@blazediff/cli

Command-line interface for the BlazeDiff image comparison library.

Installation

npm install -g @blazediff/cli

Usage

blazediff-cli <command> <image1> <image2> [options]

Commands

BlazeDiff supports multiple comparison algorithms, each optimized for different use cases:

bin - Native binary comparison (default)

The fastest option. Uses the native Rust binary with SIMD optimization for maximum performance.

blazediff-cli image1.png image2.png diff.png [options]
# Or explicitly:
blazediff-cli bin image1.png image2.png diff.png [options]

Options:

• -t, --threshold <num> - Color difference threshold (0 to 1, default: 0.1)
• -a, --antialiasing - Enable anti-aliasing detection
• --diff-mask - Output only differences (transparent background)
• --fail-on-layout - Fail immediately if images have different dimensions
• -c, --compression <num> - PNG compression level (0-9, default: 0)
• -h, --help - Show help message

core - JavaScript pixel comparison

Pure JavaScript implementation. Slower than bin but offers more customization options.

blazediff-cli core image1.png image2.png [options]

Options:

• -o, --output <path> - Output path for the diff image
• -t, --threshold <num> - Matching threshold (0 to 1, default: 0.1)
• -a, --alpha <num> - Opacity of original image in diff (default: 0.1)
• --aa-color <r,g,b> - Color for anti-aliased pixels (default: 255,255,0)
• --diff-color <r,g,b> - Color for different pixels (default: 255,0,0)
• --diff-color-alt <r,g,b> - Alternative color for dark differences
• --include-aa - Include anti-aliasing detection
• --diff-mask - Draw diff over transparent background
• --color-space <name> - Specify color space to use (yiq, ycbcr)
• --transformer <name> - Specify transformer to use (pngjs, sharp)
• -h, --help - Show help message

gmsd - Gradient Magnitude Similarity Deviation

Perceptual quality metric based on gradient similarity.

blazediff-cli gmsd image1.png image2.png [options]

Options:

• -o, --output <path> - Output path for GMS similarity map
• --downsample <0|1> - Downsample factor (0=full-res, 1=2x, default: 0)
• --gmsd-c <num> - Stability constant (default: 170)
• --transformer <name> - Specify transformer to use (pngjs, sharp)
• -h, --help - Show help message

ssim - Structural Similarity Index

Industry-standard metric for measuring structural similarity.

blazediff-cli ssim image1.png image2.png [options]

Options:

• -o, --output <path> - Output path for SSIM map visualization
• --transformer <name> - Specify transformer to use (pngjs, sharp)
• -h, --help - Show help message

msssim - Multi-Scale Structural Similarity Index

Enhanced SSIM that operates at multiple image scales.

blazediff-cli msssim image1.png image2.png [options]

Options:

• -o, --output <path> - Output path for MS-SSIM map visualization
• --transformer <name> - Specify transformer to use (pngjs, sharp)
• -h, --help - Show help message

hitchhikers-ssim - Fast SSIM

Integral image-based SSIM implementation for faster computation.

blazediff-cli hitchhikers-ssim image1.png image2.png [options]

Examples

# Native binary diff (default, fastest)
blazediff-cli image1.png image2.png diff.png
blazediff-cli bin image1.png image2.png diff.png -t 0.05 -a

# JavaScript pixel diff (more options)
blazediff-cli core image1.png image2.png -o diff.png -t 0.05

# GMSD similarity metric
blazediff-cli gmsd image1.png image2.png
blazediff-cli gmsd image1.png image2.png -o gms-map.png

# SSIM structural similarity
blazediff-cli ssim image1.png image2.png
blazediff-cli ssim image1.png image2.png -o ssim-map.png

# MS-SSIM multi-scale similarity
blazediff-cli msssim image1.png image2.png
blazediff-cli msssim image1.png image2.png -o msssim-map.png

# Use Sharp transformer for better performance (core/gmsd/ssim)
blazediff-cli core image1.jpg image2.jpg --transformer sharp

Transformers (for core, gmsd, ssim, msssim)

• pngjs - Pure JavaScript, works everywhere. Supports PNG only.
• sharp - Native bindings, significantly faster. Supports PNG and JPEG.

Exit Codes

bin/core Mode

• 0 - Images are identical
• 1 - Images have differences
• 2 - Error (file not found, invalid format, etc.)

GMSD, SSIM, MS-SSIM Modes

• 0 - Images are highly similar (score >= 0.95)
• 1 - Images have noticeable differences (score < 0.95) or error occurred