View source for OpenDocument technical specification

{{lead rewrite|date=August 2011}}
{{OpenDocument}}

This document describes the '''technical specifications of the [[OpenDocument]] office document standard''', as developed by the [[OASIS (organization)|OASIS]] industry consortium. A variety of organizations developed the standard publicly and make it publicly accessible, meaning it can be implemented by anyone without restriction. The OpenDocument format aims to provide an open alternative to [[proprietary format|proprietary]] document formats.

==File types==
===Document Representation===

The OpenDocument format supports the following two ways of document representation:
* As a '''single XML document''' - also known as ''Flat XML'' or ''Uncompressed XML Files''. Single OpenDocument XML files are not widely used. Filename extensions for a single OpenDocument XML documents are not defined in the OpenDocument technical specification, but commonly used are <code>.xml</code>, <code>.fodt</code>,<ref>{{cite web |url=http://www.ensode.net/roller/dheffelfinger/entry/openoffice_documents_version_control_with |title=OpenOffice.org Document Version Control With Mercurial |accessdate=2010-06-07}}</ref><ref>{{cite web |url=http://user.services.openoffice.org/en/forum/viewtopic.php?f=15&t=11103 |title=Flat OpenDocument fodt on Windows |accessdate=2010-06-07}}</ref> <code>.fods</code>, ... etc.
* As a '''collection of several subdocuments within a package''', each of which stores part of the complete document. This is the common representation of OpenDocument documents. It uses filename extensions such as <code>.odt</code>, <code>.ott</code>, <code>.ods</code>, <code>.odp</code> ... etc. The package is a standard [[ZIP (file format)|ZIP file]] with different filename extension and with defined structure of subdocuments. Each subdocument within a package has a different document root and stores a particular aspect of the XML document. All types of documents (e.g. text and spreadsheet documents) use the same document and subdocuments definitions.

The recommended filename extensions and [[MIME]] types are included in the official standard (OASIS, May 1, 2005 and its later revisions or versions). The MIME types and extensions contained in the ODF specification are applicable only to office documents that are contained in a package. Office documents that conform to the OpenDocument specification but are not contained in a package should use the MIME type text/xml.

The MIME type is also used in <code>office:mimetype</code> attribute. It is very important to use this attribute in flat XML files/single XML documents, where this is the only way the type of document can be detected (in a package, the MIME type is also present in a separate file ''mimetype''). Its values are the MIME types that are used for the packaged variant of office documents.

===Documents===

The most common file extensions used for OpenDocument documents are <code>.odt<code> for text documents, <code>.ods</code> for spreadsheets, <code>.odp</code> for presentation programs, and <code>.odg</code> for graphics.  These are easily remembered by considering ".od" as being short for "OpenDocument", and then noting that the last letter indicates its more specific type (such as t for text).
Here is the complete list of document types, showing the type of file, the recommended file extension, and the [[MIME]] Type:

{| class="wikitable"
|- bgcolor="#cccccc"
! File type
! Extension
! MIME Type
! ODF specification
|-
|Text
|.odt 
|application/vnd.oasis.opendocument.text
|1.0
|-
|Spreadsheet
|.ods
|application/vnd.oasis.opendocument.spreadsheet
|1.0
|-
|Presentation
|.odp
|application/vnd.oasis.opendocument.presentation
|1.0
|-
|Drawing
|.odg
|application/vnd.oasis.opendocument.graphics
|1.0
|-
|Chart
|.odc
|application/vnd.oasis.opendocument.chart
|1.0
|-
|Formula
|.odf
|application/vnd.oasis.opendocument.formula
|1.0
|-
|Image 
|.odi
|application/vnd.oasis.opendocument.image
|1.0
|-
|Master Document
|.odm
|application/vnd.oasis.opendocument.text-master
|1.0
|-
|Database
|.odb
|application/vnd.sun.xml.base<ref>{{citation |url=http://dlc.sun.com/osol/jds/downloads/sources/defaults.list |title=MIME types - OpenSolaris Default Applications |accessdate=2010-06-06}}</ref><ref>{{citation |url=http://extension.nirsoft.net/odb |title=.odb Extension - List of programs that can open .odb files |accessdate=2010-06-06}}</ref>
|not defined in ODF 1.0/1.1 specifications;<br/>used in OpenOffice.org 2.x
|-
|Database
|.odb
|application/vnd.oasis.opendocument.base
|ODF 1.2;<br/>used in OpenOffice.org 3.x
|-
|Database
|.odb
|application/vnd.oasis.opendocument.database
|defined in [http://www.iana.org/assignments/media-types/application/vnd.oasis.opendocument.database IANA registration]
|-
|all OpenDocument single/flat XML files
|not defined
|text/xml
|1.0
|}

