XSL FO

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XSL FO

• XSL Formatting Objects
• XSLFO is a pagination markup language which
  describes a rendering vocabulary capturing the
  semantics of formatting information for paginated
  presentation.
• While XSLT combined with XML has several
  applications, some of which we just learned
  about, generating an XSLFO presentational
  vocabulary is one of them.

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XML, XSLT, XSL FO putting these technologies
together
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What is XSL FO for?Styling

• Styling as two distinct processes
• Transforming (XSLT)
• Formatting (XSLFO)

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Formatting (Rendering)

• Expresses the aspects of the appearance of the
  transformed information desired for the target
  medium
• Target Mediums
• Browsers
• Books
• Printers
• Computer Speakers

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Goal of XSLFO

• Preserve the original information so that it can
  be distributed in many different ways later on,
  without committing to a single design.
• Example Rather than using the ltbgt element to
  display emphasized text, use ltemphgt to capture
  the reason for marking up the information.

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Lets get this straight

• XSL FO originally part of the XSL working group
  chartered by W3C (World Wide Web Consortium).
• What emerged were three separate technologies
• XSLT eXtensive StyleSheet Language
  Transformations
• XPATH XML Path Language
• XSL eXtensive StyleSheet Language aka XSL FO

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Why was XSL FO made?

• No language for describing the pagination of
  complex documents on the web.
• Inability to deal with long documents and complex
  layouts. No support for TOC, footnotes, endnotes
• CSS not sufficient for print documents, but only
  browsers.

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XSLFO responds to the issues

• XSLFO
• XML syntax
• Declarative
• Build on CSS
• Cross-media
• Typographic quality/multilingual market

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XML Syntax

• Two distinct advantages
• XSLT and XSLFO will work with existing XML
  parsers
• XSLT and XSLFO can be manipulated and validated
  using existing XML tools

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Declarative

• XLSFO should be comprised of a set of elements
  and attributes fully describing what the desired
  results looks like.

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Build on CSS

• Share as many styling properties and as much of
  the formatting/layout model from CSS as possible.
  
• Also provide support for more advanced features
  such as footnotes, endnotes, floats, indexes,
  TOCs, odd and even page masters.
• Support layout-driven documents such as
  newspapers, magazines, catalogues, brochures and
  web browsers.

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Cross Media

• Support a wide range of display devices
• Government mandated accessibility requirements
  (larger text, alternate fonts, high contrast font
  schemes, alternate navigation, aural
  presentation).
• Palmtop Devices requiring reflow or repagination
  of original content.

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Typographic quality/Multilingual Support

• XSLFO capabilities should match or exceed present
  capabilities of existing page formatters and be
  compatible with their underlying formatting
  models.
• Multilingual support should include the use of
  Unicode and the Unicode bidirectional rules.

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So CSS and XSLFO are the same right?

• No. CSS (Cascading Style Sheets) is an external
  stylesheet language. It applies styling to
  selected elements in HTML document.
• In contrast, XSL FO is a language for completely
  describing a styled document. Including
  everything needed to format and paginate it.

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Getting inside XSLFO - Structure
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Getting inside XSLFO The Basics
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Four areas of a page

• Regions
• Block Areas
• Line Areas
• Inline Areas

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Regions

• A region is the highest-level container in
  XSL-FO. Formatting objects that produce regions
  include foregion-body, foregion-before,
  foregion-after, foregion-start, and
  foregion-end.

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Block Areas

• A block area represents a block-level element,
  such as a paragraph or a list item.
• A block area, rather than being precisely
  positioned by coordinates, is placed sequentially
  in the area that contains it.
• Formatting objects that produce block areas
  include foblock, fotable-and-caption, and
  folist-block.

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Line Areas

• A line area represents a line of text inside a
  block.
• The formatting engine calculates the line areas
  as it decides how to wrap lines inside block
  areas.

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Inline Areas

• Inline areas are parts of a line such as a single
  character, a footnote reference, or a
  mathematical equation.
• Formatting objects that produce inline areas
  include focharacter, foexternal-graphic,
  foinline, foinstream-foreign-object, foleader,
  and fopage-number.

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root

• The foroot element exists just to declare the
  namespace and be the document root. It has no
  direct effect on page layout or formatting.
• (layout-master-set,declarations?,page-sequence)

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layout-master-set

• The folayout-master-set consists of descriptions
  of the kinds of pages that can occur in the
  document (Geometry) and their sequences.
• (simple-page-masterpage-sequence-master)
• Example
• ltfolayout-master-setgt
• ltfosimple-page-master master-name"cover
• page-height"12cm
• page-width"12cm
• margin-top"0.5cm
• margin-bottom"0.5cm
• margin-left"1cm
• margin-right"0.5cm"gt
• lt/fosimple-page-mastergt

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page-sequence

• Depending on whether for instance, the page is
  odd or even, the page-sequence, using the
  definitions from simple-page-master, can generate
  different looking pages.

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flow

• The content that is flowed to as many pages as
  required

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A simple example

• 01   lt?xml version"1.0" encoding"UTF-8"?gt
• 02   ltroot xmlns"http//www.w3.org/1999/XSL/Forma
  t"
• 03    font-size"16pt"gt
• 04    ltlayout-master-setgt
• 05    ltsimple-page-master
• 06    margin-right"15mm" margin-left"15mm
• 07    margin-bottom"15mm" margin-top"15mm"
• 08    page-width"210mm" page-height"297mm"
• 09    master-name"bookpage"gt
• 10    ltregion-body region-name"bookpage-body
• 11    margin-bottom"5mm" margin-top"5mm" /gt
• 12    lt/simple-page-mastergt
• 13    lt/layout-master-setgt
• 14    ltpage-sequence master-reference"bookpage"
  gt
• 15    lttitlegtHello world examplelt/titlegt
• 16    ltflow flow-name"bookpage-body"gt

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Example Result XSLFO - PDF
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Tools

• FOP is a command-line Java program that converts
  FO (formatting object) documents to Adobe Acrobat
  PDF files.

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Resources

• Deach, Stephen. "What Is XSL-FO and When Should I
  Use It?" 2002. 8 Jul. 2003. lthttp//www.seyboldrep
  orts.com/TSR/free/0217/techwatch.htmlgt
• Harold, Elliotte Rusty. "XSL Formatting Objects."
  12 Nov. 2001. 8 Jul. 2003. lthttp//www.ibiblio.org
  /xml/books/bible2/chapters/ch18.htmlgt
• Holman, G. Ken. "What is XSL-FO?" 20 Mar. 2002. 8
  Jul. 2003. lthttp//www.xml.com/pub/a/2002/03/20/xs
  l-fo.htmlgt
• Pawson, Dave. XSLFO An Introduction To XSL
  Formatting Objects. 2001. 8 Jul. 2003.
  ltwww.dpawson.co.uk/xsl/sect3/bk/index.htmlgt