feat: use lyon for easing

7 files changed, 214 insertions, 116 deletions

diff --git a/examples/progress_indicators/Cargo.toml b/examples/loading_spinners/Cargo.toml
index 89ceb127..f37017c6 100644
--- a/examples/progress_indicators/Cargo.toml
+++ b/examples/loading_spinners/Cargo.toml
@@ -1,5 +1,5 @@
 [package]
-name = "progress_indicators"
+name = "loading_spinners"
 version = "0.1.0"
 authors = ["Nick Senger <dev@nsenger.com>"]
 edition = "2021"
@@ -10,4 +10,5 @@ flo_curves = "0.7"
 iced = { path = "../..", features = ["canvas"] }
 iced_core = { path = "../../core" }
 iced_widget = { path = "../../widget" }
-lazy_static = "1.4"
+once_cell = "1"
+lyon = "1"
diff --git a/examples/progress_indicators/README.md b/examples/loading_spinners/README.md
index acacca8f..3573c6f6 100644
--- a/examples/progress_indicators/README.md
+++ b/examples/loading_spinners/README.md
@@ -1,6 +1,6 @@
-## Progress indicators
+## Loading Spinners
 
-Example implementation of animated indeterminate progress indicators.
+Example implementation of animated indeterminate loading spinners.
 
 <div align="center">
   <a href="https://gfycat.com/importantdevotedhammerheadbird">
@@ -10,5 +10,5 @@ Example implementation of animated indeterminate progress indicators.
 
 You can run it with `cargo run`:
 ```
-cargo run --package progress_indicators
+cargo run --package loading_spinners
 ```
diff --git a/examples/progress_indicators/src/circular.rs b/examples/loading_spinners/src/circular.rs
index 2a9f7e1e..0d01e7a1 100644
--- a/examples/progress_indicators/src/circular.rs
+++ b/examples/loading_spinners/src/circular.rs
@@ -14,7 +14,6 @@ use iced_core::{
 
 use super::easing::{self, Easing};
 
-use std::borrow::Cow;
 use std::f32::consts::PI;
 use std::time::Duration;
 
@@ -22,7 +21,7 @@ type R<Theme> = iced_widget::renderer::Renderer<Theme>;
 
 const MIN_RADIANS: f32 = PI / 8.0;
 const WRAP_RADIANS: f32 = 2.0 * PI - PI / 4.0;
-const PROCESSION_VELOCITY: u32 = u32::MAX / 120;
+const BASE_ROTATION_SPEED: u32 = u32::MAX / 80;
 
 #[allow(missing_debug_implementations)]
 pub struct Circular<'a, Theme>
@@ -32,8 +31,9 @@ where
     size: f32,
     bar_height: f32,
     style: <Theme as StyleSheet>::Style,
-    easing: Cow<'a, Easing>,
+    easing: &'a Easing,
     cycle_duration: Duration,
+    rotation_speed: u32,
 }
 
 impl<'a, Theme> Circular<'a, Theme>
@@ -46,8 +46,9 @@ where
             size: 40.0,
             bar_height: 4.0,
             style: <Theme as StyleSheet>::Style::default(),
-            easing: Cow::Borrowed(&easing::STANDARD),
+            easing: &easing::STANDARD,
             cycle_duration: Duration::from_millis(600),
+            rotation_speed: BASE_ROTATION_SPEED,
         }
     }
 
@@ -70,8 +71,8 @@ where
     }
 
     /// Sets the easing of this [`Circular`].
-    pub fn easing(mut self, easing: impl Into<Cow<'a, Easing>>) -> Self {
-        self.easing = easing.into();
+    pub fn easing(mut self, easing: &'a Easing) -> Self {
+        self.easing = easing;
         self
     }
 
