pdf-lib vs pdfkit
前端 PDF 文档生成与编辑库选型对比
pdf-libpdfkit类似的npm包:
前端 PDF 文档生成与编辑库选型对比

pdf-libpdfkit 都是用于在 JavaScript 环境中创建和操作 PDF 文档的流行库,但它们的设计目标、运行环境支持和核心能力存在显著差异。pdf-lib 专注于在浏览器和 Node.js 中读取、修改和写入现有 PDF 文件,支持文本、图像和表单字段的编辑,并原生支持 WebAssembly 以提升性能。pdfkit 则是一个从零开始生成 PDF 的库,采用类似 Canvas 的绘图 API,适合需要完全控制页面布局和内容渲染的场景,但不支持直接修改已有 PDF。两者在前端工程中的适用性取决于具体需求:是否需要编辑现有文档、是否依赖服务端渲染、以及对字体和图形的精细控制程度。

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pdf-lib3,103,3208,270-3124 年前MIT
pdfkit1,767,13010,5796.09 MB3975 个月前MIT

pdf-lib vs pdfkit:前端 PDF 生成与编辑能力深度对比

在现代 Web 应用中,PDF 操作需求日益普遍 —— 从生成电子发票到在线签署合同。pdf-libpdfkit 是两个主流选择,但它们解决的问题本质不同。本文将从真实开发场景出发,对比两者的核心能力、API 设计和适用边界。

📄 核心定位:编辑现有 PDF vs 从零生成 PDF

pdf-lib 的核心优势在于 读取和修改已有 PDF。它能解析 PDF 结构,让你添加文本、图像、注释,甚至填写表单字段,而保持原始文档的布局不变。

// pdf-lib: 加载现有 PDF 并添加文本
import { PDFDocument, rgb } from 'pdf-lib';
import existingPdfBytes from './template.pdf';

const pdfDoc = await PDFDocument.load(existingPdfBytes);
const pages = pdfDoc.getPages();
const firstPage = pages[0];

firstPage.drawText('已签署', {
  x: 100,
  y: 200,
  size: 24,
  color: rgb(1, 0, 0),
});

const modifiedPdfBytes = await pdfDoc.save();

pdfkit 则专注于 从空白画布生成全新 PDF。它提供类似 Canvas 的 API,让你逐行绘制文本、图形和图像,但无法加载或修改已有 PDF。

// pdfkit: 从零创建 PDF
import PDFDocument from 'pdfkit';
import fs from 'fs';

const doc = new PDFDocument();
doc.pipe(fs.createWriteStream('output.pdf'));

doc.fontSize(25).text('Hello World', 100, 100);
doc.end();

💡 关键区别:如果你有 PDF 模板需要填充(如合同、申请表),pdf-lib 是唯一可行方案;如果要动态生成报表(如销售数据图表),pdfkit 更灵活。

🌐 运行环境:浏览器优先 vs 服务端优先

pdf-lib 被设计为 真正的跨平台库。它在浏览器和 Node.js 中行为一致,无需额外配置即可在 React/Vue 应用中直接使用,且所有操作都在客户端完成,避免隐私敏感数据上传服务器。

// 在浏览器中直接使用 pdf-lib(无 Node.js 依赖)
const arrayBuffer = await fetch('/template.pdf').then(res => res.arrayBuffer());
const pdfDoc = await PDFDocument.load(arrayBuffer);
// ... 修改后触发下载
const blob = new Blob([await pdfDoc.save()], { type: 'application/pdf' });

pdfkit 虽然理论上可在浏览器中运行,但 实际依赖 Node.js 特性(如 fsstream)。要在前端使用,必须通过 Webpack/Browserify 打包,并手动处理字体文件(通常需转换为 base64 或 ArrayBuffer),增加了复杂度。

// pdfkit 在浏览器中需额外处理字体
import PDFDocument from 'pdfkit';
import fontData from './font.ttf'; // 需预加载为 ArrayBuffer

const doc = new PDFDocument();
doc.registerFont('CustomFont', fontData);
doc.font('CustomFont').text('自定义字体', 100, 100);

⚠️ 注意:pdfkit 的官方文档明确说明其主要面向 Node.js,浏览器支持属于“社区实验性质”,生产环境需谨慎评估。

✍️ 文本与字体处理:开箱即用 vs 手动配置

pdf-lib 内置对 标准 PDF 字体(如 Helvetica、Times-Roman)的支持,可直接使用。若需嵌入自定义字体,需提供字体文件的二进制数据(如 TTF/OTF),但 API 简洁:

// pdf-lib 嵌入自定义字体
const fontBytes = await fetch('/font.ttf').then(res => res.arrayBuffer());
const customFont = await pdfDoc.embedFont(fontBytes);

firstPage.drawText('中文', {
  x: 50,
  y: 150,
  font: customFont,
  size: 16,
});

pdfkit 对字体的控制更底层,但 必须显式注册字体。它支持 TrueType、OpenType 等格式,但浏览器中需自行处理字体加载和 CORS 问题:

// pdfkit 注册字体(Node.js 示例)
doc.font('fonts/SourceHanSansCN-Regular.otf')
   .fontSize(16)
   .text('中文', 100, 100);

📌 实践建议:若需大量中文或特殊字体,pdf-lib 的嵌入流程更直观;pdfkit 则适合已知固定字体集的服务端批量生成。

🖼️ 图像与图形支持:基础功能 vs 丰富绘图

pdf-lib 支持插入 JPEG/PNG 图像,但 不支持矢量图形绘制(如路径、贝塞尔曲线)。图像需先转为二进制数据:

// pdf-lib 插入 PNG
const pngImageBytes = await fetch('/logo.png').then(res => res.arrayBuffer());
const pngImage = await pdfDoc.embedPng(pngImageBytes);

firstPage.drawImage(pngImage, {
  x: 200,
  y: 300,
  width: 100,
  height: 50,
});

pdfkit 提供完整的 矢量绘图 API,包括线条、矩形、圆、路径、渐变等,适合生成图表或复杂布局:

// pdfkit 绘制带渐变的矩形
doc.linearGradient(100, 100, 200, 100)
   .color('#FF0000')
   .color('#0000FF')
   .rectangle(100, 100, 100, 50)
   .fill();

💡 场景匹配:若 PDF 内容主要是文本+图片(如证书、报告),pdf-lib 足够;若需动态生成图表、流程图,pdfkit 不可替代。

🔒 表单与交互:唯一选择 vs 不支持

pdf-lib目前唯一支持 PDF 表单操作的主流库。你可以获取表单字段、设置值、甚至扁平化(锁定)表单:

// pdf-lib 填写表单
const form = pdfDoc.getForm();
const nameField = form.getTextField('name');
nameField.setText('张三');

