A file viewer is a

Software application Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists ...

that represents the data stored in a

computer file A computer file is a computer resource for recording data in a computer storage device, primarily identified by its file name. Just as words can be written to paper, so can data be written to a computer file. Files can be shared with and trans ...

in a human-readable form. The file contents are formatted in a meaningful way and then displayed on the screen or

printed Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The ...

out. Also, they may be read aloud using

speech synthesis Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware products. A text-to-speech (TTS) system converts normal languag ...

Overview

File viewer applications can be split into the following categories: * File Viewer Only applications do not allow the user to edit files. * File Viewer and Converter applications allow both viewing of data and exporting data in a different

file format A file format is a standard way that information is encoded for storage in a computer file. It specifies how bits are used to encode information in a digital storage medium. File formats may be either proprietary or free. Some file format ...

or copying information the

clipboard A clipboard is a thin, rigid board with a clip at the top for holding paper in place. A clipboard is typically used to support paper with one hand while writing on it with the other, especially when other writing surfaces are not available. Th ...

. * File Viewer and Editor applications allow the user to view existing file, create a new file of specific type or modify the content of an existing file. Such division of functionality was initially a result of software licensing for proprietary file formats, such as all file formats can be read freely but software license may exist that limits file creation and modification algorithms to be used only by licensor. For example, database software

DBASE dBase (also stylized dBASE) was one of the first database management systems for microcomputers and the most successful in its day. The dBase system includes the core database engine, a query system, a forms engine, and a programming languag ...

used proprietary algorithm for creating .DBF files, but Norton Commander had a built-in viewer for .DBF files.

Acrobat Reader Adobe Acrobat is a family of application software and Web services developed by Adobe Inc. to view, create, manipulate, print and manage Portable Document Format (PDF) files. The family comprises Acrobat Reader (formerly Reader), Acrobat (forme ...

supports viewing of

.PDF 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 systems. ...

files, but another software application such as

Adobe Photoshop Adobe Photoshop is a raster graphics editor developed and published by Adobe Inc. for Windows and macOS. It was originally created in 1988 by Thomas and John Knoll. Since then, the software has become the industry standard not only in rast ...

, LibreOffice or

Microsoft Word Microsoft Word is a word processing software developed by Microsoft. It was first released on October 25, 1983, under the name ''Multi-Tool Word'' for Xenix systems. Subsequent versions were later written for several other platforms includ ...

is required to create .PDF files. File viewers need to have structure information about the file format to be viewed in order to handle different

byte order In computing, endianness, also known as byte sex, is the order or sequence of bytes of a word of digital data in computer memory. Endianness is primarily expressed as big-endian (BE) or little-endian (LE). A big-endian system stores the most si ...

code page In computing, a code page is a character encoding and as such it is a specific association of a set of printable characters and control characters with unique numbers. Typically each number represents the binary value in a single byte. (In some c ...

s or

newline Newline (frequently called line ending, end of line (EOL), next line (NEL) or line break) is a control character or sequence of control characters in character encoding specifications such as ASCII, EBCDIC, Unicode, etc. This character, or a ...

styles. On contrary, media file viewers, such as Video Player applications may have initially very small number of file formats or none recognized, but rely on video codecs to play various media, making their capability to read and represent media file data to the user expandable. Some file viewer may be classified as filters that translate binary files into plain text (e.g., antiword). However, depending on the competence of the translating routines, some information may be lost. Image viewers display graphics files onscreen. Some viewers such as IrfanView are capable of reading multiple graphics file formats but some such as

JPEGview JPEGView was a popular image viewer for Mac OS in the 1990s by Aaron Giles. Initially released in 1991, it was one of the first JPEG image viewers for Mac OS. The program was also the first postcardware. Giles said he had "received somewhere betw ...

are dedicated to a single format. Common image viewer features include

thumbnail Thumbnails are reduced-size versions of pictures or videos, used to help in recognizing and organizing them, serving the same role for images as a normal text index does for words. In the age of digital images, visual search engines and image- ...

preview and creation, image zooming and rotation, color balance and gamma correction, resizing etc. A

web browser A web browser is application software for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used on ...

is a type of file viewer, which renders

HTML The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScri ...

markup into a human-friendly presentation. Although HTML is stored in plain text files, viewing an HTML file in a browser and in a

text editor A text editor is a type of computer program that edits plain text. Such programs are sometimes known as "notepad" software (e.g. Windows Notepad). Text editors are provided with operating systems and software development packages, and can be us ...

produces significantly different results. Web browsers may also be used to view

multimedia Multimedia is a form of communication that uses a combination of different content forms such as text, audio, images, animations, or video into a single interactive presentation, in contrast to traditio ...

files such as images, videos, pre-formatted documents, interactive environments,

3D models In 3D computer graphics, 3D modeling is the process of developing a mathematical coordinate-based representation of any surface of an object (inanimate or living) in three dimensions via specialized software by manipulating edges, vertices, a ...

augmented reality Augmented reality (AR) is an interactive experience that combines the real world and computer-generated content. The content can span multiple sensory modalities, including visual, auditory, haptic, somatosensory and olfactory. AR can be d ...

and

virtual reality Virtual reality (VR) is a simulated experience that employs pose tracking and 3D near-eye displays to give the user an immersive feel of a virtual world. Applications of virtual reality include entertainment (particularly video games), ...

applets etc.

Examples

Plain text files

Less (Unix) less is a terminal pager program on Unix, Windows, and Unix-like systems used to view (but not change) the contents of a text file one screen at a time. It is similar to , but has the extended capability of allowing both forward and backward na ...

Most (Unix) most is a terminal pager program on Unix, OpenVMS, MS-DOS, Windows and Unix-like systems used to view (but not change) the contents of a text file one screen at a time. Programs of this sort are called ''pagers''. It is similar to more, but ha ...

* pg (Unix) * More (command) * vi * notepad

Microsoft Office documents

* Microsoft Word Viewer * Microsoft Excel Viewer * PowerPoint Viewer * Antiword

PDF files

Adobe Acrobat Adobe Acrobat is a family of application software and Web services developed by Adobe Inc. to view, create, manipulate, print and manage Portable Document Format (PDF) files. The family comprises Acrobat Reader (formerly Reader), Acrobat (forme ...

* Atril *

Evince Evince (), also known as GNOME Document Viewer, is a free and open source document viewer supporting many document file formats including PDF, PostScript, DjVu, TIFF, XPS and DVI. It is designed for the GNOME desktop environment. The d ...

* PDF.js *see :PDF readers

Image files

* Directory Opus * IrfanView *

ACDSee ACDSee is an image organizer, viewer, and image editor program for Windows, macOS and iOS, developed by ACD Systems International Inc. ACDSee was originally distributed as a 16-bit application for Windows 3.0 and later supplanted by a 32-bi ...

* XnView

Video and audio files

Media Player Classic Media Player Classic (MPC), Media Player Classic - Home Cinema (MPC-HC), and Media Player Classic - Black Edition (MPC-BE) are a family of free and open-source, compact, lightweight, and customizable media players for 32-bit and 64-bit Microsoft ...

Windows Media Player Windows Media Player (WMP) is the first media player (application software), media player and media library application that was developed by Microsoft for playing sound reproduction, audio, video and viewing images on personal computers runnin ...

* VLC