Xpdf

Xpdf is a free and open-source PDF viewer and toolkit based on the Qt framework.^[4] Versions prior to 4.00 were written for the X Window System and Motif.^[6]

Xpdf

XpdfReader 4.0 screenshot
Developer(s)	Glyph & Cog
Initial release	December 12, 1995; 29 years ago (1995-12-12)
Stable release	4.05[1]  / 8 February 2024
Operating system	Linux, Windows, macOS, FreeBSD, OpenVMS
Type	PDF viewer
License	GPL-2.0-only[2] or GPL-3.0-only[3] or proprietary[4][5]
Website	xpdfreader.com

Functions

Xpdf runs on nearly any Unix-like operating system. Binaries are also available for Windows. Xpdf can decode LZW and read encrypted PDFs. The official version obeys the DRM restrictions of PDF files,^[7] which can prevent copying, printing, or converting some PDF files.^[4] There are patches that make Xpdf ignore these DRM restrictions;^[8] the Debian distribution, for example, has these patches in place by default.^[9]

Xpdf includes several programs that don't need an X Window System, including some that extract images from PDF files or convert PDF to PostScript or text. These programs run on DOS, Windows, Linux and Unix.^[4]

Xpdf is also used as a back-end for other PDF readers frontends such as KPDF and GPDF,^[6] and its engine, without the X11 display components, is used for PDF viewers including BePDF on BeOS, '!PDF' on RISC OS, and PalmPDF^[10] on Palm OS^[4] and on Windows Mobile.^[11]

Two versions exist for AmigaOS. Xpdf needs a limited version of an X11 engine called Cygnix on the host system. AmigaOS 4 included AmiPDF, a PDF viewer based on 3.01 version of the Xpdf. However both Apdf and AmiPDF are native and need no X11.

xpdf-utils

The associated package "xpdf-utils" or "poppler-utils" contains tools such as pdftotext and pdfimages.

Exploit

A vulnerability in the Xpdf implementation of the JBIG2 file format, re-used in Apple's iOS phone operating software, was used by the Pegasus spyware to implement a zero-click attack on iPhones by constructing an emulated computer architecture inside a JBIG2 stream. Apple fixed this "FORCEDENTRY" vulnerability in iOS 14.8 in September 2021.^[12]

See also

• Free and open-source software portal

• Poppler, a GPL-licensed fork of the xpdf-3.0 rendering library designed for easier reuse in other programs
• List of PDF software