===Templates===
OpenDocument also supports a set of template types.
Templates represent formatting information (including styles) for documents, without
the content themselves.
The recommended filename extension begins with ".ot" (interpretable as short for "OpenDocument template"), with the last letter indicating what kind of template (such as "t" for text).
The supported set includes:

{| class="wikitable"
|- bgcolor="#cccccc"
! File type
! Extension
! MIME Type
! ODF specification
|-
|Text
|.ott
|application/vnd.oasis.opendocument.text-template
|1.0
|-
|Spreadsheet
|.ots
|application/vnd.oasis.opendocument.spreadsheet-template
|1.0
|-
|Presentation
|.otp
|application/vnd.oasis.opendocument.presentation-template
|1.0
|-
|Drawing
|.otg
|application/vnd.oasis.opendocument.graphics-template
|1.0
|-
|Chart template
|.otc
|application/vnd.oasis.opendocument.chart-template
|1.0
|-
|Formula template
|.otf
|application/vnd.oasis.opendocument.formula-template
|1.0
|-
|Image template
|.oti
|application/vnd.oasis.opendocument.image-template
|1.0
|-
|Web page template
|.oth
|application/vnd.oasis.opendocument.text-web
|1.0
|-
|}

==Capabilities==

As noted above, the OpenDocument format can describe text documents (for example, those typically edited by a word processor), spreadsheets, presentations, drawings/graphics, images, charts, mathematical formulas, and "master documents" (which can combine them).  It can also represent templates for many of them.

The official OpenDocument standard version 1.0 (OASIS, May 1, 2005) defines OpenDocument's capabilities.  The text below provides a brief summary of the format's capabilities.

===Metadata===

The OpenDocument format supports storing [[metadata]] (data about the data) by having a set of pre-defined
metadata elements, as well as allowing user-defined and custom metadata.
The format predefines the following metadata fields:

* Generator
* Title
* Description
* Subject
* Keywords
* Initial Creator
* Creator
* Printed By
* Creation Date and Time
* Modification Date and Time
* Print Date and Time
* Document Template
* Automatic Reload
* Hyperlink Behavior
* Language
* Editing Cycles
* Editing Duration
* Document Statistics

===Content===

OpenDocument's text content format supports both typical and advanced capabilities.
Headings of various levels, lists of various kinds (numbered and not), numbered paragraphs,
and change tracking are all supported.
Page sequences and section attributes can be used to control how the text is displayed.
Hyperlinks, [[ruby text]] (which provides annotations and is especially critical for some languages),
bookmarks, and references are supported as well.
Text fields (for autogenerated content), and mechanisms for automatically generating
tables such as tables of contents, indexes, and bibliographies, are included as well.

The OpenDocument format implements spreadsheets as sets of tables.  Thus it features extensive capabilities for formatting the display of tables and spreadsheets. OpenDocument also supports database ranges, filters, and "data pilots" (known in Microsoft Excel contexts as "[[pivot table]]s").
Change tracking is available for spreadsheets as well.

The graphics format supports a vector graphic representation, in which a set of layers and the contents [http://www.auton.nl/software/apps/adms/en/adms.html]
of each layer is defined.  Available drawing shapes include Rectangle, Line, Polyline, Polygon, Regular Polygon,
Path, Circle, Ellipse, and Connector.
3D Shapes are also available; the format includes information about the
Scene, Light, Cube, Sphere, Extrude, and Rotate (it is intended for use as for office data exchange,
however, and not sufficient to represent movies or other extensive 3D scenes).
Custom shapes can also be defined.

Presentations are supported.
Users can include animations in presentations, with control over the
Sound, showing a shape or text, hiding a shape or text, or dimming something,
and these can be grouped.
In OpenDocument, much of the format capabilities are reused from the
text format, simplifying implementations. However, tables are not supported within
OpenDocument as drawing objects, so may only be included in presentations as
embedded tables.

