The Apache FOP Project

The Apache™ FOP Project

FOP XSL-FO Extensions Reference

Apache FOP extends standard XSL-FO with a number of custom elements and attributes, each in its own namespace. These are registered through ElementMapping classes (see META-INF/services/org.apache.fop.fo.ElementMapping). This document lists every extension element and attribute, grouped by namespace.

Namespaces at a glance

Prefix Namespace URI Area
fox http://xmlgraphics.apache.org/fop/extensions General FOP extensions
(old) http://xml.apache.org/fop/extensions Legacy FOP 0.20.5 namespace
foi http://xmlgraphics.apache.org/fop/internal Internal (structure tree)
pdf http://xmlgraphics.apache.org/fop/extensions/pdf PDF output
afp http://xmlgraphics.apache.org/fop/extensions/afp AFP output
(ps) http://xmlgraphics.apache.org/fop/postscript PostScript output
pcl http://xmlgraphics.apache.org/fop/extensions/pcl PCL output
svg http://www.w3.org/2000/svg SVG graphics
(batik) http://xml.apache.org/batik/ext Batik SVG extensions
(xmp) adobe:ns:meta/ XMP metadata
(rdf) http://www.w3.org/1999/02/22-rdf-syntax-ns# RDF (inside XMP)
(plan) http://xmlgraphics.apache.org/fop/plan Plan example extension

1. General FOP extensions (fox)

Namespace: http://xmlgraphics.apache.org/fop/extensions

Elements

Element Purpose
fox:outline Bookmark/outline grouping (legacy bookmark mechanism).
fox:label Label text for an outline/bookmark.
fox:destination Named internal destination/anchor.
fox:external-document Import an entire external multi-page document (e.g. multi-page image/PDF) as its own page sequence. Requires src.

Attributes (used on standard FO elements)

Pagination / layout

Attribute Purpose
fox:block-progression-unit Force a fixed block-progression grid unit.
fox:widow-content-limit Minimum content kept with widows (on fo:list-block, fo:table).
fox:orphan-content-limit Minimum content kept with orphans (on fo:list-block, fo:table).
fox:disable-column-balancing Disable column balancing on the last page of a multi-column region.
fox:scale Page scaling on fo:simple-page-master; format scaleX [scaleY].
fox:transform Affine transform applied to blocks/regions.

Links / navigation

Attribute Purpose
fox:internal-destination Internal link target id.
fox:auto-toggle Auto-toggle behaviour for bookmarks/links.

Accessibility

Attribute Purpose
fox:alt-text Alternative text for accessible / tagged output.
fox:header Mark a table cell as a header for accessibility.
fox:abbreviation Expansion/abbreviation text for accessibility.

Rounded borders

Attribute Purpose
fox:border-radius Shorthand for all corner radii.
fox:border-before-radius-start Corner radius.
fox:border-before-radius-end Corner radius.
fox:border-after-radius-start Corner radius.
fox:border-after-radius-end Corner radius.
fox:border-start-radius-before Corner radius.
fox:border-start-radius-after Corner radius.
fox:border-end-radius-before Corner radius.
fox:border-end-radius-after Corner radius.
fox:border-before-start-radius Corner radius (alternate naming).
fox:border-before-end-radius Corner radius (alternate naming).
fox:border-after-start-radius Corner radius (alternate naming).
fox:border-after-end-radius Corner radius (alternate naming).

Backgrounds / layers / rules / numbering

Attribute Purpose
fox:background-image-width Explicit scaling width for a background image.
fox:background-image-height Explicit scaling height for a background image.
fox:layer Assign content to a PDF optional content group / layer.
fox:rule-style Non-standard fo:leader rule styles (e.g. square).
fox:number-conversion-features ICU number-conversion features for page/number formatting.

2. Legacy FOP extensions

Namespace: http://xml.apache.org/fop/extensions (FOP 0.20.5 and earlier)

Element Purpose
outline Legacy bookmark/outline element.
label Legacy label element.

Kept only for backward compatibility; no attributes.

