FastResize

The fastest image resizing library on the planet. 🚀

Resize 1,000 images in 2 seconds. Up to 2.9x faster than libvips, 3.1x faster than imageflow. Uses 3-4x less RAM than alternatives.

Installation • Quick Start • Documentation • Benchmarks

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🛠️ Tech Stack & Stats

💎 Ruby:

📦 CLI:

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📑 Table of Contents

• Why Fastest on the Planet?
• Performance Benchmarks
• Key Features
• Installation
• Quick Start
• API Reference
• Documentation
• Architecture
• License
• Contributing
• Contact & Support

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🏆 Why Fastest on the Planet?

FastResize has defeated the two most legendary image processing libraries in the world:

Library	Description	FastResize Advantage
libvips	The gold standard for high-performance image processing. Used by Sharp (Node.js), Shopify, and Wikipedia. Widely recognized as one of the fastest image processing libraries available.	FastResize is 1.7x - 2.9x faster
imageflow	A Rust-based image manipulation engine designed for high throughput and accuracy. Known for powering modern large-scale image resizing pipelines.	FastResize is 1.1x - 3.1x faster

💡 Want to dive deeper? Explore full details about FastResize →

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🔥 Performance Benchmarks

Resize 1,000 images to 800px width

Tested on MacBook Pro M2, macOS Sonoma

Format	FastResize	libvips (parallel)	imageflow	🚀 vs libvips	🚀 vs imageflow
JPG	2.10s ⚡	5.24s	6.60s	2.5x faster	3.1x faster 🏆
PNG	3.43s ⚡	6.18s	8.41s	1.8x faster	2.5x faster
BMP	1.65s ⚡	4.72s	❌ N/A	2.9x faster	-
WEBP	14.03s ⚡	23.52s	15.69s	1.7x faster	1.1x faster

FastResize wins in ALL formats! 🎯

📊 Speed Comparison Details

JPG Performance (1179×1409, 3 channels)

Tool	Run 1	Run 2	Avg Time	Throughput
FastResize	2.02s	2.17s	2.10s	~477 img/s ⚡
libvips (parallel)	5.20s	5.28s	5.24s	~191 img/s
libvips (sequential)	16.32s	15.91s	16.11s	~62 img/s
imageflow	6.62s	6.58s	6.60s	~151 img/s

PNG Performance (2104×1160, 4 channels)

Tool	Run 1	Run 2	Avg Time	Throughput
FastResize	3.55s	3.32s	3.43s	~292 img/s ⚡
libvips (parallel)	6.18s	6.18s	6.18s	~162 img/s
libvips (sequential)	31.95s	31.46s	31.71s	~32 img/s
imageflow	8.45s	8.37s	8.41s	~119 img/s

BMP Performance (1045×1045, 3 channels)

Tool	Run 1	Run 2	Avg Time	Throughput
FastResize	1.65s	1.64s	1.65s	~606 img/s ⚡
libvips (parallel)	4.75s	4.70s	4.72s	~212 img/s
imageflow	❌	❌	Not supported	-

WEBP Performance (4275×2451, 3 channels)

Tool	Run 1	Run 2	Avg Time	Throughput
FastResize	13.99s	14.07s	14.03s	~71 img/s ⚡
libvips (parallel)	23.94s	23.10s	23.52s	~43 img/s
imageflow	15.64s	15.73s	15.69s	~64 img/s

💾 RAM Usage Comparison

FastResize uses 3-4x less RAM than alternatives!

PNG (1000 images, 2104×1160)

Library	Time	Throughput	RAM Peak	Compared
FastResize	3.19s	313 img/s	138 MB ⚡	-
libvips	6.11s	164 img/s	439 MB	3.2x more
imageflow	8.39s	119 img/s	514 MB	3.7x more

JPG (1000 images, 1179×1409)

Library	Time	Throughput	RAM Peak	Compared
FastResize	2.03s	493 img/s	271 MB ⚡	-
libvips	5.07s	197 img/s	460 MB	1.7x more
imageflow	6.59s	152 img/s	541 MB	2.0x more

Full Benchmark Details →

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💪 Key Features

⚡ Performance Up to 3.1x faster than libvips & imageflow 3-4x less RAM usage Optimized C++ core with SIMD Multi-threaded batch processing	🖼️ Format Support JPEG (via libjpeg-turbo) PNG (via libpng) WebP (via libwebp) BMP (via stb_image)
🎯 Resize Modes Exact size - Fixed width & height Fit width - Auto height Fit height - Auto width Scale percent - Proportional resize	🔧 Quality Filters Mitchell - Balanced (default) Catmull-Rom - Sharp edges Box - Fast, lower quality Triangle - Bilinear