Charts define how to create graphical displays from numerical data.
They support titles, subtitles, a footer, and a legend to explain the chart.
The format defines the series of data that is to be used for the graphical display,
and a number of different kinds of graphical displays (such as line charts, pie charts,
and so on).

Forms are specially supported, building on the existing XForms standard.

====Objects====
A document in OpenDocument format can contain two types of objects, as follows:
* Objects that have an OpenDocument representation. These objects are:
** Formulas (represented as MathML)
** Charts
** Spreadsheets
** Text documents
** Drawings
** Presentations
*  Objects that do not have an XML representation. These objects only have a binary representation. An example for this kind of objects are [[Object Linking and Embedding|OLE]] objects. (According to the OpenDocument 1.0 specification, OLE is defined in ''Kraig Brockschmidt, Inside OLE, Microsoft Press, 1995, ISBN 1-55615-843-2''.)

Use of Microsoft Object Linking and Embedding (OLE) objects limits the interoperability, because these objects are not widely supported in programs for viewing or editing files (e.g. embedding of other files inside the file, such as tables or charts from a spreadsheet application in a text document or presentation file).<ref>{{cite web |url=http://www.linux.com/archive/feed/47307 |title=FOSS word processors compared: OOo Writer, AbiWord, and KWord |author=Bruce Byfield |date=2005-08-23 |accessdate=2010-04-06}}</ref><ref>{{cite web |url=http://www.linux.com/archive/feed/46599 |title=Sharing files between OpenOffice.org and Microsoft Office |date=2005-07-28 |accessdate=2010-04-06}}</ref><ref>{{cite web |url=http://www.linux.com/archive/feature/153229 |title=SoftMaker Office 2008 focuses on compatibility with Microsoft Office |date=2008-11-20 |accessdate=2010-04-06}}</ref><ref>{{cite web |url=http://www.linux.com/archive/feed/58330 |title=SoftMaker Office 2006 beta: Not a killer app |date=2006-11-21 |accessdate=2010-04-06}}</ref><ref>{{citation |url=http://pacsec.jp/psj06/psj06lagadec-e.pdf |format=PDF |title=OpenOffice / OpenDocument and Microsoft Office 2007 / Open XML security |author=Philippe Lagadec |date=2006-11-30 |accessdate=2010-04-06}}</ref> If a software that understands an OLE object is not available, the object is usually replaced by a picture (bitmap representation of the object) or not displayed at all.<ref>{{cite web |url=http://www.keyongtech.com/2560234-ole-object-bitmap-representation |title=OLE object - bitmap representation? |accessdate=2010-04-06}}</ref><ref>{{cite web |url=http://www.codeproject.com/KB/edit/COleRichEditCtrl.aspx |title=A Rich Edit Control That Displays Bitmaps and Other OLE Objects |accessdate=2010-04-06}}</ref><ref>{{cite web |url=http://support.microsoft.com/kb/123151 |title=ACC: Why OLE Objects Cause Databases to Grow |date=2007-01-19 |accessdate=2010-04-29}}</ref>

===Formatting===

The '''style and''' formatting controls are numerous, providing a number of controls over the display of information.

Page layout is controlled by a variety of attributes.
These include
page size, number format, paper tray, print orientation, margins, border (and its line width),
padding, shadow, background, columns, print page order, first page number, scale, table centering,
maximum footnote height and separator, and many layout grid properties.

Headers and footer can have defined fixed and minimum heights, margins,
border line width, padding, background, shadow, and dynamic spacing.

There are many attributes for specific text, paragraphs, [[ruby text]], sections,
tables, columns, lists, and fills.
Specific characters can have their fonts, sizes, generic font family names (''roman'' - [[serif]], ''swiss'' - [[sans-serif]], ''modern'' - [[monospaced font|monospace]], ''decorative'', ''script'' or ''system''), and other properties set.
Paragraphs can have their vertical space controlled through attributes on keep together, widow, and orphan, and have other attributes such as "drop caps" to provide special formatting.
The list is extremely extensive; see the references (in particular the actual standard) for details.