// 锁定表单防止后续编辑
form.flatten();

pdfkit 完全不支持表单。它生成的 PDF 是静态内容,无法包含可交互字段。

🚨 重要结论:任何涉及 PDF 表单(如在线申请、电子签名)的场景,必须选择 pdf-lib

📦 依赖与打包:零依赖 vs 多依赖

pdf-lib 作为纯 ESM/CJS 模块,无外部依赖,可直接通过 CDN 引入或在现代构建工具中 tree-shaking。

pdfkit 依赖多个 Node.js 模块(如 png-js, fontkit),在浏览器中使用时需完整打包,导致 体积显著增大,且可能引入兼容性问题。

🔄 相似之处:共同的基础能力

尽管定位不同,两者在以下方面有交集:

1. 📄 基础文本输出

两者都能输出多行文本、设置字体大小和颜色。

// pdf-lib
page.drawText('文本', { x: 50, y: 500, size: 12 });

// pdfkit
doc.text('文本', 50, 500, { fontSize: 12 });

2. 🖼️ 图像嵌入

均支持嵌入位图(JPEG/PNG),但需预处理为二进制数据。

3. 💾 输出为 ArrayBuffer/Blob

最终都可导出为二进制数据,便于前端下载或上传。

// pdf-lib
const uint8Array = await pdfDoc.save();

// pdfkit (需配合 blob-stream)
const stream = doc.pipe(blobStream());
stream.on('finish', () => {
  const blob = stream.toBlob('application/pdf');
});

📊 总结:关键差异速查表

能力pdf-libpdfkit
编辑现有 PDF✅ 完整支持❌ 不支持
从零生成 PDF✅(但布局控制弱)✅(精细绘图 API)
浏览器原生支持✅ 无需额外配置⚠️ 需打包 + 手动处理字体
PDF 表单操作✅ 填写/扁平化❌ 不支持
矢量图形绘制❌ 仅支持位图✅ 路径/渐变/形状
中文/自定义字体✅ 嵌入简单✅ 但需显式注册
典型场景合同签署、证书生成、表单填充发票、报表、数据可视化 PDF

💡 最终建议

  • pdf-lib:当你需要处理用户上传的 PDF 模板、实现电子签名、或在纯前端完成文档编辑。它是现代 Web 应用中 PDF 交互的首选。
  • pdfkit:当你在服务端生成高度定制化的 PDF(如财务报告、科学图表),且不需要修改已有文档。它在 Node.js 环境中表现卓越,但前端集成成本高。

🌟 记住:两者并非互斥。某些复杂系统会同时使用 —— 用 pdfkit 生成基础报告,再用 pdf-lib 添加数字签名或水印。

如何选择: pdf-lib vs pdfkit
  • pdf-lib:

    选择 pdf-lib 如果你需要在浏览器或 Node.js 中加载并修改现有的 PDF 文件(例如填写表单、添加水印、合并页面),或者你的应用场景要求跨平台一致的行为(如电子签名、文档批注)。它对现代前端框架(如 React、Vue)友好,且无需额外依赖即可在纯客户端运行。

  • pdfkit:

    选择 pdfkit 如果你从零开始生成高度定制化的 PDF 报告、发票或图表,且需要精细控制文本排版、矢量图形和字体嵌入。它更适合服务端渲染或构建时生成静态 PDF,但在浏览器中使用需额外处理字体和依赖,且无法直接编辑已有 PDF。

pdf-lib的README

pdf-lib

Create and modify PDF documents in any JavaScript environment.
Designed to work in any modern JavaScript runtime. Tested in Node, Browser, Deno, and React Native environments.


Learn more at pdf-lib.js.org

Table of Contents

Features

  • Create new PDFs
  • Modify existing PDFs
  • Create forms
  • Fill forms
  • Flatten forms
  • Add Pages
  • Insert Pages
  • Remove Pages
  • Copy pages between PDFs
  • Draw Text
  • Draw Images
  • Draw PDF Pages
  • Draw Vector Graphics
  • Draw SVG Paths
  • Measure width and height of text
  • Embed Fonts (supports UTF-8 and UTF-16 character sets)
  • Set document metadata
  • Read document metadata
  • Set viewer preferences
  • Read viewer preferences
  • Add attachments

Motivation

pdf-lib was created to address the JavaScript ecosystem's lack of robust support for PDF manipulation (especially for PDF modification).

Two of pdf-lib's distinguishing features are:

  1. Supporting modification (editing) of existing documents.
  2. Working in all JavaScript environments - not just in Node or the Browser.

There are other good open source JavaScript PDF libraries available. However, most of them can only create documents, they cannot modify existing ones. And many of them only work in particular environments.

Usage Examples

Create Document

This example produces this PDF.

Try the JSFiddle demo

import { PDFDocument, StandardFonts, rgb } from 'pdf-lib'

// Create a new PDFDocument
const pdfDoc = await PDFDocument.create()

// Embed the Times Roman font
const timesRomanFont = await pdfDoc.embedFont(StandardFonts.TimesRoman)

// Add a blank page to the document
const page = pdfDoc.addPage()

// Get the width and height of the page
const { width, height } = page.getSize()

// Draw a string of text toward the top of the page
const fontSize = 30
page.drawText('Creating PDFs in JavaScript is awesome!', {
  x: 50,
  y: height - 4 * fontSize,
  size: fontSize,
  font: timesRomanFont,
  color: rgb(0, 0.53, 0.71),
})

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Modify Document

This example produces this PDF (when this PDF is used for the existingPdfBytes variable).

Try the JSFiddle demo

import { degrees, PDFDocument, rgb, StandardFonts } from 'pdf-lib';

// This should be a Uint8Array or ArrayBuffer
// This data can be obtained in a number of different ways
// If your running in a Node environment, you could use fs.readFile()
// In the browser, you could make a fetch() call and use res.arrayBuffer()
const existingPdfBytes = ...

// Load a PDFDocument from the existing PDF bytes
const pdfDoc = await PDFDocument.load(existingPdfBytes)

// Embed the Helvetica font
const helveticaFont = await pdfDoc.embedFont(StandardFonts.Helvetica)

// Get the first page of the document
const pages = pdfDoc.getPages()
const firstPage = pages[0]

// Get the width and height of the first page
const { width, height } = firstPage.getSize()

// Draw a string of text diagonally across the first page
firstPage.drawText('This text was added with JavaScript!', {
  x: 5,
  y: height / 2 + 300,
  size: 50,
  font: helveticaFont,
  color: rgb(0.95, 0.1, 0.1),
  rotate: degrees(-45),
})


// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Create Form

This example produces this PDF.

