增加颜色对比中的相对值对比方法。

color-module/src/color_differ/cam16jch.rs

@@ -35,4 +35,38 @@ impl ColorDifference for Cam16Jch<f32> {
             },
         }
     }
+
+    fn difference_relative(&self, other: &Self) -> Self::Difference {
+        let hue = if self.hue.into_positive_degrees() == 0.0 {
+            0.0
+        } else {
+            (other.hue.into_positive_degrees() - self.hue.into_positive_degrees())
+                / (1.0 - self.hue.into_positive_degrees())
+        };
+        let chroma = if self.chroma == 0.0 {
+            0.0
+        } else {
+            (other.chroma - self.chroma) / self.chroma
+        };
+        let lightness = if self.lightness == 0.0 {
+            0.0
+        } else {
+            (other.lightness - self.lightness) / self.lightness
+        };
+
+        HctDiffference {
+            hue: Differ {
+                delta: other.hue.into_positive_degrees() - self.hue.into_positive_degrees(),
+                percent: hue,
+            },
+            chroma: Differ {
+                delta: other.chroma - self.chroma,
+                percent: chroma,
+            },
+            lightness: Differ {
+                delta: other.lightness - self.lightness,
+                percent: lightness,
+            },
+        }
+    }
 }

color-module/src/color_differ/hsl.rs

@@ -35,4 +35,38 @@ impl ColorDifference for Hsl {
             },
         }
     }
+
+    fn difference_relative(&self, other: &Self) -> Self::Difference {
+        let hue = if self.hue.into_positive_degrees() == 0.0 {
+            0.0
+        } else {
+            (other.hue.into_positive_degrees() - self.hue.into_positive_degrees())
+                / (1.0 - self.hue.into_positive_degrees())
+        };
+        let saturation = if self.saturation == 0.0 {
+            0.0
+        } else {
+            (other.saturation - self.saturation) / (1.0 - self.saturation)
+        };
+        let lightness = if self.lightness == 0.0 {
+            0.0
+        } else {
+            (other.lightness - self.lightness) / (1.0 - self.lightness)
+        };
+
+        HSLDifference {
+            hue: Differ {
+                delta: other.hue.into_positive_degrees() - self.hue.into_positive_degrees(),
+                percent: hue,
+            },
+            saturation: Differ {
+                delta: other.saturation - self.saturation,
+                percent: saturation,
+            },
+            lightness: Differ {
+                delta: other.lightness - self.lightness,
+                percent: lightness,
+            },
+        }
+    }
 }

color-module/src/color_differ/mod.rs

@@ -17,4 +17,5 @@ pub trait ColorDifference {
     type Difference;
 
     fn difference(&self, other: &Self) -> Self::Difference;
+    fn difference_relative(&self, other: &Self) -> Self::Difference;
 }

color-module/src/color_differ/oklch.rs

@@ -35,4 +35,38 @@ impl ColorDifference for Oklch {
             },
         }
     }
+
+    fn difference_relative(&self, other: &Self) -> Self::Difference {
+        let hue = if self.hue.into_positive_degrees() == 0.0 {
+            0.0
+        } else {
+            (other.hue.into_positive_degrees() - self.hue.into_positive_degrees())
+                / (1.0 - self.hue.into_positive_degrees())
+        };
+        let chroma = if self.chroma == 0.0 {
+            0.0
+        } else {
+            (other.chroma - self.chroma) / self.chroma
+        };
+        let lightness = if self.l == 0.0 {
+            0.0
+        } else {
+            (other.l - self.l) / (1.0 - self.l)
+        };
+
+        OklchDifference {
+            hue: Differ {
+                delta: other.hue.into_positive_degrees() - self.hue.into_positive_degrees(),
+                percent: hue,
+            },
+            chroma: Differ {
+                delta: other.chroma - self.chroma,
+                percent: chroma,
+            },
+            lightness: Differ {
+                delta: other.l - self.l,
+                percent: lightness,
+            },
+        }
+    }
 }

