Okular is a

free and open source Free and open-source software (FOSS) is software available under a license that grants users the right to use, modify, and distribute the software modified or not to everyone free of charge. FOSS is an inclusive umbrella term encompassing free ...

multiplatform

document viewer A file viewer is a utility application software on operating systems, such as Linux, macOS, or Windows. The file viewer is responsible for user access of files located on a data storage device. File viewers allow the user to open and view conte ...

developed by the

KDE KDE is an international free software community that develops free and open-source software. As a central development hub, it provides tools and resources that enable collaborative work on its projects. Its products include the KDE Plasma gra ...

community based on the Qt and

KDE Frameworks KDE Frameworks is a collection of Library (computing), libraries and software frameworks readily available to any Qt (software), Qt-based software stacks or applications on multiple operating systems. Featuring frequently needed functionality sol ...

libraries. It is distributed as part of the

KDE Applications The KDE Gear is a set of applications and supporting libraries that are developed by the KDE community, primarily used on Linux-based operating systems but mostly multiplatform, and released on a common release schedule. The bundle is compos ...

bundle. It replaced KPDF, its main predecessor, alongside KGhostView, KFax, KFaxview and KDVI in KDE 4. Its functionality can be embedded in other applications.

History

Okular was started for the

Google Summer of Code The Google Summer of Code, often abbreviated to GSoC, is an international annual program in which Google awards stipends to contributors who successfully complete a free and open-source software coding project during the summer. , the program is ...

of 2005 by Piotr Szymański. Okular was identified as a success story of the 2007 Season of Usability. In this season, the Okular toolbar mockup was created based on an analysis of other popular document viewers and a usage survey. When it was ported to Qt 5 in December 2016, the version numbering jumped from 0.26 to 1.0. Since September 2019, Okular has been available in the Windows Store. In December 2020, the software versioning scheme was changed from sequence-based identifier to CalVer. In February 2022, Okular was awarded the Blue Angel environmental label award by the German government for sustainable software design.

Okular for Windows

Okular is also available for Windows and can be installed from the

Microsoft Store The Microsoft Store (formerly known as the Windows Store) is a digital distribution platform operated by Microsoft. It was created as an app store for Windows 8 as the primary means of distributing Universal Windows Platform apps. With ...

with a click. As this version is often not the most recent version, more current "test versions" may be downloaded as an .exe file from the project's website.

Features

Okular's annotation features include commenting on PDF documents, highlighting and drawing lines, geometric shapes, adding textboxes, and stamps. Annotations are stored separately from the unmodified PDF file, or (since version 0.15 with Poppler 0.20) can be saved in the document as standard PDF annotations. Alongside regular text selection, rectangular selections can be copied or saved as images by right-clicking and dragging. Other features include reading text aloud using the Qt Speech module part of Qt since Qt 5 (previously using the Jovie,), trimming of white page borders, printing documents with a printer or to a PDF file, shifting colors, and bookmarks.

Supported file formats

Portable Document Format Portable document format (PDF), standardized as ISO 32000, is a file format developed by Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating syste ...

(PDF) with the Poppler backend *

PostScript PostScript (PS) is a page description language and dynamically typed, stack-based programming language. It is most commonly used in the electronic publishing and desktop publishing realm, but as a Turing complete programming language, it c ...

with the libspectre backend *

Tag Image File Format Tag Image File Format or Tagged Image File Format, commonly known by the abbreviations TIFF or TIF, is an image file format for storing raster graphics images, popular among graphic artists, the publishing industry, and photographers. TIFF is w ...

(TIFF) with the libTIFF backend *

Microsoft Compiled HTML Help Microsoft Compiled HTML Help (CHM) is a Microsoft proprietary online help format, consisting of a collection of HTML pages, an index and other navigation tools. The files are compressed and deployed in a binary format with the extension .CHM. Th ...

(CHM) with the libCHM backend * DjVu with the DjVuLibre backend *

Device independent file format The device independent file format (DVI) is the output file format of the TeX typesetting program, designed by David R. Fuchs in 1979. Unlike the TeX markup files used to generate them, DVI files are not intended to be human-readable; they cons ...

(DVI) *

XML Paper Specification Open XML Paper Specification (also referred to as OpenXPS) is an open specification for a page description language and a fixed-document format. Microsoft developed it as the XML Paper Specification (XPS). In June 2009, Ecma International adopte ...

(XPS) *

OpenDocument The Open Document Format for Office Applications (ODF), also known as OpenDocument, standardized as ISO 26300, is an open file format for word processor, word processing documents, spreadsheets, Presentation program, presentations and ...

format (ODF) (only OpenDocument Text) * FictionBook (*.fb2) *

ComicBook ''ComicBook.com'' is an entertainment website that offers news in the fields of comic books, television, films, video games, and anime. The site came online in 1996 serving as a holding page for sales links and press releases related to c ...

* Plucker *

ePub EPUB is an e-book file format that uses the ".epub" file extension. The term is short for ''electronic publication'' and is sometimes stylized as ''ePUB''. EPUB is supported by many e-readers, and compatible software is available for most smart ...

Mobipocket Mobipocket SA was a French company incorporated in March 2000 that created the .mobi e-book file format and produced the Mobipocket Reader software for mobile phones, personal digital assistants (PDA) and desktop operating systems. The Mobipock ...

* Various image formats, such as JPG *

Markdown Markdown is a lightweight markup language for creating formatted text using a plain-text editor. John Gruber created Markdown in 2004 as an easy-to-read markup language. Markdown is widely used for blogging and instant messaging, and also used ...

The official version obeys the

DRM DRM may refer to: Government, military and politics * Defense reform movement, U.S. campaign inspired by Col. John Boyd * Democratic Republic of Madagascar, a former socialist state (1975–1992) on Madagascar * Direction du renseignement militair ...

restrictions of PDF files by default, which may prevent copying, printing, or converting some PDF files. However, this can be turned off in the options under "Obey DRM limitations".Debian Bug report logs - #531221 okular: Arbitrarily enforces DRM by default
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References

External links