qrpdfstream

A high-performance streaming PDF generator for embedding large sets of QR codes. Memory-efficient, customizable layout, and fully compatible with PDF viewers.

Features

• ✅ Dynamic QR code layout based on target paper size
• ✅ Memory-efficient streaming writes (avoids buffering full PDF in memory)
• ✅ Custom headers, footers, and branding (e.g. logos)
• ✅ Parallel QR code generation
• ✅ Compatibility with macOS Preview, Adobe Acrobat, and modern PDF readers

Why This Library Exists

While there are many PDF generation libraries available, most are not optimized for streaming large numbers of QR codes efficiently. Existing libraries often:

• Load all content into memory, which becomes inefficient or even unworkable for generating thousands of QR codes.
• Lack fine-grained control over layout, especially for grid-based QR arrangements.
• Do not support progressive streaming to an io.Writer, making them unsuitable for real-time or large-scale use cases.
• Have compatibility or rendering issues in viewers like macOS Preview or Adobe Acrobat when embedding raw image data.

We created qrpdfstream to address these gaps with a focus on:

• Memory efficiency, using a streaming architecture.
• High performance, with parallel QR code generation.
• Customization, allowing logos, headers, footers, and precise grid control.
• Standards compliance, ensuring the output is portable and viewer-safe.

This library is purpose-built for industrial-scale QR code PDF generation, such as manufacturing, asset tagging, smart labels, and certification systems.

Performance

Test Setup:

• QR codes (80x80 grid)
• Machine: MacBook Pro M1, 16GB RAM

Qrcodes         Execution Time          File Size
100             34.9255ms               72KB
1000            220.442834ms            702KB
10000           1.566405916s            7MB
100000          13.861290208s           70.3MB

Results:

• ⏱️ PDF generation time: ~1.5 seconds/10k qrcodes
• 💾 Peak memory usage: ~45 MB
• 🧠 Memory reused via QR code buffer pools and streaming logic
• 🖨️ Streaming write every 5 MB (progressive output)

Unlike traditional libraries that load the full document into memory, qrpdfstream writes the PDF progressively, reducing GC pressure and improving responsiveness in large-scale operations.

Project Structure

qrpdfstream/
├── go.mod
├── LICENSE
├── README.md
├── cmd/
│   └── generate/              # CLI or example app
│       └── main.go
├── internal/
│   └── utils.go               # helper functions (e.g. escape string, image utils)
├── pdf/
│   └── writer.go              # PDF struct and streaming logic
├── qrcode/
│   └── generator.go           # QR code generation logic
├── layout/
│   └── layout.go              # Layout calculator
└── assets/
    └── qrcite.png            # Sample logo (for example/demo)

Install

go get github.com/Raj63/qrpdfstream

Usage

You can use qrpdfstream as a Go library.

Example

Example go code

Output

View output pdf file

Screenshot

Here’s a preview of the QR code streaming output: