Advanced PDF Compressor

A Node.js library and command-line tool for compressing PDF files using multiple optimization techniques.

Features

• Multiple compression strategies including:
  • Image optimization
  • Quality reduction
  • Metadata removal
  • Page content optimization
• Command-line interface for easy integration into scripts
• Programmatic API for integration into Node.js applications
• Support for processing individual files or directories
• Customizable compression options

Installation

Global Installation

npm install -g advanced-pdf-compressor

This will make the advanced-pdf-compressor command available globally.

Local Installation

npm install advanced-pdf-compressor

Command-Line Usage

advanced-pdf-compressor [options] <input> [output]

Arguments

• input: Path to the input PDF file or directory
• output (optional): Path to the output PDF file or directory. If not specified, adds "-compressed" to the input filename.

Options

• -i, --optimize-images: Optimize embedded images (default: true)
• -q, --image-quality <quality>: Quality of embedded images from 1-100 (default: 80)
• -m, --remove-metadata: Remove metadata (default: true)
• -c, --compression-level <level>: PDF compression level from 1-5 (default: 3)
• -g, --grayscale: Convert to grayscale (default: false)
• -r, --recursive: Process directories recursively (default: false)
• -h, --help: Display help information
• -V, --version: Display version information

Examples

Compress a single PDF file:

advanced-pdf-compressor document.pdf

Compress a PDF file with custom options:

advanced-pdf-compressor --image-quality 70 --compression-level 4 --grayscale document.pdf compressed.pdf

Compress all PDFs in a directory:

advanced-pdf-compressor --recursive ./documents ./compressed-documents

Programmatic Usage

You can also use PDF Compressor as a library in your Node.js applications.

const PDFCompressor = require('advanced-pdf-compressor');

// Create a compressor with default options
const compressor = new PDFCompressor();

// Compress a PDF file
compressor.compressPDF('input.pdf', 'output.pdf')
  .then(result => {
    console.log(`Original size: ${result.inputSize} bytes`);
    console.log(`Compressed size: ${result.outputSize} bytes`);
    console.log(`Savings: ${result.savings} bytes (${result.percentReduction})`);
  })
  .catch(error => {
    console.error('Compression failed:', error);
  });

// Create a compressor with custom options
const customCompressor = new PDFCompressor({
  optimizeImages: true,
  imageQuality: 60,
  removeMetadata: true,
  compressionLevel: 5,
  grayscale: true
});

// Compress a PDF file with custom options
customCompressor.compressPDF('input.pdf', 'output.pdf')
  .then(result => {
    console.log(`Compression successful: ${result.percentReduction} reduction`);
  });

// Update options after initialization
compressor.setOptions({
  imageQuality: 50,
  grayscale: true
});

// Get current options
const options = compressor.getOptions();
console.log(options);

API Reference

PDFCompressor

Main class for PDF compression.

Constructor

const compressor = new PDFCompressor(options);

Options:

• optimizeImages (boolean): Whether to optimize embedded images (default: true)
• imageQuality (number): Quality of embedded images from 1-100 (default: 80)
• removeMetadata (boolean): Whether to remove metadata (default: true)
• compressionLevel (number): PDF compression level from 1-5 (default: 3)
• grayscale (boolean): Convert to grayscale (default: false)

Methods

compressPDF(inputPath, outputPath, options)

Compresses a PDF file.

Parameters:

• inputPath (string): Path to the input PDF file
• outputPath (string): Path to save the compressed PDF
• options (object, optional): Override default options

Returns:

Promise resolving to an object with compression statistics:

{
  success: true,
  inputSize: 1000000,        // Original file size in bytes
  outputSize: 500000,        // Compressed file size in bytes
  savings: 500000,           // Bytes saved
  percentReduction: "50.00%", // Percentage reduction
  inputPath: "input.pdf",    // Input file path
  outputPath: "output.pdf"   // Output file path
}

getOptions()

Returns the current options.

Returns:

Object containing the current compression options.

setOptions(options)

Updates the compression options.

Parameters:

• options (object): New options to set

Returns:

The PDFCompressor instance (for chaining).

Compression Techniques

PDF Compressor uses multiple strategies to reduce file size:

1. Image Optimization: Reduces the quality and size of embedded images.
2. Metadata Removal: Strips unnecessary metadata from the PDF.
3. Quality Reduction: Reduces the overall quality of the PDF while maintaining readability.
4. Page Optimization: Optimizes content streams and removes unnecessary elements.

Requirements

• Node.js 12.0.0 or higher
• For some advanced features, you might need external tools like Ghostscript installed on your system

License

ISC