Try the JSFiddle demo

See also Creating and Filling Forms

import { PDFDocument } from 'pdf-lib'

// Create a new PDFDocument
const pdfDoc = await PDFDocument.create()

// Add a blank page to the document
const page = pdfDoc.addPage([550, 750])

// Get the form so we can add fields to it
const form = pdfDoc.getForm()

// Add the superhero text field and description
page.drawText('Enter your favorite superhero:', { x: 50, y: 700, size: 20 })

const superheroField = form.createTextField('favorite.superhero')
superheroField.setText('One Punch Man')
superheroField.addToPage(page, { x: 55, y: 640 })

// Add the rocket radio group, labels, and description
page.drawText('Select your favorite rocket:', { x: 50, y: 600, size: 20 })

page.drawText('Falcon Heavy', { x: 120, y: 560, size: 18 })
page.drawText('Saturn IV', { x: 120, y: 500, size: 18 })
page.drawText('Delta IV Heavy', { x: 340, y: 560, size: 18 })
page.drawText('Space Launch System', { x: 340, y: 500, size: 18 })

const rocketField = form.createRadioGroup('favorite.rocket')
rocketField.addOptionToPage('Falcon Heavy', page, { x: 55, y: 540 })
rocketField.addOptionToPage('Saturn IV', page, { x: 55, y: 480 })
rocketField.addOptionToPage('Delta IV Heavy', page, { x: 275, y: 540 })
rocketField.addOptionToPage('Space Launch System', page, { x: 275, y: 480 })
rocketField.select('Saturn IV')

// Add the gundam check boxes, labels, and description
page.drawText('Select your favorite gundams:', { x: 50, y: 440, size: 20 })

page.drawText('Exia', { x: 120, y: 400, size: 18 })
page.drawText('Kyrios', { x: 120, y: 340, size: 18 })
page.drawText('Virtue', { x: 340, y: 400, size: 18 })
page.drawText('Dynames', { x: 340, y: 340, size: 18 })

const exiaField = form.createCheckBox('gundam.exia')
const kyriosField = form.createCheckBox('gundam.kyrios')
const virtueField = form.createCheckBox('gundam.virtue')
const dynamesField = form.createCheckBox('gundam.dynames')

exiaField.addToPage(page, { x: 55, y: 380 })
kyriosField.addToPage(page, { x: 55, y: 320 })
virtueField.addToPage(page, { x: 275, y: 380 })
dynamesField.addToPage(page, { x: 275, y: 320 })

exiaField.check()
dynamesField.check()

// Add the planet dropdown and description
page.drawText('Select your favorite planet*:', { x: 50, y: 280, size: 20 })

const planetsField = form.createDropdown('favorite.planet')
planetsField.addOptions(['Venus', 'Earth', 'Mars', 'Pluto'])
planetsField.select('Pluto')
planetsField.addToPage(page, { x: 55, y: 220 })

// Add the person option list and description
page.drawText('Select your favorite person:', { x: 50, y: 180, size: 18 })

const personField = form.createOptionList('favorite.person')
personField.addOptions([
  'Julius Caesar',
  'Ada Lovelace',
  'Cleopatra',
  'Aaron Burr',
  'Mark Antony',
])
personField.select('Ada Lovelace')
personField.addToPage(page, { x: 55, y: 70 })

// Just saying...
page.drawText(`* Pluto should be a planet too!`, { x: 15, y: 15, size: 15 })

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Fill Form

This example produces this PDF (when this PDF is used for the formPdfBytes variable, this image is used for the marioImageBytes variable, and this image is used for the emblemImageBytes variable).

Try the JSFiddle demo

See also Creating and Filling Forms

import { PDFDocument } from 'pdf-lib'

// These should be Uint8Arrays or ArrayBuffers
// This data can be obtained in a number of different ways
// If your running in a Node environment, you could use fs.readFile()
// In the browser, you could make a fetch() call and use res.arrayBuffer()
const formPdfBytes = ...
const marioImageBytes = ...
const emblemImageBytes = ...

// Load a PDF with form fields
const pdfDoc = await PDFDocument.load(formPdfBytes)

// Embed the Mario and emblem images
const marioImage = await pdfDoc.embedPng(marioImageBytes)
const emblemImage = await pdfDoc.embedPng(emblemImageBytes)

// Get the form containing all the fields
const form = pdfDoc.getForm()

// Get all fields in the PDF by their names
const nameField = form.getTextField('CharacterName 2')
const ageField = form.getTextField('Age')
const heightField = form.getTextField('Height')
const weightField = form.getTextField('Weight')
const eyesField = form.getTextField('Eyes')
const skinField = form.getTextField('Skin')
const hairField = form.getTextField('Hair')

const alliesField = form.getTextField('Allies')
const factionField = form.getTextField('FactionName')
const backstoryField = form.getTextField('Backstory')
const traitsField = form.getTextField('Feat+Traits')
const treasureField = form.getTextField('Treasure')

const characterImageField = form.getButton('CHARACTER IMAGE')
const factionImageField = form.getTextField('Faction Symbol Image')

// Fill in the basic info fields
nameField.setText('Mario')
ageField.setText('24 years')
heightField.setText(`5' 1"`)
weightField.setText('196 lbs')
eyesField.setText('blue')
skinField.setText('white')
hairField.setText('brown')

// Fill the character image field with our Mario image
characterImageField.setImage(marioImage)

// Fill in the allies field
alliesField.setText(
  [
    `Allies:`,
    `  • Princess Daisy`,
    `  • Princess Peach`,
    `  • Rosalina`,
    `  • Geno`,
    `  • Luigi`,
    `  • Donkey Kong`,
    `  • Yoshi`,
    `  • Diddy Kong`,
    ``,
    `Organizations:`,
    `  • Italian Plumbers Association`,
  ].join('\n'),
)

// Fill in the faction name field
factionField.setText(`Mario's Emblem`)

// Fill the faction image field with our emblem image
factionImageField.setImage(emblemImage)

// Fill in the backstory field
backstoryField.setText(
  `Mario is a fictional character in the Mario video game franchise, owned by Nintendo and created by Japanese video game designer Shigeru Miyamoto. Serving as the company's mascot and the eponymous protagonist of the series, Mario has appeared in over 200 video games since his creation. Depicted as a short, pudgy, Italian plumber who resides in the Mushroom Kingdom, his adventures generally center upon rescuing Princess Peach from the Koopa villain Bowser. His younger brother and sidekick is Luigi.`,
)

// Fill in the traits field
traitsField.setText(
  [
    `Mario can use three basic three power-ups:`,
    `  • the Super Mushroom, which causes Mario to grow larger`,
    `  • the Fire Flower, which allows Mario to throw fireballs`,
    `  • the Starman, which gives Mario temporary invincibility`,
  ].join('\n'),
)

// Fill in the treasure field
treasureField.setText(['• Gold coins', '• Treasure chests'].join('\n'))

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Flatten Form

This example produces this PDF (when this PDF is used for the formPdfBytes variable).

Try the JSFiddle demo

import { PDFDocument } from 'pdf-lib'

// This should be a Uint8Array or ArrayBuffer
// This data can be obtained in a number of different ways
// If your running in a Node environment, you could use fs.readFile()
// In the browser, you could make a fetch() call and use res.arrayBuffer()
const formPdfBytes = ...