@@ -80,6 +81,14 @@ where
         self.cycle_duration = duration / 2;
         self
     }
+
+    /// Sets the rotation speed of this [`Circular`]. Must be set to between 0.0 and 10.0.
+    /// Defaults to 1.0.
+    pub fn rotation_speed(mut self, speed: f32) -> Self {
+        let multiplier = speed.min(10.0).max(0.0);
+        self.rotation_speed = (BASE_ROTATION_SPEED as f32 * multiplier) as u32;
+        self
+    }
 }
 
 impl<'a, Theme> Default for Circular<'a, Theme>
@@ -121,13 +130,13 @@ impl State {
             Self::Expanding { procession, .. } => Self::Contracting {
                 start: now,
                 progress: 0.0,
-                procession: procession.wrapping_add(PROCESSION_VELOCITY),
+                procession: procession.wrapping_add(BASE_ROTATION_SPEED),
             },
             Self::Contracting { procession, .. } => Self::Expanding {
                 start: now,
                 progress: 0.0,
                 procession: procession.wrapping_add(
-                    PROCESSION_VELOCITY.wrapping_add(
+                    BASE_ROTATION_SPEED.wrapping_add(
                         ((WRAP_RADIANS / (2.0 * PI)) * u32::MAX as f32) as u32,
                     ),
                 ),
@@ -143,18 +152,24 @@ impl State {
         }
     }
 
-    fn timed_transition(&self, cycle_duration: Duration, now: Instant) -> Self {
+    fn timed_transition(
+        &self,
+        cycle_duration: Duration,
+        rotation_speed: u32,
+        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),
+            _ => self.with_elapsed(cycle_duration, rotation_speed, elapsed),
         }
     }
 
     fn with_elapsed(
         &self,
         cycle_duration: Duration,
+        rotation_speed: u32,
         elapsed: Duration,
     ) -> Self {
         let progress = elapsed.as_secs_f32() / cycle_duration.as_secs_f32();
@@ -164,14 +179,14 @@ impl State {
             } => Self::Expanding {
                 start: *start,
                 progress,
-                procession: procession.wrapping_add(PROCESSION_VELOCITY),
+                procession: procession.wrapping_add(rotation_speed),
             },
             Self::Contracting {
                 start, procession, ..
             } => Self::Contracting {
                 start: *start,
                 progress,
-                procession: procession.wrapping_add(PROCESSION_VELOCITY),
+                procession: procession.wrapping_add(rotation_speed),
             },
         }
     }
@@ -231,7 +246,11 @@ where
         let state = tree.state.downcast_mut::<State>();
 
         if let Event::Window(window::Event::RedrawRequested(now)) = event {
-            *state = state.timed_transition(self.cycle_duration, now);
+            *state = state.timed_transition(
+                self.cycle_duration,
+                self.rotation_speed,
+                now,
+            );
 
