PDF

Displays PDF, Postscript, DjVu, comic books, TIFF, DVI, XPS formats, supports editing PDF annotations, remembers individual zoom and position settings, includes search.

Multi-platform document viewer supporting PDF, EPUB, comics and images with annotation tools, sidebar navigation, signature verification, and text-to-speech.

Handwritten notes and PDF annotation app with pen input, shape drawing, customizable toolbar, image insertion, audio recording, and multi-platform support.

Highly versatile PDF and XPS solution offering customizable rendering and viewing with features like digital signatures, redactions, and annotations.

Ghostscript is an interpreter for the PostScript® language and PDF files.

Polar is a powerful desktop app for managing all your web content, books, and notes. Polar keeps all your content in one place, supports tagging, annotation, highlighting and keeps track of your reading progress.

qpdfview is a Qt-based tabbed document viewer using the Poppler library for PDF rendering and CUPS for printing. Support for the DjVu and PostScript formats can be added via plugins.

Atril is a simple multi-page document viewer. It can display and print PostScript (PS), Encapsulated PostScript (EPS), DJVU, DVI, XPS and Portable Document Format (PDF) files. When supported by the document, it also allows searching for text, copying text to the clipboard...

The Universal Data Tool is a User Interface for editing and annotating Images (Computer Vision, Bounding Boxes, Segmentation), Text (Named Entity Recognition, Classification) or general purpose data entry. to view and edit any data defined in the extensible the .udt.

Notetaking and blackboard replacement application. Inspired by Xournal. Written in C++/Qt for Linux / Windows. It has the ability to annotate PDF files and has a few other options (e.g. markdown support).

Multi-monitor pdf presentation tool. This Qt-based presentation viewer shows a presentation and notes for the speaker in separate windows. The modular interface supports different forms of notes and interactive tools.

Emacs document annotator, using Org-mode.