===Spreadsheet formulas===

OpenDocument version 1.2 fully describes mathematical formulas displayable on-screen. It is fully capable of exchanging spreadsheet data, formats, [[pivot table]]s, and other information typically included in a spreadsheet. OpenDocument exchanges formulas as values of the attribute table:formula.

The allowed syntax of table:formula was not defined in sufficient detail in the OpenDocument version 1.0 specification, which defined spreadsheet formulas using a set of simple examples showing, for example, how to specify ranges and the SUM() function.  The [[OASIS (organization)|OASIS]] OpenDocument Formula sub group therefore standardized the table:formula in the [[OpenFormula]] specification.  For more information ''(see the [[OpenFormula]] article)''.

==Format internals==

An OpenDocument file commonly consists of a standard [[ZIP (file format)|ZIP]] archive ([[JAR (file format)|JAR]] archive<ref>{{cite web |url=http://www-03.ibm.com/able/resources/odfintro.html |title=Web resources & interesting links - easy and simple introduction to OpenDocument Format (ODF) |accessdate=2010-06-07}}</ref>) containing a number of files and directories; but OpenDocument file can also consist only of a single XML document. OpenDocument file is commonly a collection of several subdocuments within a (ZIP) ''package''. OpenDocument file as a ''single XML'' is not widely used.
According to the OpenDocument 1.0 specification, the ZIP file specification is defined in ''Info-ZIP Application Note 970311, 1997''.<ref>{{cite web |url=http://tools.oasis-open.org/issues/browse/OFFICE-2205 |title=NEEDS-DISCUSSION: ZIP reference - N 1309 |accessdate=2010-06-07}}</ref><ref>{{cite web |url=http://tools.oasis-open.org/issues/browse/OFFICE-2082 |title= Zip reference is neither public nor authoritative |date=2009-10-11 |accessdate=2010-06-07}}</ref> 
The simple compression mechanism used for a package normally makes OpenDocument files significantly smaller than equivalent Microsoft "<code>.doc</code>" or "<code>.ppt</code>" files.  This smaller size is important for organizations who store a vast number of documents for long periods of time, and to those organizations who must exchange documents over low bandwidth connections.  Once uncompressed, most data is contained in simple text-based XML files, so the uncompressed data contents have the typical ease of modification and processing of XML files. The standard also allows for the creation of a single XML document, which uses ''<office:document>'' as the root element, for use in document processing.

The standard allows the inclusion of directories to store images, non-[[Synchronized Multimedia Integration Language|SMIL]] animations, and other files that are used by the document but cannot be expressed directly in the XML.

Due to the openly specified compression format used, it is possible for a user to extract the container file to manually edit the contained files.  This allows repair of a corrupted file or low-level manipulation of the contents.  It is known{{By whom|date=February 2010}} that many programs which implement the OpenDocument format do not utilise high compression levels.  Users can therefore optimise the file sizes by using more aggressive compression-programs.  This may be coupled with a number of image optimisation programs being used on the contained pictures and has been seen to give over 40% reduction in file size over a file directly saved from an OpenDocument compatible program.<ref name="optimod">
{{
cite web
|url=http://www.oooforum.org/forum/viewtopic.phtml?t=27452
|title=Discussion of a Linux Shell script for OpenDocument compaction
}}
</ref>

The zipped set of files and directories includes the following:

* XML files
** content.xml
** meta.xml
** settings.xml
** styles.xml
* Other files
** mimetype
* Directories
** META-INF/
*** manifest.xml
** Thumbnails/
*** thumbnail.png

The OpenDocument format provides a strong separation between content, layout and metadata. The most notable components of the format are described in the subsections below.  The files in XML format are further defined using the [[RELAX NG]] language for defining XML schemas.  RELAX NG is itself defined by an OASIS specification, as well as by part two of the international standard ISO/IEC 19757: Document Schema Definition Languages (DSDL).

===content.xml===

'''content.xml''', the most important file, carries the actual content of the document (except for binary data, such as images). The base format is inspired by HTML, and though far more complex, it should be reasonably legible to humans:

<source lang="xml">
<text:h style-name="Heading_2">This is a title</text:h>
<text:p style-name="Text_body"/>
<text:p style-name="Text_body">
   This is a paragraph. The formatting information is
   in the Text_body style. The empty text:p tag above
   is a blank paragraph (an empty line).
</text:p>
</source>

===styles.xml===
'''styles.xml''' contains style information. OpenDocument makes heavy use of styles for formatting and layout. Most of the style information is here (though some is in content.xml). Styles types include:
* Paragraph styles
* Page styles
* Character styles
* Frame styles
* List styles

The OpenDocument format is somewhat unusual in that using styles for formatting cannot be avoided. Even "manual" formatting is implemented through styles (the application dynamically makes new styles as needed).

