Struct image::math::nq::NeuQuant

pub struct NeuQuant { /* fields omitted */ }

👎 Deprecated:

Use the color_quant crate instead

Neural network color quantizer

Examples

use image::imageops::colorops::{index_colors, ColorMap};
use image::math::nq::NeuQuant;
use image::{ImageBuffer, Rgba, RgbaImage};

// Create simple color image with RGBA pixels.
let (w, h) = (2, 2);
let red: Rgba<u8> = [255, 0, 0, 255].into();
let green: Rgba<u8> = [0, 255, 0, 255].into();
let blue: Rgba<u8> = [0, 0, 255, 255].into();
let white: Rgba<u8> = [255, 255, 255, 255].into();
let mut color_image = RgbaImage::new(w, h);
color_image.put_pixel(0, 0, red);
color_image.put_pixel(1, 0, green);
color_image.put_pixel(0, 1, blue);
color_image.put_pixel(1, 1, white);

// Create a `NeuQuant` colormap that will build an approximate color palette that best matches
// the original image.
// Note, the NeuQuant algorithm is only designed to work with 6-8 bit output, so `colors`
// should be a power of 2 in the range [64, 256].
let pixels = color_image.clone().into_raw();
let cmap = NeuQuant::new(1, 256, &pixels);
// Map the original image through the color map to create an indexed image stored in a
// `GrayImage`.
let palletized = index_colors(&color_image, &cmap);
// Map indexed image back `RgbaImage`.  Note the NeuQuant algorithm creates an approximation of
// the original colors, so even in this simple example the output is not pixel equivalent to
// the original.
let mapped = ImageBuffer::from_fn(w, h, |x, y| -> Rgba<u8> {
    let p = palletized.get_pixel(x, y);
    cmap.lookup(p.0[0] as usize)
        .expect("indexed color out-of-range")
        .into()
});

Implementations

impl NeuQuant

The implementation only calls the corresponding inner color_quant methods.

These exist purely to keep a type separate from color_quant::NeuQuant and the interface stable for this major version. The type will be changed to a pure re-export in the next version or might be removed.

pub fn new(samplefac: i32, colors: usize, pixels: &[u8]) -> Self

pub fn init(&mut self, pixels: &[u8])

pub fn map_pixel(&self, pixel: &mut [u8])

pub fn index_of(&self, pixel: &[u8]) -> usize

pub fn lookup(&self, idx: usize) -> Option<[u8; 4]>

Trait Implementations

impl ColorMap for NeuQuant

type Color = Rgba<u8>

The color type on which the map operates on

fn index_of(&self, color: &Rgba<u8>) -> usize

Returns the index of the closest match of color in the color map.

fn lookup(&self, idx: usize) -> Option<Self::Color>

Looks up color by index in the color map. If idx is out of range for the color map, or ColorMap doesn’t implement lookup None is returned.

fn has_lookup(&self) -> bool

Indicate NeuQuant implements lookup.

fn map_color(&self, color: &mut Rgba<u8>)

Maps color to the closest color in the color map.

impl From<NeuQuant> for NeuQuant

fn from(inner: NeuQuant) -> Self

Performs the conversion.