Merge branch 'master' into feature/canvas-interaction

8 files changed, 621 insertions, 5 deletions

diff --git a/Cargo.toml b/Cargo.toml
index d394d516..6dd30b42 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,6 +24,8 @@ debug = ["iced_winit/debug"]
 tokio = ["iced_futures/tokio"]
 # Enables `async-std` as the `executor::Default` on native platforms
 async-std = ["iced_futures/async-std"]
+# Enables advanced color conversion via `palette`
+palette = ["iced_core/palette"]
 
 [badges]
 maintenance = { status = "actively-developed" }
@@ -39,6 +41,7 @@ members = [
     "winit",
     "examples/bezier_tool",
     "examples/clock",
+    "examples/color_palette",
     "examples/counter",
     "examples/custom_widget",
     "examples/download_progress",
@@ -58,6 +61,7 @@ members = [
 ]
 
 [dependencies]
+iced_core = { version = "0.2", path = "core" }
 iced_futures = { version = "0.1", path = "futures" }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
diff --git a/core/Cargo.toml b/core/Cargo.toml
index 837f6aae..b52bf315 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -8,3 +8,7 @@ license = "MIT"
 repository = "https://github.com/hecrj/iced"
 
 [dependencies]
+
+[dependencies.palette]
+version = "0.5.0"
+optional = true
diff --git a/core/src/color.rs b/core/src/color.rs
index db509b88..a4c3d87c 100644
--- a/core/src/color.rs
+++ b/core/src/color.rs
@@ -1,10 +1,16 @@
+#[cfg(feature = "palette")]
+use palette::rgb::{Srgb, Srgba};
+
 /// A color in the sRGB color space.
-#[derive(Debug, Clone, Copy, PartialEq)]
-#[allow(missing_docs)]
+#[derive(Debug, Clone, Copy, PartialEq, Default)]
 pub struct Color {
+    /// Red component, 0.0 - 1.0
     pub r: f32,
+    /// Green component, 0.0 - 1.0
     pub g: f32,
+    /// Blue component, 0.0 - 1.0
     pub b: f32,
+    /// Transparency, 0.0 - 1.0
     pub a: f32,
 }
 
@@ -33,11 +39,45 @@ impl Color {
         a: 0.0,
     };
 
+    /// Creates a new [`Color`].
+    ///
+    /// In debug mode, it will panic if the values are not in the correct
+    /// range: 0.0 - 1.0
+    ///
+    /// [`Color`]: struct.Color.html
+    pub fn new(r: f32, g: f32, b: f32, a: f32) -> Color {
+        debug_assert!(
+            (0.0..=1.0).contains(&r),
+            "Red component must be on [0, 1]"
+        );
+        debug_assert!(
+            (0.0..=1.0).contains(&g),
+            "Green component must be on [0, 1]"
+        );
+        debug_assert!(
+            (0.0..=1.0).contains(&b),
+            "Blue component must be on [0, 1]"
+        );
+        debug_assert!(
+            (0.0..=1.0).contains(&a),
+            "Alpha component must be on [0, 1]"
+        );
+
+        Color { r, g, b, a }
+    }
+
     /// Creates a [`Color`] from its RGB components.
     ///
     /// [`Color`]: struct.Color.html
     pub const fn from_rgb(r: f32, g: f32, b: f32) -> Color {
-        Color { r, g, b, a: 1.0 }
+        Color::from_rgba(r, g, b, 1.0f32)
+    }
+
+    /// Creates a [`Color`] from its RGBA components.
+    ///
+    /// [`Color`]: struct.Color.html
+    pub const fn from_rgba(r: f32, g: f32, b: f32, a: f32) -> Color {
+        Color { r, g, b, a }
     }
 
