fastimageresize

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

Supported pixel formats and available optimisations: - U8x4 - four u8 components per pixel (RGB, RGBA, CMYK and other): - native Rust-code without forced SIMD - SSE4.1 - AVX2 - I32 - one i32 component per pixel: - native Rust-code without forced SIMD - F32 - one f32 component per pixel: - native Rust-code without forced SIMD - U8 - one u8 component per pixel: - native Rust-code without forced SIMD - AVX2

Benchmarks

Environment: - CPU: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz - RAM: DDR4 3000 MHz - Ubuntu 20.04 (linux 5.11) - Rust 1.56.1 - fastimageresize = "0.4" - glassbench = "0.3.0"

Other Rust libraries used to compare of resizing speed: - image = "0.23.14" (https://crates.io/crates/image) - resize = "0.7.2" (https://crates.io/crates/resize)

Resize algorithms: - Nearest - Convolution with Bilinear filter - Convolution with CatmullRom filter - Convolution with Lanczos3 filter

Resize RGB image 4928x3279 => 852x567

Pipeline:

src_image => resize => dst_image

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

| | Nearest | Bilinear | CatmullRom | Lanczos3 | |------------|:-------:|:--------:|:----------:|:--------:| | image | 106.320 | 199.150 | 288.609 | 380.830 | | resize | 15.550 | 72.122 | 132.152 | 192.081 | | fir rust | 0.476 | 56.451 | 86.984 | 119.357 | | fir sse4.1 | - | 11.798 | 17.768 | 25.296 | | fir avx2 | - | 8.995 | 13.533 | 19.525 |

Resize RGBA image 4928x3279 => 852x567

Pipeline:

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

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

| | Nearest | Bilinear | CatmullRom | Lanczos3 | |------------|:-------:|:--------:|:----------:|:--------:| | image | 107.186 | 191.834 | 281.246 | 372.796 | | resize | 18.163 | 79.871 | 149.159 | 218.684 | | fir rust | 13.630 | 69.949 | 100.425 | 133.011 | | fir sse4.1 | 12.034 | 23.566 | 29.809 | 37.232 | | fir avx2 | 6.890 | 15.015 | 18.394 | 23.827 |

Resize grayscale 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 table is mean duration of image resizing in milliseconds.

| | Nearest | Bilinear | CatmullRom | Lanczos3 | |----------|:-------:|:--------:|:----------:|:--------:| | image | 92.171 | 141.153 | 184.442 | 230.455 | | resize | 9.890 | 26.205 | 53.054 | 81.181 | | fir rust | 0.197 | 26.333 | 29.450 | 43.266 | | fir avx2 | - | 14.766 | 12.567 | 16.641 |

Examples

Resize image

```rust use std::io::BufWriter; use std::num::NonZeroU32;

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

use fastimageresize as fr;

[test]

fn resizeimageexample() { // Read source image from file let img = ImageReader::open("./data/nasa-4928x3279.png") .unwrap() .decode() .unwrap(); let width = NonZeroU32::new(img.width()).unwrap(); let height = NonZeroU32::new(img.height()).unwrap(); let mut srcimage = fr::Image::fromvecu8( width, height, img.torgba8().into_raw(), fr::PixelType::U8x4, ) .unwrap();

// Create MulDiv instance
let alpha_mul_div: fr::MulDiv = Default::default();
// Multiple RGB channels of source image by alpha channel
alpha_mul_div
    .multiply_alpha_inplace(&mut src_image.view_mut())
    .unwrap();

// Create wrapper that own data of destination image
let dst_width = NonZeroU32::new(1024).unwrap();
let dst_height = NonZeroU32::new(768).unwrap();
let mut dst_image = fr::Image::new(dst_width, dst_height, src_image.pixel_type());

// Get mutable view of destination image data
let mut dst_view = dst_image.view_mut();

// Create Resizer instance and resize source image
// into buffer of destination image
let mut resizer = fr::Resizer::new(fr::ResizeAlg::Convolution(fr::FilterType::Lanczos3));
resizer.resize(&src_image.view(), &mut dst_view).unwrap();

// Divide RGB channels of destination image by alpha
alpha_mul_div.divide_alpha_inplace(&mut dst_view).unwrap();

// Write destination image as PNG-file
let mut result_buf = BufWriter::new(Vec::new());
PngEncoder::new(&mut result_buf)
    .encode(
        dst_image.buffer(),
        dst_width.get(),
        dst_height.get(),
        ColorType::Rgba8,
    )
    .unwrap();

} ```

Change CPU extensions used by resizer

```rust use fastimageresize as fr;

fn main() { let mut resizer = fr::Resizer::new(fr::ResizeAlg::Convolution(fr::FilterType::Lanczos3)); unsafe { resizer.setcpuextensions(fr::CpuExtensions::Sse4_1); } } ```