Introduction to XSL-FO
What You Should Already KnowBefore you study XSL-FO you should have a basic understanding of XML and XML Namespaces.
If you want to study these subjects first, please read our XML Tutorial.
What is XSL-FO?XSL-FO is a language for formatting XML data XSL-FO stands for Extensible Stylesheet Language Formatting Objects XSL-FO is a W3C Recommendation XSL-FO is now formally named XSL XSL-FO is About FormattingXSL-FO is an XML based markup language describing the formatting of XML data for output to screen, paper or other media.
XSL-FO is Formally Named XSLWhy this confusion? Is XSL-FO and XSL the same thing?
Yes it is, but we will give you an explanation:
Styling is both about transforming and formatting information. When the World Wide Web Consortium (W3C) made their first XSL Working Draft, it contained the language syntax for both transforming and formatting XML documents.
Later the XSL Working Group at W3C split the original draft into separate Recommendations:
XSLT, a language for transforming information XSL or XSL-FO, a language for formatting information XPath, a language for defining parts of an XML document The rest of this tutorial is about formatting information: XSL-FO also called XSL.
You can read more about XSLT in our XSLT Tutorial.
You can read more about XPath in our XPath Tutorial.
XSL-FO is a Web StandardXSL-FO became a W3C Recommendation 15. October 2001. Formally named XSL.
To read more about the XSL activities at W3C please read our W3C Tutorial.
XSL-FO Documents
XSL-FO DocumentsXSL-FO documents are XML files with output information. They contain information about the output layout and output contents.
XSL-FO documents are stored in files with a *.fo or a *.fob extension. It is also quite normal to see XSL-FO documents stored with the *.xml extension, because this makes them more accessible to XML editors.
XSL-FO Document StructureXSL-FO documents have a structure like this:
<?xml version="1.0" encoding="ISO-8859-1"?>
<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format"><fo:layout-master-set> <fo:simple-page-master master-name="A4"> <!-- Page template goes here --> </fo:simple-page-master></fo:layout-master-set><fo:page-sequence master-reference="A4"> <!-- Page content goes here --></fo:page-sequence>
</fo:root>
Structure explainedXSL-FO documents are XML documents, and must always start with an XML declaration:
<?xml version="1.0" encoding="ISO-8859-1"?>
The <fo:root> element contains the XSL-FO document. It also declares the namespace for XSL-FO:
<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format"> <!-- The full XSL-FO document goes here --></fo:root>
The <fo:layout-master-set> element contains one or more page templates:
<fo:layout-master-set> <!-- All page templates go here --></fo:layout-master-set>
Each <fo:simple-page-master> element contains a single page template. Each template must have a unique name (master-name):
<fo:simple-page-master master-name="A4"> <!-- One page template goes here --></fo:simple-page-master>
One or more <fo:page-sequence> elements describe page contents. The master-reference attribute refers to the simple-page-master template with the same name:
<fo:page-sequence master-reference="A4"> <!-- Page content goes here --></fo:page-sequence>
Note: The master-reference "A4" does not actually describe a predefined page format. It is just a name. You can use any name like "MyPage", "MyTemplate", etc.
XSL-FO Areas
XSL-FO AreasThe XSL formatting model defines a number of rectangular areas (boxes) to display output.
All output (text, pictures, or whatever) will be formatted into these boxes and then displayed or printed to a target media.
We will take a closer look at the following areas:
Pages Regions Block areas Line areas Inline areas XSL-FO PagesXSL-FO output is formatted into pages. Printed output will normally go into many separate pages. Browser output will often go into one long page.
XSL-FO Pages contain Regions.
XSL-FO RegionsEach XSL-FO Page contains a number of Regions:
region-body (the body of the page) region-before (the header of the page) region-after (the footer of the page) region-start (the left sidebar) region-end (the right sidebar) XSL-FO Regions contain Block areas.
XSL-FO Block AreasXSL-FO Block areas define small block elements (the ones that normally starts with a new line) like paragraphs, tables and lists.
XSL-FO Block areas can contain other Block areas, but most often they contain Line areas.
XSL-FO Line AreasXSL-FO Line areas define text lines inside Block areas.
XSL-FO Line areas contain Inline areas.
XSL-FO Inline AreasXSL-FO Inline areas define text inside Lines (bullets, single character, graphics, and more).
XSL-FO Output
XSL-FO Page, Flow, and Block"Blocks" of content "Flows" into "Pages" and then to the output media.
