Okular is a multiplatform document viewer developed by the KDE community and based on Qt and

KDE Frameworks KDE Frameworks is a collection of libraries and software frameworks readily available to any Qt-based software stacks or applications on multiple operating systems. Featuring frequently needed functionality solutions like hardware integration, fi ...

libraries. It is distributed as part of the

KDE Applications The KDE Gear (also known as the KDE Applications Bundle or KDE Applications) 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 ...

bundle. Its origins are from KPDF and it replaces KPDF, 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 is available in the Windows Store. In December 2020, the software versioning scheme was changed from sequence-based identifier to

CalVer Calver (Old English ''Calf Slope'') is a village and civil parish in Derbyshire, England. The population of the civil parish at the 2011 census was 710. Overview Calver is a small village situated in the Derwent Valley, Derbyshire. The village ...

. In February 2022, Okular was awarded the Blue Angel environmental label award by the

German government The Federal Cabinet or Federal Government (german: link=no, Bundeskabinett or ') is the chief executive body of the Federal Republic of Germany. It consists of the Federal Chancellor and cabinet ministers. The fundamentals of the cabinet's or ...

for sustainable software design.

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. It is possible to select parts of the document for copying text or image to the clipboard. 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 and setting of bookmarks.

File format support

It supports the following 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 with the libspectre backend *

Tagged Image File Format Tag Image File Format, abbreviated TIFF or TIF, is an image file format for storing raster graphics images, popular among graphic artists, the publishing industry, and photographers. TIFF is widely supported by scanning, faxing, word process ...

(TIFF) with the

libTIFF LibTIFF is a library for reading and writing Tagged Image File Format (abbreviated TIFF) files. The set also contains command line tools for processing TIFFs. It is distributed in source code and can be found as binary builds for all kinds of pla ...

backend *

Microsoft Compiled HTML Help Microsoft Compiled HTML Help 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, for Com ...

(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 and implemented by Donald E. Knuth in 1982. Unlike the TeX markup files used to generate them, DVI files are not inte ...

(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, is an open file format for word processing documents, spreadsheets, presentations and graphics and using ZIP-compressed XML files. It was developed wi ...

format (ODF) (only OpenDocument Text) *

FictionBook FictionBook is an open XML-based e-book format which originated and gained popularity in Russia. FictionBook files have the filename extension. Some readers also support ZIP-compressed FictionBook files ( or ) The FictionBook format does not ...

(*.fb2) *

ComicBook A comic book, also called comicbook, comic magazine or (in the United Kingdom and Ireland) simply comic, is a publication that consists of comics art in the form of sequential juxtaposed panels that represent individual scenes. Panels are oft ...

* Plucker * ePub * Mobipocket * Various image formats, such as JPG *

Markdown Markdown is a lightweight markup language for creating formatted text using a plain-text editor. John Gruber and Aaron Swartz created Markdown in 2004 as a markup language that is appealing to human readers in its source code form. Markdown i ...

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 milita ...

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

References

External links

*
Okular user wiki
{{KDE Applications using D-Bus EPUB readers Free PDF readers KDE Applications Linux text-related software PostScript

History

Features

File format support

See also

References

External links