# fast_image_resize
[](https://github.com/Cykooz/fast_image_resize)
[](https://crates.io/crates/fast_image_resize)
[](https://docs.rs/fast_image_resize)
Rust library for fast image resizing with using of SIMD instructions.
[CHANGELOG](https://github.com/Cykooz/fast_image_resize/blob/main/CHANGELOG.md)
Supported pixel formats and available optimizations:
| U8 | One `u8` component per pixel (e.g. L) | + | + | + | + |
| U8x2 | Two `u8` components per pixel (e.g. LA) | + | + | + | + |
| U8x3 | Three `u8` components per pixel (e.g. RGB) | + | + | + | + |
| U8x4 | Four `u8` components per pixel (e.g. RGBA, RGBx, CMYK) | + | + | + | + |
| U16 | One `u16` components per pixel (e.g. L16) | + | + | + | + |
| U16x2 | Two `u16` components per pixel (e.g. LA16) | + | + | + | + |
| U16x3 | Three `u16` components per pixel (e.g. RGB16) | + | + | + | + |
| U16x4 | Four `u16` components per pixel (e.g. RGBA16, RGBx16, CMYK16) | + | + | + | + |
| I32 | One `i32` component per pixel (e.g. L32) | - | - | - | - |
| F32 | One `f32` component per pixel (e.g. L32F) | + | + | - | - |
| F32x2 | Two `f32` components per pixel (e.g. LA32F) | + | + | - | - |
| F32x3 | Three `f32` components per pixel (e.g. RGB32F) | + | + | - | - |
| F32x4 | Four `f32` components per pixel (e.g. RGBA32F) | + | + | - | - |
## 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](http://www.ericbrasseur.org/gamma.html)
about resizing with respect to color space.
This crate provides the
[PixelComponentMapper](https://docs.rs/fast_image_resize/latest/fast_image_resize/struct.PixelComponentMapper.html)
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](https://docs.rs/rayon/latest/rayon/) thread pool.
## Some benchmarks in single-threaded mode for x86_64
_All benchmarks:_
[_x86_64_](https://github.com/Cykooz/fast_image_resize/blob/main/benchmarks-x86_64.md),
[_ARM64_](https://github.com/Cykooz/fast_image_resize/blob/main/benchmarks-arm64.md),
[_WASM32_](https://github.com/Cykooz/fast_image_resize/blob/main/benchmarks-wasm32.md).
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](https://github.com/Cykooz/fast_image_resize/blob/main/data/nasa-4928x3279.png)
- Numbers in the table mean a duration of image resizing in milliseconds.
| image | 34.13 | - | 88.09 | 142.99 | 191.80 |
| resize | 8.87 | 26.97 | 53.08 | 98.26 | 145.74 |
| libvips | 2.38 | 61.57 | 5.66 | 9.70 | 16.03 |
| fir rust | 0.28 | 10.93 | 15.35 | 25.77 | 37.09 |
| fir sse4.1 | 0.28 | 3.43 | 5.39 | 9.82 | 15.34 |
| fir avx2 | 0.28 | 2.62 | 3.80 | 6.89 | 13.22 |
### Resize RGBA8 image (U8x4) 4928x3279 => 852x567
Pipeline:
`src_image => multiply by alpha => resize => divide by alpha => dst_image`
- Source image
[nasa-4928x3279-rgba.png](https://github.com/Cykooz/fast_image_resize/blob/main/data/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 | 9.90 | 37.85 | 74.20 | 133.72 | 201.29 |
| libvips | 4.17 | 169.03 | 141.52 | 232.30 | 330.89 |
| fir rust | 0.19 | 20.66 | 26.02 | 37.27 | 50.21 |
| fir sse4.1 | 0.19 | 9.59 | 11.99 | 17.79 | 24.83 |
| fir avx2 | 0.19 | 7.21 | 8.61 | 13.22 | 22.41 |
### Resize L8 image (U8) 4928x3279 => 852x567
Pipeline:
`src_image => resize => dst_image`
- Source image [nasa-4928x3279.png](https://github.com/Cykooz/fast_image_resize/blob/main/data/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.
| image | 29.07 | - | 60.25 | 89.15 | 117.51 |
| resize | 6.42 | 11.26 | 20.87 | 42.87 | 69.50 |
| libvips | 2.57 | 25.05 | 6.82 | 9.85 | 12.68 |
| fir rust | 0.15 | 4.45 | 5.57 | 9.02 | 12.31 |
| fir sse4.1 | 0.15 | 1.52 | 2.09 | 3.52 | 5.65 |
| fir avx2 | 0.15 | 1.54 | 1.76 | 2.80 | 4.03 |
## Examples
### Resize RGBA8 image
Note: You must enable `"image"` feature to support of
[image::DynamicImage](https://docs.rs/image/latest/image/enum.DynamicImage.html).
Otherwise, you have to convert such images into supported by the crate image type.
```rust
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
```rust
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
```rust, no_run
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);
}
}
```