Add trait for clamping colors (#12525)

# Objective

- Resolves #12463 

## Solution

- Added `ClampColor`
Due to consistency, `is_within_bounds` is a method of `ClampColor`, like
`is_fully_transparent` is a method of `Alpha`

---

## Changelog

### Added
- `ClampColor` trait

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>

crates/bevy_color/src/color_ops.rs

@@ -61,3 +61,20 @@ pub trait Alpha: Sized {
         self.alpha() >= 1.0
     }
 }
+
+/// Trait with methods for asserting a colorspace is within bounds.
+///
+/// During ordinary usage (e.g. reading images from disk, rendering images, picking colors for UI), colors should always be within their ordinary bounds (such as 0 to 1 for RGB colors).
+/// However, some applications, such as high dynamic range rendering or bloom rely on unbounded colors to naturally represent a wider array of choices.
+pub trait ClampColor: Sized {
+    /// Return a new version of this color clamped, with all fields in bounds.
+    fn clamped(&self) -> Self;
+
+    /// Changes all the fields of this color to ensure they are within bounds.
+    fn clamp(&mut self) {
+        *self = self.clamped();
+    }
+
+    /// Are all the fields of this color in bounds?
+    fn is_within_bounds(&self) -> bool;
+}

crates/bevy_color/src/hsla.rs

@@ -1,4 +1,6 @@
-use crate::{Alpha, Hsva, Hwba, Lcha, LinearRgba, Luminance, Mix, Srgba, StandardColor, Xyza};
+use crate::{
+    Alpha, ClampColor, Hsva, Hwba, Lcha, LinearRgba, Luminance, Mix, Srgba, StandardColor, Xyza,
+};
 use bevy_reflect::prelude::*;
 use serde::{Deserialize, Serialize};
 
@@ -166,6 +168,24 @@ impl Luminance for Hsla {
     }
 }
 
+impl ClampColor for Hsla {
+    fn clamped(&self) -> Self {
+        Self {
+            hue: self.hue.rem_euclid(360.),
+            saturation: self.saturation.clamp(0., 1.),
+            lightness: self.lightness.clamp(0., 1.),
+            alpha: self.alpha.clamp(0., 1.),
+        }
+    }
+
+    fn is_within_bounds(&self) -> bool {
+        (0. ..=360.).contains(&self.hue)
+            && (0. ..=1.).contains(&self.saturation)
+            && (0. ..=1.).contains(&self.lightness)
+            && (0. ..=1.).contains(&self.alpha)
+    }
+}
+
 impl From<Hsla> for Hsva {
     fn from(
         Hsla {
@@ -357,4 +377,21 @@ mod tests {
             assert_approx_eq!(color.hue, reference.hue, 0.001);
         }
     }
+
+    #[test]
+    fn test_clamp() {
+        let color_1 = Hsla::hsl(361., 2., -1.);
+        let color_2 = Hsla::hsl(250.2762, 1., 0.67);
+        let mut color_3 = Hsla::hsl(-50., 1., 1.);
+
+        assert!(!color_1.is_within_bounds());
+        assert_eq!(color_1.clamped(), Hsla::hsl(1., 1., 0.));
+
+        assert!(color_2.is_within_bounds());
+        assert_eq!(color_2, color_2.clamped());
+
+        color_3.clamp();
+        assert!(color_3.is_within_bounds());
+        assert_eq!(color_3, Hsla::hsl(310., 1., 1.));
+    }
 }

crates/bevy_color/src/hsva.rs

@@ -1,4 +1,4 @@
-use crate::{Alpha, Hwba, Lcha, LinearRgba, Srgba, StandardColor, Xyza};
+use crate::{Alpha, ClampColor, Hwba, Lcha, LinearRgba, Srgba, StandardColor, Xyza};
 use bevy_reflect::prelude::*;
 use serde::{Deserialize, Serialize};
 