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📦 Installation

💎 Ruby gem install fast_resize 🍎 macOS (Homebrew) brew tap tranhuucanh/fast_resize brew install fast_resize 🐧 Linux # Download latest release VERSION="1.0.0" wget https://github.com/tranhuucanh/fast_resize/releases/download/v${VERSION}/fast_resize-${VERSION}-linux-x86_64.tar.gz tar -xzf fast_resize-${VERSION}-linux-x86_64.tar.gz sudo cp fast_resize /usr/local/bin/ sudo chmod +x /usr/local/bin/fast_resize # Verify installation fast_resize --version

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🎯 Quick Start

CLI

# Resize to width 800 (auto height)
fast_resize input.jpg output.jpg 800

# Resize to exact 800x600
fast_resize input.jpg output.jpg 800 600

# Batch resize all images in directory
fast_resize batch input_dir/ output_dir/ --width 800

# Batch resize specific files (from stdin, NULL-separated)
printf 'photo1.jpg\0photo2.jpg\0photo3.jpg' | fast_resize batch --stdin output_dir/ -w 800

# Convert format (JPG → PNG)
fast_resize input.jpg output.png 800

💎 Ruby

require 'fast_resize'

# Simple resize (width 800, auto height)
FastResize.resize('input.jpg', 'output.jpg', width: 800)

# Exact dimensions
FastResize.resize('input.jpg', 'output.jpg', width: 800, height: 600)

# With quality and filter options
FastResize.resize('input.jpg', 'output.jpg',
  width: 800,
  quality: 90,
  filter: :catmull_rom
)

# Batch resize - all images in directory
result = FastResize.batch_resize('images/', 'output/', width: 800)
puts "Processed: #{result[:success]}/#{result[:total]}"

# Batch resize - specific files only
files = ['photo1.jpg', 'photo2.jpg', 'photo3.jpg']
result = FastResize.batch_resize(files, 'output/', width: 800)
puts "Processed: #{result[:success]}/#{result[:total]}"

# Maximum speed mode (uses more RAM)
FastResize.batch_resize('images/', 'output/',
  width: 800,
  max_speed: true
)

Full Ruby Guide → • Full CLI Guide →

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📖 API Reference

Resize Options

Option	Type	Default	Description
width	int	-	Target width in pixels
height	int	-	Target height in pixels
scale	float	-	Scale factor (0.5 = 50%)
quality	int	85	JPEG/WebP quality (1-100)
keep_aspect_ratio	bool	true	Maintain aspect ratio
filter	symbol	:mitchell	Resize filter algorithm

Resize Modes

Mode	When	Example
Fit Width	Only width specified	width: 800 → height auto
Fit Height	Only height specified	height: 600 → width auto
Exact Size	Both specified	width: 800, height: 600
Scale	scale specified	scale: 0.5 → 50% size

Filter Options

Filter	Quality	Speed	Best For
:mitchell	★★★★☆	★★★☆☆	General use (default)
:catmull_rom	★★★★★	★★☆☆☆	Sharp edges, text
:triangle	★★★☆☆	★★★★☆	Smooth gradients
:box	★★☆☆☆	★★★★★	Maximum speed

Batch Options

Option	Type	Default	Description
threads	int	auto	Number of threads (0 = auto)
stop_on_error	bool	false	Stop on first error
max_speed	bool	false	Enable pipeline mode (faster, uses more RAM)

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📚 Documentation

Complete usage guides:

• CLI Usage Guide - Complete command-line reference
• Ruby Usage Guide - Ruby integration and examples
• Benchmark Details - Full performance analysis
• API Reference - Complete API documentation

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🏗️ Architecture

FastResize is built on industry-standard, high-performance libraries:

Library	License	Purpose
libjpeg-turbo	BSD-3-Clause	JPEG decode/encode with SIMD
libpng	libpng license	PNG decode/encode
libwebp	BSD-3-Clause	WebP decode/encode
stb_image	Public Domain	BMP and fallback decode
stb_image_resize2	Public Domain	High-quality resize with SIMD

Why So Fast?

• ⚡ SIMD Optimization - SSE2/AVX (x86) and NEON (ARM) acceleration
• 🚀 Zero-copy Pipeline - Minimal memory allocation
• 💪 Multi-threaded - Parallel batch processing
• 🔥 Memory-mapped I/O - Efficient file reading

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📄 License

FastResize is licensed under the BSD-3-Clause License.

See LICENSE for full details.

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🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

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🐛 Bug Reports

Found a bug? Please open an issue with:

• Your OS and version
• FastResize version
• Steps to reproduce
• Expected vs actual behavior

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💖 Support This Project

If FastResize helps you save time and money:

• ⭐ Star this repository
• 🐛 Report bugs and suggest features
• 📖 Improve documentation
• 💬 Share FastResize with others

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📮 Contact & Support

GitHub: @tranhuucanh • Issues • Discussions

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🙏 Acknowledgments

Built with: libjpeg-turbo • libpng • libwebp • stb by Sean Barrett

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Made with ❤️ by FastResize Project

If FastResize saves you time, give us a star! ⭐

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