bevy_color: Created a private trait StandardColor (bevyengine#12072)

# Objective

- Assist Bevy contributors in the creation of `bevy_color` spaces by
ensuring consistent API implementation.

## Solution

Created a `pub(crate)` trait `StandardColor` which has all the
requirements for a typical color space (e.g, `Srgba`, `Color`, etc.).

---

## Changelog

- Implemented traits missing from certain color spaces.

## Migration Guide

_No migration required_

crates/bevy_color/src/color.rs

@@ -1,10 +1,14 @@
-use crate::{Hsla, Lcha, LinearRgba, Oklaba, Srgba};
+use crate::{Alpha, Hsla, Lcha, LinearRgba, Oklaba, Srgba, StandardColor};
+use bevy_reflect::{Reflect, ReflectDeserialize, ReflectSerialize};
+use bevy_render::color::Color as LegacyColor;
+use serde::{Deserialize, Serialize};
 
 /// An enumerated type that can represent any of the color types in this crate.
 ///
 /// This is useful when you need to store a color in a data structure that can't be generic over
 /// the color type.
-#[derive(Debug, Clone, Copy, PartialEq)]
+#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize, Reflect)]
+#[reflect(PartialEq, Serialize, Deserialize)]
 pub enum Color {
     /// A color in the sRGB color space with alpha.
     Srgba(Srgba),
@@ -18,6 +22,8 @@ pub enum Color {
     Oklaba(Oklaba),
 }
 
+impl StandardColor for Color {}
+
 impl Color {
     /// Return the color as a linear RGBA color.
     pub fn linear(&self) -> LinearRgba {
@@ -37,6 +43,32 @@ impl Default for Color {
     }
 }
 
+impl Alpha for Color {
+    fn with_alpha(&self, alpha: f32) -> Self {
+        let mut new = *self;
+
+        match &mut new {
+            Color::Srgba(x) => *x = x.with_alpha(alpha),
+            Color::LinearRgba(x) => *x = x.with_alpha(alpha),
+            Color::Hsla(x) => *x = x.with_alpha(alpha),
+            Color::Lcha(x) => *x = x.with_alpha(alpha),
+            Color::Oklaba(x) => *x = x.with_alpha(alpha),
+        }
+
+        new
+    }
+
+    fn alpha(&self) -> f32 {
+        match self {
+            Color::Srgba(x) => x.alpha(),
+            Color::LinearRgba(x) => x.alpha(),
+            Color::Hsla(x) => x.alpha(),
+            Color::Lcha(x) => x.alpha(),
+            Color::Oklaba(x) => x.alpha(),
+        }
+    }
+}
+
 impl From<Srgba> for Color {
     fn from(value: Srgba) -> Self {
         Self::Srgba(value)
@@ -126,3 +158,26 @@ impl From<Color> for Oklaba {
         }
     }
 }
+
+impl From<LegacyColor> for Color {
+    fn from(value: LegacyColor) -> Self {
+        match value {
+            LegacyColor::Rgba { .. } => Srgba::from(value).into(),
+            LegacyColor::RgbaLinear { .. } => LinearRgba::from(value).into(),
+            LegacyColor::Hsla { .. } => Hsla::from(value).into(),
+            LegacyColor::Lcha { .. } => Lcha::from(value).into(),
+        }
+    }
+}
+
+impl From<Color> for LegacyColor {
+    fn from(value: Color) -> Self {
+        match value {
+            Color::Srgba(x) => x.into(),
+            Color::LinearRgba(x) => x.into(),
+            Color::Hsla(x) => x.into(),
+            Color::Lcha(x) => x.into(),
+            Color::Oklaba(x) => x.into(),
+        }
+    }
+}

crates/bevy_color/src/hsla.rs

@@ -1,4 +1,4 @@
-use crate::{Alpha, LinearRgba, Luminance, Mix, Srgba};
+use crate::{Alpha, Lcha, LinearRgba, Luminance, Mix, Oklaba, Srgba, StandardColor};
 use bevy_reflect::{Reflect, ReflectDeserialize, ReflectSerialize};
 use bevy_render::color::HslRepresentation;
 use serde::{Deserialize, Serialize};
@@ -17,6 +17,8 @@ pub struct Hsla {
     pub alpha: f32,
 }
 
+impl StandardColor for Hsla {}
+
 impl Hsla {
     /// Construct a new [`Hsla`] color from components.
     ///
@@ -119,12 +121,6 @@ impl From<Srgba> for Hsla {
     }
 }
 
-impl From<LinearRgba> for Hsla {
-    fn from(value: LinearRgba) -> Self {
-        Hsla::from(Srgba::from(value))
-    }
-}
-
 impl From<Hsla> for bevy_render::color::Color {
     fn from(value: Hsla) -> Self {
         bevy_render::color::Color::Hsla {
@@ -150,6 +146,24 @@ impl From<bevy_render::color::Color> for Hsla {
     }
 }
 
