fast_image_resize

Rust library for fast image resizing with using of SIMD instructions.

CHANGELOG

Supported pixel formats and available optimizations:

Colorspace

Resizer from this crate does not convert image into linear colorspace during a resize process. If it is important for you to resize images with a non-linear color space (e.g. sRGB) correctly, then you have to convert it to a linear color space before resizing and convert back to the color space of result image. Read more about resizing with respect to color space.

This crate provides the PixelComponentMapper structure that allows you to create colorspace converters for images whose pixels based on u8 and u16 components.

In addition, the crate contains functions create_gamma_22_mapper() and create_srgb_mapper() to create instance of PixelComponentMapper that converts images from sRGB or gamma 2.2 into linear colorspace and back.

Multi-threading

You should enable "rayon" feature to turn on image processing in rayon thread pool.

Some benchmarks in single-threaded mode for x86_64

All benchmarks: x86_64, ARM64, WASM32.

Other libraries used to compare of resizing speed:

• image (https://crates.io/crates/image)
• resize (https://crates.io/crates/resize, single-threaded mode)
• libvips (single-threaded mode)

Resize RGB8 image (U8x3) 4928x3279 => 852x567

Pipeline:

src_image => resize => dst_image

• Source image nasa-4928x3279.png
• Numbers in the table mean a duration of image resizing in milliseconds.

Resize RGBA8 image (U8x4) 4928x3279 => 852x567

Pipeline:

src_image => multiply by alpha => resize => divide by alpha => dst_image

• Source image nasa-4928x3279-rgba.png
• Numbers in the table mean a duration of image resizing in milliseconds.
• The image crate does not support multiplying and dividing by alpha channel.

Resize L8 image (U8) 4928x3279 => 852x567

Pipeline:

src_image => resize => dst_image

• Source image nasa-4928x3279.png has converted into grayscale image with one byte per pixel.
• Numbers in the table mean a duration of image resizing in milliseconds.

Examples

Resize RGBA8 image

Note: You must enable "image" feature to support of image::DynamicImage. Otherwise, you have to convert such images into supported by the crate image type.

use std::io::BufWriter;

use image::codecs::png::PngEncoder;
use image::{ExtendedColorType, ImageEncoder, ImageReader};

use fast_image_resize::{IntoImageView, Resizer};
use fast_image_resize::images::Image;

fn main() {
    // Read source image from file
    let src_image = ImageReader::open("./data/nasa-4928x3279.png")
        .unwrap()
        .decode()
        .unwrap();

    // Create container for data of destination image
    let dst_width = 1024;
    let dst_height = 768;
    let mut dst_image = Image::new(
        dst_width,
        dst_height,
        src_image.pixel_type().unwrap(),
    );

    // Create Resizer instance and resize source image
    // into buffer of destination image
    let mut resizer = Resizer::new();
    resizer.resize(&src_image, &mut dst_image, None).unwrap();

    // Write destination image as PNG-file
    let mut result_buf = BufWriter::new(Vec::new());
    PngEncoder::new(&mut result_buf)
        .write_image(
            dst_image.buffer(),
            dst_width,
            dst_height,
            src_image.color().into(),
        )
        .unwrap();
}

Resize with cropping

use image::codecs::png::PngEncoder;
use image::{ColorType, ImageReader, GenericImageView};

use fast_image_resize::{IntoImageView, Resizer, ResizeOptions};
use fast_image_resize::images::Image;

fn main() {
    let img = ImageReader::open("./data/nasa-4928x3279.png")
        .unwrap()
        .decode()
        .unwrap();

    // Create container for data of destination image
    let mut dst_image = Image::new(
        1024,
        768,
        img.pixel_type().unwrap(),
    );

    // Create Resizer instance and resize cropped source image
    // into buffer of destination image
    let mut resizer = Resizer::new();
    resizer.resize(
        &img,
        &mut dst_image,
        &ResizeOptions::new().crop(
            10.0,   // left 
            10.0,   // top
            2000.0, // width
            2000.0, // height
        ),
    ).unwrap();
}

Change CPU extensions used by resizer

use fast_image_resize as fr;

fn main() {
    let mut resizer = fr::Resizer::new();
    #[cfg(target_arch = "x86_64")]
    unsafe {
        resizer.set_cpu_extensions(fr::CpuExtensions::Sse4_1);
    }
}