Using XSL Formatting Objects, Part 2
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•Part one of this series |
This article is the second part of our series on using XSL Formatting Objects. You should read the first article before proceeding with this one.
Having tackled the cover and contents page in the previous article, we're now ready to put the main content into the Spanish handbook. Let's start off with:
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The headings and paragraph will be <fo:block> elements, and the bold and underlined words will be <fo:inline> elements. Let's start with a description of the first heading.
<fo:block
font-size="14pt" font-family="sans-serif"
font-weight="bold" color="green"
space-before="6pt" space-after="6pt">
Introduction
<fo:block>
the space-before and space-after are two of the many properties that you may set for a block. Many of them are exactly the same as the properties you can use in Cascading Style Sheets (CSS)
- Font Properties
- font-family, font-weight, font-style (italic), font-size, font-stretch, font-variant (small-caps)
- Background Properties
- background-color, background-image, background-repeat, background-attachment (scroll or fixed)
- Border Properties
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border-location-info where:
location is one of before, after, start, end, top, bottom, left, or right
info is one of style, width, or color - Padding Properties
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padding-location where:
location is one of before, after, start, end, top, bottom, left, or right - Margin Properties
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margin-location where:
location is one of top, bottom, left, or right - Text Alignment Properties
- text-align and text-align-last (for last line of text in block ); values can be start, end, left, right, or center
- Indentation Properties
- text-indent (first line), start-indent, end-indent
- Miscellaneous Properties
- wrap-option (no-wrap or wrap); widows and orphans (determining how many lines must be left at top or bottom of a page) break-after and break-before (when to do page or column breaks); reference-orientation (rotated text in 90-degree increments)
Given the plethora of options, we can have a fairly complicated block definition for the paragraph. The definition below uses the dot-notation “compound datatype” to allow the page layout mechanism some flexibility in paragraph spacing:
<fo:block
text-indent="1em"
font-family="sans-serif" font-size="12pt"
space-before.minimum="2pt"
space-before.maximum="6pt"
space-before.optimum="4pt"
space-after.minimum="2pt"
space-after.maximum="6pt"
space-after.optimum="4pt">
This handbook covers the major topics in Spanish, but is by
no means complete.
<fo:block>
If your document has twenty or thirty headings and seventy or eighty paragraphs, you don't want to type (or copy and paste) all of these Formatting Objects elements. This is where XSLT comes in. We will write our document in HTML and then use an XSLT to transform it to the far more verbose XSL:FO version. Here's the HTML so far:
<h3>Introduction</h3> <p> This handbook covers the major topics in Spanish, but is by no means complete. </p> <h3>Accents</h3> <p> When we pronounce English words, one syllable is usually emphasized (<b>stressed</b>, in linguistic terms). The stressed syllable is underlined in the following words: com<u>pu</u>ter, <u>lan</u>guage, de<u>vel</u>opment, suc<u>ceeds</u>. Spanish words also have a stressed syllable, and there are rules for determining which syllable carries the emphasis. </p>
And here are the templates you'll need to do the headings and paragraphs:
<xsl:template match="h3">
<fo:block font-size="14pt" font-family="sans-serif"
font-weight="bold" color="green"
space-before="6pt" space-after="6pt">
<xsl:apply-templates/>
</fo:block>
</xsl:template>
<xsl:template match="p">
<fo:block
text-indent="1em"
font-family="sans-serif" font-size="12pt"
space-before.minimum="2pt"
space-before.maximum="6pt"
space-before.optimum="4pt"
space-after.minimum="2pt"
space-after.maximum="6pt"
space-after.optimum="4pt">
<xsl:apply-templates/>
</fo:block>
</xsl:template>
What happens to all of the page-initialization code from the past article? It goes into templates that handle the <html> and <body> tags. We won't repeat it here, but you can peruse it in another browser window.
That leaves the <b> and <u> tags. Those are inline elements handled via <fo:inline> (with <i> thrown in as a bonus).
<xsl:template match="b">
<fo:inline font-weight="bold"><xsl:apply-templates/></fo:inline>
</xsl:template>
<xsl:template match="u">
<fo:inline text-decoration="underline"><xsl:apply-templates/></fo:inline>
</xsl:template>
<xsl:template match="i">
<fo:inline font-style="italic"><xsl:apply-templates/></fo:inline>
</xsl:template>
Once we set up the HTML file and run it through XSLT and FOP, we come up with:
Lists
Next, we will add lists to the document. Here's the content to be added:
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Four elements are used to set up a list. An <fo:list-block> contains individual <fo:list-items>. Each list item is composed of a <fo:list-item-label> and a <fo:list-item-body>. You set the spacing by setting the attributes shown in the diagram below:
- provisional-distance-between-starts
- provisional-label-separation
- start-indent for list-item-label
- start-indent for list-item-body
- end-indent for list-item-label
- end-indent for list-item-body
Now we can create an XSLT template to handle an ordered list. We'll set the start indent of the list item label, and leave the rest up to FOP. By using the relative em spacing, lists will give reasonable spacing with any size font.
<xsl:template match="ol">
<fo:list-block
space-before="0.25em" space-after="0.25em">
<xsl:apply-templates/>
</fo:list-block>
</xsl:template>
<xsl:template match="ol/li">
<fo:list-item space-after="0.5ex">
<fo:list-item-label start-indent="1em">
<fo:block>
<xsl:number/>.
</fo:block>
</fo:list-item-label>
<fo:list-item-body>
<fo:block>
<xsl:apply-templates/>
</fo:block>
</fo:list-item-body>
</fo:list-item>
</xsl:template>