===meta.xml===

'''meta.xml''' contains the file metadata. For example, Author, "Last modified by", date of last modification, etc. The contents look somewhat like this:

<source lang="xml">
<meta:creation-date>2003-09-10T15:31:11</meta:creation-date>
<dc:creator>Daniel Carrera</dc:creator>
<dc:date>2005-06-29T22:02:06</dc:date>
<dc:language>es-ES</dc:language>
<meta:document-statistic
      table-count="6" object-count="0"
      page-count="59" paragraph-count="676"
      image-count="2" word-count="16701"
      character-count="98757"/>
</source>

The names of the <dc:...> tags come from the [[Dublin Core]] XML standard.

===settings.xml===
'''settings.xml''' includes settings such as the zoom factor or the cursor position. These are properties that are not content or layout.

===mimetype (file)===
'''mimetype''' is just a one-line file with the mimetype of the document. One implication of this is that the file extension is actually immaterial to the format. The file extension is only there for the benefit of the user.

===Thumbnails (directory)===
'''Thumbnails''' is a separate folder for a document thumbnail. The thumbnail must be saved as “thumbnail.png”. A thumbnail representation of a document should be generated by default when the file is saved. It should be a representation of the first page, first sheet, etc. of the document. The required size for the thumbnails is 128x128 pixel. In order to conform to the Thumbnail Managing Standard (TMS) at www.freedesktop.org, thumbnails must be saved as 24bit, non-interlaced PNG image with full alpha transparency.

===META-INF (directory)===
META-INF is a separate folder. Information about the files contained in the OpenDocument package is stored in an XML file called the manifest file. The manifest file is always stored at the pathname META-INF/manifest.xml. The main pieces of information stored in the manifest are:
* A list of all of the files in the package.
* The media type of each file in the package.
* If a file stored in the package is encrypted, the information required to decrypt the file is stored in the manifest.

===Pictures (directory)===
Pictures is a separate folder for images included in the document. This folder is not defined in the OpenDocument specification. Files in this folder can use various image formats, depending on the format of inserted file. While the image data may have an arbitrary format, it is recommended that bitmap graphics are stored in the PNG format and vector graphics in the SVG format.

===Reuse of existing formats===
By design, OpenDocument reuses existing open XML standards whenever they are available, and it creates new tags only where no existing standard can provide the needed functionality. Thus OpenDocument uses a subset of [[DublinCore]] for [[metadata]], [[MathML]] for displayed [[formula]]s, [[Synchronized Multimedia Integration Language|SMIL]] for [[multimedia]], [[XLink]] for [[hyperlink]]s etc.

Although not fully reusing [[Scalable Vector Graphics|SVG]] for [[vector graphics]], OpenDocument does use SVG-compatible vector graphics within an ODF-format-specific namespace, but also includes non-SVG graphics.

== History ==
* Version 1.0 became an OASIS Standard on 2005-05-01<ref>
{{cite web
| url         = http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=office
| title       = OASIS Open Document Format for Office Applications (OpenDocument) TC
| work        = OASIS website
| publisher   = OASIS
| accessdate  = 2010-02-08
| quote       = The OpenDocument v1.0 specification was approved as an OASIS Standard on 1 May 2005
}}
</ref>
* Version 1.1 became an OASIS Standard on 2007-02-07<ref>
{{cite web
| url         = http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=office#odf11
| title       = OpenDocument v1.1 Specification
| work        = OASIS website
| publisher   = OASIS
| accessdate  = 2010-02-08
| quote       = The OpenDocument v1.1 specification was approved as OASIS Standard on 2 February 2007. 
}}
</ref>
* Version 1.2 became an OASIS Standard on 2011-09-29<ref name="odf12">{{citation |url=http://www.oasis-open.org/news/pr/odf-1-2-approval |title=Members Approve OpenDocument Format (ODF) Version 1.2 as OASIS Standard |date=2011-10-05 |accessdate=2012-04-12}}</ref>

== Versions detection ==
To indicate which version of the OpenDocument specification a file complies with, all root elements take an <code>office:version</code> attribute. The version number is in the format ''revision.version'' (e.g. office:version="1.1").  The <code>office:version</code> attribute identifies the version of ODF specification that defined the associated element, its schema, its complete content, and its interpretation.

