Function distance_transform

pub fn distance_transform(image: &GrayImage, norm: Norm) -> GrayImage

Returns an image showing the distance of each pixel from a foreground pixel in the original image.

A pixel belongs to the foreground if it has non-zero intensity. As the image has a bit-depth of 8, distances saturate at 255.

Examples

use image::GrayImage;
use imageproc::distance_transform::{distance_transform, Norm};

let image = gray_image!(
    0,   0,   0,   0,   0;
    0,   0,   0,   0,   0;
    0,   0,   1,   0,   0;
    0,   0,   0,   0,   0;
    0,   0,   0,   0,   0
);

// L1 norm
let l1_distances = gray_image!(
    4,   3,   2,   3,   4;
    3,   2,   1,   2,   3;
    2,   1,   0,   1,   2;
    3,   2,   1,   2,   3;
    4,   3,   2,   3,   4
);

assert_pixels_eq!(distance_transform(&image, Norm::L1), l1_distances);

// LInf norm
let linf_distances = gray_image!(
    2,   2,   2,   2,   2;
    2,   1,   1,   1,   2;
    2,   1,   0,   1,   2;
    2,   1,   1,   1,   2;
    2,   2,   2,   2,   2
);

assert_pixels_eq!(distance_transform(&image, Norm::LInf), linf_distances);