Working with Images in Rust: image, photon-rs, and Other Libraries

Working with Images in Rust: Libraries, Tools, and Practical Examples

Rust is a modern systems programming language that is increasingly used for tasks related to graphics and image processing. Thanks to its high performance, safe memory management, and rich ecosystem of crates, Rust is well-suited for creating image processing tools: from simple format converters to complex filters and computer vision algorithms.

In this article, we will review the key libraries for working with images in Rust, explore their capabilities, and provide working code examples.

Main Libraries for Working with Images

The Rust ecosystem offers several mature crates for image processing. The most popular ones are:

• image — a fundamental library for loading, saving, and basic image transformations. Supports PNG, JPEG, GIF, BMP, ICO, TIFF, and other formats.
• photon-rs — a high-performance library for applying photo filters and effects. Works with Rust and WebAssembly.
• imageproc — an extension for image, providing advanced algorithms: Hough transforms, segmentation, morphological operations.
• rusttype — a library for working with fonts and rendering text on images.

Installation and Setup

Add the dependencies to your Cargo.toml file:

[dependencies]image = "0.25"photon-rs = "0.3"imageproc = "0.25"

Loading, Resizing, and Saving an Image

Let's start with a basic example — load an image, reduce it by half, and save it in a different format.

use image::{DynamicImage, GenericImageView, ImageFormat};use std::fs::File;

fn main() -> Result<(), Box<dyn std::error::Error>> {    // Load the image    let img = image::open("input.jpg")?;    println!("Size: {} x {}", img.width(), img.height());

    // Scale to half the original size    let resized = img.resize_exact(        img.width() / 2,        img.height() / 2,        image::imageops::FilterType::Lanczos3    );

    // Save in PNG format    let mut output = File::create("output.png")?;    resized.write_to(&mut output, ImageFormat::Png)?;

    println!("Done! Saved as output.png");    Ok(())}

Applying Photo Filters with photon-rs

The photon-rs library allows you to quickly apply filters, adjust colors, and add effects.

use photon_rs::PhotonImage;use photon_rs::transform::resize;use photon_rs::filters::filter;

fn main() {    // Open the image    let mut img = photon_rs::open_image("input.jpg");

    // Apply the "sepia" filter    filter(&mut img, "sepia", 1.0);

    // Adjust brightness    photon_rs::channels::brighten(&mut img, 30);

    // Resize    let resized = resize(&img, 800, 600, photon_rs::transform::SamplingFilter::Nearest);

    // Save the result    photon_rs::save_image(resized, "output_photon.jpg");    println!("Filter applied, saved to output_photon.jpg");}

Working with Pixels and Drawing

Sometimes you need to directly manipulate pixels or draw primitives. For this, we use image in conjunction with imageproc.

use image::{RgbImage, Rgb};use imageproc::drawing::draw_filled_circle_mut;

fn main() {    // Create an empty 400x300 image with a white background    let mut img = RgbImage::new(400, 300);

    // Fill the background with light blue    for pixel in img.pixels_mut() {        *pixel = Rgb([200, 220, 255]);    }

    // Draw a red circle (x=200, y=150, radius=80)    draw_filled_circle_mut(        &mut img,\