Stylus Studio XML Editor

Table of contents

Appendices

6.8 Formatting Objects for Lists

Formatting Objects for Lists

Introduction[top]

Introduction

There are four formatting objects used to construct lists: fo:list-block, fo:list-item, fo:list-item-label, and fo:list-item-body.

Tree representation of the Formatting Objects for lists

Tree representation of the formatting Objects for Lists.

The fo:list-block has the role of containing the complete list and of specifying values used for the list geometry in the inline-progression-direction (see details below).

The children of the fo:list-block are one or more fo:list-item, each containing a pair of fo:list-item-label and fo:list-item-body.

The fo:list-item has the role of containing each item in a list.

The fo:list-item-label has the role of containing the content, block-level formatting objects, of the label for the list-item; typically an fo:block containing a number, a dingbat character, or a term.

The fo:list-item-body has the role of containing the content, block-level formatting objects, of the body of the list-item; typically one or more fo:block.

The placement, in the block-progression-direction, of the label with respect to the body is made in accordance with the "vertical-align" property of the fo:list-item.

Areas generated by a list

The specification of the list geometry in the inline-progression-direction is achieved by:

  • Specifying appropriate values of the "provisional-distance-between-starts" and "provisional-label-separation" properties. The "provisional-distance-between-starts" specifies the desired distance between the start-indents of the label and the body of the list-item. The "provisional-label-separation" specifies the desired separation between the end-indent of the label and the start-indent of the body of the list-item.

  • Specifying end-indent="label-end()" on the fo:list-item-label.

    Specifying start-indent="body-start()" on the fo:list-item-body.

    NOTE: 

    These list specific functions are defined in [provisional-label-separation] and [provisional-distance-between-starts] .

The start-indent of the list-item-label and end-indent of the list-item-body, if desired, are typically specified as a length.

Examples[top]

Examples
Enumerated List[top]
Enumerated List

The list-items are contained in an "ol" element. The items are contained in "item" elements and contain text (as opposed to paragraphs).

The style is to enumerate the items alphabetically with a dot after the letter.

Input sample:

<ol>
<item>List item 1.</item>
<item>List item 2.</item>
<item>List item 3.</item>
</ol>

XSL Stylesheet:

<?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:fo="http://www.w3.org/1999/XSL/Format"
                version='1.0'>

<xsl:template match="ol">
  <fo:list-block provisional-distance-between-starts="15mm"
   provisional-label-separation="5mm">
    <xsl:apply-templates/>
  </fo:list-block>
</xsl:template>

<xsl:template match="ol/item">
  <fo:list-item>
    <fo:list-item-label start-indent="5mm" end-indent="label-end()">
      <fo:block>
        <xsl:number format="a."/>
      </fo:block>
    </fo:list-item-label>
    <fo:list-item-body start-indent="body-start()">
      <fo:block>
        <xsl:apply-templates/>
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>
</xsl:template>

</xsl:stylesheet>

Result Instance: elements and attributes in the fo: namespace

<fo:list-block provisional-distance-between-starts="15mm"
  provisional-label-separation="5mm">

  <fo:list-item>
    <fo:list-item-label start-indent="5mm" end-indent="label-end()">
      <fo:block>a.
      </fo:block>
    </fo:list-item-label>
    <fo:list-item-body start-indent="body-start()">
      <fo:block>List item 1.
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>

  <fo:list-item>
    <fo:list-item-label start-indent="5mm" end-indent="label-end()">
      <fo:block>b.
      </fo:block>
    </fo:list-item-label>
    <fo:list-item-body start-indent="body-start()">
      <fo:block>List item 2.
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>

  <fo:list-item>
    <fo:list-item-label start-indent="5mm" end-indent="label-end()">
      <fo:block>c.
      </fo:block>
    </fo:list-item-label>
    <fo:list-item-body start-indent="body-start()">
      <fo:block>List item 3.
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>

</fo:list-block>
HTML-style "dl" lists[top]
HTML-style "dl" lists

In this example the stylesheet processes HTML-style "dl" lists, which contain unwrapped pairs of "dt" and "dd" elements, transforming them into fo:list-blocks.

Balanced pairs of "dt"/"dd"s are converted into fo:list-items. For unbalanced "dt"/"dd"s, the stylesheet makes the following assumptions:

  • Multiple "dt"s are grouped together into a single fo:list-item-label in a single list-item.

