Issue with Text Selection and Highlighting in Japanese Vertical Text PDFs

[rakunavi]

Hello all,

I would like to report some issues when handling Japanese vertical text PDFs downloaded from the Japanese government's official legal search service (e-Gov 法令検索 - https://laws.e-gov.go.jp/).

• sample.pdf
• sample_full.pdf

When searching, selecting text, or adding highlights to these vertical PDFs, I encountered the following issues:

1. Search highlight misalignment:
   The highlights in the document appear shifted from the actual position of the matching text.
2. Extra spaces in search results:
   In the search results pane, extra spaces appear between characters. These spaces are also reflected in the highlights within the document.
3. Selection and Annotation shift:
   When using the Select Text Tool, the selection area for each line is misaligned. Consequently, any highlight annotations added are also displayed in the wrong positions.
4. Erratic selection behavior:
   While dragging the Select Text Tool, if the cursor passes over an area without text, the selection area temporarily becomes glitchy or abnormal.

Video 1:
I searched for the keyword "株式" (Stock) and browsed through the results. This demonstrates issues #1 and #2.

Note that while I referred to "extra spaces" in the explanation for issue #2, these extra spaces displayed on the screen may actually be line breaks. This is because when adding bookmarks using the "Generate Bookmarks From Page Text" feature based on the keyword "株式" used in the search, you need to specify "株\n式" as the text pattern, not just "株式".

• video1.webm
  
  
  figure1.png

Video 2:
I used the Select Text Tool to select text via two different mouse paths (Route A and Route B, as shown in the diagram), then added a highlight. This demonstrates issues #3 and #4. Please note how the selection area flickers or changes erratically in PDF-XChange Editor when following Route B.

• figure2.png
  
  
  video2.webm
  
  
  figure3.png
  
  
  figure4.png

Comparison with Adobe Acrobat:
Please note that Adobe Acrobat handles these files perfectly—search results, text selection, and highlighting all work as expected.
The PDFs from this government service are generated using Antenna House's PDF library (https://www.antennahouse.com/formatter-v7). Given that it is used for official government services, it is highly likely that the library is strictly compliant with PDF standards. Improving compatibility with files generated by this library would be a significant benefit for all Japanese users.

Hoping that the above information will be of some help to you.
Thank you so much for your continued support.

Best regards,
rakunavi

- PDF-XChange Editor PRO Version: 10.8.2 build 407
- OS Version: Windows 11 Pro / Home 25H2 Build 26200.7840
- Adobe Acrobat Reader Continuous Release Version 2025.001.21223
- PC Model: GMKtec Nucbox M7 Pro with HUION Kamvas Pro 19 / Lenovo IdeaPad C340-15IWL

[Sean - PDF-XChange]

Hi Rakunavi,

Thanks for the detailed report - I have let the development team know.

Kind regards,