// Load a PDF with form fields
const pdfDoc = await PDFDocument.load(formPdfBytes)

// Get the form containing all the fields
const form = pdfDoc.getForm()

// Fill the form's fields
form.getTextField('Text1').setText('Some Text');

form.getRadioGroup('Group2').select('Choice1');
form.getRadioGroup('Group3').select('Choice3');
form.getRadioGroup('Group4').select('Choice1');

form.getCheckBox('Check Box3').check();
form.getCheckBox('Check Box4').uncheck();

form.getDropdown('Dropdown7').select('Infinity');

form.getOptionList('List Box6').select('Honda');

// Flatten the form's fields
form.flatten();

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Copy Pages

This example produces this PDF (when this PDF is used for the firstDonorPdfBytes variable and this PDF is used for the secondDonorPdfBytes variable).

Try the JSFiddle demo

import { PDFDocument } from 'pdf-lib'

// Create a new PDFDocument
const pdfDoc = await PDFDocument.create()

// These should be Uint8Arrays or ArrayBuffers
// This data can be obtained in a number of different ways
// If your running in a Node environment, you could use fs.readFile()
// In the browser, you could make a fetch() call and use res.arrayBuffer()
const firstDonorPdfBytes = ...
const secondDonorPdfBytes = ...

// Load a PDFDocument from each of the existing PDFs
const firstDonorPdfDoc = await PDFDocument.load(firstDonorPdfBytes)
const secondDonorPdfDoc = await PDFDocument.load(secondDonorPdfBytes)

// Copy the 1st page from the first donor document, and
// the 743rd page from the second donor document
const [firstDonorPage] = await pdfDoc.copyPages(firstDonorPdfDoc, [0])
const [secondDonorPage] = await pdfDoc.copyPages(secondDonorPdfDoc, [742])

// Add the first copied page
pdfDoc.addPage(firstDonorPage)

// Insert the second copied page to index 0, so it will be the
// first page in `pdfDoc`
pdfDoc.insertPage(0, secondDonorPage)

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Embed PNG and JPEG Images

This example produces this PDF (when this image is used for the jpgImageBytes variable and this image is used for the pngImageBytes variable).

Try the JSFiddle demo

import { PDFDocument } from 'pdf-lib'

// These should be Uint8Arrays or ArrayBuffers
// This data can be obtained in a number of different ways
// If your running in a Node environment, you could use fs.readFile()
// In the browser, you could make a fetch() call and use res.arrayBuffer()
const jpgImageBytes = ...
const pngImageBytes = ...

// Create a new PDFDocument
const pdfDoc = await PDFDocument.create()

// Embed the JPG image bytes and PNG image bytes
const jpgImage = await pdfDoc.embedJpg(jpgImageBytes)
const pngImage = await pdfDoc.embedPng(pngImageBytes)

// Get the width/height of the JPG image scaled down to 25% of its original size
const jpgDims = jpgImage.scale(0.25)

// Get the width/height of the PNG image scaled down to 50% of its original size
const pngDims = pngImage.scale(0.5)

// Add a blank page to the document
const page = pdfDoc.addPage()

// Draw the JPG image in the center of the page
page.drawImage(jpgImage, {
  x: page.getWidth() / 2 - jpgDims.width / 2,
  y: page.getHeight() / 2 - jpgDims.height / 2,
  width: jpgDims.width,
  height: jpgDims.height,
})

// Draw the PNG image near the lower right corner of the JPG image
page.drawImage(pngImage, {
  x: page.getWidth() / 2 - pngDims.width / 2 + 75,
  y: page.getHeight() / 2 - pngDims.height,
  width: pngDims.width,
  height: pngDims.height,
})

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Embed PDF Pages

This example produces this PDF (when this PDF is used for the americanFlagPdfBytes variable and this PDF is used for the usConstitutionPdfBytes variable).

Try the JSFiddle demo

import { PDFDocument } from 'pdf-lib'

// These should be Uint8Arrays or ArrayBuffers
// This data can be obtained in a number of different ways
// If your running in a Node environment, you could use fs.readFile()
// In the browser, you could make a fetch() call and use res.arrayBuffer()
const americanFlagPdfBytes = ...
const usConstitutionPdfBytes = ...

// Create a new PDFDocument
const pdfDoc = await PDFDocument.create()

// Embed the American flag PDF bytes
const [americanFlag] = await pdfDoc.embedPdf(americanFlagPdfBytes)

// Load the U.S. constitution PDF bytes
const usConstitutionPdf = await PDFDocument.load(usConstitutionPdfBytes)

// Embed the second page of the constitution and clip the preamble
const preamble = await pdfDoc.embedPage(usConstitutionPdf.getPages()[1], {
  left: 55,
  bottom: 485,
  right: 300,
  top: 575,
})

// Get the width/height of the American flag PDF scaled down to 30% of
// its original size
const americanFlagDims = americanFlag.scale(0.3)

// Get the width/height of the preamble clipping scaled up to 225% of
// its original size
const preambleDims = preamble.scale(2.25)

// Add a blank page to the document
const page = pdfDoc.addPage()

// Draw the American flag image in the center top of the page
page.drawPage(americanFlag, {
  ...americanFlagDims,
  x: page.getWidth() / 2 - americanFlagDims.width / 2,
  y: page.getHeight() - americanFlagDims.height - 150,
})

// Draw the preamble clipping in the center bottom of the page
page.drawPage(preamble, {
  ...preambleDims,
  x: page.getWidth() / 2 - preambleDims.width / 2,
  y: page.getHeight() / 2 - preambleDims.height / 2 - 50,
})

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Embed Font and Measure Text

pdf-lib relies on a sister module to support embedding custom fonts: @pdf-lib/fontkit. You must add the @pdf-lib/fontkit module to your project and register it using pdfDoc.registerFontkit(...) before embedding custom fonts.

See below for detailed installation instructions on installing @pdf-lib/fontkit as a UMD or NPM module.

This example produces this PDF (when this font is used for the fontBytes variable).

Try the JSFiddle demo

import { PDFDocument, rgb } from 'pdf-lib'
import fontkit from '@pdf-lib/fontkit'

// This should be a Uint8Array or ArrayBuffer
// This data can be obtained in a number of different ways
// If you're running in a Node environment, you could use fs.readFile()
// In the browser, you could make a fetch() call and use res.arrayBuffer()
const fontBytes = ...

// Create a new PDFDocument
const pdfDoc = await PDFDocument.create()

// Register the `fontkit` instance
pdfDoc.registerFontkit(fontkit)

// Embed our custom font in the document
const customFont = await pdfDoc.embedFont(fontBytes)

// Add a blank page to the document
const page = pdfDoc.addPage()

// Create a string of text and measure its width and height in our custom font
const text = 'This is text in an embedded font!'
const textSize = 35
const textWidth = customFont.widthOfTextAtSize(text, textSize)
const textHeight = customFont.heightAtSize(textSize)

// Draw the string of text on the page
page.drawText(text, {
  x: 40,
  y: 450,
  size: textSize,
  font: customFont,
  color: rgb(0, 0.53, 0.71),
})

// Draw a box around the string of text
page.drawRectangle({
  x: 40,
  y: 450,
  width: textWidth,
  height: textHeight,
  borderColor: rgb(1, 0, 0),
  borderWidth: 1.5,
})

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Add Attachments

This example produces this PDF (when this image is used for the jpgAttachmentBytes variable and this PDF is used for the pdfAttachmentBytes variable).

