Invalid PDF Generated by Aspose.PDF.Drawing v24.10.0

Aspose.PDF Product Family
1

Issue Description: Invalid PDF Generated by Aspose.PDF.Drawing v24.10.0
We are experiencing an issue with the Aspose.PDF library (“Aspose.PDF.Drawing” Version=“24.10.0”). When using the Merge feature to combine multiple PDFs into one, the resulting PDF is invalid. Below are the details of the issue:

Problem Summary:

  1. Validation Behavior:
    • The Validate method in Aspose always returns true, indicating the document is valid.
    • The Repair feature throws the error: “PDF document is invalid”, failing to fix the file.
  2. Ghostscript Check:
    • While Aspose doesn’t throw errors when Validate and Repair are bypassed, Ghostscript detects issues.
    • Specific page elements indicate the PDF is invalid (as shown in the attached screenshot).

Technical Analysis:

Page Dictionary Definition:

45 0 obj  
/Type /Page  
/Parent 44 0 R  
/MediaBox [0 0 595.299988 841.900024]  
/Contents 46 0 R  
/Resources  
  /Font
    /FAAAAI 47 0 R 
    /FAAABC 52 0 R
  /XObject  
<< >>  <--- Empty XObject dictionary  
/Group  
  /Type /Group  
  /S /Transparency  
  /CS /DeviceRGB  
>>>

Critical Issue: Missing XObject Resource

  • The content stream refers to a missing XObject resource:
    47.244095 0 0 -47.244095 0 47.244095 cm /X1 Do  <--- Reference to "X1" XObject
    • Issue: “X1” is not defined.
    • The /XObject dictionary is empty.
    • This results in a “Couldn’t find a named resource” error during rendering.

Font Resources:

/Font  
  /FAAAAI 47 0 R    # Calibri-Bold  
  /FAAABC 52 0 R    # Calibri
  • Fonts are correctly defined and referenced.

Content Stream:

46 0 obj  
/Filter /FlateDecode  
/Length 1654
  • The stream appears structured but may contain malformed operators, particularly at the end.

Suggested Fixes:

  1. Missing XObject Definition:
    • Define the missing XObject resource:
      /Resources
  /Font
    /FAAAAI 47 0 R
    /FAAABC 52 0 R
  /XObject
    /X1 [reference to actual XObject] R  <--- Add proper reference

 ```
  • Alternatively:
    • Remove the /X1 Do command if not necessary.
    • Or replace /X1 with an existing valid XObject.
  1. Content Stream Termination:
    • Ensure content streams terminate properly:
      • Every q (save graphics state) operation should match with a Q (restore graphics state).
      • Check for malformed operators.

Possible Causes:

  • The document generation process may be truncating or omitting XObject definitions.
  • Resource naming/referencing errors.
  • A template used during merging could be referring to a missing or incorrectly defined XObject.

Please advise on how to proceed with resolving this issue, as it is critical for generating valid PDFs.

2

@jwo
Thanks for the information provided - but we need the documents and code that this happened to so we can reproduce and investigate the issue.

3

@sergei.shibanov Many thanks for answering! My Colleague has already posted the same issue, hence you can close or link to his feed.

4

@jwo
Okay, accepted.