XSL-FO output is normally nested inside <fo:block> elements, nested inside <fo:flow> elements, nested inside <fo:page-sequence> elements:
<fo:page-sequence> <fo:flow flow-name="xsl-region-body"> <fo:block> <!-- Output goes here --> </fo:block> </fo:flow></fo:page-sequence>
XSL-FO ExampleIt is time to look at a real XSL-FO example:
<?xml version="1.0" encoding="ISO-8859-1"?>
<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format"><fo:layout-master-set> <fo:simple-page-master master-name="A4"> </fo:simple-page-master></fo:layout-master-set><fo:page-sequence master-reference="A4"> <fo:flow flow-name="xsl-region-body"> <fo:block>Hello W3Schools</fo:block> </fo:flow></fo:page-sequence>
</fo:root>
The output from this code would be something like this:
Hello W3Schools
XSL-FO Flow
XSL-FO Page SequencesXSL-FO uses <fo:page-sequence> elements to define output pages.
Each output page refers to a page master which defines the layout.
Each output page has a <fo:flow> element defining the output.
Each output page is printed (or displayed) in sequence.
XSL-FO FlowXSL-FO pages are filled with content from the <fo:flow> element.
The <fo:flow> element contains all the elements to be printed to the page.
When the page is full, the same page master will be used over (and over) again until all the text is printed.
Where To Flow?The <fo:flow> element has a "flow-name" attribute.
The value of the flow-name attribute defines where the content of the <fo:flow> element will go.
The legal values are:
xsl-region-body (into the region-body) xsl-region-before (into the region-before) xsl-region-after (into the region-after) xsl-region-start (into the region-start) xsl-region-end (into the region-end) XSL-FO Pages
XSL-FO Page TemplatesXSL-FO uses page templates called "Page Masters" to define the layout of pages. Each template must have a unique name:
<fo:simple-page-master master-name="intro"> <fo:region-body margin="5in" /></fo:simple-page-master>
<fo:simple-page-master master-name="left"> <fo:region-body margin-left="2in" margin-right="3in" /></fo:simple-page-master>
<fo:simple-page-master master-name="right"> <fo:region-body margin-left="3in" margin-right="2in" /></fo:simple-page-master>
In the example above, three <fo:simple-page-master> elements, define three different templates. Each template (page-master) has a different name.
The first template is called "intro". It could be used as a template for introduction pages.
The second and third templates are called "left" and "right". They could be used as templates for even and odd page numbers.
XSL-FO Page SizeXSL-FO uses the following attributes to define the size of a page:
page-width defines the width of a page page-height defines the height of a page XSL-FO Page MarginsXSL-FO uses the following attributes to define the margins of a page:
margin-top defines the top margin margin-bottom defines the bottom margin margin-left defines the left margin margin-right defines the right margin margin defines all four margins XSL-FO Page RegionsXSL-FO uses the following elements to define the regions of a page:
region-body defines the body region region-before defines the top region (header) region-after defines the bottom region (footer) region-start defines the left region (left sidebar) region-end defines the right region (right sidebar) Note that the region-before, region-after, region-start, and region-end is a part of the body region. To avoid text in the body region to overwrite text in these regions, the body region must have margins at least the size of these regions.
Margin Top
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XSL-FO ExampleThis is an extract from an XSL-FO document:
<fo:simple-page-master master-name="A4" page-width="297mm" page-height="210mm" margin-top="1cm" margin-bottom="1cm" margin-left="1cm" margin-right="1cm"> <fo:region-body margin="3cm"/> <fo:region-before extent="2cm"/> <fo:region-after extent="2cm"/> <fo:region-start extent="2cm"/> <fo:region-end extent="2cm"/></fo:simple-page-master>
The code above defines a "Simple Page Master Template" with the name "A4".
The width of the page is 297 millimeters and the height is 210 millimeters.
The top, bottom, left, and right margins of the page are all 1 centimeter.
The body has a 3 centimeter margin (on all sides).
The before, after, start, and end regions (of the body) are all 2 centimeters.
The width of the body in the example above can be calculated by subtracting the left and right margins and the region-body margins from the width of the page itself:
297mm - (2 x 1cm) - (2 x 3cm) = 297mm - 20mm - 60mm = 217mm.
Note that the regions (region-start and region-end) are not a part of the calculation. As described earlier, these regions are parts of the body.
XSL-FO Blocks
XSL-FO Pages, Flow, and Block"Blocks" of content "Flow" into "Pages" of the output media.