Try the JSFiddle demo

import { PDFDocument } from 'pdf-lib'

// These should be Uint8Arrays or ArrayBuffers
// This data can be obtained in a number of different ways
// If your running in a Node environment, you could use fs.readFile()
// In the browser, you could make a fetch() call and use res.arrayBuffer()
const jpgAttachmentBytes = ...
const pdfAttachmentBytes = ...

// Create a new PDFDocument
const pdfDoc = await PDFDocument.create()

// Add the JPG attachment
await pdfDoc.attach(jpgAttachmentBytes, 'cat_riding_unicorn.jpg', {
  mimeType: 'image/jpeg',
  description: 'Cool cat riding a unicorn! 🦄🐈🕶️',
  creationDate: new Date('2019/12/01'),
  modificationDate: new Date('2020/04/19'),
})

// Add the PDF attachment
await pdfDoc.attach(pdfAttachmentBytes, 'us_constitution.pdf', {
  mimeType: 'application/pdf',
  description: 'Constitution of the United States 🇺🇸🦅',
  creationDate: new Date('1787/09/17'),
  modificationDate: new Date('1992/05/07'),
})

// Add a page with some text
const page = pdfDoc.addPage();
page.drawText('This PDF has two attachments', { x: 135, y: 415 })

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Set Document Metadata

This example produces this PDF.

Try the JSFiddle demo

import { PDFDocument, StandardFonts } from 'pdf-lib'

// Create a new PDFDocument
const pdfDoc = await PDFDocument.create()

// Embed the Times Roman font
const timesRomanFont = await pdfDoc.embedFont(StandardFonts.TimesRoman)

// Add a page and draw some text on it
const page = pdfDoc.addPage([500, 600])
page.setFont(timesRomanFont)
page.drawText('The Life of an Egg', { x: 60, y: 500, size: 50 })
page.drawText('An Epic Tale of Woe', { x: 125, y: 460, size: 25 })

// Set all available metadata fields on the PDFDocument. Note that these fields
// are visible in the "Document Properties" section of most PDF readers.
pdfDoc.setTitle('🥚 The Life of an Egg 🍳')
pdfDoc.setAuthor('Humpty Dumpty')
pdfDoc.setSubject('📘 An Epic Tale of Woe 📖')
pdfDoc.setKeywords(['eggs', 'wall', 'fall', 'king', 'horses', 'men'])
pdfDoc.setProducer('PDF App 9000 🤖')
pdfDoc.setCreator('pdf-lib (https://github.com/Hopding/pdf-lib)')
pdfDoc.setCreationDate(new Date('2018-06-24T01:58:37.228Z'))
pdfDoc.setModificationDate(new Date('2019-12-21T07:00:11.000Z'))

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Read Document Metadata

Try the JSFiddle demo

import { PDFDocument } from 'pdf-lib'

// This should be a Uint8Array or ArrayBuffer
// This data can be obtained in a number of different ways
// If your running in a Node environment, you could use fs.readFile()
// In the browser, you could make a fetch() call and use res.arrayBuffer()
const existingPdfBytes = ...

// Load a PDFDocument without updating its existing metadata
const pdfDoc = await PDFDocument.load(existingPdfBytes, {
  updateMetadata: false
})

// Print all available metadata fields
console.log('Title:', pdfDoc.getTitle())
console.log('Author:', pdfDoc.getAuthor())
console.log('Subject:', pdfDoc.getSubject())
console.log('Creator:', pdfDoc.getCreator())
console.log('Keywords:', pdfDoc.getKeywords())
console.log('Producer:', pdfDoc.getProducer())
console.log('Creation Date:', pdfDoc.getCreationDate())
console.log('Modification Date:', pdfDoc.getModificationDate())

This script outputs the following (when this PDF is used for the existingPdfBytes variable):

Title: Microsoft Word - Basic Curriculum Vitae example.doc
Author: Administrator
Subject: undefined
Creator: PScript5.dll Version 5.2
Keywords: undefined
Producer: Acrobat Distiller 8.1.0 (Windows)
Creation Date: 2010-07-29T14:26:00.000Z
Modification Date: 2010-07-29T14:26:00.000Z

Set Viewer Preferences

import {
  PDFDocument,
  StandardFonts,
  NonFullScreenPageMode,
  ReadingDirection,
  PrintScaling,
  Duplex,
  PDFName,
} from 'pdf-lib'

// Create a new PDFDocument
const pdfDoc = await PDFDocument.create()

// Embed the Times Roman font
const timesRomanFont = await pdfDoc.embedFont(StandardFonts.TimesRoman)

// Add a page and draw some text on it
const page = pdfDoc.addPage([500, 600])
page.setFont(timesRomanFont)
page.drawText('The Life of an Egg', { x: 60, y: 500, size: 50 })
page.drawText('An Epic Tale of Woe', { x: 125, y: 460, size: 25 })

// Set all available viewer preferences on the PDFDocument:
const viewerPrefs = pdfDoc.catalog.getOrCreateViewerPreferences()
viewerPrefs.setHideToolbar(true)
viewerPrefs.setHideMenubar(true)
viewerPrefs.setHideWindowUI(true)
viewerPrefs.setFitWindow(true)
viewerPrefs.setCenterWindow(true)
viewerPrefs.setDisplayDocTitle(true)

// Set the PageMode (otherwise setting NonFullScreenPageMode has no meaning)
pdfDoc.catalog.set(PDFName.of('PageMode'), PDFName.of('FullScreen'))

// Set what happens when fullScreen is closed
viewerPrefs.setNonFullScreenPageMode(NonFullScreenPageMode.UseOutlines)

viewerPrefs.setReadingDirection(ReadingDirection.L2R)
viewerPrefs.setPrintScaling(PrintScaling.None)
viewerPrefs.setDuplex(Duplex.DuplexFlipLongEdge)
viewerPrefs.setPickTrayByPDFSize(true)

// We can set the default print range to only the first page
viewerPrefs.setPrintPageRange({ start: 0, end: 0 })

// Or we can supply noncontiguous ranges (e.g. pages 1, 3, and 5-7)
viewerPrefs.setPrintPageRange([
  { start: 0, end: 0 },
  { start: 2, end: 2 },
  { start: 4, end: 6 },
])

viewerPrefs.setNumCopies(2)

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Read Viewer Preferences

import { PDFDocument } from 'pdf-lib'

// This should be a Uint8Array or ArrayBuffer
// This data can be obtained in a number of different ways
// If your running in a Node environment, you could use fs.readFile()
// In the browser, you could make a fetch() call and use res.arrayBuffer()
const existingPdfBytes = ...