+impl From<LinearRgba> for Hsla {
+    fn from(value: LinearRgba) -> Self {
+        Srgba::from(value).into()
+    }
+}
+
+impl From<Oklaba> for Hsla {
+    fn from(value: Oklaba) -> Self {
+        Srgba::from(value).into()
+    }
+}
+
+impl From<Lcha> for Hsla {
+    fn from(value: Lcha) -> Self {
+        Srgba::from(value).into()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

crates/bevy_color/src/lcha.rs

@@ -1,4 +1,4 @@
-use crate::{Alpha, LinearRgba, Luminance, Mix, Srgba};
+use crate::{Alpha, Hsla, LinearRgba, Luminance, Mix, Oklaba, Srgba, StandardColor};
 use bevy_reflect::{Reflect, ReflectDeserialize, ReflectSerialize};
 use bevy_render::color::LchRepresentation;
 use serde::{Deserialize, Serialize};
@@ -17,6 +17,8 @@ pub struct Lcha {
     pub alpha: f32,
 }
 
+impl StandardColor for Lcha {}
+
 impl Lcha {
     /// Construct a new [`Lcha`] color from components.
     ///
@@ -165,6 +167,18 @@ impl From<bevy_render::color::Color> for Lcha {
     }
 }
 
+impl From<Oklaba> for Lcha {
+    fn from(value: Oklaba) -> Self {
+        Srgba::from(value).into()
+    }
+}
+
+impl From<Hsla> for Lcha {
+    fn from(value: Hsla) -> Self {
+        Srgba::from(value).into()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

crates/bevy_color/src/lib.rs

@@ -87,3 +87,25 @@ pub use lcha::*;
 pub use linear_rgba::*;
 pub use oklaba::*;
 pub use srgba::*;
+
+use bevy_render::color::Color as LegacyColor;
+
+/// Describes the traits that a color should implement for consistency.
+pub(crate) trait StandardColor
+where
+    Self: core::fmt::Debug,
+    Self: Clone + Copy,
+    Self: PartialEq,
+    Self: serde::Serialize + for<'a> serde::Deserialize<'a>,
+    Self: bevy_reflect::Reflect,
+    Self: Default,
+    Self: From<Color> + Into<Color>,
+    Self: From<LegacyColor> + Into<LegacyColor>,
+    Self: From<Srgba> + Into<Srgba>,
+    Self: From<LinearRgba> + Into<LinearRgba>,
+    Self: From<Hsla> + Into<Hsla>,
+    Self: From<Lcha> + Into<Lcha>,
+    Self: From<Oklaba> + Into<Oklaba>,
+    Self: Alpha,
+{
+}

crates/bevy_color/src/linear_rgba.rs

@@ -1,5 +1,6 @@
 use crate::{
     color_difference::EuclideanDistance, oklaba::Oklaba, Alpha, Hsla, Luminance, Mix, Srgba,
+    StandardColor,
 };
 use bevy_math::Vec4;
 use bevy_reflect::{Reflect, ReflectDeserialize, ReflectSerialize};
@@ -20,6 +21,8 @@ pub struct LinearRgba {
     pub alpha: f32,
 }
 
+impl StandardColor for LinearRgba {}
+
 impl LinearRgba {
     /// Construct a new [`LinearRgba`] color from components.
     pub const fn new(red: f32, green: f32, blue: f32, alpha: f32) -> Self {

crates/bevy_color/src/oklaba.rs

@@ -1,5 +1,9 @@
-use crate::{color_difference::EuclideanDistance, Alpha, LinearRgba, Luminance, Mix, Srgba};
+use crate::{
+    color_difference::EuclideanDistance, Alpha, Hsla, Lcha, LinearRgba, Luminance, Mix, Srgba,
+    StandardColor,
+};
 use bevy_reflect::{Reflect, ReflectDeserialize, ReflectSerialize};
+use bevy_render::color::Color as LegacyColor;
 use serde::{Deserialize, Serialize};
 
 /// Color in Oklaba color space, with alpha
@@ -16,6 +20,8 @@ pub struct Oklaba {
     pub alpha: f32,
 }
 
+impl StandardColor for Oklaba {}
+
 impl Oklaba {
     /// Construct a new [`Oklaba`] color from components.
     ///
@@ -132,6 +138,30 @@ impl From<Srgba> for Oklaba {
     }
 }
 
+impl From<Lcha> for Oklaba {
+    fn from(value: Lcha) -> Self {
+        LinearRgba::from(value).into()
+    }
+}
+
+impl From<Hsla> for Oklaba {
+    fn from(value: Hsla) -> Self {
+        LinearRgba::from(value).into()
+    }
+}
+
+impl From<LegacyColor> for Oklaba {
+    fn from(value: LegacyColor) -> Self {
+        LinearRgba::from(value).into()
+    }
+}
+
+impl From<Oklaba> for LegacyColor {
+    fn from(value: Oklaba) -> Self {
+        LinearRgba::from(value).into()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

crates/bevy_color/src/srgba.rs

@@ -1,6 +1,6 @@
 use crate::color_difference::EuclideanDistance;
 use crate::oklaba::Oklaba;
-use crate::{Alpha, Hsla, LinearRgba, Luminance, Mix};
+use crate::{Alpha, Hsla, LinearRgba, Luminance, Mix, StandardColor};
 use bevy_math::Vec4;
 use bevy_reflect::{Reflect, ReflectDeserialize, ReflectSerialize};
 use bevy_render::color::{HexColorError, HslRepresentation, SrgbColorSpace};
@@ -20,6 +20,8 @@ pub struct Srgba {
     pub alpha: f32,
 }
 
+impl StandardColor for Srgba {}
+
 impl Srgba {
     // The standard VGA colors, with alpha set to 1.0.
     // https://en.wikipedia.org/wiki/Web_colors#Basic_colors