     /// Creates a [`Color`] from its RGB8 components.
@@ -80,16 +120,114 @@ impl Color {
             self.a,
         ]
     }
+
+    /// Inverts the [`Color`] in-place.
+    ///
+    /// [`Color`]: struct.Color.html
+    pub fn invert(&mut self) {
+        self.r = 1.0f32 - self.r;
+        self.b = 1.0f32 - self.g;
+        self.g = 1.0f32 - self.b;
+    }
+
+    /// Returns the inverted [`Color`].
+    ///
+    /// [`Color`]: struct.Color.html
+    pub fn inverse(self) -> Color {
+        Color::new(1.0f32 - self.r, 1.0f32 - self.g, 1.0f32 - self.b, self.a)
+    }
 }
 
 impl From<[f32; 3]> for Color {
     fn from([r, g, b]: [f32; 3]) -> Self {
-        Color { r, g, b, a: 1.0 }
+        Color::new(r, g, b, 1.0)
     }
 }
 
 impl From<[f32; 4]> for Color {
     fn from([r, g, b, a]: [f32; 4]) -> Self {
-        Color { r, g, b, a }
+        Color::new(r, g, b, a)
+    }
+}
+
+#[cfg(feature = "palette")]
+/// Converts from palette's `Srgba` type to a [`Color`].
+///
+/// [`Color`]: struct.Color.html
+impl From<Srgba> for Color {
+    fn from(srgba: Srgba) -> Self {
+        Color::new(srgba.red, srgba.green, srgba.blue, srgba.alpha)
+    }
+}
+
+#[cfg(feature = "palette")]
+/// Converts from [`Color`] to palette's `Srgba` type.
+///
+/// [`Color`]: struct.Color.html
+impl From<Color> for Srgba {
+    fn from(c: Color) -> Self {
+        Srgba::new(c.r, c.g, c.b, c.a)
+    }
+}
+
+#[cfg(feature = "palette")]
+/// Converts from palette's `Srgb` type to a [`Color`].
+///
+/// [`Color`]: struct.Color.html
+impl From<Srgb> for Color {
+    fn from(srgb: Srgb) -> Self {
+        Color::new(srgb.red, srgb.green, srgb.blue, 1.0)
+    }
+}
+
+#[cfg(feature = "palette")]
+/// Converts from [`Color`] to palette's `Srgb` type.
+///
+/// [`Color`]: struct.Color.html
+/// [`Srgb`]: ../palette/rgb/type.Srgb.html
+impl From<Color> for Srgb {
+    fn from(c: Color) -> Self {
+        Srgb::new(c.r, c.g, c.b)
+    }
+}
+
+#[cfg(feature = "palette")]
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use palette::Blend;
+
+    #[test]
+    fn srgba_traits() {
+        let c = Color::from_rgb(0.5, 0.4, 0.3);
+        // Round-trip conversion to the palette:Srgba type
+        let s: Srgba = c.into();
+        let r: Color = s.into();
+        assert_eq!(c, r);
+    }
+
+    #[test]
+    fn color_manipulation() {
+        let c1 = Color::from_rgb(0.5, 0.4, 0.3);
+        let c2 = Color::from_rgb(0.2, 0.5, 0.3);
+
+        // Convert to linear color for manipulation
+        let l1 = Srgba::from(c1).into_linear();
+        let l2 = Srgba::from(c2).into_linear();
+
+        // Take the lighter of each of the RGB components
+        let lighter = l1.lighten(l2);
+
+        // Convert back to our Color
+        let r: Color = Srgba::from_linear(lighter).into();
+        assert_eq!(
+            r,
+            Color {
+                r: 0.5,
+                g: 0.5,
+                b: 0.3,
+                a: 1.0
+            }
+        );
     }
 }
diff --git a/examples/README.md b/examples/README.md
index 5d880d71..7e7bda9d 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -71,6 +71,7 @@ A bunch of simpler examples exist:
 