===ODF 1.0/1.1===
If the file has a version known to an XML processor, it may validate the document. Otherwise, it is optional to validate the document, but the document must be well formed. It is not mandatory to use <code>office:version</code> attribute in ODF 1.0 and ODF 1.1 files.

===ODF 1.2===
The <code>office:version</code> attribute shall be present in each and every <office:document>, <office:document-content>, <office:document-styles>, <office:document-meta>, and <office:document-settings> element in the XML documents that comprise an OpenDocument 1.2 document. The value of the office:version attribute shall be "1.2".

When an element has office:version="1.1" the element and its content are based on the OpenDocument v1.1 specification. For office:version="1.0" the element and its content are based on the OpenDocument v1.0 specification. When an element has office:version omitted, the element is based on a version of the OpenDocument specification earlier than v1.2. In these cases and in the case of values other than "1.2", the elements do not comprise an OpenDocument 1.2 document.<ref>{{cite web |url=http://docs.oasis-open.org/office/v1.2/os/OpenDocument-v1.2-os-part1.html#__RefHeading__1417682_253892949 |title=office:version attribute - OpenDocument Version 1.2, Part 1, 29 September 2011 |accessdate=2012-12-05}}</ref>

== Conformance ==
=== ODF 1.0/1.1 ===
The OpenDocument specification does not specify which elements and attributes conforming application must, should, or may support. Even typical office applications may only support a subset of the elements and attributes defined in the specification. The specification contains a non-normative table that provides an overview which element and attributes usually are supported by
typical office application.

Documents that conform to the OpenDocument specification may contain elements and attributes not specified within the OpenDocument schema. Such elements and attributes must not be part of a namespace that is defined within the specification and are called foreign elements and attributes.

Conforming applications either shall read documents that are valid against the OpenDocument schema if all foreign elements and attributes are removed before validation takes place, or shall write documents that are valid against the OpenDocument schema if all foreign elements and attributes are removed before validation takes place.
Conforming applications that read and write documents may preserve foreign elements and attributes. In addition to this, conforming applications should preserve meta information and the content of styles.

Conforming applications shall read documents containing processing instructions and should preserve them.

=== ODF 1.2 ===
ODF 1.2 defines precisely the conformance needs.  The specification defines conformance for documents, consumers, and producers, with two conformance classes called conforming and extended conforming. It further defines conforming text, spreadsheet, drawing, presentation, chart, image, formula and database front end documents. Chapter 2 defines the basic requirements for the individual conformance targets. <ref> 
 {{cite web |url=http://docs.oasis-open.org/office/v1.2/OpenDocument-v1.2-part1.html#__RefHeading__440342_826425813 |title=Conformance defined in OpenDocument Version 1.2, Part 1, 29 September 2011 |accessdate=2012-12-05}}</ref>

== Footnotes ==
{{reflist}}

==References==
{{refbegin}}
* [https://www.oasis-open.org/standards#opendocumentv1.2 OpenDocument 1.2 specification] in ODT, HTML and PDF formats
* [https://www.oasis-open.org/standards#opendocumentv1.1 OpenDocument 1.1 specification] in ODT, HTML and PDF formats
* [https://www.oasis-open.org/standards#opendocumentv1.0 OpenDocument 1.0 specification] in PDF format

==External links==
* [http://www.oooforum.org/forum/viewtopic.phtml?t=27452 Discussion of a Linux Shell Script for OpenDocument compaction]
* [http://www.iana.org/assignments/media-types/application/ Application Media Types] IANA.
* [http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=45245 Open Document Format (ISO/IEC 26300) / Office Open XML (ISO/IEC 29500) Translation Guidelines] - ISO/IEC PDTR 29166 

{{DEFAULTSORT:Opendocument Technical Specification}}
[[Category:OpenDocument]]
[[Category:Technical specifications]]