FO to PDF/a Conversion with Apache FOP Java Library

问题

I'm trying to convert .fo files to PDF/a with Apache FOP 2.1 with the exemple code given in the documentation. I managed to convert the helloworld.fo file into PDF but, when I tried to convert it into PDF/a file I get this error:

org.apache.fop.pdf.PDFConformanceException: For PDF/A-1a, all fonts, even the base 14 fonts, have to be embedded! Offending font: /Helvetica

That's why I tried to embedded fonts in the fop.xconf file:

  <fonts>

    <font kerning="yes" embed-url="C:/Users/thinkpad/workspace/FopConverter/Fonts/arial.ttf" name="Arial">
      <font-triplet name="Arial" style="normal" weight="700"/>
    </font>
    <font kerning="yes" embed-url="C:/Users/thinkpad/workspace/FopConverter/Fonts/arialbd.ttf" name="Arial Bold">
      <font-triplet name="Arial" style="normal" weight="bold"/>
    </font>
    <font kerning="yes" embed-url="C:/Users/thinkpad/workspace/FopConverter/Fonts/ariali.ttf" name="Arial Italique">
      <font-triplet name="Arial" style="italic" weight="700"/>
    </font>
    <font kerning="yes" embed-url="C:/Users/thinkpad/workspace/FopConverter/Fonts/arialbi.ttf" name="Helvetica Bold Italique">
      <font-triplet name="Arial" style="italic" weight="bold"/>
    </font>

    <directory>C:\Users\thinkpad\workspace\FopConverter\Fonts</directory>
    <directory>C:\Users\thinkpad\workspace\FopConverter\Fonts\ghostFonts</directory>

   <substitutions>
     <substitution>
       <from font-family="Helvetica" font-weight="700..900"/>
       <to font-family="Arial"/>
     </substitution>
   </substitutions>
   <auto-detect/>
  </fonts>

But even after doing so I still have the same error: org.apache.fop.pdf.PDFConformanceException: For PDF/A-1a, all fonts, even the base 14 fonts, have to be embedded! Offending font: /Helvetica

I also tried to modify the helloworld.fo by adding font-family="Helvetica" font-weight="normal" font-style="normal" in the <fo:root"> because some forum topic said to do so but it didn't changed anything.

Please, help me in solving my embedding font error. Thank for reading this topic.

[EDIT]: Here is the entire error message:

FOP ExampleFO2PDF

Preparing...
Input: XSL-FO (.\xml\fo\helloworld.fo)
Output: PDF (.\out\ResultFO2PDF.pdf)

Transforming...
août 07, 2017 11:26:49 AM org.apache.fop.events.LoggingEventListener processEvent
INFOS: Rendered page #1.
org.apache.fop.pdf.PDFConformanceException: For PDF/A-1b, all fonts, even the base 14 fonts, have to be embedded! Offending font: /Helvetica
    at org.apache.fop.pdf.PDFFont.validate(PDFFont.java:170)
    at org.apache.fop.pdf.PDFFont.output(PDFFont.java:179)
    at org.apache.fop.pdf.PDFDocument.outputIndirectObject(PDFDocument.java:1053)
    at org.apache.fop.pdf.PDFDocument.streamIndirectObject(PDFDocument.java:1018)
    at org.apache.fop.pdf.PDFDocument.output(PDFDocument.java:994)
    at org.apache.fop.pdf.PDFDocument.outputTrailer(PDFDocument.java:1097)
    at org.apache.fop.render.pdf.PDFDocumentHandler.endDocument(PDFDocumentHandler.java:191)
    at org.apache.fop.render.intermediate.util.IFDocumentHandlerProxy.endDocument(IFDocumentHandlerProxy.java:187)
    at org.apache.fop.render.intermediate.IFRenderer.stopRenderer(IFRenderer.java:295)
    at org.apache.fop.area.RenderPagesModel.endDocument(RenderPagesModel.java:265)
    at org.apache.fop.area.AreaTreeHandler.endDocument(AreaTreeHandler.java:342)
    at org.apache.fop.fo.FOTreeBuilder.endDocument(FOTreeBuilder.java:170)
    at org.apache.xalan.transformer.TransformerIdentityImpl.endDocument(TransformerIdentityImpl.java:963)
    at org.apache.xerces.parsers.AbstractSAXParser.endDocument(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentScannerImpl.endEntity(Unknown Source)
    at org.apache.xerces.impl.XMLEntityManager.endEntity(Unknown Source)
    at org.apache.xerces.impl.XMLEntityScanner.load(Unknown Source)
    at org.apache.xerces.impl.XMLEntityScanner.skipSpaces(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentScannerImpl$TrailingMiscDispatcher.dispatch(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
    at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
    at org.apache.xalan.transformer.TransformerIdentityImpl.transform(TransformerIdentityImpl.java:485)
    at ConverterFO2PDFa.convertFO2PDF(ConverterFO2PDFa.java:104)
    at ConverterFO2PDFa.main(ConverterFO2PDFa.java:154)

回答1:

I was able to create a PDF/A output using the same example files after a few changes:

in the input FO file, I explicitly added font-family="Helvetica" (or your favourite font family) in a position where it effected all the text

Without this, even if FOP defaults to using Helvetica when no font-family is set, it apparently is not able to find a configuration for it.

in the configuration file, I mapped the Helvetica font family to an existing font, for example Arial

<font kerning="yes" embed-url="/Library/Fonts/arial.ttf">
  <font-triplet name="Helvetica" style="normal" weight="normal"/>
</font>

in the Java code, I configured FOP to use my configuration file, and the user agent to enable accessibility

import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.DefaultConfigurationBuilder;
import org.apache.fop.apps.FopFactoryBuilder;

...
DefaultConfigurationBuilder cfgBuilder = new DefaultConfigurationBuilder();
Configuration cfg = cfgBuilder.buildFromFile(new File("/Users/lfurini/fop.xconf"));
FopFactoryBuilder fopFactoryBuilder = new FopFactoryBuilder(new File(".").toURI()).setConfiguration(cfg);
FopFactory fopFactory = fopFactoryBuilder.build();

FOUserAgent foUserAgent = fopFactory.newFOUserAgent();
// configure foUserAgent as desired
foUserAgent.setAccessibility(true);
foUserAgent.getRendererOptions().put("pdf-a-mode", "PDF/A-1b");
...

来源：https://stackoverflow.com/questions/45435698/fo-to-pdf-a-conversion-with-apache-fop-java-library

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