I am trying to use JBIG2ImageReader to parse JBIG2 data from a PDF (the
image stream and globals are being provided - we are not using PdfBox to
parse the PDF itself). Please let me know if I should be using a different
communication avenue for JBIG2 specific questions.
Here's what I'm trying to do:
JBIG2ImageReader jbig2Reader = new JBIG2ImageReader(new
JBIG2ImageReaderSpi());
byte[] globalBytes = //raw bytes from PDF
DECODEPARAMS, JBIG2GLOBALS
ImageInputStream globalsInputStream = new
DefaultInputStreamFactory().getInputStream(new
ByteArrayInputStream(globalBytes));
JBIG2Globals globals =
jbig2Reader.processGlobals(globalsInputStream);
jbig2Reader.setGlobals(globals);
byte[] imageBytes = // raw JBIG2 image stream bytes from
PDF
ImageInputStream imageInputStream = new
DefaultInputStreamFactory().getInputStream(new
ByteArrayInputStream(image.getImageAsBytes()));
jbig2Reader.setInput(imageInputStream);
return jbig2Reader.read(0);
When I do this, I get a null pointer exception:
Exception in thread "main" java.lang.RuntimeException: Can't instantiate
segment classException in thread "main" java.lang.RuntimeException: Can't
instantiate segment class at
org.apache.pdfbox.jbig2.SegmentHeader.getSegmentData(SegmentHeader.java:420)
at org.apache.pdfbox.jbig2.JBIG2Page.createNormalPage(JBIG2Page.java:202)
at org.apache.pdfbox.jbig2.JBIG2Page.createPage(JBIG2Page.java:168) at
org.apache.pdfbox.jbig2.JBIG2Page.composePageBitmap(JBIG2Page.java:157) at
org.apache.pdfbox.jbig2.JBIG2Page.getBitmap(JBIG2Page.java:133) at
org.apache.pdfbox.jbig2.JBIG2ImageReader.read(JBIG2ImageReader.java:249) at
javax.imageio.ImageReader.read(ImageReader.java:939)
....
Caused by: java.lang.NullPointerException at
org.apache.pdfbox.jbig2.segments.TextRegion.initSymbols(TextRegion.java:1010)
at
org.apache.pdfbox.jbig2.segments.TextRegion.getSymbols(TextRegion.java:273)
at
org.apache.pdfbox.jbig2.segments.TextRegion.parseHeader(TextRegion.java:154)
at org.apache.pdfbox.jbig2.segments.TextRegion.init(TextRegion.java:1128)
at
org.apache.pdfbox.jbig2.SegmentHeader.getSegmentData(SegmentHeader.java:413)
... 19 more
The SegmentHeader array in TextRegion looks like this:
(org.apache.pdfbox.jbig2.SegmentHeader[]) [null,
#SegmentNr: 377
SegmentType: 0
PageAssociation: 1
Referred-to segments: none
]
Note that the first element is null. I'm not sure why this is (maybe it's
not a valid JBIG2 data stream??). This file opens and displays fine in PDF
viewers, so I'm assuming it must be something that I'm doing wrong.
Any pointers?
- K
Kevin Day
*trumpet**p| *480.961.6003 x1002
*e| *ke...@trumpetinc.com
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