 - [`bezier_tool`](bezier_tool), a Paint-like tool for drawing Bézier curves using the `Canvas` widget.
 - [`clock`](clock), an application that uses the `Canvas` widget to draw a clock and its hands to display the current time.
+- [`color_palette`](color_palette), a color palette generator based on a user-defined root color.
 - [`counter`](counter), the classic counter example explained in the [`README`](../README.md).
 - [`custom_widget`](custom_widget), a demonstration of how to build a custom widget that draws a circle.
 - [`download_progress`](download_progress), a basic application that asynchronously downloads a dummy file of 100 MB and tracks the download progress.
diff --git a/examples/color_palette/Cargo.toml b/examples/color_palette/Cargo.toml
new file mode 100644
index 00000000..00f33e20
--- /dev/null
+++ b/examples/color_palette/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "color_palette"
+version = "0.1.0"
+authors = ["Clark Moody <clark@clarkmoody.com>"]
+edition = "2018"
+publish = false
+
+[dependencies]
+iced = { path = "../..", features = ["canvas", "palette"] }
+palette = "0.5.0"
diff --git a/examples/color_palette/README.md b/examples/color_palette/README.md
new file mode 100644
index 00000000..e70188f8
--- /dev/null
+++ b/examples/color_palette/README.md
@@ -0,0 +1,15 @@
+## Color palette
+
+A color palette generator, based on a user-defined root color.
+
+<div align="center">
+  <a href="https://gfycat.com/dirtylonebighornsheep">
+    <img src="https://github.com/hecrj/iced/raw/1a8d253611d3796b0a32b2f096bb54565a5292e0/examples/color_palette/screenshot.png">
+  </a>
+</div>
+
+You can run it with `cargo run`:
+
+```
+cargo run --package color_palette
+```
diff --git a/examples/color_palette/screenshot.png b/examples/color_palette/screenshot.png
new file mode 100644
index 00000000..aa4772e0
--- /dev/null
+++ b/examples/color_palette/screenshot.png
diff --git a/examples/color_palette/src/main.rs b/examples/color_palette/src/main.rs
new file mode 100644
index 00000000..073a6734
--- /dev/null
+++ b/examples/color_palette/src/main.rs
@@ -0,0 +1,444 @@
+use iced::{
+    canvas, slider, Align, Canvas, Color, Column, Element, HorizontalAlignment,
+    Length, Point, Row, Sandbox, Settings, Size, Slider, Text, Vector,
+    VerticalAlignment,
+};
+use palette::{self, Limited};
+use std::marker::PhantomData;
+use std::ops::RangeInclusive;
+
+pub fn main() {
+    ColorPalette::run(Settings {
+        antialiasing: true,
+        ..Settings::default()
+    })
+}
+
+#[derive(Default)]
+pub struct ColorPalette {
+    theme: Theme,
+    rgb: ColorPicker<Color>,
+    hsl: ColorPicker<palette::Hsl>,
+    hsv: ColorPicker<palette::Hsv>,
+    hwb: ColorPicker<palette::Hwb>,
+    lab: ColorPicker<palette::Lab>,
+    lch: ColorPicker<palette::Lch>,
+    canvas_layer: canvas::layer::Cache<Theme>,
+}
+
+#[derive(Debug, Clone, Copy)]
+pub enum Message {
+    RgbColorChanged(Color),
+    HslColorChanged(palette::Hsl),
+    HsvColorChanged(palette::Hsv),
+    HwbColorChanged(palette::Hwb),
+    LabColorChanged(palette::Lab),
+    LchColorChanged(palette::Lch),
+}
+
+impl Sandbox for ColorPalette {
+    type Message = Message;
+
+    fn new() -> Self {
+        Self::default()
+    }
+
+    fn title(&self) -> String {
+        String::from("Color palette - Iced")
+    }
+
+    fn update(&mut self, message: Message) {
+        let srgb = match message {
+            Message::RgbColorChanged(rgb) => palette::Srgb::from(rgb),
+            Message::HslColorChanged(hsl) => palette::Srgb::from(hsl),
+            Message::HsvColorChanged(hsv) => palette::Srgb::from(hsv),
+            Message::HwbColorChanged(hwb) => palette::Srgb::from(hwb),
+            Message::LabColorChanged(lab) => palette::Srgb::from(lab),
