feat(style): add conversions from the palette crate colors (#1172)

This is behind the "palette" feature flag.

```rust
use palette::{LinSrgb, Srgb};
use ratatui::style::Color;

let color = Color::from(Srgb::new(1.0f32, 0.0, 0.0));
let color = Color::from(LinSrgb::new(1.0f32, 0.0, 0.0));
```

Cargo.toml

@@ -33,6 +33,7 @@ document-features = { version = "0.2.7", optional = true }
 itertools = "0.13"
 lru = "0.12.0"
 paste = "1.0.2"
+palette = { version = "0.7.6", optional = true }
 serde = { version = "1", optional = true, features = ["derive"] }
 stability = "0.2.0"
 strum = { version = "0.26", features = ["derive"] }
@@ -122,6 +123,9 @@ serde = ["dep:serde", "bitflags/serde", "compact_str/serde"]
 ## enables the [`border!`] macro.
 macros = []
 
+## enables conversions from colors in the [`palette`] crate to [`Color`](crate::style::Color).
+palette = ["dep:palette"]
+
 ## enables all widgets.
 all-widgets = ["widget-calendar"]
 

src/layout/layout.rs

@@ -1881,14 +1881,11 @@ mod tests {
 
             let chunks = Layout::default()
                 .direction(Direction::Vertical)
-                .constraints(
-                    [
-                        Constraint::Percentage(10),
-                        Constraint::Max(5),
-                        Constraint::Min(1),
-                    ]
-                    .as_ref(),
-                )
+                .constraints([
+                    Constraint::Percentage(10),
+                    Constraint::Max(5),
+                    Constraint::Min(1),
+                ])
                 .split(target);
 
             assert_eq!(target.height, chunks.iter().map(|r| r.height).sum::<u16>());

src/style.rs

@@ -71,13 +71,14 @@
 use std::fmt;
 
 use bitflags::bitflags;
-
-mod color;
-mod stylize;
-
 pub use color::{Color, ParseColorError};
 pub use stylize::{Styled, Stylize};
+
+mod color;
 pub mod palette;
+#[cfg(feature = "palette")]
+mod palette_conversion;
+mod stylize;
 
 bitflags! {
     /// Modifier changes the way a piece of text is displayed.

src/style/palette_conversion.rs

@@ -0,0 +1,83 @@
+//! Conversions from colors in the `palette` crate to [`Color`].
+
+use ::palette::{
+    bool_mask::LazySelect,
+    num::{Arithmetics, MulSub, PartialCmp, Powf, Real},
+    LinSrgb,
+};
+use palette::{stimulus::IntoStimulus, Srgb};
+
+use super::Color;
+
+/// Convert an [`palette::Srgb`] color to a [`Color`].
+///
+/// # Examples
+///
+/// ```
+/// use palette::Srgb;
+/// use ratatui::style::Color;
+///
+/// let color = Color::from(Srgb::new(1.0f32, 0.0, 0.0));
+/// assert_eq!(color, Color::Rgb(255, 0, 0));
+/// ```
+impl<T: IntoStimulus<u8>> From<Srgb<T>> for Color {
+    fn from(color: Srgb<T>) -> Self {
+        let (red, green, blue) = color.into_format().into_components();
+        Color::Rgb(red, green, blue)
+    }
+}
+
+/// Convert a [`palette::LinSrgb`] color to a [`Color`].
+///
+/// Note: this conversion only works for floating point linear sRGB colors. If you have a linear
+/// sRGB color in another format, you need to convert it to floating point first.
+///
+/// # Examples
+///
+/// ```
+/// use palette::LinSrgb;
+/// use ratatui::style::Color;
+///
+/// let color = Color::from(LinSrgb::new(1.0f32, 0.0, 0.0));
+/// assert_eq!(color, Color::Rgb(255, 0, 0));
+/// ```
+impl<T: IntoStimulus<u8>> From<LinSrgb<T>> for Color
+where
+    T: Real + Powf + MulSub + Arithmetics + PartialCmp + Clone,
+    T::Mask: LazySelect<T>,
+{
+    fn from(color: LinSrgb<T>) -> Self {
+        let srgb_color = Srgb::<T>::from_linear(color);
+        Color::from(srgb_color)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn from_srgb() {
+        const RED: Color = Color::Rgb(255, 0, 0);
+        assert_eq!(Color::from(Srgb::new(255u8, 0, 0)), RED);
+        assert_eq!(Color::from(Srgb::new(65535u16, 0, 0)), RED);
+        assert_eq!(Color::from(Srgb::new(1.0f32, 0.0, 0.0)), RED);
+
+        assert_eq!(
+            Color::from(Srgb::new(0.5f32, 0.5, 0.5)),
+            Color::Rgb(128, 128, 128)
+        );
+    }
+
+    #[test]
+    fn from_lin_srgb() {
+        const RED: Color = Color::Rgb(255, 0, 0);
+        assert_eq!(Color::from(LinSrgb::new(1.0f32, 0.0, 0.0)), RED);
+        assert_eq!(Color::from(LinSrgb::new(1.0f64, 0.0, 0.0)), RED);
+
+        assert_eq!(
+            Color::from(LinSrgb::new(0.5f32, 0.5, 0.5)),
+            Color::Rgb(188, 188, 188)
+        );
+    }
+}

src/widgets/barchart/bar_group.rs

@@ -78,7 +78,8 @@ impl<'a> From<&[(&'a str, u64)]> for BarGroup<'a> {
 
 impl<'a, const N: usize> From<&[(&'a str, u64); N]> for BarGroup<'a> {
     fn from(value: &[(&'a str, u64); N]) -> Self {
-        Self::from(value.as_ref())
+        let value: &[(&'a str, u64)] = value.as_ref();
+        Self::from(value)
     }
 }