: &renderer::Style,
+        layout: Layout<'_>,
+        _cursor_position: Point,
+        _viewport: &Rectangle,
+    ) {
+        let bounds = layout.bounds();
+        let custom_style = theme.appearance(&self.style);
+        let state = tree.state.downcast_ref::<State>();
+
+        renderer.fill_quad(
+            renderer::Quad {
+                bounds: Rectangle {
+                    x: bounds.x,
+                    y: bounds.y,
+                    width: bounds.width,
+                    height: bounds.height,
+                },
+                border_radius: 0.0.into(),
+                border_width: 0.0,
+                border_color: Color::TRANSPARENT,
+            },
+            Background::Color(custom_style.track_color),
+        );
+
+        match state {
+            State::Expanding { progress, .. } => renderer.fill_quad(
+                renderer::Quad {
+                    bounds: Rectangle {
+                        x: bounds.x,
+                        y: bounds.y,
+                        width: self.easing.y_at_x(*progress) * bounds.width,
+                        height: bounds.height,
+                    },
+                    border_radius: 0.0.into(),
+                    border_width: 0.0,
+                    border_color: Color::TRANSPARENT,
+                },
+                Background::Color(custom_style.bar_color),
+            ),
+
+            State::Contracting { progress, .. } => renderer.fill_quad(
+                renderer::Quad {
+                    bounds: Rectangle {
+                        x: bounds.x
+                            + self.easing.y_at_x(*progress) * bounds.width,
+                        y: bounds.y,
+                        width: (1.0 - self.easing.y_at_x(*progress))
+                            * bounds.width,
+                        height: bounds.height,
+                    },
+                    border_radius: 0.0.into(),
+                    border_width: 0.0,
+                    border_color: Color::TRANSPARENT,
+                },
+                Background::Color(custom_style.bar_color),
+            ),
+        }
+    }
+}
+
+impl<'a, Message, Renderer> From<Linear<'a, Renderer>>
+    for Element<'a, Message, Renderer>
+where
+    Message: Clone + 'a,
+    Renderer: iced_core::Renderer + 'a,
+    Renderer::Theme: StyleSheet,
+{
+    fn from(linear: Linear<'a, Renderer>) -> Self {
+        Self::new(linear)
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct Appearance {
+    /// The track [`Color`] of the progress indicator.
+    pub track_color: Color,
+    /// The bar [`Color`] of the progress indicator.
+    pub bar_color: Color,
+}
+
+impl std::default::Default for Appearance {
+    fn default() -> Self {
+        Self {
+            track_color: Color::TRANSPARENT,
+            bar_color: Color::BLACK,
+        }
+    }
+}
+
+/// A set of rules that dictate the style of an indicator.
+pub trait StyleSheet {
+    /// The supported style of the [`StyleSheet`].
+    type Style: Default;
+
+    /// Produces the active [`Appearance`] of a indicator.
+    fn appearance(&self, style: &Self::Style) -> Appearance;
+}
+
+impl StyleSheet for iced::Theme {
+    type Style = ();
+
+    fn appearance(&self, _style: &Self::Style) -> Appearance {
+        let palette = self.extended_palette();
+
+        Appearance {
+            track_color: palette.background.weak.color,
+            bar_color: palette.primary.base.color,
+        }
+    }
+}