+            Message::LchColorChanged(lch) => palette::Srgb::from(lch),
+        };
+
+        self.theme = Theme::new(srgb.clamp());
+        self.canvas_layer.clear();
+    }
+
+    fn view(&mut self) -> Element<Message> {
+        let base = self.theme.base;
+
+        let srgb = palette::Srgb::from(base);
+        let hsl = palette::Hsl::from(srgb);
+        let hsv = palette::Hsv::from(srgb);
+        let hwb = palette::Hwb::from(srgb);
+        let lab = palette::Lab::from(srgb);
+        let lch = palette::Lch::from(srgb);
+
+        Column::new()
+            .padding(10)
+            .spacing(10)
+            .push(self.rgb.view(base).map(Message::RgbColorChanged))
+            .push(self.hsl.view(hsl).map(Message::HslColorChanged))
+            .push(self.hsv.view(hsv).map(Message::HsvColorChanged))
+            .push(self.hwb.view(hwb).map(Message::HwbColorChanged))
+            .push(self.lab.view(lab).map(Message::LabColorChanged))
+            .push(self.lch.view(lch).map(Message::LchColorChanged))
+            .push(
+                Canvas::new()
+                    .width(Length::Fill)
+                    .height(Length::Fill)
+                    .push(self.canvas_layer.with(&self.theme)),
+            )
+            .into()
+    }
+}
+
+#[derive(Debug)]
+pub struct Theme {
+    lower: Vec<Color>,
+    base: Color,
+    higher: Vec<Color>,
+}
+
+impl Theme {
+    pub fn new(base: impl Into<Color>) -> Theme {
+        use palette::{Hsl, Hue, Shade, Srgb};
+
+        let base = base.into();
+
+        // Convert to HSL color for manipulation
+        let hsl = Hsl::from(Srgb::from(base));
+
+        let lower = [
+            hsl.shift_hue(-135.0).lighten(0.075),
+            hsl.shift_hue(-120.0),
+            hsl.shift_hue(-105.0).darken(0.075),
+            hsl.darken(0.075),
+        ];
+
+        let higher = [
+            hsl.lighten(0.075),
+            hsl.shift_hue(105.0).darken(0.075),
+            hsl.shift_hue(120.0),
+            hsl.shift_hue(135.0).lighten(0.075),
+        ];
+
+        Theme {
+            lower: lower
+                .iter()
+                .map(|&color| Srgb::from(color).clamp().into())
+                .collect(),
+            base,
+            higher: higher
+                .iter()
+                .map(|&color| Srgb::from(color).clamp().into())
+                .collect(),
+        }
+    }
+
+    pub fn len(&self) -> usize {
+        self.lower.len() + self.higher.len() + 1
+    }
+
+    pub fn colors(&self) -> impl Iterator<Item = &Color> {
+        self.lower
+            .iter()
+            .chain(std::iter::once(&self.base))
+            .chain(self.higher.iter())
+    }
+}
+
+impl canvas::Drawable for Theme {
+    fn draw(&self, frame: &mut canvas::Frame) {
+        use canvas::Path;
+        use palette::{Hsl, Srgb};
+
+        let pad = 20.0;
+
+        let box_size = Size {
+            width: frame.width() / self.len() as f32,
+            height: frame.height() / 2.0 - pad,
+        };
+
+        let triangle = Path::new(|path| {
+            path.move_to(Point { x: 0.0, y: -0.5 });
+            path.line_to(Point { x: -0.5, y: 0.0 });
+            path.line_to(Point { x: 0.5, y: 0.0 });
+            path.close();
+        });
+
+        let mut text = canvas::Text {
+            horizontal_alignment: HorizontalAlignment::Center,
+            vertical_alignment: VerticalAlignment::Top,
+            size: 15.0,
+            ..canvas::Text::default()
+        };
+
+        for (i, &color) in self.colors().enumerate() {
+            let anchor = Point {
+                x: (i as f32) * box_size.width,
+                y: 0.0,
+            };
+            let rect = Path::rectangle(anchor, box_size);
