gpdf Package

import "github.com/gpdf-dev/gpdf"

// Using facade
doc := gpdf.NewDocument(gpdf.WithPageSize(gpdf.A4))

import (
    "github.com/gpdf-dev/gpdf/template"
    "github.com/gpdf-dev/gpdf/document"
)

// Using packages directly (recommended)
doc := template.New(template.WithPageSize(document.A4))

func NewDocument(opts ...template.Option) *template.Document

doc := gpdf.NewDocument(
    gpdf.WithPageSize(gpdf.A4),
    gpdf.WithMargins(document.UniformEdges(document.Mm(20))),
)

func FromJSON(schema []byte, data any, opts ...template.Option) (*template.Document, error)

doc, err := gpdf.FromJSON(schema, map[string]any{"title": "Report"})

func FromTemplate(tmpl *template.Template, data any, opts ...template.Option) (*template.Document, error)

func TemplateFuncMap() template.FuncMap

gpdf.WithMetadata(document.DocumentMetadata{
    Title:   "Invoice #INV-2026-001",
    Author:  "ACME Corporation",
    Subject: "Monthly Invoice",
    Creator: "gpdf v1.0.3",
})

func (d *Document) AddPage() *PageBuilder

func (d *Document) Header(fn func(p *PageBuilder))
func (d *Document) Footer(fn func(p *PageBuilder))

func (d *Document) Generate() ([]byte, error)
func (d *Document) Render(w io.Writer) error

func (p *PageBuilder) Row(height document.Value, fn func(r *RowBuilder))
func (p *PageBuilder) AutoRow(fn func(r *RowBuilder))

func (r *RowBuilder) Col(span int, fn func(c *ColBuilder))

func Open(data []byte, opts ...template.Option) (*template.ExistingDocument, error)

doc, err := gpdf.Open(pdfBytes)

doc, err := gpdf.Open(pdfBytes, gpdf.WithFont("NotoSans", fontData))

// Add watermark on page 1
doc.Overlay(0, func(p *template.PageBuilder) {
    p.Absolute(document.Mm(40), document.Mm(120), func(c *template.ColBuilder) {
        c.Text("DRAFT", template.FontSize(72),
            template.TextColor(pdf.Gray(0.85)))
    })
})

// Add page numbers on every page
count, _ := doc.PageCount()
doc.EachPage(func(i int, p *template.PageBuilder) {
    p.Absolute(document.Mm(170), document.Mm(285), func(c *template.ColBuilder) {
        c.Text(fmt.Sprintf("%d / %d", i+1, count),
            template.FontSize(10), template.AlignRight())
    }, template.AbsoluteWidth(document.Mm(20)))
})

result, err := doc.Save()

func Merge(sources []Source, opts ...MergeOption) ([]byte, error)

merged, err := gpdf.Merge([]gpdf.Source{
    {Data: cover},
    {Data: body},
})

type Source struct {
    Data  []byte    // raw PDF bytes
    Pages PageRange // which pages to include; zero value = all pages
}

type PageRange struct {
    From int  // 1-based start page; 0 means first page
    To   int  // 1-based end page; 0 means last page
}

merged, err := gpdf.Merge(
    []gpdf.Source{
        {Data: cover},
        {Data: body},
        {Data: appendix},
    },
    gpdf.WithMergeMetadata("Policy Bundle", "Example Ltd", "gpdf"),
)

func WithEncryption(opts ...encrypt.Option) template.Option

doc := gpdf.NewDocument(
    gpdf.WithPageSize(gpdf.A4),
    gpdf.WithEncryption(
        encrypt.WithOwnerPassword("owner-pass"),
        encrypt.WithUserPassword("user-pass"),
        encrypt.WithPermissions(encrypt.PermPrint|encrypt.PermCopy),
    ),
)

func WithPDFA(opts ...pdfa.Option) template.Option

doc := gpdf.NewDocument(
    gpdf.WithPageSize(gpdf.A4),
    gpdf.WithPDFA(
        pdfa.WithLevel(pdfa.LevelA2b),
        pdfa.WithMetadata(pdfa.MetadataInfo{
            Title:  "Archived Report",
            Author: "gpdf",
        }),
    ),
)

func SignDocument(pdfData []byte, signer signature.Signer, opts ...signature.Option) ([]byte, error)

data, _ := doc.Generate()

signed, err := gpdf.SignDocument(data, signature.Signer{
    Certificate: cert,
    PrivateKey:  key,
    Chain:       intermediates, // optional
},
    signature.WithReason("Approved"),
    signature.WithLocation("Tokyo"),
)

type Signer struct {
    Certificate *x509.Certificate
    PrivateKey  crypto.PrivateKey    // *rsa.PrivateKey or *ecdsa.PrivateKey
    Chain       []*x509.Certificate  // intermediate certificates (optional)
}