# 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 | 29.28 | - | 83.28 | 136.97 | 189.93 |
| resize | 7.42 | 26.82 | 49.29 | 93.22 | 140.26 |
| libvips | 2.42 | 61.73 | 5.66 | 9.81 | 15.78 |
| fir rust | 0.28 | 10.87 | 16.12 | 26.63 | 38.08 |
| fir sse4.1 | 0.28 | 3.37 | 5.34 | 9.89 | 15.30 |
| fir avx2 | 0.28 | 2.52 | 3.67 | 6.80 | 13.21 |
### 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 | 9.59 | 34.02 | 64.61 | 126.43 | 187.18 |
| libvips | 4.19 | 169.02 | 142.22 | 228.64 | 330.24 |
| fir rust | 0.19 | 20.30 | 25.25 | 36.57 | 49.69 |
| fir sse4.1 | 0.19 | 9.51 | 11.90 | 17.78 | 24.49 |
| fir avx2 | 0.19 | 7.11 | 8.39 | 13.68 | 21.72 |
### 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 | 26.90 | - | 56.49 | 85.11 | 112.72 |
| resize | 6.57 | 11.06 | 18.83 | 38.44 | 63.98 |
| libvips | 2.62 | 24.92 | 6.81 | 9.84 | 12.73 |
| fir rust | 0.16 | 4.42 | 5.45 | 8.69 | 12.04 |
| fir sse4.1 | 0.16 | 1.45 | 2.02 | 3.37 | 5.44 |
| fir avx2 | 0.16 | 1.51 | 1.73 | 2.74 | 4.11 |
## 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);
}
}
```