GxPDF - Enterprise-Grade PDF Library for Go

GxPDF is a modern, high-performance PDF library for Go, built with clean architecture and Go 1.25+ best practices.

View Example PDF - See what GxPDF can create!

Key Features

PDF Creation (Creator API)

• Text & Typography - Rich text with multiple fonts, styles, and colors
• Graphics - Lines, rectangles, circles, polygons, ellipses, Bezier curves
• Gradients - Linear and radial gradient fills
• Color Spaces - RGB and CMYK support
• Tables - Complex tables with merged cells, borders, backgrounds
• Images - JPEG and PNG with transparency support
• Fonts - Standard 14 PDF fonts + TTF/OTF embedding with full Unicode support (Cyrillic, CJK, symbols)
• Document Structure - Chapters, auto-generated Table of Contents
• Annotations - Sticky notes, highlights, underlines, stamps
• Interactive Forms - Text fields, checkboxes, radio buttons, dropdowns
• Security - RC4 (40/128-bit) and AES (128/256-bit) encryption
• Watermarks - Text watermarks with rotation and opacity
• Page Operations - Merge, split, rotate, append

PDF Reading & Extraction

• Table Extraction - Industry-leading accuracy (100% on bank statements)
• Text Extraction - Full text with positions and Unicode support
• Image Extraction - Extract embedded images
• Export Formats - CSV, JSON, Excel

Installation

go get github.com/coregx/gxpdf

Requirements: Go 1.25 or later

Quick Start

Creating a PDF Document

package main

import (
    "log"
    "github.com/coregx/gxpdf/creator"
)

func main() {
    c := creator.New()
    c.SetTitle("My Document")
    c.SetAuthor("GxPDF")

    page, _ := c.NewPage()

    // Add text
    page.AddText("Hello, GxPDF!", 100, 750, creator.HelveticaBold, 24)
    page.AddText("Professional PDF creation in Go", 100, 720, creator.Helvetica, 12)

    // Draw shapes
    page.DrawRectangle(100, 600, 200, 100, &creator.RectangleOptions{
        FillColor:   &creator.Blue,
        StrokeColor: &creator.Black,
        StrokeWidth: 2,
    })

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

Unicode Text with Custom Fonts

c := creator.New()
page, _ := c.NewPage()

// Load custom font with Unicode support
font, _ := c.LoadFont("/path/to/arial.ttf")

// Cyrillic text
page.AddTextCustomFont("Привет, мир!", 100, 700, font, 18)

// CJK text (requires appropriate font like Malgun Gothic)
cjkFont, _ := c.LoadFont("/path/to/malgun.ttf")
page.AddTextCustomFont("你好世界 • 안녕하세요", 100, 670, cjkFont, 16)

c.WriteToFile("unicode.pdf")

Creating Encrypted PDFs

c := creator.New()

c.SetEncryption(creator.EncryptionOptions{
    UserPassword:  "user123",
    OwnerPassword: "owner456",
    Permissions:   creator.PermissionPrint | creator.PermissionCopy,
    Algorithm:     creator.EncryptionAES256,
})

page, _ := c.NewPage()
page.AddText("This document is encrypted!", 100, 750, creator.Helvetica, 14)
c.WriteToFile("encrypted.pdf")

Creating Documents with Chapters and TOC

c := creator.New()
c.EnableTOC()

ch1 := creator.NewChapter("Introduction")
ch1.Add(creator.NewParagraph("Introduction content..."))

ch1_1 := ch1.NewSubChapter("Background")
ch1_1.Add(creator.NewParagraph("Background information..."))

ch2 := creator.NewChapter("Methods")
ch2.Add(creator.NewParagraph("Methods description..."))

c.AddChapter(ch1)
c.AddChapter(ch2)

c.WriteToFile("document_with_toc.pdf")

Interactive Forms (AcroForm)

import "github.com/coregx/gxpdf/creator/forms"

c := creator.New()
page, _ := c.NewPage()

// Text field
nameField := forms.NewTextField("name", 100, 700, 200, 20)
nameField.SetLabel("Full Name:")
nameField.SetRequired(true)
page.AddField(nameField)