@@ -91,6 +91,24 @@ impl Alpha for Hsva {
     }
 }
 
+impl ClampColor for Hsva {
+    fn clamped(&self) -> Self {
+        Self {
+            hue: self.hue.rem_euclid(360.),
+            saturation: self.saturation.clamp(0., 1.),
+            value: self.value.clamp(0., 1.),
+            alpha: self.alpha.clamp(0., 1.),
+        }
+    }
+
+    fn is_within_bounds(&self) -> bool {
+        (0. ..=360.).contains(&self.hue)
+            && (0. ..=1.).contains(&self.saturation)
+            && (0. ..=1.).contains(&self.value)
+            && (0. ..=1.).contains(&self.alpha)
+    }
+}
+
 impl From<Hsva> for Hwba {
     fn from(
         Hsva {
@@ -212,4 +230,21 @@ mod tests {
             assert_approx_eq!(color.hsv.alpha, hsv2.alpha, 0.001);
         }
     }
+
+    #[test]
+    fn test_clamp() {
+        let color_1 = Hsva::hsv(361., 2., -1.);
+        let color_2 = Hsva::hsv(250.2762, 1., 0.67);
+        let mut color_3 = Hsva::hsv(-50., 1., 1.);
+
+        assert!(!color_1.is_within_bounds());
+        assert_eq!(color_1.clamped(), Hsva::hsv(1., 1., 0.));
+
+        assert!(color_2.is_within_bounds());
+        assert_eq!(color_2, color_2.clamped());
+
+        color_3.clamp();
+        assert!(color_3.is_within_bounds());
+        assert_eq!(color_3, Hsva::hsv(310., 1., 1.));
+    }
 }

crates/bevy_color/src/hwba.rs

@@ -2,7 +2,7 @@
 //! in [_HWB - A More Intuitive Hue-Based Color Model_] by _Smith et al_.
 //!
 //! [_HWB - A More Intuitive Hue-Based Color Model_]: https://web.archive.org/web/20240226005220/http://alvyray.com/Papers/CG/HWB_JGTv208.pdf
-use crate::{Alpha, Lcha, LinearRgba, Srgba, StandardColor, Xyza};
+use crate::{Alpha, ClampColor, Lcha, LinearRgba, Srgba, StandardColor, Xyza};
 use bevy_reflect::prelude::*;
 use serde::{Deserialize, Serialize};
 
@@ -95,6 +95,24 @@ impl Alpha for Hwba {
     }
 }
 
+impl ClampColor for Hwba {
+    fn clamped(&self) -> Self {
+        Self {
+            hue: self.hue.rem_euclid(360.),
+            whiteness: self.whiteness.clamp(0., 1.),
+            blackness: self.blackness.clamp(0., 1.),
+            alpha: self.alpha.clamp(0., 1.),
+        }
+    }
+
+    fn is_within_bounds(&self) -> bool {
+        (0. ..=360.).contains(&self.hue)
+            && (0. ..=1.).contains(&self.whiteness)
+            && (0. ..=1.).contains(&self.blackness)
+            && (0. ..=1.).contains(&self.alpha)
+    }
+}
+
 impl From<Srgba> for Hwba {
     fn from(
         Srgba {
@@ -245,4 +263,21 @@ mod tests {
             assert_approx_eq!(color.hwb.alpha, hwb2.alpha, 0.001);
         }
     }
+
+    #[test]
+    fn test_clamp() {
+        let color_1 = Hwba::hwb(361., 2., -1.);
+        let color_2 = Hwba::hwb(250.2762, 1., 0.67);
+        let mut color_3 = Hwba::hwb(-50., 1., 1.);
+
+        assert!(!color_1.is_within_bounds());
+        assert_eq!(color_1.clamped(), Hwba::hwb(1., 1., 0.));
+
+        assert!(color_2.is_within_bounds());
+        assert_eq!(color_2, color_2.clamped());
+
+        color_3.clamp();
+        assert!(color_3.is_within_bounds());
+        assert_eq!(color_3, Hwba::hwb(310., 1., 1.));
+    }
 }

crates/bevy_color/src/laba.rs

@@ -1,5 +1,6 @@
 use crate::{
-    Alpha, Hsla, Hsva, Hwba, LinearRgba, Luminance, Mix, Oklaba, Srgba, StandardColor, Xyza,
+    Alpha, ClampColor, Hsla, Hsva, Hwba, LinearRgba, Luminance, Mix, Oklaba, Srgba, StandardColor,
+    Xyza,
 };
 use bevy_reflect::prelude::*;
 use serde::{Deserialize, Serialize};
@@ -110,6 +111,24 @@ impl Alpha for Laba {
     }
 }
 
+impl ClampColor for Laba {
+    fn clamped(&self) -> Self {
+        Self {
+            lightness: self.lightness.clamp(0., 1.5),
+            a: self.a.clamp(-1.5, 1.5),
+            b: self.b.clamp(-1.5, 1.5),
+            alpha: self.alpha.clamp(0., 1.),
+        }
+    }
+
+    fn is_within_bounds(&self) -> bool {
+        (0. ..=1.5).contains(&self.lightness)
+            && (-1.5..=1.5).contains(&self.a)
+            && (-1.5..=1.5).contains(&self.b)
+            && (0. ..=1.).contains(&self.alpha)
+    }
+}
+
 impl Luminance for Laba {
     #[inline]
     fn with_luminance(&self, lightness: f32) -> Self {
@@ -353,4 +372,21 @@ mod tests {
             assert_approx_eq!(color.lab.alpha, laba.alpha, 0.001);
         }
     }
+
+    #[test]
+    fn test_clamp() {
+        let color_1 = Laba::lab(-1., 2., -2.);
+        let color_2 = Laba::lab(1., 1.5, -1.2);
+        let mut color_3 = Laba::lab(-0.4, 1., 1.);
+
+        assert!(!color_1.is_within_bounds());
+        assert_eq!(color_1.clamped(), Laba::lab(0., 1.5, -1.5));
+
+        assert!(color_2.is_within_bounds());
+        assert_eq!(color_2, color_2.clamped());
+
+        color_3.clamp();
+        assert!(color_3.is_within_bounds());
+        assert_eq!(color_3, Laba::lab(0., 1., 1.));
+    }
 }

crates/bevy_color/src/lcha.rs

@@ -1,4 +1,4 @@
-use crate::{Alpha, Laba, LinearRgba, Luminance, Mix, Srgba, StandardColor, Xyza};
+use crate::{Alpha, ClampColor, Laba, LinearRgba, Luminance, Mix, Srgba, StandardColor, Xyza};
 use bevy_reflect::prelude::*;
 use serde::{Deserialize, Serialize};
 
@@ -166,6 +166,24 @@ impl Luminance for Lcha {
     }
 }
 
+impl ClampColor for Lcha {
+    fn clamped(&self) -> Self {
+        Self {
+            lightness: self.lightness.clamp(0., 1.5),
+            chroma: self.chroma.clamp(0., 1.5),
+            hue: self.hue.rem_euclid(360.),
+            alpha: self.alpha.clamp(0., 1.),
+        }
+    }
+
+    fn is_within_bounds(&self) -> bool {
+        (0. ..=1.5).contains(&self.lightness)
+            && (0. ..=1.5).contains(&self.chroma)
+            && (0. ..=360.).contains(&self.hue)
+            && (0. ..=1.).contains(&self.alpha)
+    }
+}
+
 impl From<Lcha> for Laba {
     fn from(
         Lcha {
@@ -313,4 +331,21 @@ mod tests {
             assert_approx_eq!(color.lch.alpha, lcha.alpha, 0.001);
         }
     }
+
+    #[test]
+    fn test_clamp() {
+        let color_1 = Lcha::lch(-1., 2., 400.);
+        let color_2 = Lcha::lch(1., 1.5, 249.54);
+        let mut color_3 = Lcha::lch(-0.4, 1., 1.);
+
+        assert!(!color_1.is_within_bounds());
+        assert_eq!(color_1.clamped(), Lcha::lch(0., 1.5, 40.));
+
+        assert!(color_2.is_within_bounds());
+        assert_eq!(color_2, color_2.clamped());
+
+        color_3.clamp();
+        assert!(color_3.is_within_bounds());
+        assert_eq!(color_3, Lcha::lch(0., 1., 1.));
+    }
 }

crates/bevy_color/src/linear_rgba.rs

@@ -1,6 +1,8 @@
 use std::ops::{Div, Mul};
 
