[jira] [Commented] (FOP-3271) pdf-images: Fail to render accessible pdf image in accessible PDF output when "Artifact" elements present in image

    [ https://issues.apache.org/jira/browse/FOP-3271?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18065408#comment-18065408 ] 

Mark Gibson  commented on FOP-3271:
-----------------------------------

I can test, but I don't think it will make any difference.  I spoke with the PDFBox team at the time.  The eventual result of that conversation was that PDFBox was doing the right thing.  It was representing the PDF in the way it was written to file.

> pdf-images: Fail to render accessible pdf image in accessible PDF output when "Artifact" elements present in image
> ------------------------------------------------------------------------------------------------------------------
>
>                 Key: FOP-3271
>                 URL: https://issues.apache.org/jira/browse/FOP-3271
>             Project: FOP
>          Issue Type: Bug
>          Components: renderer/pdf
>    Affects Versions: 2.10, 2.11
>            Reporter: Mark Gibson 
>            Priority: Major
>         Attachments: image1-artifactNotInParentsChildren.png, image2-artifactNotInParentsChildren.png, reproduction.zip
>
>
> We have PDF images that are exported direct from Excel (with accessibility enabled).  When rendering an accessible PDF output, the images fail to get rendered in final PDF output.
> FOP logs show an index out of bounds exception:
> {code:java}
> Caused by: java.lang.IndexOutOfBoundsException: Index -1 out of bounds for length 6
>         at java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:100)
>         at java.base/jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:106)
>         at java.base/jdk.internal.util.Preconditions.checkIndex(Preconditions.java:302)
>         at java.base/java.util.Objects.checkIndex(Objects.java:385)
>         at java.base/java.util.ArrayList.get(ArrayList.java:427)
>         at org.apache.fop.pdf.PDFStructElem.addKidInSpecificOrder(PDFStructElem.java:208)
>         at org.apache.fop.render.pdf.pdfbox.StructureTreeMerger.createParents(StructureTreeMerger.java:209)
>         at org.apache.fop.render.pdf.pdfbox.StructureTreeMerger.createParents(StructureTreeMerger.java:154)
>         at org.apache.fop.render.pdf.pdfbox.StructureTreeMerger.copyStructure(StructureTreeMerger.java:89)
>         at org.apache.fop.render.pdf.pdfbox.TaggedPDFConductor.handleLogicalStructure(TaggedPDFConductor.java:68)
>         at org.apache.fop.render.pdf.pdfbox.AbstractPDFBoxHandler.createStreamForPDF(AbstractPDFBoxHandler.java:114)
>         at org.apache.fop.render.pdf.pdfbox.PDFBoxImageHandler.handleImage(PDFBoxImageHandler.java:77)
>         ... 62 more{code}
>  
> Because the following method returns -1 ...
> {code:java}
> public final class StructureTreeMergerUtil {
>     public static int findObjectPositionInKidsArray(COSObject kidObj) {
>         COSDictionary kid = (COSDictionary) kidObj.getObject();
>         COSObject parentObj = (COSObject) kid.getItem(COSName.P);
>         COSDictionary parent = (COSDictionary) parentObj.getObject();
>         COSBase kids = parent.getItem(COSName.K);
>         if (kids instanceof COSArray) {
>             COSArray kidsArray = (COSArray)kids;
>             return kidsArray.indexOfObject(kid);
>         } else {
>             return 0;
>         }
>     } {code}
> It turns out that the Excel exported PDF images have records that do not exist in that record's parent's children.  This can be seen in the attached images, and are always "Artifact" records (although I'm not sure that means all artifact records are always broken).
> I've also attached a reproduction with a simple fo file, and two pdf images that present this issue.  Command to execute it is
> {code:java}
> fop.bat -a -fo test.fo -pdf test.pdf {code}
>  
> My PDF spec knowledge is low.  So I'm currently unsure whether Excel is producing broken PDFs, or whether there is a bug in FOP's pdf-image handling when copying over the structure tree on externally imported PDF images.
>  
> Hoping someone can shed some light here.  
>  
> Maybe the fix would be as simple as returning 0 instead of -1 from the above method?



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