Letter

Overview

The Letter component generates a formal business letter PDF with sender/recipient headers, date, subject, body paragraphs, and signature block.

Usage

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

doc := template.Letter(template.LetterData{
    From: template.LetterParty{
        Name: "ACME Corporation",
        Address: []string{
            "123 Business Street",
            "Suite 100",
            "San Francisco, CA 94105",
            "contact@acme.com",
        },
    },
    To: template.LetterParty{
        Name: "Mr. John Smith",
        Address: []string{
            "Tech Solutions Inc.",
            "456 Client Avenue",
            "New York, NY 10001",
        },
    },
    Date:     "March 1, 2026",
    Subject:  "Partnership Proposal",
    Greeting: "Dear Mr. Smith,",
    Body: []string{
        "I am writing to express our interest in establishing a strategic partnership " +
            "between ACME Corporation and Tech Solutions Inc. Over the past year, we have " +
            "observed the remarkable growth of your organization and believe that a collaboration " +
            "would be mutually beneficial.",
        "Our proposal includes joint development of cloud-based solutions targeting " +
            "the enterprise market. ACME Corporation brings extensive experience in PDF " +
            "generation and document processing, while Tech Solutions Inc. has demonstrated " +
            "excellence in frontend technologies and user experience design.",
        "We would like to schedule a meeting at your earliest convenience to discuss " +
            "the details of this proposal. Please feel free to contact me directly at " +
            "ceo@acme.com or call our office at (415) 555-0100.",
    },
    Closing:     "Sincerely,",
    Signature:   "Jane Doe",
    SignerTitle: "Chief Executive Officer",
})

data, err := doc.Generate()

┌─ A4 ──────────────────────────────────────────────┐
│                                                   │
│  ACME Corporation                                 │
│  123 Business Street                              │
│  Suite 100                                        │
│  San Francisco, CA 94105                          │
│  contact@acme.com                                 │
│                                                   │
│                                  March 1, 2026    │
│                                                   │
│  Mr. John Smith                                   │
│  Tech Solutions Inc.                              │
│  456 Client Avenue                                │
│  New York, NY 10001                               │
│                                                   │
│  RE: Partnership Proposal                         │
│  ──────────────────────────────────────────────── │
│                                                   │
│  Dear Mr. Smith,                                  │
│                                                   │
│  I am writing to express our interest in          │
│  establishing a strategic partnership between     │
│  ACME Corporation and Tech Solutions Inc...       │
│                                                   │
│  Our proposal includes joint development of       │
│  cloud-based solutions targeting the enterprise   │
│  market...                                        │
│                                                   │
│  We would like to schedule a meeting at your      │
│  earliest convenience to discuss the details...   │
│                                                   │
│                                                   │
│  Sincerely,                                       │
│                                                   │
│  Jane Doe                                         │
│  Chief Executive Officer                          │
│                                                   │
└───────────────────────────────────────────────────┘

Data Types

LetterData

Field	Type	Description
`From`	`LetterParty`	Sender information
`To`	`LetterParty`	Recipient information
`Date`	`string`	Letter date
`Subject`	`string`	Subject line
`Greeting`	`string`	Opening greeting (e.g., "Dear Mr. Smith,")
`Body`	`[]string`	Body paragraphs
`Closing`	`string`	Closing phrase (e.g., "Sincerely,")
`Signature`	`string`	Signer name
`SignerTitle`	`string`	Signer title

LetterParty

type LetterParty struct {
    Name    string
    Address []string
}

Customization

Pass document options to customize the letter:

fontData, _ := os.ReadFile("fonts/NotoSansJP-Regular.ttf")

doc := template.Letter(letterData,
    template.WithFont("NotoSansJP", fontData),
    template.WithDefaultFont("NotoSansJP", 12),
    template.WithPageSize(document.Letter),
)

Using the Facade

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

doc := gpdf.NewLetter(letterData)