lib.rs - source
Description: Source of the Rust file `src/lib.rs`.
Keywords: rust, rustlang, rust-lang

      1
      2
      3
      4
      5
      6
      7
      8
      9
     10
     11
     12
     13
     14
     15
     16
     17
     18
     19
     20
     21
     22
     23
     24
     25
     26
     27
     28
     29
     30
     31
     32
     33
     34
     35
     36
     37
     38
     39
     40
     41
     42
     43
     44
     45
     46
     47
     48
     49
     50
     51
     52
     53
     54
     55
     56
     57
     58
     59
     60
     61
     62
     63
     64
     65
     66
     67
     68
     69
     70
     71
     72
     73
     74
     75
     76
     77
     78
     79
     80
     81
     82
     83
     84
     85
     86
     87
     88
     89
     90
     91
     92
     93
     94
     95
     96
     97
     98
     99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150
    151
    152
    153
    154
    155
    156
    157
    158
    159
    160
    161
    162
    163
    164
    165
    166
    167
    168
    169
    170
    171
    172
    173
    174
    175
    176
    177
    178
    179
    180
    181
    182
    183
    184
    185
    186
    187
    188
    189
    190
    191
    192
    193
    194
    195
    196
    197
    198
    199
    200
    201
    202
    203
    204
    205
    206
    207
    208
    209
    210
    211
    212
    213
    214
    215
    216
    217
    218
    219
    220
    221
    222
    223
    224
    225
    226
    227
    228
    229
    230
    231
    232
    233
    234
    235
    236
    237
    238
    239
    240
    241
    242
    243
    244
    245
    246

    #![warn(missing_docs)]
    //! Calculate [Delta E](http://www.colorwiki.com/wiki/Delta_E:_The_Color_Difference)
    //! (color difference) between two colors in CIE Lab space.
    //!
    //! # Examples
    //!
    //! ```
    //! use std::error::Error;
    //! use deltae::*;
    //!
    //! fn main() -> Result<(), Box<dyn Error>>{
    //!     // Lab from a string
    //!     let lab0: LabValue = "89.73, 1.88, -6.96".parse()?;
    //!     // Lab directly from values
    //!     let lab1 = LabValue {
    //!         l: 95.08,
    //!         a: -0.17,
    //!         b: -10.81,
    //!     }.validate()?; // Validate that the values are in range
    //!
    //!     // Create your own Lab type
    //!     #[derive(Clone, Copy)]
    //!     struct MyLab(f32, f32, f32);
    //!
    //!     // Types that implement Into<LabValue> also implement the Delta trait
    //!     impl From<MyLab> for LabValue {
    //!         fn from(mylab: MyLab) -> Self {
    //!             LabValue { l: mylab.0, a: mylab.1, b: mylab.2 }
    //!         }
    //!     }
    //!     let mylab = MyLab(95.08, -0.17, -10.81);
    //!
    //!     // Implement DeltaEq for your own types
    //!     impl<D: Delta + Copy> DeltaEq<D> for MyLab {}
    //!
    //!     // Assert that colors are equivalent within a tolerance
    //!     assert_delta_eq!(mylab, lab1, DE2000, 0.0, "mylab is not equal to lab1!");
    //!
    //!     // Calculate DeltaE between two lab values
    //!     let de0 = DeltaE::new(&lab0, &lab1, DE2000);
    //!     // Use the Delta trait
    //!     let de1 = lab0.delta(lab1, DE2000);
    //!     assert_eq!(de0, de1);
    //!
    //!     // Convert to other color types
    //!     let lch0 = LchValue::from(lab0);
    //!     let xyz0 = XyzValue::from(lab1);
    //!     // If DE2000 is less than 1.0, the colors are considered equivalent
    //!     assert!(lch0.delta_eq(&lab0, DE2000, 1.0));
    //!     assert!(xyz0.delta_eq(&lab1, DE2000, 1.0));
    //!
    //!     // Calculate DeltaE between different color types
    //!     let de2 = lch0.delta(xyz0, DE2000);
    //!     assert_eq!(de2.round_to(4), de0.round_to(4));
    //!     // There is some loss of accuracy in the conversion.
    //!     // Usually rounding to 4 decimal places is more than enough.
    //!
    //!     // Recalculate DeltaE with different method
    //!     let de3 = de2.with_method(DE1976);
    //!
    //!     println!("{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n",
    //!         lab0, // [L:89.73, a:1.88, b:-6.96]
    //!         lab1, // [L:95.08, a:-0.17, b:-10.81]
    //!         lch0, // [L:89.73, c:7.2094383, h:285.11572]
    //!         xyz0, // [X:0.84574246, Y:0.8780792, Z:0.8542397]
    //!         de0,  // 5.316941
    //!         de1,  // 5.316941
    //!         de2,  // 5.316937
    //!         de3,  // 6.902717
    //!     );
    //!
    //!     Ok(())
    //! }
    //! ```

    pub mod color;
    mod convert;
    mod delta;
    pub mod eq;
    mod round;
    mod validate;

