pic-scale 0.1.7

High performance image scaling
Documentation

Image scaling library in Rust

Rust image scale in different color spaces using SIMD and multithreading.

Supported only NEON and SSE.

Colorspace

This library provides for you some conveniences to scale in different color spaces.

Example integration with image crate

let img = ImageReader::open("./assets/asset.png")
    .unwrap()
    .decode()
    .unwrap();
let dimensions = img.dimensions();
let mut bytes = Vec::from(img.as_bytes());

let mut scaler = LinearScaler::new(ResamplingFunction::Lanczos3);
scaler.set_threading_policy(ThreadingPolicy::Adaptive);
let store =
    ImageStore::<u8, 4>::from_slice(&mut bytes, dimensions.0 as usize, dimensions.1 as usize);
let resized = scaler.resize_rgba(
    ImageSize::new(dimensions.0 as usize / 2, dimensions.1 as usize / 2),
    store,
    true
);

Performance

Faster or comparable to fast-image-resize, when implemented equal SIMD and pixel type.

Example comparison time for downscale RGB 4928x3279 image in two times for x86_64 SSE.

Lanczos3
pic-scale 26.13
fir sse 26.84

M3 Pro. NEON

Lanczos3
pic-scale 23.04
fir sse 37.00

Example comparison time for downscale RGBA 4928x3279 image in two times for x86_64 SSE with premultiplying alpha.

Lanczos3
pic-scale 42.35
fir sse 42.96

M3 Pro. NEON

Lanczos3
pic-scale 47.45
fir sse 53.81

Example comparison time for downscale RGBA 4928x3279 image in two times for x86_64 SSE without premultiplying alpha.

Lanczos3
pic-scale 26.92
fir sse 38.30

M3 Pro. NEON

Lanczos3
pic-scale 38.75
fir sse 45.79

Example in sRGB

In common, you should not downsize an image in sRGB colorspace, however if speed is more preferable than more proper scale you may omit linearizing

let mut scaler = Scaler::new(ResamplingFunction::Hermite);
scaler.set_threading_policy(ThreadingPolicy::Single);
let store =
    ImageStore::<u8, 4>::from_slice(&mut bytes, width, height);
let resized = scaler.resize_rgba(
    ImageSize::new(new_width, new_height),
    store,
    true
);

Example in linear

At the moment only sRGB transfer function is supported. This is also good optimized path so it is reasonably fast.

let mut scaler = LinearScaler::new(ResamplingFunction::Lanczos3);
scaler.set_threading_policy(ThreadingPolicy::Single);
let store =
    ImageStore::<u8, 4>::from_slice(&mut bytes, width, height);
let resized = scaler.resize_rgba(
    ImageSize::new(new_width, new_height),
    store,
    true
);

Example in CIE L*a*b

let mut scaler = LabScaler::new(ResamplingFunction::Hermite);
scaler.set_threading_policy(ThreadingPolicy::Single);
let store =
    ImageStore::<u8, 4>::from_slice(&mut bytes, width, height);
let resized = scaler.resize_rgba(
    ImageSize::new(new_width, new_height),
    store,
    true
);

Example in CIE L*u*v

let mut scaler = LuvScaler::new(ResamplingFunction::Hermite);
scaler.set_threading_policy(ThreadingPolicy::Single);
let store =
    ImageStore::<u8, 4>::from_slice(&mut bytes, width, height);
let resized = scaler.resize_rgba(
    ImageSize::new(new_width, new_height),
    store,
    true
);

Resampling filters

Over 30 resampling filters is supported.

Bilinear,
Nearest,
Cubic,
MitchellNetravalli,
CatmullRom,
Hermite,
BSpline,
Hann,
Bicubic,
Hamming,
Hanning,
Blackman,

And others