// Load a PDFDocument without updating its existing metadata
const pdfDoc = await PDFDocument.load(existingPdfBytes)
const viewerPrefs = pdfDoc.catalog.getOrCreateViewerPreferences()

// Print all available viewer preference fields
console.log('HideToolbar:', viewerPrefs.getHideToolbar())
console.log('HideMenubar:', viewerPrefs.getHideMenubar())
console.log('HideWindowUI:', viewerPrefs.getHideWindowUI())
console.log('FitWindow:', viewerPrefs.getFitWindow())
console.log('CenterWindow:', viewerPrefs.getCenterWindow())
console.log('DisplayDocTitle:', viewerPrefs.getDisplayDocTitle())
console.log('NonFullScreenPageMode:', viewerPrefs.getNonFullScreenPageMode())
console.log('ReadingDirection:', viewerPrefs.getReadingDirection())
console.log('PrintScaling:', viewerPrefs.getPrintScaling())
console.log('Duplex:', viewerPrefs.getDuplex())
console.log('PickTrayByPDFSize:', viewerPrefs.getPickTrayByPDFSize())
console.log('PrintPageRange:', viewerPrefs.getPrintPageRange())
console.log('NumCopies:', viewerPrefs.getNumCopies())

This script outputs the following (when this PDF is used for the existingPdfBytes variable):

HideToolbar: true
HideMenubar: true
HideWindowUI: false
FitWindow: true
CenterWindow: true
DisplayDocTitle: true
NonFullScreenPageMode: UseNone
ReadingDirection: R2L
PrintScaling: None
Duplex: DuplexFlipLongEdge
PickTrayByPDFSize: true
PrintPageRange: [ { start: 1, end: 1 }, { start: 3, end: 4 } ]
NumCopies: 2

Draw SVG Paths

This example produces this PDF.

Try the JSFiddle demo

import { PDFDocument, rgb } from 'pdf-lib'

// SVG path for a wavy line
const svgPath =
  'M 0,20 L 100,160 Q 130,200 150,120 C 190,-40 200,200 300,150 L 400,90'

// Create a new PDFDocument
const pdfDoc = await PDFDocument.create()

// Add a blank page to the document
const page = pdfDoc.addPage()
page.moveTo(100, page.getHeight() - 5)

// Draw the SVG path as a black line
page.moveDown(25)
page.drawSvgPath(svgPath)

// Draw the SVG path as a thick green line
page.moveDown(200)
page.drawSvgPath(svgPath, { borderColor: rgb(0, 1, 0), borderWidth: 5 })

// Draw the SVG path and fill it with red
page.moveDown(200)
page.drawSvgPath(svgPath, { color: rgb(1, 0, 0) })

// Draw the SVG path at 50% of its original size
page.moveDown(200)
page.drawSvgPath(svgPath, { scale: 0.5 })

// Serialize the PDFDocument to bytes (a Uint8Array)
const pdfBytes = await pdfDoc.save()

// For example, `pdfBytes` can be:
//   • Written to a file in Node
//   • Downloaded from the browser
//   • Rendered in an <iframe>

Deno Usage

pdf-lib fully supports the exciting new Deno runtime! All of the usage examples work in Deno. The only thing you need to do is change the imports for pdf-lib and @pdf-lib/fontkit to use the Skypack CDN, because Deno requires all modules to be referenced via URLs.

See also How to Create and Modify PDF Files in Deno With pdf-lib

Creating a Document with Deno

Below is the create document example modified for Deno:

import {
  PDFDocument,
  StandardFonts,
  rgb,
} from 'https://cdn.skypack.dev/pdf-lib@^1.11.1?dts';

const pdfDoc = await PDFDocument.create();
const timesRomanFont = await pdfDoc.embedFont(StandardFonts.TimesRoman);

const page = pdfDoc.addPage();
const { width, height } = page.getSize();
const fontSize = 30;
page.drawText('Creating PDFs in JavaScript is awesome!', {
  x: 50,
  y: height - 4 * fontSize,
  size: fontSize,
  font: timesRomanFont,
  color: rgb(0, 0.53, 0.71),
});

const pdfBytes = await pdfDoc.save();

await Deno.writeFile('out.pdf', pdfBytes);

If you save this script as create-document.ts, you can execute it using Deno with the following command:

deno run --allow-write create-document.ts

The resulting out.pdf file will look like this PDF.

Embedding a Font with Deno

Here's a slightly more complicated example demonstrating how to embed a font and measure text in Deno:

import {
  degrees,
  PDFDocument,
  rgb,
  StandardFonts,
} from 'https://cdn.skypack.dev/pdf-lib@^1.11.1?dts';
import fontkit from 'https://cdn.skypack.dev/@pdf-lib/fontkit@^1.0.0?dts';

const url = 'https://pdf-lib.js.org/assets/ubuntu/Ubuntu-R.ttf';
const fontBytes = await fetch(url).then((res) => res.arrayBuffer());

const pdfDoc = await PDFDocument.create();

pdfDoc.registerFontkit(fontkit);
const customFont = await pdfDoc.embedFont(fontBytes);

const page = pdfDoc.addPage();

const text = 'This is text in an embedded font!';
const textSize = 35;
const textWidth = customFont.widthOfTextAtSize(text, textSize);
const textHeight = customFont.heightAtSize(textSize);

page.drawText(text, {
  x: 40,
  y: 450,
  size: textSize,
  font: customFont,
  color: rgb(0, 0.53, 0.71),
});
page.drawRectangle({
  x: 40,
  y: 450,
  width: textWidth,
  height: textHeight,
  borderColor: rgb(1, 0, 0),
  borderWidth: 1.5,
});

const pdfBytes = await pdfDoc.save();

await Deno.writeFile('out.pdf', pdfBytes);

If you save this script as custom-font.ts, you can execute it with the following command:

deno run --allow-write --allow-net custom-font.ts

The resulting out.pdf file will look like this PDF.

Complete Examples

The usage examples provide code that is brief and to the point, demonstrating the different features of pdf-lib. You can find complete working examples in the apps/ directory. These apps are used to do manual testing of pdf-lib before every release (in addition to the automated tests).

There are currently four apps:

  • node - contains tests for pdf-lib in Node environments. These tests are a handy reference when trying to save/load PDFs, fonts, or images with pdf-lib from the filesystem. They also allow you to quickly open your PDFs in different viewers (Acrobat, Preview, Foxit, Chrome, Firefox, etc...) to ensure compatibility.
  • web - contains tests for pdf-lib in browser environments. These tests are a handy reference when trying to save/load PDFs, fonts, or images with pdf-lib in a browser environment.
  • rn - contains tests for pdf-lib in React Native environments. These tests are a handy reference when trying to save/load PDFs, fonts, or images with pdf-lib in a React Native environment.
  • deno - contains tests for pdf-lib in Deno environments. These tests are a handy reference when trying to save/load PDFs, fonts, or images with pdf-lib from the filesystem.