    #[cfg(test)]
    mod tests;

    pub use DEMethod::*;
    pub use color::*;
    pub use delta::*;
    pub use eq::*;
    pub use round::*;
    pub use validate::*;

    use std::fmt;
    use std::io;

    pub(crate) type ValueResult<T> = Result<T, color::ValueError>;

    /// ## The measured difference between two colors
    ///
    /// There are many different methods of calculating color difference. Different methods have a
    /// specific purpose, mainly in determining the level of tolerance for describing the difference
    /// between two colors. Regardless of the [`DEMethod`] used, [`DeltaE`] is always calculated based on the
    /// [`LabValue`]s of the two colors.
    #[derive(Debug, Clone, Copy)]
    pub struct DeltaE {
        /// The mathematical method used for calculating color difference
        method: DEMethod,
        /// The calculated Delta E value
        value: f32,
        /// The reference color
        reference: LabValue,
        /// The sample color
        sample: LabValue,
    }

    impl DeltaE {
        /// New [`DeltaE`] from two colors and a [`DEMethod`].
        /// ```
        /// use deltae::{LabValue, DeltaE, DEMethod::DE2000};
        ///
        /// let lab0 = LabValue::new(89.73, 1.88, -6.96).unwrap();
        /// let lab1 = LabValue::new(95.08, -0.17, -10.81).unwrap();
        /// let de0 = DeltaE::new(&lab0, &lab1, DE2000);
        /// assert_eq!(de0, 5.316941);
        /// ```
        #[inline]
        pub fn new<A, B>(a: A, b: B, method: DEMethod) -> DeltaE
        where A: Delta, B: Delta {
            a.delta(b, method)
        }

        /// Recalculate [`DeltaE`] with another [`DEMethod`]
        /// ```
        /// use deltae::{Delta, DeltaE, LabValue, DEMethod};
        ///
        /// let lab0 = LabValue::new(89.73, 1.88, -6.96).unwrap();
        /// let lab1 = LabValue::new(95.08, -0.17, -10.81).unwrap();
        /// let de2000 = lab0.delta(lab1, DEMethod::DE2000);
        /// let de1976 = de2000.with_method(DEMethod::DE1976);
        /// assert_eq!(de1976, 6.902716);
        /// ```
        #[inline]
        pub fn with_method(self, method: DEMethod) -> Self {
            self.reference.delta(self.sample, method)
        }

        /// Return a reference to the [`DeltaE`] method used in the calculation
        pub fn method(&self) -> &DEMethod {
            &self.method
        }

        /// Return a reference to the [`DeltaE`] value
        pub fn value(&self) -> &f32 {
            &self.value
        }

        /// Return a reference to the reference [`LabValue`] used in the calculation. A reference color
        /// is the base color to which the sample color is being compared.
        pub fn reference(&self) -> &LabValue {
            &self.reference
        }

        /// Return a reference to the sample [`LabValue`] used in the calculation. A sample color is
        /// the color being compared to the reference color.
        pub fn sample(&self) -> &LabValue {
            &self.sample
        }
    }

    impl fmt::Display for DeltaE {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            write!(f, "{}", &self.value)
        }
    }

    impl PartialEq<f32> for DeltaE {
        fn eq(&self, f: &f32) -> bool {
            &self.value == f
        }
    }

    impl PartialEq for DeltaE {
        fn eq(&self, other: &Self) -> bool {
            self.value == other.value
        }
    }

    /// One should be careful when ordering DeltaE. A `DE2000:1.0` value is not
    /// necessarily the same amount of color difference as a amount of color
    /// difference `DE1976:1.0` value.
    impl PartialOrd for DeltaE {
        fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
            self.value.partial_cmp(&other.value)
        }
    }

    /// The most common DeltaE methods
    #[derive(Debug, PartialEq, Clone, Copy)]
    pub enum DEMethod{
        /// The default DeltaE method
        DE2000,
        /// An implementation of DeltaE with separate tolerances for Lightness and Chroma
        DECMC(
            /// Lightness tolerance
            f32,
            /// Chroma tolerance
            f32,
        ),
        /// CIE94 DeltaE implementation, weighted with a tolerance for graphics
        DE1994G,
        /// CIE94 DeltaE implementation, weighted with a tolerance for textiles
        DE1994T,
        /// The original DeltaE implementation, a basic euclidian distance formula
        DE1976,
    }

    /// DeltaE CMC (1:1)
    pub const DECMC1: DEMethod = DECMC(1.0, 1.0);
    /// DeltaE CMC (2:1)
    pub const DECMC2: DEMethod = DECMC(2.0, 1.0);

    impl Eq for DEMethod {}

    impl Default for DEMethod {
        fn default() -> DEMethod {
            DEMethod::DE2000
        }
    }

    impl fmt::Display for DEMethod {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            match self {
                DECMC(tl, tc) => {
                    if (tl, tc) == (&1.0, &1.0) {
                        write!(f, "DECMC1")
                    } else if (tl, tc) == (&2.0, &1.0) {
                        write!(f, "DECMC2")
                    } else {
                        write!(f, "DECMC({:0.2}:{:0.2})", tl, tc)
                    }
                }
                _ => write!(f, "{:?}", self)
            }
        }
    }