  • Multiple DDs are:

    • Output as individual FO list-items with an empty list-item-label if the stylesheet variable $allow-naked-dd is true.

    • Are grouped together into a single FO list-item-body if $allow-naked-dd is false.

In other words, given a structure like this:

<doc>
<dl>
  <dt>term</dt>
  <dd>definition</dd>
  <dt>term</dt>
  <dt>term</dt>
  <dd>definition</dd>
  <dt>term</dt>
  <dd>definition</dd>
  <dd>definition</dd>
</dl>
</doc>

If $allow-naked-dd is true, the result instance: elements and attributes in the fo: namespace is:

<fo:list-block provisional-distance-between-starts="35mm"
  provisional-label-separation="5mm">
  <fo:list-item>
    <fo:list-item-label end-indent="label-end()">
      <fo:block>term
      </fo:block>
    </fo:list-item-label>
    <fo:list-item-body start-indent="body-start()">
      <fo:block>definition
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>
  <fo:list-item>
    <fo:list-item-label end-indent="label-end()">
      <fo:block>term
      </fo:block>
      <fo:block>term
      </fo:block>
    </fo:list-item-label>
    <fo:list-item-body start-indent="body-start()">
      <fo:block>definition
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>
  <fo:list-item>
    <fo:list-item-label end-indent="label-end()">
      <fo:block>term
      </fo:block>
    </fo:list-item-label>
    <fo:list-item-body start-indent="body-start()">
      <fo:block>definition
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>
  <fo:list-item>
    <fo:list-item-label end-indent="label-end()">
    </fo:list-item-label>
    <fo:list-item-body start-indent="body-start()">
      <fo:block>definition
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>
</fo:list-block>

If $allow-naked-dd is false, the result instance: elements and attributes in the fo: namespace is:

<fo:list-block provisional-distance-between-starts="35mm"
  provisional-label-separation="5mm">
  <fo:list-item>
    <fo:list-item-label end-indent="label-end()">
      <fo:block>term
      </fo:block>
    </fo:list-item-label>
    <fo:list-item-body start-indent="body-start()">
      <fo:block>definition
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>
  <fo:list-item>
    <fo:list-item-label end-indent="label-end()">
      <fo:block>term
      </fo:block>
      <fo:block>term
      </fo:block>
    </fo:list-item-label>
    <fo:list-item-body start-indent="body-start()">
      <fo:block>definition
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>
  <fo:list-item>
    <fo:list-item-label end-indent="label-end()">
      <fo:block>term
      </fo:block>
    </fo:list-item-label>
    <fo:list-item-body start-indent="body-start()">
      <fo:block>definition
      </fo:block>
      <fo:block>definition
      </fo:block>
    </fo:list-item-body>
  </fo:list-item>
</fo:list-block>

XSL Stylesheet:

<?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:fo="http://www.w3.org/1999/XSL/Format"
                version='1.0'>

<xsl:include href="dtdd.xsl"/>

<xsl:template match="doc">
  <xsl:apply-templates/>
</xsl:template>

<xsl:template match="dl">
  <xsl:call-template name="process.dl"/>
</xsl:template>

<xsl:template match="dt|dd">
  <fo:block>
    <xsl:apply-templates/>
  </fo:block>
</xsl:template>

</xsl:stylesheet>

Included stylesheet "dtdd.xsl"

<?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:fo="http://www.w3.org/1999/XSL/Format"
                version='1.0'>

<xsl:variable name="allow-naked-dd" select="true()"/>

<xsl:template name="process.dl">
  <fo:list-block provisional-distance-between-starts="35mm"
   provisional-label-separation="5mm">
    <xsl:choose>
      <xsl:when test="$allow-naked-dd">
        <xsl:call-template name="process.dl.content.with.naked.dd"/>
      </xsl:when>
      <xsl:otherwise>
        <xsl:call-template name="process.dl.content"/>
      </xsl:otherwise>
    </xsl:choose>
  </fo:list-block>
</xsl:template>

<xsl:template name="process.dl.content.with.naked.dd">
  <xsl:param name="dts" select="./force-list-to-be-empty"/>
  <xsl:param name="nodes" select="*"/>

  <xsl:choose>
    <xsl:when test="count($nodes)=0">
      <!-- Out of nodes, output any pending DTs -->
      <xsl:if test="count($dts)>0">
        <fo:list-item>
          <fo:list-item-label end-indent="label-end()">
            <xsl:apply-templates select="$dts"/>
          </fo:list-item-label>
          <fo:list-item-body start-indent="body-start()"/>
        </fo:list-item>
      </xsl:if>
    </xsl:when>

