openpdf

README

OpenPDF - PDF for Go

OpenPDF is an MIT-licensed PDF library for Go (golang) for creating, reading and processing PDF files.

Contents

• Installation
• Quick start
• Features
• Packages
• Examples
• Contributing
• License

Installation

Requires Go 1.27 or later.

go get github.com/OpenMellon/openpdf

Quick start

Create a PDF

package main

import (
	"log"

	"github.com/OpenMellon/openpdf/creator"
)

func main() {
	c := creator.New()
	c.NewPage()

	p := c.NewStyledParagraph()
	p.SetText("Hello, OpenPDF")
	p.SetFontSize(20)
	if err := c.Draw(p); err != nil {
		log.Fatal(err)
	}

	if err := c.WriteToFile("hello.pdf"); err != nil {
		log.Fatal(err)
	}
}

Extract text

reader, f, err := model.NewPdfReaderFromFile("in.pdf", nil)
if err != nil {
	log.Fatal(err)
}
defer f.Close()

page, err := reader.GetPage(1)
if err != nil {
	log.Fatal(err)
}
ex, err := extractor.New(page)
if err != nil {
	log.Fatal(err)
}
text, err := ex.ExtractText()

Merge and split

// Merge in1.pdf and in2.pdf into out.pdf (last argument: merge form fields too).
err := pdfutil.MergePdf([]string{"in1.pdf", "in2.pdf"}, "out.pdf", false)

// Keep pages 2-4 only.
err = pdfutil.ExtractPageRange("in.pdf", "pages.pdf", 2, 4, false)

Imports used above: github.com/OpenMellon/openpdf/{creator,extractor,model,pdfutil}.

Features

Each feature links to a runnable example, or to the package that provides it where there is no example yet.

Feature	Example / package
Create reports, tables, invoices and styled paragraphs	example, creator
Add images and watermarks to pages	example, creator
Merge PDFs	example, pdfutil
Split, rotate and reorder pages	example, pdfutil, model
Extract text (with size, position and formatting) and images	example, extractor
Compress and optimise PDF files	example, model/optimize
Password protection and unlocking	example, model
Create, fill and flatten forms	example, annotator
FDF and JSON form data	fdf, fjson
Digital signing and signature validation	example, model/sighandler, timestamp
Redaction	example, redactor
Sanitisation	sanitize
PDF/A and PDF/UA	model/pdfa, model/pdfua
Render pages to images	render
OCR integration	ocr
Charts, Arabic shaping and complex text layout	unichart, garabic, textshaping, typesetting

Packages

Package	Use it to
creator	Build documents: pages, text, tables, images, headers, footers, TOC
model	Read and write PDFs at page level; encryption, forms, signatures
extractor	Pull text, images and fonts out of pages
pdfutil	One-call merge, page-range extraction, grayscale
annotator	Form fields, signature fields and annotation appearances
core	Low-level PDF objects and parsing
contentstream	Parse and generate page content streams

Full API reference: pkg.go.dev/github.com/OpenMellon/openpdf.

Examples

Examples are Go testable examples: Example functions in example_test.go files that appear beside the API on pkg.go.dev and are compiled and run by go test, so they cannot go stale.

go test ./... -run Example -v

Contributing

Contributions are welcome. See CONTRIBUTING.md for development setup and how to open a pull request, and SUPPORT.md for where to ask questions. Report security vulnerabilities privately as described in SECURITY.md. Everyone taking part is expected to follow the Code of Conduct.

License

MIT - see LICENSE. OpenPDF is a derivative of UniPDF, Copyright 2020 FoxyUtils ehf., which was released under the MIT licence; the original copyright notices are retained in the source files and must stay with any copy. Packages derived from other projects, now separate modules under github.com/OpenMellon/ (freetype, garabic, go-xmp, pkcs7, timestamp, typesetting, unichart, unitype) keep their own licences; see ACKNOWLEDGEMENTS.md.

Documentation

Overview

Package openpdf is a comprehensive PDF library for Go (golang). The library has advanced capabilities for generating, processing and modifying PDFs. OpenPDF is written and supported by the owners of the FoxyUtils.com website, where the library is used to power many of the PDF services offered.

Getting More Information

Check out the Getting Started and Example sections, which showcase how to install openpdf and provide numerous examples of using openpdf to generate, process or modify PDF files. https://github.com/OpenMellon/openpdf

The GoDoc for openpdf provides a detailed breakdown of the API and documentation for packages, types and methods. https://godoc.org/github.com/OpenMellon/openpdf

Overview of Major Packages

The API is composed of a few major packages:

• common: Provides common shared types such as Logger and utilities to check license validity.

• core: The core package defines the primitive PDF object types and handles the file reading I/O and parsing the primitive objects.

• model: The model package builds on the core package, to represent the PDF as a structured model of the PDF primitive types. It has a reader and a writer to read and process a PDF file based on the structured model. This serves as a basis to perform a number of numerous tasks and can be used to work with a PDF in a medium to high level interface, although it does require an understanding of the PDF format and structure.

• creator: The PDF creator makes it easy to create new PDFs or modify existing PDFs. It can also enable loading a template PDF, adding text/images and generating an output PDF. It can be used to add text, images, and generate text and graphical reports. It is designed with simplicity in mind, with the goal of making it easy to create reports without needing any knowledge about the PDF format or specifications.

• extractor: Package extractor is used for quickly extracting PDF content through a simple interface. Currently offers functionality for extracting textual content.