             shell.request_redraw(RedrawRequest::NextFrame);
         }
@@ -263,7 +282,7 @@ where
                         state,
                         style: &self.style,
                         bar_height: self.bar_height,
-                        easing: self.easing.as_ref(),
+                        easing: self.easing,
                     },
                     &(),
                     renderer,
diff --git a/examples/loading_spinners/src/easing.rs b/examples/loading_spinners/src/easing.rs
new file mode 100644
index 00000000..04befa15
--- /dev/null
+++ b/examples/loading_spinners/src/easing.rs
@@ -0,0 +1,132 @@
+use iced_core::Point;
+use lyon::algorithms::measure::PathMeasurements;
+use lyon::path::builder::NoAttributes;
+use lyon::path::path::BuilderImpl;
+use lyon::path::Path;
+
+use once_cell::sync::Lazy;
+
+pub static EMPHASIZED: Lazy<Easing> = Lazy::new(|| {
+    Easing::builder()
+        .cubic_bezier_to([0.05, 0.0], [0.133333, 0.06], [0.166666, 0.4])
+        .cubic_bezier_to([0.208333, 0.82], [0.25, 1.0], [1.0, 1.0])
+        .build()
+});
+
+pub static EMPHASIZED_DECELERATE: Lazy<Easing> = Lazy::new(|| {
+    Easing::builder()
+        .cubic_bezier_to([0.05, 0.7], [0.1, 1.0], [1.0, 1.0])
+        .build()
+});
+
+pub static EMPHASIZED_ACCELERATE: Lazy<Easing> = Lazy::new(|| {
+    Easing::builder()
+        .cubic_bezier_to([0.3, 0.0], [0.8, 0.15], [1.0, 1.0])
+        .build()
+});
+
+pub static STANDARD: Lazy<Easing> = Lazy::new(|| {
+    Easing::builder()
+        .cubic_bezier_to([0.2, 0.0], [0.0, 1.0], [1.0, 1.0])
+        .build()
+});
+
+pub static STANDARD_DECELERATE: Lazy<Easing> = Lazy::new(|| {
+    Easing::builder()
+        .cubic_bezier_to([0.0, 0.0], [0.0, 1.0], [1.0, 1.0])
+        .build()
+});
+
+pub static STANDARD_ACCELERATE: Lazy<Easing> = Lazy::new(|| {
+    Easing::builder()
+        .cubic_bezier_to([0.3, 0.0], [1.0, 1.0], [1.0, 1.0])
+        .build()
+});
+
+pub struct Easing {
+    path: Path,
+    measurements: PathMeasurements,
+}
+
+impl Easing {
+    pub fn builder() -> Builder {
+        Builder::new()
+    }
+
+    pub fn y_at_x(&self, x: f32) -> f32 {
+        let mut sampler = self.measurements.create_sampler(
+            &self.path,
+            lyon::algorithms::measure::SampleType::Normalized,
+        );
+        let sample = sampler.sample(x);
+
+        sample.position().y
+    }
+}
+
+pub struct Builder(NoAttributes<BuilderImpl>);
+
+impl Builder {
+    pub fn new() -> Self {
+        let mut builder = Path::builder();
+        builder.begin(lyon::geom::point(0.0, 0.0));
+
+        Self(builder)
+    }
+
+    /// Adds a line segment. Points must be between 0,0 and 1,1
+    pub fn line_to(mut self, to: impl Into<Point>) -> Self {
+        self.0.line_to(Self::point(to));
+
+        self
+    }
+
+    /// Adds a quadratic bézier curve. Points must be between 0,0 and 1,1
+    pub fn quadratic_bezier_to(
+        mut self,
+        ctrl: impl Into<Point>,
+        to: impl Into<Point>,
+    ) -> Self {
+        self.0
+            .quadratic_bezier_to(Self::point(ctrl), Self::point(to));
+
+        self
+    }
+
+    /// Adds a cubic bézier curve. Points must be between 0,0 and 1,1
+    pub fn cubic_bezier_to(
+        mut self,
+        ctrl1: impl Into<Point>,
+        ctrl2: impl Into<Point>,
+        to: impl Into<Point>,
+    ) -> Self {
+        self.0.cubic_bezier_to(
+            Self::point(ctrl1),
+            Self::point(ctrl2),
+            Self::point(to),
+        );
+
+        self
+    }
+
+    pub fn build(mut self) -> Easing {
+        self.0.line_to(lyon::geom::point(1.0, 1.0));
+        self.0.end(false);
+
+        let path = self.0.build();
+        let measurements = PathMeasurements::from_path(&path, 0.0);
+
+        Easing { path, measurements }
+    }
+
+    fn point(p: impl Into<Point>) -> lyon::geom::Point<f32> {
+        let p: Point = p.into();
+        lyon::geom::point(p.x.min(1.0).max(0.0), p.y.min(1.0).max(0.0))
+    }
+}
+
+impl Default for Builder {
+    fn default() -> Self {
+        Self::new()
+    }
+}
diff --git a/examples/progress_indicators/src/linear.rs b/examples/loading_spinners/src/linear.rs
index 735892e7..eb8a7408 100644
--- a/examples/progress_indicators/src/linear.rs
+++ b/examples/loading_spinners/src/linear.rs
@@ -13,7 +13,6 @@ use iced_core::{
 
 use super::easing::{self, Easing};
 
-use std::borrow::Cow;
 use std::time::Duration;
 
 #[allow(missing_debug_implementations)]
@@ -25,7 +24,7 @@ where
     width: Length,
     height: Length,
     style: <Renderer::Theme as StyleSheet>::Style,
-    easing: Cow<'a, Easing>,
+    easing: &'a Easing,
     cycle_duration: Duration,
 }
 
@@ -40,7 +39,7 @@ where
             width: Length::Fixed(100.0),
             height: Length::Fixed(4.0),
             style: <Renderer::Theme as StyleSheet>::Style::default(),
-            easing: Cow::Borrowed(&easing::STANDARD),
+            easing: &easing::STANDARD,
             cycle_duration: Duration::from_millis(600),
         }
     }
@@ -67,8 +66,8 @@ where
     }
 
     /// Sets the motion easing of this [`Linear`].
-    pub fn easing(mut self, easing: impl Into<Cow<'a, Easing>>) -> Self {
-        self.easing = easing.into();
+    pub fn easing(mut self, easing: &'a Easing) -> Self {
+        self.easing = easing;
         self
     }
 
diff --git a/examples/progress_indicators/src/main.rs b/examples/loading_spinners/src/main.rs
index 136b8d8c..a78e9590 100644
--- a/examples/progress_indicators/src/main.rs
+++ b/examples/loading_spinners/src/main.rs
@@ -12,17 +12,17 @@ use circular::Circular;
 use linear::Linear;
 
 pub fn main() -> iced::Result {
-    ProgressIndicators::run(Settings {
+    LoadingSpinners::run(Settings {
         antialiasing: true,
         ..Default::default()
     })
 }
 
-struct ProgressIndicators {
+struct LoadingSpinners {
     cycle_duration: f32,
 }
 
-impl Default for ProgressIndicators {
+impl Default for LoadingSpinners {
     fn default() -> Self {
         Self {
             cycle_duration: 2.0,
@@ -35,7 +35,7 @@ enum Message {
     CycleDurationChanged(f32),
 }
 
-impl Application for ProgressIndicators {
+impl Application for LoadingSpinners {
     type Message = Message;
     type Flags = ();
     type Executor = executor::Default;
@@ -46,7 +46,7 @@ impl Application for ProgressIndicators {
     }
 
     fn title(&self) -> String {
-        String::from("Progress Indicators - Iced")
+        String::from("Loading Spinners - Iced")
     }
 
     fn update(&mut self, message: Message) -> Command<Message> {
@@ -60,25 +60,39 @@ impl Application for ProgressIndicators {
     }
 
     fn view(&self) -> Element<Message> {
-        let column = easing::EXAMPLES
-            .iter()
-            .zip(["Decelerating:", "Accelerating:", "Standard:"])
-            .fold(column![], |column, (easing, label)| {
-                column.push(
-                    row![
-                        text(label).width(150),
-                        Linear::new().easing(easing).cycle_duration(
-                            Duration::from_secs_f32(self.cycle_duration)
-                        ),
-                        Circular::new().easing(easing).cycle_duration(
-                            Duration::from_secs_f32(self.cycle_duration)
-                        )
-                    ]
-                    .align_items(iced::Alignment::Center)
-                    .spacing(20.0),
-                )
-            })
-            .spacing(20);
+        let column = [
+            &easing::EMPHASIZED,
+            &easing::EMPHASIZED_DECELERATE,
+            &easing::EMPHASIZED_ACCELERATE,
+            &easing::STANDARD,
+            &easing::STANDARD_DECELERATE,
+            &easing::STANDARD_ACCELERATE,
+        ]
+        .iter()
+        .zip([
+            "Emphasized:",
+            "Emphasized Decelerate:",
+            "Emphasized Accelerate:",
+            "Standard:",
+            "Standard Decelerate:",
+            "Standard Accelerate:",
+        ])
+        .fold(column![], |column, (easing, label)| {
+            column.push(
+                row![
+                    text(label).width(250),
+                    Linear::new().easing(easing).cycle_duration(
+                        Duration::from_secs_f32(self.cycle_duration)
+                    ),
+                    Circular::new().easing(easing).cycle_duration(
+                        Duration::from_secs_f32(self.cycle_duration)
+                    )
+                ]
+                .align_items(iced::Alignment::Center)
+                .spacing(20.0),
+            )
+        })
+        .spacing(20);
 
         container(
             column.push(
@@ -87,7 +101,7 @@ impl Application for ProgressIndicators {
                     slider(1.0..=1000.0, self.cycle_duration * 100.0, |x| {
                         Message::CycleDurationChanged(x / 100.0)
                     })
-                    .width(150.0)
+                    .width(200.0)
                     .into(),
                     text(format!("{:.2}s", self.cycle_duration)).into(),
                 ])
diff --git a/examples/progress_indicators/src/easing.rs b/examples/progress_indicators/src/easing.rs
deleted file mode 100644
index 10479659..00000000
--- a/examples/progress_indicators/src/easing.rs
+++ /dev/null
@@ -1,67 +0,0 @@
-use flo_curves::bezier::Curve;
-use flo_curves::*;
-use lazy_static::lazy_static;
-
-use std::borrow::Cow;
-
-lazy_static! {
-    pub static ref EXAMPLES: [Easing; 3] = [
-        Easing::CubicBezier(Curve::from_points(
-            Coord2(0.0, 0.0),
-            (Coord2(0.05, 0.7), Coord2(0.1, 1.0)),
-            Coord2(1.0, 1.0),
-        )),
-        Easing::CubicBezier(Curve::from_points(
-            Coord2(0.0, 0.0),
-            (Coord2(0.3, 0.0), Coord2(0.8, 0.15)),
-            Coord2(1.0, 1.0),
-        )),
-        Easing::CubicBezier(Curve::from_points(
-            Coord2(0.0, 0.0),
-            (Coord2(0.2, 0.0), Coord2(0.0, 1.0)),
-            Coord2(1.0, 1.0),
-        ))
-    ];
-    pub static ref STANDARD: Easing = {
-        Easing::CubicBezier(Curve::from_points(
-            Coord2(0.0, 0.0),
-            (Coord2(0.2, 0.0), Coord2(0.0, 1.0)),
-            Coord2(1.0, 1.0),
-        ))
-    };
-}
-
-#[derive(Clone, Debug)]
-pub enum Easing {
-    BezierPath(Vec<Curve<Coord2>>),
-    CubicBezier(Curve<Coord2>),
-}
-
-impl Easing {
-    pub fn y_at_x(&self, x: f32) -> f32 {
-        let x = x as f64;
-
-        match self {
-            Self::BezierPath(curves) => curves
-                .iter()
-                .find_map(|curve| {
-                    (curve.start_point().0 <= x && curve.end_point().0 >= x)
-                        .then(|| curve.point_at_pos(x).1 as f32)
-                })
-                .unwrap_or_default(),
-            Self::CubicBezier(curve) => curve.point_at_pos(x).1 as f32,
-        }
-    }
-}
-
-impl<'a> From<Easing> for Cow<'a, Easing> {
-    fn from(easing: Easing) -> Self {
-        Cow::Owned(easing)
-    }
-}
-
-impl<'a> From<&'a Easing> for Cow<'a, Easing> {
-    fn from(easing: &'a Easing) -> Self {
-        Cow::Borrowed(easing)
-    }
-}