+            frame.fill(&rect, color);
+
+            // We show a little indicator for the base color
+            if color == self.base {
+                let triangle_x = anchor.x + box_size.width / 2.0;
+
+                frame.with_save(|frame| {
+                    frame.translate(Vector::new(triangle_x, 0.0));
+                    frame.scale(10.0);
+                    frame.rotate(std::f32::consts::PI);
+
+                    frame.fill(&triangle, Color::WHITE);
+                });
+
+                frame.with_save(|frame| {
+                    frame.translate(Vector::new(triangle_x, box_size.height));
+                    frame.scale(10.0);
+
+                    frame.fill(&triangle, Color::WHITE);
+                });
+            }
+
+            frame.fill_text(canvas::Text {
+                content: color_hex_string(&color),
+                position: Point {
+                    x: anchor.x + box_size.width / 2.0,
+                    y: box_size.height,
+                },
+                ..text
+            });
+        }
+
+        text.vertical_alignment = VerticalAlignment::Bottom;
+
+        let hsl = Hsl::from(Srgb::from(self.base));
+        for i in 0..self.len() {
+            let pct = (i as f32 + 1.0) / (self.len() as f32 + 1.0);
+            let graded = Hsl {
+                lightness: 1.0 - pct,
+                ..hsl
+            };
+            let color: Color = Srgb::from(graded.clamp()).into();
+
+            let anchor = Point {
+                x: (i as f32) * box_size.width,
+                y: box_size.height + 2.0 * pad,
+            };
+
+            let rect = Path::rectangle(anchor, box_size);
+            frame.fill(&rect, color);
+
+            frame.fill_text(canvas::Text {
+                content: color_hex_string(&color),
+                position: Point {
+                    x: anchor.x + box_size.width / 2.0,
+                    y: box_size.height + 2.0 * pad,
+                },
+                ..text
+            });
+        }
+    }
+}
+
+impl Default for Theme {
+    fn default() -> Self {
+        Theme::new(Color::from_rgb8(75, 128, 190))
+    }
+}
+
+fn color_hex_string(color: &Color) -> String {
+    format!(
+        "#{:x}{:x}{:x}",
+        (255.0 * color.r).round() as u8,
+        (255.0 * color.g).round() as u8,
+        (255.0 * color.b).round() as u8
+    )
+}
+
+#[derive(Default)]
+struct ColorPicker<C: ColorSpace> {
+    sliders: [slider::State; 3],
+    color_space: PhantomData<C>,
+}
+
+trait ColorSpace: Sized {
+    const LABEL: &'static str;
+    const COMPONENT_RANGES: [RangeInclusive<f32>; 3];
+
+    fn new(a: f32, b: f32, c: f32) -> Self;
+
+    fn components(&self) -> [f32; 3];
+
+    fn to_string(&self) -> String;
+}
+
+impl<C: 'static + ColorSpace + Copy> ColorPicker<C> {
+    fn view(&mut self, color: C) -> Element<C> {
+        let [c1, c2, c3] = color.components();
+        let [s1, s2, s3] = &mut self.sliders;
+        let [cr1, cr2, cr3] = C::COMPONENT_RANGES;
+
+        Row::new()
+            .spacing(10)
+            .align_items(Align::Center)
+            .push(Text::new(C::LABEL).width(Length::Units(50)))
+            .push(Slider::new(s1, cr1, c1, move |v| C::new(v, c2, c3)))
+            .push(Slider::new(s2, cr2, c2, move |v| C::new(c1, v, c3)))
+            .push(Slider::new(s3, cr3, c3, move |v| C::new(c1, c2, v)))
+            .push(
+                Text::new(color.to_string())
+                    .width(Length::Units(185))
+                    .size(14),
+            )
+            .into()
+    }
+}
+
+impl ColorSpace for Color {
+    const LABEL: &'static str = "RGB";
+    const COMPONENT_RANGES: [RangeInclusive<f32>; 3] =
+        [0.0..=1.0, 0.0..=1.0, 0.0..=1.0];
+
+    fn new(r: f32, g: f32, b: f32) -> Self {