-use crate::{color_difference::EuclideanDistance, Alpha, Luminance, Mix, StandardColor};
+use crate::{
+    color_difference::EuclideanDistance, Alpha, ClampColor, Luminance, Mix, StandardColor,
+};
 use bevy_math::Vec4;
 use bevy_reflect::prelude::*;
 use bytemuck::{Pod, Zeroable};
@@ -256,6 +258,24 @@ impl EuclideanDistance for LinearRgba {
     }
 }
 
+impl ClampColor for LinearRgba {
+    fn clamped(&self) -> Self {
+        Self {
+            red: self.red.clamp(0., 1.),
+            green: self.green.clamp(0., 1.),
+            blue: self.blue.clamp(0., 1.),
+            alpha: self.alpha.clamp(0., 1.),
+        }
+    }
+
+    fn is_within_bounds(&self) -> bool {
+        (0. ..=1.).contains(&self.red)
+            && (0. ..=1.).contains(&self.green)
+            && (0. ..=1.).contains(&self.blue)
+            && (0. ..=1.).contains(&self.alpha)
+    }
+}
+
 impl From<LinearRgba> for [f32; 4] {
     fn from(color: LinearRgba) -> Self {
         [color.red, color.green, color.blue, color.alpha]
@@ -455,4 +475,21 @@ mod tests {
         let twice_as_light = color.lighter(0.2);
         assert!(lighter2.distance_squared(&twice_as_light) < 0.0001);
     }
+
+    #[test]
+    fn test_clamp() {
+        let color_1 = LinearRgba::rgb(2., -1., 0.4);
+        let color_2 = LinearRgba::rgb(0.031, 0.749, 1.);
+        let mut color_3 = LinearRgba::rgb(-1., 1., 1.);
+
+        assert!(!color_1.is_within_bounds());
+        assert_eq!(color_1.clamped(), LinearRgba::rgb(1., 0., 0.4));
+
+        assert!(color_2.is_within_bounds());
+        assert_eq!(color_2, color_2.clamped());
+
+        color_3.clamp();
+        assert!(color_3.is_within_bounds());
+        assert_eq!(color_3, LinearRgba::rgb(0., 1., 1.));
+    }
 }

crates/bevy_color/src/oklaba.rs

@@ -1,6 +1,6 @@
 use crate::{
-    color_difference::EuclideanDistance, Alpha, Hsla, Hsva, Hwba, Lcha, LinearRgba, Luminance, Mix,
+    color_difference::EuclideanDistance, Alpha, ClampColor, Hsla, Hsva, Hwba, Lcha, LinearRgba,
-    Srgba, StandardColor, Xyza,
+    Luminance, Mix, Srgba, StandardColor, Xyza,
 };
 use bevy_reflect::prelude::*;
 use serde::{Deserialize, Serialize};
@@ -149,6 +149,24 @@ impl EuclideanDistance for Oklaba {
     }
 }
 