    <xsl:when test="name($nodes[1])='dd'">
      <!-- We found a DD, output the DTs and the DD -->
      <fo:list-item>
        <fo:list-item-label end-indent="label-end()">
          <xsl:apply-templates select="$dts"/>
        </fo:list-item-label>
        <fo:list-item-body start-indent="body-start()">
          <xsl:apply-templates select="$nodes[1]"/>
        </fo:list-item-body>
      </fo:list-item>
      <xsl:call-template name="process.dl.content.with.naked.dd">
        <xsl:with-param name="nodes" select="$nodes[position()>1]"/>
      </xsl:call-template>
    </xsl:when>

    <xsl:when test="name($nodes[1])='dt'">
      <!-- We found a DT, add it to the list of DTs and loop -->
      <xsl:call-template name="process.dl.content.with.naked.dd">
        <xsl:with-param name="dts" select="$dts|$nodes[1]"/>
        <xsl:with-param name="nodes" select="$nodes[position()>1]"/>
      </xsl:call-template>
    </xsl:when>

    <xsl:otherwise>
      <!-- This shouldn't happen -->
      <xsl:message>
        <xsl:text>DT/DD list contained something bogus (</xsl:text>
        <xsl:value-of select="name($nodes[1])"/>
        <xsl:text>).</xsl:text>
      </xsl:message>
    </xsl:otherwise>
  </xsl:choose>
</xsl:template>

<xsl:template name="process.dl.content">
  <xsl:param name="dts" select="./force-list-to-be-empty"/>
  <xsl:param name="dds" select="./force-list-to-be-empty"/>
  <xsl:param name="output-on"></xsl:param>
  <xsl:param name="nodes" select="*"/>

  <!-- The algorithm here is to build up a list of DTs and DDs, -->
  <!-- outputing them only on the transition from DD back to DT -->

  <xsl:choose>
    <xsl:when test="count($nodes)=0">
      <!-- Out of nodes, output any pending elements -->
      <xsl:if test="count($dts)>0 or count($dds)>0">
        <fo:list-item>
          <fo:list-item-label end-indent="label-end()">
            <xsl:apply-templates select="$dts"/>
          </fo:list-item-label>
          <fo:list-item-body start-indent="body-start()">
            <xsl:apply-templates select="$dds"/>
          </fo:list-item-body>
        </fo:list-item>
      </xsl:if>
    </xsl:when>

    <xsl:when test="name($nodes[1])=$output-on">
      <!-- We're making the transition from DD back to DT -->
      <fo:list-item>
        <fo:list-item-label end-indent="label-end()">
          <xsl:apply-templates select="$dts"/>
        </fo:list-item-label>
        <fo:list-item-body start-indent="body-start()">
          <xsl:apply-templates select="$dds"/>
        </fo:list-item-body>
      </fo:list-item>

      <!-- Reprocess this node (and the rest of the node list) -->
      <!-- resetting the output-on state to nil -->
      <xsl:call-template name="process.dl.content">
        <xsl:with-param name="nodes" select="$nodes"/>
      </xsl:call-template>
    </xsl:when>

    <xsl:when test="name($nodes[1])='dt'">
      <!-- We found a DT, add it to the list and loop -->
      <xsl:call-template name="process.dl.content">
        <xsl:with-param name="dts" select="$dts|$nodes[1]"/>
        <xsl:with-param name="dds" select="$dds"/>
        <xsl:with-param name="nodes" select="$nodes[position()>1]"/>
      </xsl:call-template>
    </xsl:when>

    <xsl:when test="name($nodes[1])='dd'">
      <!-- We found a DD, add it to the list and loop, noting that -->
      <!-- the next time we cross back to DT's, we need to output the -->
      <!-- current DT/DDs. -->
      <xsl:call-template name="process.dl.content">
        <xsl:with-param name="dts" select="$dts"/>
        <xsl:with-param name="dds" select="$dds|$nodes[1]"/>
        <xsl:with-param name="output-on">dt</xsl:with-param>
        <xsl:with-param name="nodes" select="$nodes[position()>1]"/>
      </xsl:call-template>
    </xsl:when>

    <xsl:otherwise>
      <!-- This shouldn't happen -->
      <xsl:message>
        <xsl:text>DT/DD list contained something bogus (</xsl:text>
        <xsl:value-of select="name($nodes[1])"/>
        <xsl:text>).</xsl:text>
      </xsl:message>
    </xsl:otherwise>
  </xsl:choose>
</xsl:template>

</xsl:stylesheet>

The "dtdd.xsl" stylesheet may be customized in the following ways:

  • Set the value of $allow-naked-dd to control the processing of unbalanced "dd"s.

