shrinkray

A high-performance Rust library for image processing powered by libvips.

Features

• Fast image processing - Built on libvips for exceptional performance
• Fluent API - Intuitive builder pattern for chaining operations
• Format conversion - Support for JPEG, PNG, WebP, and AVIF
• Resizing & cropping - Multiple fit modes (crop, clip, max)
• Filters & effects - Vintage, sepia, monochrome, duotone, and more
• Image adjustments - Sharpen, blur, tint, rotation, and trimming
• Type-safe - Strong typing for colours, formats, and options

Installation

cargo add shrinkray

System Dependencies

• libvips 8.17.3 (for older 8.16.x libvips versions use shrinkray 1.0.1)
• libaom (for AVIF support via libheif)
• libheif
• libjpeg
• libpng
• libwebp

For more information on installing the required dependencies, see the Ubuntu and Alpine base images.

Usage

Basic Example

use shrinkray::ImageProcessor;
use shrinkray::options::{Format, Fit};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Read input image
    let image_bytes = std::fs::read("input.jpg")?;

    // Process the image
    let result = ImageProcessor::new(&image_bytes)
        .resize(800, 600)
        .quality(85)
        .format(Format::Webp)
        .fit(Fit::Crop)
        .process()?;

    // Save the result
    std::fs::write("output.webp", result.bytes())?;

    Ok(())
}

Create Thumbnails

let thumbnail = ImageProcessor::new(&image_bytes)
    .thumbnail(200)  // 200x200 square thumbnail
    .process()?;

Apply Filters

let filtered = ImageProcessor::new(&image_bytes)
    .vintage(80)
    .sharpen(40)
    .process()?;

Duotone Effect

let duotone = ImageProcessor::new(&image_bytes)
    .duotone(
        0, 50, 100,      // Shadow colour (dark blue)
        255, 165, 0      // Highlight colour (orange)
    )
    .duotone_alpha(75)   // 75% opacity
    .process()?;

Rotation and Trimming

let trimmed = ImageProcessor::new(&image_bytes)
    .rotate(90)
    .trim()  // Auto-trim transparent/whitespace borders
    .process()?;

Custom Aspect Ratio

let cropped = ImageProcessor::new(&image_bytes)
    .aspect_ratio(16, 9)
    .width(1920)
    .fit(Fit::Crop)
    .process()?;

Device Pixel Ratio (Retina Support)

let retina = ImageProcessor::new(&image_bytes)
    .width(400)
    .height(300)
    .device_pixel_ratio(2)  // Output will be 800x600
    .process()?;

Available Options

Resizing

• width(i32) - Set output width
• height(i32) - Set output height
• resize(i32, i32) - Set both width and height
• thumbnail(i32) - Create square thumbnail
• fit(Fit) - Resize behavior (Crop, Clip, Max)
• device_pixel_ratio(i32) - DPR multiplier
• aspect_ratio(i32, i32) - Target aspect ratio

Format & Quality

• format(Format) - Output format (Jpeg, Png, Webp, Avif)
• quality(i32) - Quality 1-100 (default: 75)
• lossless(bool) - Enable lossless compression

Adjustments

• rotate(u16) - Rotate 90, 180, or 270 degrees
• sharpen(u8) - Sharpening intensity 1-100
• blur(u8) - Blur amount 1-100
• trim() - Auto-trim borders
• trim_colour(u8, u8, u8) - Trim specific colour
• background(u8, u8, u8) - Background colour for padding/flattening

Filters

• grayscale() - Convert to grayscale
• monochrome(u8) - Monochrome with intensity
• sepia(u8) - Sepia tone filter
• vintage(u8) - Vintage film effect
• polaroid(u8) - Polaroid effect
• kodachrome(u8) - Kodachrome film simulation
• technicolor(u8) - Technicolor effect
• tint(u8, u8, u8) - Colour tint overlay
• duotone(u8, u8, u8, u8, u8, u8) - Duotone with shadow and highlight colours
• duotone_alpha(u8) - Duotone opacity 1-100

Safety Limits

• max_megapixels(f64) - Maximum input image size
• max_output_resolution(u32) - Maximum output dimension

ProcessedImage API

The process() method returns a ProcessedImage with these methods:

• bytes(&self) -> &[u8] - Get image bytes as a slice
• into_bytes(self) -> Vec<u8> - Consume and get owned bytes
• format(&self) -> Format - Get the output format
• mime_type(&self) -> &'static str - Get MIME type string

Full Server Implementation

This library powers the shrinkray image server, which provides:

• HTTP/S3/file backend routing
• HMAC signature verification
• Prometheus metrics
• OpenTelemetry tracing
• Kubernetes deployment configs

See the main repository for the complete server implementation.

License

MIT License - see LICENSE for details.