+impl ClampColor for Oklaba {
+    fn clamped(&self) -> Self {
+        Self {
+            lightness: self.lightness.clamp(0., 1.),
+            a: self.a.clamp(-1., 1.),
+            b: self.b.clamp(-1., 1.),
+            alpha: self.alpha.clamp(0., 1.),
+        }
+    }
+
+    fn is_within_bounds(&self) -> bool {
+        (0. ..=1.).contains(&self.lightness)
+            && (-1. ..=1.).contains(&self.a)
+            && (-1. ..=1.).contains(&self.b)
+            && (0. ..=1.).contains(&self.alpha)
+    }
+}
+
 #[allow(clippy::excessive_precision)]
 impl From<LinearRgba> for Oklaba {
     fn from(value: LinearRgba) -> Self {
@@ -326,4 +344,21 @@ mod tests {
         assert_approx_eq!(oklaba.b, oklaba2.b, 0.001);
         assert_approx_eq!(oklaba.alpha, oklaba2.alpha, 0.001);
     }
+
+    #[test]
+    fn test_clamp() {
+        let color_1 = Oklaba::lab(-1., 2., -2.);
+        let color_2 = Oklaba::lab(1., 0.42, -0.4);
+        let mut color_3 = Oklaba::lab(-0.4, 1., 1.);
+
+        assert!(!color_1.is_within_bounds());
+        assert_eq!(color_1.clamped(), Oklaba::lab(0., 1., -1.));
+
+        assert!(color_2.is_within_bounds());
+        assert_eq!(color_2, color_2.clamped());
+
+        color_3.clamp();
+        assert!(color_3.is_within_bounds());
+        assert_eq!(color_3, Oklaba::lab(0., 1., 1.));
+    }
 }

crates/bevy_color/src/oklcha.rs

@@ -1,6 +1,6 @@
 use crate::{
-    color_difference::EuclideanDistance, Alpha, Hsla, Hsva, Hwba, Laba, Lcha, LinearRgba,
+    color_difference::EuclideanDistance, Alpha, ClampColor, Hsla, Hsva, Hwba, Laba, Lcha,
-    Luminance, Mix, Oklaba, Srgba, StandardColor, Xyza,
+    LinearRgba, Luminance, Mix, Oklaba, Srgba, StandardColor, Xyza,
 };
 use bevy_reflect::prelude::*;
 use serde::{Deserialize, Serialize};
@@ -209,6 +209,24 @@ impl From<Oklcha> for Oklaba {
     }
 }
 
+impl ClampColor for Oklcha {
+    fn clamped(&self) -> Self {
+        Self {
+            lightness: self.lightness.clamp(0., 1.),
+            chroma: self.chroma.clamp(0., 1.),
+            hue: self.hue.rem_euclid(360.),
+            alpha: self.alpha.clamp(0., 1.),
+        }
+    }
+
+    fn is_within_bounds(&self) -> bool {
+        (0. ..=1.).contains(&self.lightness)
+            && (0. ..=1.).contains(&self.chroma)
+            && (0. ..=360.).contains(&self.hue)
+            && (0. ..=1.).contains(&self.alpha)
+    }
+}
+
 // Derived Conversions
 
 impl From<Hsla> for Oklcha {
@@ -355,4 +373,21 @@ mod tests {
         assert_approx_eq!(oklcha.hue, oklcha2.hue, 0.001);
         assert_approx_eq!(oklcha.alpha, oklcha2.alpha, 0.001);
     }
+
+    #[test]
+    fn test_clamp() {
+        let color_1 = Oklcha::lch(-1., 2., 400.);
+        let color_2 = Oklcha::lch(1., 1., 249.54);
+        let mut color_3 = Oklcha::lch(-0.4, 1., 1.);
+
+        assert!(!color_1.is_within_bounds());
+        assert_eq!(color_1.clamped(), Oklcha::lch(0., 1., 40.));
+
+        assert!(color_2.is_within_bounds());
+        assert_eq!(color_2, color_2.clamped());
+
+        color_3.clamp();
+        assert!(color_3.is_within_bounds());
+        assert_eq!(color_3, Oklcha::lch(0., 1., 1.));
+    }
 }

crates/bevy_color/src/srgba.rs

@@ -1,7 +1,7 @@
 use std::ops::{Div, Mul};
 
 use crate::color_difference::EuclideanDistance;
-use crate::{Alpha, LinearRgba, Luminance, Mix, StandardColor, Xyza};
+use crate::{Alpha, ClampColor, LinearRgba, Luminance, Mix, StandardColor, Xyza};
 use bevy_math::Vec4;
 use bevy_reflect::prelude::*;
 use serde::{Deserialize, Serialize};
@@ -307,6 +307,24 @@ impl EuclideanDistance for Srgba {
     }
 }
 