XSL-FO output is normally nested inside <fo:block> elements, nested inside <fo:flow> elements, nested inside <fo:page-sequence> elements:
<fo:page-sequence> <fo:flow flow-name="xsl-region-body"> <fo:block> <!-- Output goes here --> </fo:block> </fo:flow></fo:page-sequence>
Block Area AttributesBlocks are sequences of output in rectangular boxes:
<fo:block border-width="1mm">This block of output will have a one millimeter border around it.</fo:block>
Since block areas are rectangular boxes, they share many common area properties: space before and space after margin border padding space before
margin
border
padding
content
space after
The space before and space after is the empty space separating the block from the other blocks.
The margin is the empty area on the outside of the block.
The border is the rectangle drawn around the external edge of the area. It can have different widths on all four sides. It can also be filled with different colors and background images.
The padding is the area between the border and the content area.
The content area contains the actual content like text, pictures, graphics, or whatever.
Block Marginmargin margin-top margin-bottom margin-left margin-right Block BorderBorder style attributes:
border-style border-before-style border-after-style border-start-style border-end-style border-top-style (same as border-before) border-bottom-style (same as border-after) border-left-style (same as border-start) border-right-style (same as border-end) Border color attributes:
border-color border-before-color border-after-color border-start-color border-end-color border-top-color (same as border-before) border-bottom-color (same as border-after) border-left-color (same as border-start) border-right-color (same as border-end) Border width attributes:
border-width border-before-width border-after-width border-start-width border-end-width border-top-width (same as border-before) border-bottom-width (same as border-after) border-left-width (same as border-start) border-right-width (same as border-end) Block Paddingpadding padding-before padding-after padding-start padding-end padding-top (same as padding-before) padding-bottom (same as padding-after) padding-left (same as padding-start) padding-right (same as padding-end) Block Backgroundbackground-color background-image background-repeat background-attachment (scroll or fixed) Block Styling AttributesBlocks are sequences of output that can be styled individually:
<fo:block font-size="12pt" font-family="sans-serif">This block of output will be written in a 12pt sans-serif font.</fo:block>
Font attributes:
font-family font-weight font-style font-size font-variant Text attributes:
text-align text-align-last text-indent start-indent end-indent wrap-option (defines word wrap)
break-before (defines page breaks)
break-after (defines page breaks) reference-orientation (defines text rotation in 90" increments) Example<fo:block font-size="14pt" font-family="verdana" font-color="red" space-before="5mm" space-after="5mm">W3Schools</fo:block>
<fo:block text-indent="5mm" font-family="verdana" font-size="12pt" space-before="5mm" space-after="5mm">At W3Schools you will find all the Web-building tutorials youneed, from basic HTML and XHTML to advanced XML, XSL, Multimediaand WAP.</fo:block>
Result:
W3Schools
At W3Schools you will find all the Web-building tutorials you need, from basic HTML and XHTML to advanced XML, XSL, Multimedia and WAP.
When you look at the example above, you can see that it will take a lot of code to produce a document with many headers and paragraphs.
Normally XSL-FO document do not combine formatting information and content like we have done here.
With a little help from XSLT we can put the formatting information into templates and write a cleaner content.
You will learn more about how to combine XSL-FO with XSLT templates in a later chapter in this tutorial.
XSL-FO Lists
XSL-FO List BlocksThere are four XSL-FO objects used to create lists:
fo:list-block (contains the whole list) fo:list-item (contains each item in the list) fo:list-item-label (contains the label for the list-item - typically an <fo:block> containing a number, character, etc.) fo:list-item-body (contains the content/body of the list-item - typically one or more <fo:block> objects) An XSL-FO list example:
<fo:list-block>
<fo:list-item> <fo:list-item-label> <fo:block>*</fo:block> </fo:list-item-label> <fo:list-item-body> <fo:block>Volvo</fo:block> </fo:list-item-body></fo:list-item>
<fo:list-item> <fo:list-item-label> <fo:block>*</fo:block> </fo:list-item-label> <fo:list-item-body> <fo:block>Saab</fo:block> </fo:list-item-body></fo:list-item>
</fo:list-block>
The output from this code would be:
* Volvo
* Saab
XSL-FO Tables
XSL-FO TablesThe XSL-FO table model is not very different from the HTML table model.
There are nine XSL-FO objects used to create tables:
fo:table-and-caption fo:table fo:table-caption fo:table-column fo:table-header fo:table-footer fo:table-body fo:table-row fo:table-cell XSL-FO uses the <fo:table-and-caption> element to define a table. It contains a <fo:table> and an optional <fo:caption> element.
