# gpdf

> A pure Go, zero-dependency PDF generation library with first-class CJK support. 10-30x faster than alternatives.

## Overview

gpdf is an open-source (MIT license) PDF generation library written in pure Go. It has zero external dependencies — using only the Go standard library. It provides first-class support for Japanese, Chinese, and Korean (CJK) text rendering with TrueType font embedding.

## Key Features

- **Zero Dependencies**: Pure Go, stdlib only. No CGO, no external libraries. Single binary deployment.
- **First-Class CJK Support**: Native Japanese, Chinese, Korean text rendering. TrueType font embedding. No tofu, no mojibake.
- **10-30x Faster**: Benchmarked against gofpdf, gopdf, and Maroto v2. Complex PDFs in under 5ms. Single-page generation ~13µs.
- **12-Column Grid Layout**: Bootstrap-style declarative layout system with rows, columns, and responsive spacing.
- **Declarative Builder API**: PageBuilder → RowBuilder → ColBuilder fluent API for intuitive document construction.
- **Templates**: Ready-to-use invoice, receipt, and estimate templates.
- **PDF Features**: TrueType fonts, images (JPEG/PNG), barcodes, QR codes, headers/footers, page numbers, overlay, merge, form flattening.

## Installation

```
go get github.com/gpdf-dev/gpdf
```

## Quick Example

```go
doc := gpdf.New()
doc.AddPage(gpdf.A4()).
    Row(func(r) {
        r.Col(12).Text("Hello, PDF!")
    })
doc.Output("hello.pdf")
```

## Architecture

gpdf uses a 3-layer architecture:
- **Layer 3 (template)**: Declarative Builder API, 12-col Grid, JSON Schema, Go Templates
- **Layer 2 (document)**: Nodes, Box Model, Layout Engine, Renderer
- **Layer 1 (pdf)**: PDF Writer, TrueType Fonts (CJK-aware), Streams, Images, Barcode/QR

## Documentation

- [Quickstart](https://gpdf.dev/docs/quickstart)
- [Installation](https://gpdf.dev/docs/guide/installation)
- [Basic Usage](https://gpdf.dev/docs/guide/basic-usage)
- [Grid Layout](https://gpdf.dev/docs/guide/grid-layout)
- [Styling](https://gpdf.dev/docs/guide/styling)
- [Fonts](https://gpdf.dev/docs/guide/fonts)
- [API Reference](https://gpdf.dev/docs/api-reference/gpdf-package)
- [Examples](https://gpdf.dev/docs/examples/basics)

## Writing gpdf JSON with an AI

A single-file canonical spec for having an AI (or a person) write the JSON that `template.FromJSON` accepts: prose, the JSON Schema, and examples that gpdf's test suite validates and renders. Hand the whole file to the model.

- [gpdf JSON spec (EN)](https://gpdf.dev/spec/gpdf-json-spec.en.md)
- [gpdf JSON spec (JA)](https://gpdf.dev/spec/gpdf-json-spec.ja.md)
- [JSON Schema](https://gpdf.dev/schema/gpdf.schema.json)

## Blog

Long-form articles, migration guides, and deep dives. Same content in six languages (EN / JA / ZH / KO / ES / PT) under locale-prefixed paths (e.g. `/ja/blog/...`).

- [Blog Index (EN)](https://gpdf.dev/blog)
- [Blog Index (JA)](https://gpdf.dev/ja/blog)
- [Blog Index (ZH)](https://gpdf.dev/zh/blog)
- [Atom Feed (EN)](https://gpdf.dev/rss.xml)
- [Atom Feed (JA)](https://gpdf.dev/ja/rss.xml)

Featured posts:

- [gofpdf is archived — migration guide to gpdf](https://gpdf.dev/blog/gofpdf-migration) — maps every gofpdf API to gpdf with five before/after pairs; covers CJK fonts, tables, headers/footers, and output calls.

## Links

- Website: https://gpdf.dev
- GitHub: https://github.com/gpdf-dev/gpdf
- Go Package: https://pkg.go.dev/github.com/gpdf-dev/gpdf
- Full LLM context: https://gpdf.dev/llms-full.txt