+impl ClampColor for Srgba {
+    fn clamped(&self) -> Self {
+        Self {
+            red: self.red.clamp(0., 1.),
+            green: self.green.clamp(0., 1.),
+            blue: self.blue.clamp(0., 1.),
+            alpha: self.alpha.clamp(0., 1.),
+        }
+    }
+
+    fn is_within_bounds(&self) -> bool {
+        (0. ..=1.).contains(&self.red)
+            && (0. ..=1.).contains(&self.green)
+            && (0. ..=1.).contains(&self.blue)
+            && (0. ..=1.).contains(&self.alpha)
+    }
+}
+
 impl From<LinearRgba> for Srgba {
     #[inline]
     fn from(value: LinearRgba) -> Self {
@@ -490,4 +508,21 @@ mod tests {
         assert!(matches!(Srgba::hex("yyy"), Err(HexColorError::Parse(_))));
         assert!(matches!(Srgba::hex("##fff"), Err(HexColorError::Parse(_))));
     }
+
+    #[test]
+    fn test_clamp() {
+        let color_1 = Srgba::rgb(2., -1., 0.4);
+        let color_2 = Srgba::rgb(0.031, 0.749, 1.);
+        let mut color_3 = Srgba::rgb(-1., 1., 1.);
+
+        assert!(!color_1.is_within_bounds());
+        assert_eq!(color_1.clamped(), Srgba::rgb(1., 0., 0.4));
+
+        assert!(color_2.is_within_bounds());
+        assert_eq!(color_2, color_2.clamped());
+
+        color_3.clamp();
+        assert!(color_3.is_within_bounds());
+        assert_eq!(color_3, Srgba::rgb(0., 1., 1.));
+    }
 }

crates/bevy_color/src/xyza.rs

@@ -1,4 +1,4 @@
-use crate::{Alpha, LinearRgba, Luminance, Mix, StandardColor};
+use crate::{Alpha, ClampColor, LinearRgba, Luminance, Mix, StandardColor};
 use bevy_reflect::prelude::*;
 use serde::{Deserialize, Serialize};
 
@@ -134,6 +134,24 @@ impl Mix for Xyza {
     }
 }
 
+impl ClampColor for Xyza {
+    fn clamped(&self) -> Self {
+        Self {
+            x: self.x.clamp(0., 1.),
+            y: self.y.clamp(0., 1.),
+            z: self.z.clamp(0., 1.),
+            alpha: self.alpha.clamp(0., 1.),
+        }
+    }
+
+    fn is_within_bounds(&self) -> bool {
+        (0. ..=1.).contains(&self.x)
+            && (0. ..=1.).contains(&self.y)
+            && (0. ..=1.).contains(&self.z)
+            && (0. ..=1.).contains(&self.alpha)
+    }
+}
+
 impl From<LinearRgba> for Xyza {
     fn from(
         LinearRgba {
@@ -208,4 +226,21 @@ mod tests {
             assert_approx_eq!(color.xyz.alpha, xyz2.alpha, 0.001);
         }
     }
+
+    #[test]
+    fn test_clamp() {
+        let color_1 = Xyza::xyz(2., -1., 0.4);
+        let color_2 = Xyza::xyz(0.031, 0.749, 1.);
+        let mut color_3 = Xyza::xyz(-1., 1., 1.);
+
+        assert!(!color_1.is_within_bounds());
+        assert_eq!(color_1.clamped(), Xyza::xyz(1., 0., 0.4));
+
+        assert!(color_2.is_within_bounds());
+        assert_eq!(color_2, color_2.clamped());
+
+        color_3.clamp();
+        assert!(color_3.is_within_bounds());
+        assert_eq!(color_3, Xyza::xyz(0., 1., 1.));
+    }
 }