Evince is a document viewer for PDF, PostScript, DjVu, TIFF, XPS and DVI formats. It was designed for the GNOME desktop environment. The developers of Evince intended to replace the multiple GNOME document viewers with a single and simple application. The Evince motto sums up the project aim: “Simply a Document Viewer”. GNOME releases have included Evince since GNOME 2.12 (September 2005). Evince code consists mainly of C, with a small part (the code that interfaces with Poppler) written in C++.
Xpdf is a free and open-source PDF document viewer for operating systems supported by the Qt toolkit. Versions prior to 4.00 were written for the X Window System and Motif. Xpdf runs on nearly any Unix-like operating system, but binaries are also available for Windows. Xpdf can decode LZW and read encrypted PDFs. The official version obeys the DRM restrictions of PDF files, which can prevent copying, printing, or converting some PDF files.