Friday, April 5, 2013

PDF Generation with XSL - FOP

Create report in PDF format using XSLFO and Apache FOP

XSLFO is XSL Formatting Objects and can be used for formatting XML data.Apache FOP (Formatting Objects Processor) is a Java application that reads a formatting objects tree and renders the resulting pages to a specified output (PDF in our case)

Requires:

- XSLT document (.xsl) with the :fo directives embedded into it. This XSLT document can be used in a java program to output the XSL-FO document 
- XML data or Java Object (convert Java Object to XML)
- Use Apache FOP driver to run the FO document against that Xml data to produce the PDF by using an XSLT Processor

Two stages of process

- XSLT to XSL-FO 
- XSL-FO to PDF

That process is similar with the following command of Apache FOP
Windows: fop -xml name.xml -xsl name2fo.xsl -pdf name.pdf

Required Jars

  1. xml-apis.jar
  2. jaxb-api-2.2.3.jar
  3. fop-1.0.jar
  4. avalon-framework-4.1.3.jar
  5. commons-io-2.0.1.jar
  6. commons-logging-1.0.3.jar
  7. xmlgraphics-commons-1.4.jar

XSLT Processor/Engine

XSLT processor aims for transforming XML documents into HTML, text, or other XML document types.

Apache FOP use JAXP as default factory.Avoid relying on the JAXP factory mechanism for selecting your transformation engine. Instead load the engine you want explicitly: it's much more reliable and much faster. 

 For Saxon, replace the call on TransformerFactory.newInstance()
with new net.sf.saxon.TransformerFactoryImpl()
 
For Xalan use
new org.apache.xalan.processor.TransformerFactoryImpl()

Generate font metadata & for embedding fonts

Use Apache FOP to generate font metadate
- Setup classpath to run Apache FOP:
cmd> set CLASSPATH=fop.jar;lib\avalon-framework-4.2.0.jar;lib\commons-logging-1.0.4.jar;lib\commons-io-1.3.1.jar; lib\xmlgraphics-commons-1.4.jar

- Create the metrics file:
cmd> java org.apache.fop.fonts.apps.TTFReader FontName.TTF FONTNAME.xml

Custom configuration & embed fonts in jar

Create  conf.xml

 <font metrics-url="/fonts/FontName.xml" kerning="yes" embed-url="/fonts/FontName.ttf">
       <font-triplet name="FontName" style="normal" weight="normal" />
       font-triplet name="FontName" style="italic" weight="normal" />
 </font>
             
<font metrics-url="/fonts/FontName.xml" kerning="yes" embed-url="/fonts/FontName.ttf">
     <font-triplet name="FontName" style="italic" weight="normal" />
</font> 



Reference:

http://xmlgraphics.apache.org/fop/ 
http://www.e-zest.net/blog/integrating-apache-fop-with-java-project-to-generate-pdf-files/