The <fo:table> element contains optional <fo:table-column> elements, an optional <fo:table-header> element, a <fo:table-body> element, and an optional <fo:table-footer> element. Each of these elements has one or more <fo:table-row> elements, with one or more <fo:table-cell> elements:
<fo:table-and-caption><fo:table><fo:table-column column-width="25mm"/><fo:table-column column-width="25mm"/><fo:table-header> <fo:table-cell> <fo:block font-weight="bold">Car</fo:block> </fo:table-cell> <fo:table-cell> <fo:block font-weight="bold">Price</fo:block> </fo:table-cell></fo:table-header><fo:table-body> <fo:table-row> <fo:table-cell> <fo:block>Volvo</fo:block> </fo:table-cell> <fo:table-cell> <fo:block>$50000</fo:block> </fo:table-cell> </fo:table-row> <fo:table-row> <fo:table-cell> <fo:block>SAAB</fo:block> </fo:table-cell> <fo:table-cell> <fo:block>$48000</fo:block> </fo:table-cell> </fo:table-row></fo:table-body></fo:table></fo:table-and-caption>
The output from this code would something like this:
CarPriceVolvo
$50000
SAAB
$48000
XSL-FO and XSLT
Remember this Example?<fo:block font-size="14pt" font-family="verdana" font-color="red" space-before="5mm" space-after="5mm">W3Schools</fo:block>
<fo:block text-indent="5mm" font-family="verdana" font-size="12pt" space-before="5mm" space-after="5mm">At W3Schools you will find all the Web-building tutorials youneed, from basic HTML and XHTML to advanced XML, XSL, Multimediaand WAP.</fo:block>
Result:
W3Schools
At W3Schools you will find all the Web-building tutorials you need, from basic HTML and XHTML to advanced XML, XSL, Multimedia and WAP.
The example above is from the chapter about XSL-FO Blocks.
With a Little Help from XSLTRemove the XSL-FO information from the document:
<header>W3Schools</header>
<paragraph>At W3Schools you will find all the Web-building tutorials youneed, from basic HTML and XHTML to advanced XML, XSL, Multimediaand WAP.</paragraph>
Add an XSLT transformation:
<xsl:template match="header"><fo:block font-size="14pt" font-family="verdana" font-color="red" space-before="5mm" space-after="5mm"> <xsl:apply-templates/></fo:block></xsl:template><xsl:template match="paragraph"><fo:block text-indent="5mm" font-family="verdana" font-size="12pt" space-before="5mm" space-after="5mm"> <xsl:apply-templates/></fo:block></xsl:template>
And the result will be the same:
W3Schools
At W3Schools you will find all the Web-building tutorials you need, from basic HTML and XHTML to advanced XML, XSL, Multimedia and WAP.
XSL-FO Software
XSL-FO ProcessorsAn XSL-FO processor is a software program for formatting XSL documents for output.
Most XSL-FO processors can output PDF document, and quality print as well as HTML and other formats.
Here is a list of the most common XSL-FO processors:
XSL FormatterXSL Formatter is a software to format XML documents for production-quality printing and output to PDF.
Antenna House has been providing version V2 of the same product since January, 2002 in the global market, and XSL Formatter was rated as one of the best quality product at the XML 2002, XML 2003 conferences held in Europe.
Building on over 4 years of experience developing XSL-FO software, Antenna House has completely written from scratch an entirely new Formatter that offers significant enhancements and provides a solid foundation on which to continue to move forward.
Visit Antenna House
Xinc Beta ReleaseXinc is an XSL-FO processor by Lunasil LTD.
Xinc is designed to be fast, multithreaded and memory efficient. A Swing based XSL-FO viewer allows you to view and print XSL-FO files as well as generate PDF files with the click of a button. Xinc can be used as a server component via its Java API. Xinc can also be used in a Microsoft server environment by using its COM interface. New features include hyphenation, basic-link, PDF output, memory/speed optimizations and a simple COM interface.
Visit Lunasil Ltd
ScripturaInventive Designers Scriptura is a cross-platform document design and generation solution based on XSLT and XSL-FO.
Scriptura has a WYSIWYG design tool and engine. The XSL-FO formatter used in the engine is no longer based on Apache FOP, but is written from scratch by Inventive Designers. The new features in this release are: support for bulleted and numbered lists, 'break-before' and 'break-after' properties, extended bar code options and improved number and currency formatting. A free trial version is available for download.
Visit Inventive Designers
