@privyid/ghoulscript

@privyid/ghoulscript

Compress, merge, split, and render pages to image using Ghostscript

Installation

yarn add @privyid/ghoulscript

How to Use

Using on Browser (Vite)

import { optimizePDF } from '@privyid/ghoulscript'

const input = document.querySelector('input[type="file"]')

input.addEventListener('change', async () => {
  if (input.files) {
    const file      = input.files[0]
    const output    = await optimizePDF(file)
    const outputURL = URL.createObjectURL(new Blob([output], { type: 'application/pdf' }))

    window.open(outputURL, '_blank')
  }
})

Using on NodeJS

import fs from 'node:fs/promises'
import { resolve } from 'node:path'
import { optimizePDF } from '@privyid/ghoulscript'

const buffer = await fs.readFile(resolve(__dirname, './sample.pdf'))
const output = await optimizePDF(buffer)

await fs.writeFile(resolve(__dirname, './sample.compressed.pdf'), output)

Utilities

optimizePDF (file: Buffer, options?: CompressOptions)

Compress and optimize PDF for Web Viewer.

import { optimizePDF } from '@privyid/ghoulscript'

const buffer = await fs.readFile(resolve(__dirname, './sample.pdf'))
const output = await optimizePDF(buffer, { password: '******' })

await fs.writeFile(resolve(__dirname, './sample.compressed.pdf'), output)

CompressOptions

Options	Type	Default	Description
password	String	-	Document protection password
pdfSettings	String	screen	Preset setting, valid value is screen, ebook, printer, prepress, default
fastWebView	Boolean	true	Enable Fast Web View (Linearization)
compatibilityLevel	String	1.4	Compability version
colorConversionStrategy	String	RGB	Color conversion strategy, valid value is RGB, CMYK
noTransparency	Boolean	true	Remove transparency
keepPassword	Boolean	true	Keep document password if document have a password protection
userPassword	String	-	Set User Password to document
ownerPassword	String	-	Set Owner Password to document
colorImageResolution	Number	300	Color image resolution
grayImageResolution	Number	300	Gray image resolution
monoImageResolution	Number	300	Mono image resolution
args	String[]	-	Additional arguments

combinePDF (files: Buffer[], options?: CompressOptions)

Combine multiple PDF files into single PDF

import { combinePDF } from '@privyid/ghoulscript'

const bufferA = await fs.readFile(resolve(__dirname, './sample-1.pdf'))
const bufferB = await fs.readFile(resolve(__dirname, './sample-2.pdf'))
const output  = await combinePDF([bufferA, bufferB])

await fs.writeFile(resolve(__dirname, './sample.combine.pdf'), output)

splitPdf (file: Buffer, pageList: PageList[], options?: CompressOptions)

Split single PDF into multiple files

import { splitPdf } from '@privyid/ghoulscript'

const buffer  = await fs.readFile(resolve(__dirname, './sample.pdf'))
const outputs = await splitPdf(buffer, ['1-5', '5-12'])

await fs.writeFile(resolve(__dirname, './sample.part1.pdf'), outputs[0])
await fs.writeFile(resolve(__dirname, './sample.part2.pdf'), outputs[1])

addPassword (file: Buffer, userPassword: string, ownerPassword?: string)

Set new User Password and Owner Password

import { addPassword } from '@privyid/ghoulscript'

const buffer = await fs.readFile(resolve(__dirname, './sample.pdf'))
const output = await addPassword(buffer, '123456', '112233')

await fs.writeFile(resolve(__dirname, './sample.protected.pdf'), output)

It's equal to compressPDF's userPassword and ownerPassword options

removePassword (file: Buffer, oldPassword: string)

Remove existing encrypted PDF

import { removePassword } from '@privyid/ghoulscript'

const buffer = await fs.readFile(resolve(__dirname, './sample.protected.pdf'))
const output = await removePassword(buffer, '123456')

await fs.writeFile(resolve(__dirname, './sample.unprotected.pdf'), output)

It's equal to compressPDF's keepPassword: false

renderPageAsImage (file: Buffer, page: number = 1, options?: RenderOptions)

Convert specific page to image

import { renderPageAsImage } from '@privyid/ghoulscript'

const buffer = await fs.readFile(resolve(__dirname, './sample.pdf'))
const output = await renderPageAsImage(buffer, 5, { format: 'jpg' })

await fs.writeFile(resolve(__dirname, './sample.jpg'), output)

RenderOptions

Options	Type	Default	Description
resolution	Number	96	Render resolution
textAlphaBits	Number	4	Text alpha bits, valid value is 1-4
graphicsAlphaBits	Number	4	Graphic alpha bits, valid value is 1-4
format	String	jpg	Render format, valid value is jpg or png
args	String[]	-	Additional arguments

getInfo (file: Buffer, options?: { password: string })

Extract pages info

import { getInfo } from '@privyid/ghoulscript'

const buffer = await fs.readFile(resolve(__dirname, './sample.pdf'))
const info   = await getInfo(buffer)

console.log(info)
/*
{
  numPages: 5,
  pages: [
    {
      page: 1,
      width: 612,
      height: 792,
    },
    {
      page: 2,
      width: 612,
      height: 792,
    },
    {
      page: 3,
      width: 612,
      height: 792,
    },
  ]
}
*/

isRequirePassword (file: Buffer)

Check document is require password or not to open.

import { isRequirePassword } from '@privyid/ghoulscript'

const bufferA = await fs.readFile(resolve(__dirname, './sample.pdf'))
const bufferB = await fs.readFile(resolve(__dirname, './sample.protected.pdf'))

console.log(await isRequirePassword(bufferA)) // false
console.log(await isRequirePassword(bufferB)) // true

License

AGPL-3.0