swatchthis 0.2.0

Colour swatch extraction from images using k-means clustering
Documentation 
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use crate::color::Rgb;

/// A colour swatch extracted from an image.
///
/// Contains the dominant colour and the number of pixels assigned to it
/// during clustering.
///
/// # Example
///
/// ```
/// use swatchthis::color::Rgb;
/// use swatchthis::swatch::Swatch;
///
/// let swatch = Swatch::new(Rgb::new(255, 0, 0), 120);
/// assert_eq!(swatch.hex(), "#ff0000");
/// assert_eq!(swatch.population, 120);
/// ```
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Swatch {
    pub color: Rgb,
    pub population: u32,
}

impl Swatch {
    pub fn new(color: Rgb, population: u32) -> Self {
        Self { color, population }
    }

    /// Returns the colour as a lowercase hex string (e.g. `"#ff0000"`).
    pub fn hex(&self) -> String {
        self.color.to_hex()
    }

    /// Returns the complementary colour swatch (hue rotated 180° in HSL space).
    pub fn complement(&self) -> Swatch {
        let rgb = self.color.to_hsl().complement().to_rgb();
        Swatch::new(rgb, self.population)
    }
}

/// Returns the complementary swatch for each input swatch.
pub fn complementary_swatches(swatches: &[Swatch]) -> Vec<Swatch> {
    swatches.iter().map(|s| s.complement()).collect()
}

pub fn swatches_to_json(swatches: &[Swatch]) -> String {
    let entries: Vec<String> = swatches
        .iter()
        .map(|s| {
            format!(
                r#"{{"hex":"{}","r":{},"g":{},"b":{},"population":{}}}"#,
                s.hex(),
                s.color.r,
                s.color.g,
                s.color.b,
                s.population
            )
        })
        .collect();
    format!("[{}]", entries.join(","))
}