// Checkbox
agreeBox := forms.NewCheckbox("agree", 100, 660, 15, 15)
agreeBox.SetLabel("I agree to the terms")
page.AddField(agreeBox)

// Dropdown
countryDropdown := forms.NewDropdown("country", 100, 620, 150, 20)
countryDropdown.AddOption("us", "United States")
countryDropdown.AddOption("uk", "United Kingdom")
page.AddField(countryDropdown)

c.WriteToFile("form.pdf")

Reading and Filling Forms

// Read form fields from existing PDF
doc, _ := gxpdf.Open("form.pdf")
defer doc.Close()

// Check if document has a form
if doc.HasForm() {
    fields, _ := doc.GetFormFields()
    for _, f := range fields {
        fmt.Printf("%s (%s): %v\n", f.Name(), f.Type(), f.Value())
    }
}

// Fill form fields
app, _ := creator.NewAppender("form.pdf")
defer app.Close()

app.SetFieldValue("name", "John Doe")
app.SetFieldValue("email", "john@example.com")
app.SetFieldValue("agree", true)  // Checkbox
app.SetFieldValue("country", "USA")  // Dropdown

app.WriteToFile("filled_form.pdf")

Flattening Forms

// Convert form fields to static content (non-editable)
app, _ := creator.NewAppender("filled_form.pdf")
defer app.Close()

app.FlattenForm()  // Flatten all fields
// Or: app.FlattenFields("signature", "date")  // Specific fields

app.WriteToFile("flattened.pdf")

Extracting Tables from PDFs

doc, _ := gxpdf.Open("bank_statement.pdf")
defer doc.Close()

tables := doc.ExtractTables()
for _, table := range tables {
    fmt.Printf("Table: %d rows x %d cols\n", table.RowCount(), table.ColumnCount())

    // Export to CSV
    csv, _ := table.ToCSV()
    fmt.Println(csv)
}

Package Structure

github.com/coregx/gxpdf
├── gxpdf.go          # Main entry point
├── export/           # Export formats (CSV, JSON, Excel)
├── creator/          # PDF creation API
│   └── forms/        # Interactive form fields
└── internal/         # Private implementation
    ├── application/  # Use cases (extraction, reading)
    └── infrastructure/ # PDF parsing, encoding, writing

Documentation

• API Reference - Full API documentation
• Examples - Code examples for all features
• Enterprise Brochure (PDF) - Sample PDF created with GxPDF
• Architecture - DDD architecture overview
• Contributing - Contribution guidelines
• Security - Security policy

Testing

# Run all tests
go test ./...

# Run with race detector
go test -race ./...

# Run with coverage
go test -cover ./...

Roadmap

v0.1.x (Stable)

• PDF reading and parsing (PDF 1.0-2.0)
• Text extraction with positions
• Table extraction (100% accuracy)
• CSV/JSON/Excel export
• Creator API (text, graphics, tables)
• JPEG/PNG image support
• TTF/OTF font embedding with full Unicode
• RC4/AES encryption
• Chapters and TOC
• Annotations
• Interactive forms (AcroForm)
• Watermarks
• Page operations (merge, split, rotate)

v0.2.0 "Graphics Revolution" (In Development)

Skia-like Graphics API for GoGPU/gg integration:

• Alpha channel / transparency (ExtGState)
• Push/Pop graphics state stack
• Fill/Stroke separation with Paint interface
• Path Builder API (MoveTo, LineTo, CubicTo, etc.)
• Linear and Radial gradients
• ClipPath support

Forms API (Read, Fill, Flatten):

• Form field reader (GetFormFields, GetFieldValue)
• Form field writer (SetFieldValue with validation)
• Form flattening (FlattenForm, FlattenFields)

WASM/Platform Support:

• WASM API (WriteTo, Bytes for in-memory generation)

v0.3.0+ (Planned)

• Digital signatures
• PDF/A compliance
• Object streams (30% compression)
• SVG import

License

GxPDF is released under the MIT License. See LICENSE for details.

Support

• Issues: GitHub Issues
• Discussions: GitHub Discussions

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Built with Go 1.25+ and Domain-Driven Design