Installation

NPM Module

To install the latest stable version:

# With npm
npm install --save pdf-lib

# With yarn
yarn add pdf-lib

This assumes you're using npm or yarn as your package manager.

UMD Module

You can also download pdf-lib as a UMD module from unpkg or jsDelivr. The UMD builds have been compiled to ES5, so they should work in any modern browser. UMD builds are useful if you aren't using a package manager or module bundler. For example, you can use them directly in the <script> tag of an HTML page.

The following builds are available:

NOTE: if you are using the CDN scripts in production, you should include a specific version number in the URL, for example:

When using a UMD build, you will have access to a global window.PDFLib variable. This variable contains all of the classes and functions exported by pdf-lib. For example:

// NPM module
import { PDFDocument, rgb } from 'pdf-lib';

// UMD module
var PDFDocument = PDFLib.PDFDocument;
var rgb = PDFLib.rgb;

Fontkit Installation

pdf-lib relies upon a sister module to support embedding custom fonts: @pdf-lib/fontkit. You must add the @pdf-lib/fontkit module to your project and register it using pdfDoc.registerFontkit(...) before embedding custom fonts (see the font embedding example). This module is not included by default because not all users need it, and it increases bundle size.

Installing this module is easy. Just like pdf-lib itself, @pdf-lib/fontkit can be installed with npm/yarn or as a UMD module.

Fontkit NPM Module

# With npm
npm install --save @pdf-lib/fontkit

# With yarn
yarn add @pdf-lib/fontkit

To register the fontkit instance:

import { PDFDocument } from 'pdf-lib'
import fontkit from '@pdf-lib/fontkit'

const pdfDoc = await PDFDocument.create()
pdfDoc.registerFontkit(fontkit)

Fontkit UMD Module

The following builds are available:

NOTE: if you are using the CDN scripts in production, you should include a specific version number in the URL, for example:

When using a UMD build, you will have access to a global window.fontkit variable. To register the fontkit instance:

var pdfDoc = await PDFLib.PDFDocument.create()
pdfDoc.registerFontkit(fontkit)

Documentation

API documentation is available on the project site at https://pdf-lib.js.org/docs/api/.

The repo for the project site (and generated documentation files) is located here: https://github.com/Hopding/pdf-lib-docs.

Fonts and Unicode

When working with PDFs, you will frequently come across the terms "character encoding" and "font". If you have experience in web development, you may wonder why these are so prevalent. Aren't they just annoying details that you shouldn't need to worry about? Shouldn't PDF libraries and readers be able to handle all of this for you like web browsers can? Unfortunately, this is not the case. The nature of the PDF file format makes it very difficult to avoid thinking about character encodings and fonts when working with PDFs.

pdf-lib does its best to simplify things for you. But it can't perform magic. This means you should be aware of the following:

  • There are 14 standard fonts defined in the PDF specification. They are as follows: Times Roman (normal, bold, and italic), Helvetica (normal, bold, and italic), Courier (normal, bold, and italic), ZapfDingbats (normal), and Symbol (normal). These 14 fonts are guaranteed to be available in PDF readers. As such, you do not need to embed any font data if you wish to use one of these fonts. You can use a standard font like so:
    import { PDFDocument, StandardFonts } from 'pdf-lib'
    const pdfDoc = await PDFDocument.create()
    const courierFont = await pdfDoc.embedFont(StandardFonts.Courier)
    const page = pdfDoc.addPage()
    page.drawText('Some boring latin text in the Courier font', {
      font: courierFont,
    })
    
  • The standard fonts do not support all characters available in Unicode. The Times Roman, Helvetica, and Courier fonts use WinAnsi encoding (aka Windows-1252). The WinAnsi character set only supports 218 characters in the Latin alphabet. For this reason, many users will find the standard fonts insufficient for their use case. This is unfortunate, but there's nothing that PDF libraries can do to change this. This is a result of the PDF specification and its age. Note that the ZapfDingbats and Symbol fonts use their own specialized encodings that support 203 and 194 characters, respectively. However, the characters they support are not useful for most use cases. See here for an example of all 14 standard fonts.
  • You can use characters outside the Latin alphabet by embedding your own fonts. Embedding your own font requires to you load the font data (from a file or via a network request, for example) and pass it to the embedFont method. When you embed your own font, you can use any Unicode characters that it supports. This capability frees you from the limitations imposed by the standard fonts. Most PDF files use embedded fonts. You can embed and use a custom font like so (see also):
    import { PDFDocument } from 'pdf-lib'
    import fontkit from '@pdf-lib/fontkit'
    
    const url = 'https://pdf-lib.js.org/assets/ubuntu/Ubuntu-R.ttf'
    const fontBytes = await fetch(url).then((res) => res.arrayBuffer())
    
    const pdfDoc = await PDFDocument.create()
    
    pdfDoc.registerFontkit(fontkit)
    const ubuntuFont = await pdfDoc.embedFont(fontBytes)
    
    const page = pdfDoc.addPage()
    page.drawText('Some fancy Unicode text in the ŪЬȕǹƚü font', {
      font: ubuntuFont,
    })
    

Note that encoding errors will be thrown if you try to use a character with a font that does not support it. For example, Ω is not in the WinAnsi character set. So trying to draw it on a page with the standard Helvetica font will throw the following error:

Error: WinAnsi cannot encode "Ω" (0x03a9)
    at Encoding.encodeUnicodeCodePoint

Font Subsetting

Embedding a font in a PDF document will typically increase the file's size. You can reduce the amount a file's size is increased by subsetting the font so that only the necessary characters are embedded. You can subset a font by setting the subset option to true. For example:

const font = await pdfDoc.embedFont(fontBytes, { subset: true });

Note that subsetting does not work for all fonts. See https://github.com/Hopding/pdf-lib/issues/207#issuecomment-537210471 for additional details.

Creating and Filling Forms

pdf-lib can create, fill, and read PDF form fields. The following field types are supported:

See the form creation and form filling usage examples for code samples. Tests 1, 14, 15, 16, and 17 in the complete examples contain working example code for form creation and filling in a variety of different JS environments.

IMPORTANT: The default font used to display text in buttons, dropdowns, option lists, and text fields is the standard Helvetica font. This font only supports characters in the latin alphabet (see Fonts and Unicode for details). This means that if any of these field types are created or modified to contain text outside the latin alphabet (as is often the case), you will need to embed and use a custom font to update the field appearances. Otherwise an error will be thrown (likely when you save the PDFDocument).

