# Crate deltae

Expand description

Calculate Delta E (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(())
}``````

## Re-exports

• `pub use DEMethod::*;`
• `pub use color::*;`
• `pub use eq::*;`

## Modules

• Manipulate and convert CIE L*a*b* and Lch colors.
• `Tolerance` and `DeltaEq` traits

## Macros

• Convenience macro for asserting two values are equivalent within a tolerance
• Convenience macro for asserting two values are equivalent within a tolerance

## Structs

• The measured difference between two colors

## Traits

• Trait to determine color difference between various types. As long as the type can be converted to Lab, we can calculate DeltaE.
• Trait for rounding values to a number of decimal places
• Trait to validate whether a type has appropriate values