  • Change "dt" to the name of the element which is a term in the list.

  • Change "dd" to the name of the element which is a definition in the list.

  • In the, perhaps unlikely, event that the documents may contain an element named "force-list-to-be-empty", that element name should be changed to a name that is not used in the documents.

In the stylesheet using the "dtdd.xsl" stylesheet change the "dl" to the name of the element which is the wrapper for the list.

fo:list-block[top]

fo:list-block

Common Usage:

The fo:list-block flow object is used to format a list.

Areas:

The fo:list-block formatting object generates one or more normal block-areas. The fo:list-block returns these areas, any page-level-out-of-line areas, and any reference-level-out-of-line areas returned by the children of the fo:list-block.

Constraints:

No area may have more than one normal child area returned by the same fo:list-block formatting object.

The children of each normal area returned by an fo:list-block formatting object must be normal block-areas returned by the children of the fo:list-block, must be properly stacked, and must be properly ordered.

Contents:

(list-item+)

In addition this formatting object may have a sequence of zero or more fo:markers as its initial children.

The following properties apply to this formatting object:

fo:list-item[top]

fo:list-item

Common Usage:

The fo:list-item formatting object contains the label and the body of an item in a list.

Areas:

The fo:list-item formatting object generates one or more normal block-areas. The fo:list-item returns these areas, any page-level-out-of-line areas, and any reference-level-out-of-line areas returned by the children of the fo:list-item.

Constraints:

No area may have more than one normal child area returned by the same fo:list-item formatting object.

The children of each normal area returned by an fo:list-item formatting object must be normal block-areas returned by the fo:list-item-label and the fo:list-item-body flow objects and must be properly ordered. Those returned by the fo:list-item-label must be properly stacked and those returned by the fo:list-item-body must be properly stacked.

The children of each normal area returned by an fo:list-item formatting object returned by the fo:list-item-label and fo:list-item-body objects are positioned in the block-progression-direction with respect to each other according to the relative-align trait.

In the inline-progression-direction these areas are positioned in the usual manner for properly stacked areas. It is an error if the content-rectangles of the areas overlap.

The block-progression-dimension of the content-rectangle of an area generated by the fo:list-item is just large enough so that the allocation-rectangles of all its child areas are contained in it. In particular, the space-before and space-after of the child areas have no effect on the spacing of the list item. For purposes of the block-stacking constraints the areas generated by fo:list-item are treated as if there they have a fence preceding and a fence following them.

NOTE: 

These areas are not reference-areas, hence the indents on all objects within them are measured relative to the reference-area that holds the content of the fo:list-block.

Contents:

(list-item-label,list-item-body)

In addition this formatting object may have a sequence of zero or more fo:markers as its initial children.

The following properties apply to this formatting object:

fo:list-item-body[top]

fo:list-item-body

Common Usage:

The fo:list-item-body formatting object contains the content of the body of a list-item.

Areas:

The fo:list-item-body formatting object does not generate any areas. The fo:list-item-body formatting object returns the sequence of areas created by concatenating the sequences of areas returned by each of the children of the fo:list-item-body.

Constraints:

The order of concatenation of the sequences of areas returned by the children of the fo:list-item-body is the same order as the children are ordered under the fo:list-item-body.

Contents:

(%block;)+

In addition this formatting object may have a sequence of zero or more fo:markers as its initial children.

The following properties apply to this formatting object:

fo:list-item-label[top]

fo:list-item-label

Common Usage:

The fo:list-item-label formatting object contains the content of the label of a list-item, typically used to either enumerate, identify, or adorn the list-item's body.

Areas:

The fo:list-item-label formatting object does not generate any areas. The fo:list-item-label formatting object returns the sequence of areas created by concatenating the sequences of areas returned by each of the children of the fo:list-item-label.

Constraints:

The order of concatenation of the sequences of areas returned by the children of the fo:list-item-label is the same order as the children are ordered under the fo:list-item-label.

Contents:

(%block;)+

In addition this formatting object may have a sequence of zero or more fo:markers as its initial children.

The following properties apply to this formatting object: