Contour tracing library

A 2D library to trace contours.
How it works in a live demo: https://stpr.github.io/contour_tracing/

Features

Core features:

• Trace contours using the Theo Pavlidis' algorithm (connectivity: 4-connected)
• Trace outlines in clockwise direction
• Trace holes in counterclockwise direction
• Input format: a 2D array of bits or an image buffer
• Output format: a string of SVG Path commands

Manual parameters:

• User can specify to close or not the paths (with the SVG Path Z command)

An example with an array of bits

1. Add the following line to your Cargo.toml file in the dependencies section:

contour_tracing = { version = "*", features = ["array"] }

2. Then use the library:

use contour_tracing::array::bits_to_paths;

fn main() {
    let bits = vec![vec![ 1,0,0 ],
                    vec![ 0,1,0 ],
                    vec![ 0,0,1 ]];

    println!("{}", bits_to_paths(bits, true));
}

An example with an image buffer

1. Add the following line to your Cargo.toml file in the dependencies section:

contour_tracing = { version = "*", features = ["image"] }

2. Then use the library:

use image::{GrayImage, Luma};
use contour_tracing::image::single_l8_to_paths;

fn main() {
    let mut image_buffer = GrayImage::new(3, 3);
    let foreground_color: image::Luma<u8> = Luma([1]);

    image_buffer.put_pixel(0, 0, foreground_color);
    image_buffer.put_pixel(1, 1, foreground_color);
    image_buffer.put_pixel(2, 2, foreground_color);

    println!("{}", single_l8_to_paths(&mut image_buffer, foreground_color, true));
}

Both examples should print: M0 0H1V1H0ZM1 1H2V2H1ZM2 2H3V3H2Z

For more examples, have a look at the documentation:

License

Contour tracing library https://github.com/STPR/contour_tracing

Copyright (c) 2022, STPR - https://github.com/STPR

SPDX-License-Identifier: EUPL-1.2

Contribution

Your contribution is highly appreciated. Do not hesitate to open an issue or a pull request. Note that any contribution submitted for inclusion in the project will be licensed according to the terms given in LICENSE.txt.