color-module/src/color_differ/rgb.rs

@@ -35,4 +35,37 @@ impl ColorDifference for Srgb {
             },
         }
     }
+
+    fn difference_relative(&self, other: &Self) -> Self::Difference {
+        let r = if self.red == 0.0 {
+            0.0
+        } else {
+            (other.red - self.red) / (1.0 - self.red)
+        };
+        let g = if self.green == 0.0 {
+            0.0
+        } else {
+            (other.green - self.green) / (1.0 - self.green)
+        };
+        let b = if self.blue == 0.0 {
+            0.0
+        } else {
+            (other.blue - self.blue) / (1.0 - self.blue)
+        };
+
+        RGBDifference {
+            r: Differ {
+                delta: other.red - self.red,
+                percent: r,
+            },
+            g: Differ {
+                delta: other.green - self.green,
+                percent: g,
+            },
+            b: Differ {
+                delta: other.blue - self.blue,
+                percent: b,
+            },
+        }
+    }
 }

color-module/src/lib.rs

@@ -440,6 +440,20 @@ pub fn differ_in_rgb(
     Ok(srgb.difference(&other_srgb))
 }
 
+#[wasm_bindgen]
+pub fn relative_differ_in_rgb(
+    color: &str,
+    other: &str,
+) -> Result<color_differ::rgb::RGBDifference, errors::ColorError> {
+    let srgb = Srgb::from_str(color)
+        .map_err(|_| errors::ColorError::UnrecogniazedRGB(color.to_string()))?
+        .into_format::<f32>();
+    let other_srgb = Srgb::from_str(other)
+        .map_err(|_| errors::ColorError::UnrecogniazedRGB(other.to_string()))?
+        .into_format::<f32>();
+    Ok(srgb.difference_relative(&other_srgb))
+}
+
 #[wasm_bindgen]
 pub fn differ_in_hsl(
     color: &str,
@@ -458,6 +472,24 @@ pub fn differ_in_hsl(
     Ok(hsl.difference(&other_hsl))
 }
 
+#[wasm_bindgen]
+pub fn relative_differ_in_hsl(
+    color: &str,
+    other: &str,
+) -> Result<color_differ::hsl::HSLDifference, errors::ColorError> {
+    let hsl = Hsl::from_color(
+        Srgb::from_str(color)
+            .map_err(|_| errors::ColorError::UnrecogniazedRGB(color.to_string()))?
+            .into_format::<f32>(),
+    );
+    let other_hsl = Hsl::from_color(
+        Srgb::from_str(other)
+            .map_err(|_| errors::ColorError::UnrecogniazedRGB(other.to_string()))?
+            .into_format::<f32>(),
+    );
+    Ok(hsl.difference_relative(&other_hsl))
+}
+
 #[wasm_bindgen]
 pub fn differ_in_hct(
     color: &str,
@@ -480,6 +512,28 @@ pub fn differ_in_hct(
     Ok(hct.difference(&other_hct))
 }
 
+#[wasm_bindgen]
+pub fn relative_differ_in_hct(
+    color: &str,
+    other: &str,
+) -> Result<color_differ::cam16jch::HctDiffference, errors::ColorError> {
+    let hct = Cam16Jch::from_xyz(
+        Srgb::from_str(color)
+            .map_err(|_| errors::ColorError::UnrecogniazedRGB(color.to_string()))?
+            .into_format::<f32>()
+            .into_color(),
+        Parameters::default_static_wp(40.0),
+    );
+    let other_hct = Cam16Jch::from_xyz(
+        Srgb::from_str(other)
+            .map_err(|_| errors::ColorError::UnrecogniazedRGB(other.to_string()))?
+            .into_format::<f32>()
+            .into_color(),
+        Parameters::default_static_wp(40.0),
+    );
+    Ok(hct.difference_relative(&other_hct))
+}
+
 #[wasm_bindgen]
 pub fn differ_in_oklch(
     color: &str,
@@ -498,6 +552,24 @@ pub fn differ_in_oklch(
     Ok(oklch.difference(&other_oklch))
 }
 
+#[wasm_bindgen]
+pub fn relative_differ_in_oklch(
+    color: &str,
+    other: &str,
+) -> Result<color_differ::oklch::OklchDifference, errors::ColorError> {
+    let oklch = Oklch::from_color(
+        Srgb::from_str(color)
+            .map_err(|_| errors::ColorError::UnrecogniazedRGB(color.to_string()))?
+            .into_format::<f32>(),
+    );
+    let other_oklch = Oklch::from_color(
+        Srgb::from_str(other)
+            .map_err(|_| errors::ColorError::UnrecogniazedRGB(other.to_string()))?
+            .into_format::<f32>(),
+    );
+    Ok(oklch.difference_relative(&other_oklch))
+}
+
 #[wasm_bindgen]
 pub fn tint_scale(
     basic_color: &str,