+        Color::from_rgb(r, g, b)
+    }
+
+    fn components(&self) -> [f32; 3] {
+        [self.r, self.g, self.b]
+    }
+
+    fn to_string(&self) -> String {
+        format!(
+            "rgb({:.0}, {:.0}, {:.0})",
+            255.0 * self.r,
+            255.0 * self.g,
+            255.0 * self.b
+        )
+    }
+}
+
+impl ColorSpace for palette::Hsl {
+    const LABEL: &'static str = "HSL";
+    const COMPONENT_RANGES: [RangeInclusive<f32>; 3] =
+        [0.0..=360.0, 0.0..=1.0, 0.0..=1.0];
+
+    fn new(hue: f32, saturation: f32, lightness: f32) -> Self {
+        palette::Hsl::new(
+            palette::RgbHue::from_degrees(hue),
+            saturation,
+            lightness,
+        )
+    }
+
+    fn components(&self) -> [f32; 3] {
+        [
+            self.hue.to_positive_degrees(),
+            self.saturation,
+            self.lightness,
+        ]
+    }
+
+    fn to_string(&self) -> String {
+        format!(
+            "hsl({:.1}, {:.1}%, {:.1}%)",
+            self.hue.to_positive_degrees(),
+            100.0 * self.saturation,
+            100.0 * self.lightness
+        )
+    }
+}
+
+impl ColorSpace for palette::Hsv {
+    const LABEL: &'static str = "HSV";
+    const COMPONENT_RANGES: [RangeInclusive<f32>; 3] =
+        [0.0..=360.0, 0.0..=1.0, 0.0..=1.0];
+
+    fn new(hue: f32, saturation: f32, value: f32) -> Self {
+        palette::Hsv::new(palette::RgbHue::from_degrees(hue), saturation, value)
+    }
+
+    fn components(&self) -> [f32; 3] {
+        [self.hue.to_positive_degrees(), self.saturation, self.value]
+    }
+
+    fn to_string(&self) -> String {
+        format!(
+            "hsv({:.1}, {:.1}%, {:.1}%)",
+            self.hue.to_positive_degrees(),
+            100.0 * self.saturation,
+            100.0 * self.value
+        )
+    }
+}
+
+impl ColorSpace for palette::Hwb {
+    const LABEL: &'static str = "HWB";
+    const COMPONENT_RANGES: [RangeInclusive<f32>; 3] =
+        [0.0..=360.0, 0.0..=1.0, 0.0..=1.0];
+
+    fn new(hue: f32, whiteness: f32, blackness: f32) -> Self {
+        palette::Hwb::new(
+            palette::RgbHue::from_degrees(hue),
+            whiteness,
+            blackness,
+        )
+    }
+
+    fn components(&self) -> [f32; 3] {
+        [
+            self.hue.to_positive_degrees(),
+            self.whiteness,
+            self.blackness,
+        ]
+    }
+
+    fn to_string(&self) -> String {
+        format!(
+            "hwb({:.1}, {:.1}%, {:.1}%)",
+            self.hue.to_positive_degrees(),
+            100.0 * self.whiteness,
+            100.0 * self.blackness
+        )
+    }
+}
+
+impl ColorSpace for palette::Lab {
+    const LABEL: &'static str = "Lab";
+    const COMPONENT_RANGES: [RangeInclusive<f32>; 3] =
+        [0.0..=100.0, -128.0..=127.0, -128.0..=127.0];
+
+    fn new(l: f32, a: f32, b: f32) -> Self {
+        palette::Lab::new(l, a, b)
+    }
+
+    fn components(&self) -> [f32; 3] {
+        [self.l, self.a, self.b]
+    }
+
+    fn to_string(&self) -> String {
+        format!("Lab({:.1}, {:.1}, {:.1})", self.l, self.a, self.b)
+    }
+}
+
+impl ColorSpace for palette::Lch {
+    const LABEL: &'static str = "Lch";
+    const COMPONENT_RANGES: [RangeInclusive<f32>; 3] =
+        [0.0..=100.0, 0.0..=128.0, 0.0..=360.0];
+
+    fn new(l: f32, chroma: f32, hue: f32) -> Self {
+        palette::Lch::new(l, chroma, palette::LabHue::from_degrees(hue))
+    }
+
+    fn components(&self) -> [f32; 3] {
+        [self.l, self.chroma, self.hue.to_positive_degrees()]
+    }
+
+    fn to_string(&self) -> String {
+        format!(
+            "Lch({:.1}, {:.1}, {:.1})",
+            self.l,
+            self.chroma,
+            self.hue.to_positive_degrees()
+        )
+    }
+}