You can use an embedded font when filling form fields as follows:

import { PDFDocument } from 'pdf-lib';
import fontkit from '@pdf-lib/fontkit';

// Fetch the PDF with form fields
const formUrl = 'https://pdf-lib.js.org/assets/dod_character.pdf';
const formBytes = await fetch(formUrl).then((res) => res.arrayBuffer());

// Fetch the Ubuntu font
const fontUrl = 'https://pdf-lib.js.org/assets/ubuntu/Ubuntu-R.ttf';
const fontBytes = await fetch(fontUrl).then((res) => res.arrayBuffer());

// Load the PDF with form fields
const pdfDoc = await PDFDocument.load(formBytes);

// Embed the Ubuntu font
pdfDoc.registerFontkit(fontkit);
const ubuntuFont = await pdfDoc.embedFont(fontBytes);

// Get two text fields from the form
const form = pdfDoc.getForm();
const nameField = form.getTextField('CharacterName 2');
const ageField = form.getTextField('Age');

// Fill the text fields with some fancy Unicode characters (outside
// the WinAnsi latin character set)
nameField.setText('Ӎӑȑїõ');
ageField.setText('24 ŷȇȁŗš');

// **Key Step:** Update the field appearances with the Ubuntu font
form.updateFieldAppearances(ubuntuFont);

// Save the PDF with filled form fields
const pdfBytes = await pdfDoc.save();

Handy Methods for Filling, Creating, and Reading Form Fields

Existing form fields can be accessed with the following methods of PDFForm:

New form fields can be created with the following methods of PDFForm:

Below are some of the most commonly used methods for reading and filling the aforementioned subclasses of PDFField:





Limitations

  • pdf-lib can extract the content of text fields (see PDFTextField.getText), but it cannot extract plain text on a page outside of a form field. This is a difficult feature to implement, but it is within the scope of this library and may be added to pdf-lib in the future. See #93, #137, #177, #329, and #380.
  • pdf-lib can remove and edit the content of text fields (see PDFTextField.setText), but it does not provide APIs for removing or editing text on a page outside of a form field. This is also a difficult feature to implement, but is within the scope of pdf-lib and may be added in the future. See #93, #137, #177, #329, and #380.
  • pdf-lib does not support the use of HTML or CSS when adding content to a PDF. Similarly, pdf-lib cannot embed HTML/CSS content into PDFs. As convenient as such a feature might be, it would be extremely difficult to implement and is far beyond the scope of this library. If this capability is something you need, consider using Puppeteer.

Help and Discussion

Discussions is the best place to chat with us, ask questions, and learn more about pdf-lib!

See also MAINTAINERSHIP.md#communication and MAINTAINERSHIP.md#discord.

Encryption Handling

pdf-lib does not currently support encrypted documents. You should not use pdf-lib with encrypted documents. However, this is a feature that could be added to pdf-lib. Please create an issue if you would find this feature helpful!

When an encrypted document is passed to PDFDocument.load(...), an error will be thrown:

import { PDFDocument, EncryptedPDFError } from 'pdf-lib'

const encryptedPdfBytes = ...

// Assignment fails. Throws an `EncryptedPDFError`.
const pdfDoc = PDFDocument.load(encryptedPdfBytes)

This default behavior is usually what you want. It allows you to easily detect if a given document is encrypted, and it prevents you from trying to modify it. However, if you really want to load the document, you can use the { ignoreEncryption: true } option:

import { PDFDocument } from 'pdf-lib'

const encryptedPdfBytes = ...

// Assignment succeeds. Does not throw an error.
const pdfDoc = PDFDocument.load(encryptedPdfBytes, { ignoreEncryption: true })

Note that using this option does not decrypt the document. This means that any modifications you attempt to make on the returned PDFDocument may fail, or have unexpected results.

You should not use this option. It only exists for backwards compatibility reasons.

Contributing

We welcome contributions from the open source community! If you are interested in contributing to pdf-lib, please take a look at the CONTRIBUTING.md file. It contains information to help you get pdf-lib setup and running on your machine. (We try to make this as simple and fast as possible! :rocket:)

Maintainership

Check out MAINTAINERSHIP.md for details on how this repo is maintained and how we use issues, PRs, and discussions.

Tutorials and Cool Stuff

Prior Art

  • pdfkit is a PDF generation library for Node and the Browser. This library was immensely helpful as a reference and existence proof when creating pdf-lib. pdfkit's code for font embedding, PNG embedding, and JPG embedding was especially useful.
  • pdf.js is a PDF rendering library for the Browser. This library was helpful as a reference when writing pdf-lib's parser. Some of the code for stream decoding was ported directly to TypeScript for use in pdf-lib.
  • pdfbox is a PDF generation and modification library written in Java. This library was an invaluable reference when implementing form creation and filling APIs for pdf-lib.
  • jspdf is a PDF generation library for the browser.
  • pdfmake is a PDF generation library for the browser.
  • hummus is a PDF generation and modification library for Node environments. hummus is a Node wrapper around a C++ library, so it doesn't work in many JavaScript environments - like the Browser or React Native.
  • react-native-pdf-lib is a PDF generation and modification library for React Native environments. react-native-pdf-lib is a wrapper around C++ and Java libraries.
  • pdfassembler is a PDF generation and modification library for Node and the browser. It requires some knowledge about the logical structure of PDF documents to use.

Git History Rewrite

This repo used to contain a file called pdf_specification.pdf in the root directory. This was a copy of the PDF 1.7 specification, which is made freely available by Adobe. On 8/30/2021, we received a DMCA complaint requiring us to remove the file from this repo. Simply removing the file via a new commit to master was insufficient to satisfy the complaint. The file needed to be completely removed from the repo's git history. Unfortunately, the file was added over two years ago, this meant we had to rewrite the repo's git history and force push to master 😔.

Steps We Took

We removed the file and rewrote the repo's history using BFG Repo-Cleaner as outlined here. For full transparency, here are the exact commands we ran:

$ git clone git@github.com:Hopding/pdf-lib.git
$ cd pdf-lib
$ rm pdf_specification.pdf
$ git commit -am 'Remove pdf_specification.pdf'
$ bfg --delete-files pdf_specification.pdf
$ git reflog expire --expire=now --all && git gc --prune=now --aggressive
$ git push --force

Why Should I Care?

If you're a user of pdf-lib, you shouldn't care! Just keep on using pdf-lib like normal 😃 ✨!

If you are a pdf-lib developer (meaning you've forked pdf-lib and/or have an open PR) then this does impact you. If you forked or cloned the repo prior to 8/30/2021 then your fork's git history is out of sync with this repo's master branch. Unfortunately, this will likely be a headache for you to deal with. Sorry! We didn't want to rewrite the history, but there really was no alternative.

It's important to note that pdf-lib's source code has not changed at all. It's exactly the same as it was before the git history rewrite. The repo still has the exact same number of commits (and even the same commit contents, except for the commit that added pdf_specification.pdf). What has changed are the SHAs of those commits.

The simplest way to deal with this fact is to:

  1. Reclone pdf-lib
  2. Manually copy any changes you've made from your old clone to the new one
  3. Use your new clone going forward
  4. Reopen your unmerged PRs using your new clone

See this StackOverflow answer for a great, in depth explanation of what a git history rewrite entails.

License

MIT