fastimageresize

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

Supported pixel formats and available optimisations: - U8x4 - four u8 components per pixel: - 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

Benchmarks

Environment: - CPU: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz - RAM: DDR4 3000 MHz - Ubuntu 20.04 (linux 5.8) - Rust 1.54 - fastimageresize = "0.3" - 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 | 106.303 | 199.011 | 291.423 | 382.793 | | resize | 16.099 | 71.947 | 132.481 | 205.961 | | fir rust | 0.478 | 55.376 | 84.567 | 117.269 | | fir sse4.1 | - | 11.847 | 17.823 | 25.459 | | fir avx2 | - | 8.598 | 11.864 | 17.549 |

Compiled with rustflags = ["-C", "target-cpu=native"]

| | Nearest | Bilinear | CatmullRom | Lanczos3 | |------------|:-------:|:--------:|:----------:|:--------:| | image | 91.787 | 182.502 | 282.821 | 385.492 | | resize | 15.908 | 62.011 | 114.741 | 167.815 | | fir rust | 0.471 | 56.330 | 61.589 | 85.443 | | fir sse4.1 | - | 11.204 | 16.510 | 23.442 | | fir avx2 | - | 8.402 | 11.550 | 16.987 |

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 | 102.564 | 205.981 | 309.851 | 423.252 | | resize | 19.003 | 92.075 | 169.876 | 247.993 | | fir rust | 13.619 | 67.097 | 97.157 | 125.865 | | fir sse4.1 | 12.182 | 23.555 | 29.506 | 37.118 | | fir avx2 | 6.931 | 15.052 | 18.391 | 23.812 |

Compiled with rustflags = ["-C", "target-cpu=native"]

| | Nearest | Bilinear | CatmullRom | Lanczos3 | |------------|:-------:|:--------:|:----------:|:--------:| | image | 90.421 | 193.379 | 306.635 | 422.674 | | resize | 19.572 | 69.091 | 130.327 | 192.235 | | fir rust | 9.987 | 69.005 | 76.551 | 103.646 | | fir sse4.1 | 7.860 | 18.375 | 23.601 | 30.603 | | fir avx2 | 6.897 | 14.907 | 18.034 | 23.677 |

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::ImageData::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.dst_view())
    .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::ImageData::new(dst_width, dst_height, src_image.pixel_type());

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

// 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.src_view(), &mut dst_view);

// 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());
let encoder = PngEncoder::new(&mut result_buf);
encoder
    .encode(
        dst_image.get_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); } // ... } ```