Struct image::imageops::colorops::BiLevel

pub struct BiLevel;

A bi-level color map

Examples

use image::imageops::colorops::{index_colors, BiLevel, ColorMap};
use image::{ImageBuffer, Luma};

let (w, h) = (16, 16);
// Create an image with a smooth horizontal gradient from black (0) to white (255).
let gray = ImageBuffer::from_fn(w, h, |x, y| -> Luma<u8> { [(255 * x / w) as u8].into() });
// Mapping the gray image through the `BiLevel` filter should map gray pixels less than half
// intensity (127) to black (0), and anything greater to white (255).
let cmap = BiLevel;
let palletized = index_colors(&gray, &cmap);
let mapped = ImageBuffer::from_fn(w, h, |x, y| {
    let p = palletized.get_pixel(x, y);
    cmap.lookup(p.0[0] as usize)
        .expect("indexed color out-of-range")
});
// Create an black and white image of expected output.
let bw = ImageBuffer::from_fn(w, h, |x, y| -> Luma<u8> {
    if x <= (w / 2) {
        [0].into()
    } else {
        [255].into()
    }
});
assert_eq!(mapped, bw);

Trait Implementations

impl Clone for BiLevel

fn clone(&self) -> BiLevel

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl ColorMap for BiLevel

fn has_lookup(&self) -> bool

Indicate NeuQuant implements lookup.

type Color = Luma<u8>

The color type on which the map operates on

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

Maps color to the closest color in the color map.

impl Copy for BiLevel