3. Internal extensions (foi)

Namespace: http://xmlgraphics.apache.org/fop/internal

No public elements. Used internally for the accessibility structure tree.

Attribute Purpose
foi:struct-id Identifies a structure-tree element (tagged PDF).
foi:struct-ref References a structure-tree element.
foi:scope Scope of a table header cell for the structure tree.

4. PDF extensions (pdf)

Namespace: http://xmlgraphics.apache.org/fop/extensions/pdf

Used to inject raw PDF objects/dictionaries. Typically placed within fo:declarations or page/document contexts.

Element Purpose Key attributes
pdf:catalog Entries injected into the document Catalog dictionary. dictionary entries
pdf:page Entries injected into a page dictionary. page-numbers (*, ranges n-m, n-LAST, comma lists)
pdf:info Document Information dictionary entries. dictionary entries
pdf:vt PDF/VT (variable transactional) dictionary. dictionary entries
pdf:pagepiece PagePiece dictionary (private page-level data). dictionary entries
pdf:dictionary Generic / nested dictionary. key (when nested)
pdf:action PDF action dictionary. type (required), id
pdf:navigator Navigation node dictionary. id, entries
pdf:layer Optional content group (OCG / layer) dictionary. id, entries
pdf:embedded-file Attach an embedded file (child of fo:declarations). src (required), filename, description
pdf:array Array-valued collection entry. key
pdf:boolean Boolean-valued entry. key
pdf:name Name-valued entry. key
pdf:number Number-valued entry. key
pdf:string String-valued entry. key
pdf:reference Indirect object reference entry. refid (required), key

Attribute notes: dictionary elements accept id (when the type uses an id) and key (when the dictionary is itself an entry); collection-entry elements require key when they are a dictionary child.

5. AFP extensions (afp)

Namespace: http://xmlgraphics.apache.org/fop/extensions/afp

Element Purpose Key attributes
afp:tag-logical-element Emit a Tag Logical Element (TLE) structured field for indexing. name, value, encoding, placement
afp:include-page-segment Include an AFP page segment resource. name, src
afp:include-page-overlay Include a page overlay at an offset. name, x, y
afp:include-form-map Include a Form Map (IFM) resource. name, src (required)
afp:no-operation Insert a No Operation (NOP) structured field carrying arbitrary data. name, value/text, encoding, placement
afp:invoke-medium-map Invoke a Medium Map (IMM) on an fo:page-sequence. name

Page grouping is handled through two further namespace names used programmatically: afp:page-group and afp:add-to-previous-page-group.

6. PostScript extensions

Namespace: http://xmlgraphics.apache.org/fop/postscript

Element Purpose
ps-setup-code Document-level PostScript setup code.
ps-page-setup-code Per-page PostScript setup code.
ps-page-trailer-code-before PostScript code emitted before the page trailer.
ps-setpagedevice Emit a PostScript setpagedevice call for device configuration.
ps-comment-before Insert a PostScript %%-comment before content.
ps-comment-after Insert a PostScript %%-comment after content.

7. PCL extensions (pcl)

Namespace: http://xmlgraphics.apache.org/fop/extensions/pcl

No elements — attributes only.

Attribute Purpose
pcl:paper-source Select the PCL printer paper input source/tray.
pcl:output-bin Select the PCL printer output bin.
pcl:duplex-mode Set the PCL duplex (double-sided) printing mode.

8. SVG and Batik

9. XMP / RDF metadata

Used to embed document metadata, usually inside fo:declarations.

Element Namespace Purpose
xmpmeta adobe:ns:meta/ Root of embedded XMP metadata.
RDF http://www.w3.org/1999/02/22-rdf-syntax-ns# The rdf:RDF container inside xmpmeta.

10. Plan (example extension)

Namespace: http://xmlgraphics.apache.org/fop/plan

A sample/demo extension under fop/examples/plan (not part of fop-core). The <plan:plan> root element (plus a catch-all for descendants) builds a project-plan diagram and transforms it into SVG.

Notes