Function dominant_hue
pub fn dominant_hue(pixels: &[u8]) -> Option<f32>Expand description
The dominant OKLCH hue of an RGBA8 image (pixels.len() a multiple of
four), or None for an image with no hue to speak of.
Cheap and deterministic: a fixed stride of at most [HUE_SAMPLES] pixels,
each voting for its hue with its chroma (greys do not vote, transparent
pixels do not vote), into a 10° histogram smoothed over its neighbours.
The peak bin’s chroma-weighted circular mean is the answer. Only the hue
is reported: a caller deriving a neutral temperature from a wallpaper
takes its hue and never its chroma.