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https://issues.apache.org/jira/browse/PDFBOX-5868?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17878077#comment-17878077
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Manish S N commented on PDFBOX-5868:
------------------------------------
It is the modern word processors that put actual unicode of glyphs in actual
text tags but in older PDFs with embedded CID fonts like [^page.pdf] there is
no such tags and the ligatures are left out without unicode mappings (there is
no single unicode for these). but when i extracted font files using pdfbox (
[code|https://gist.githubusercontent.com/incubated-geek-cc/640a74920b184274374af257cd1587bb/raw/c6fb02fa82f9883670d96b812bfe7f2f55b18125/Main.java]
) and analysed it using font forge to find the font files do contain data
about these ligatures..
So if we can process that data and assign these glyphs the data (unicode
combination for that ligature) from font, there is no need to worry about
parsing actualText and I believe it would improve text extraction from
non-latin languages to a great extent. thus solution to your problem of
misusing actual text to prevent text extraction [~tilman]
> PDFBox not extracting text of non-latin languages(tamil, bengali) properly
> but adobe reader's save as text does
> ---------------------------------------------------------------------------------------------------------------
>
> Key: PDFBOX-5868
> URL: https://issues.apache.org/jira/browse/PDFBOX-5868
> Project: PDFBox
> Issue Type: Bug
> Components: Text extraction
> Affects Versions: 2.0.32, 3.0.3 PDFBox
> Environment: Ubuntu 22.04.4 LTS x86_64
> Reporter: Manish S N
> Assignee: Tilman Hausherr
> Priority: Major
> Labels: ActualText
> Fix For: 2.0.33, 3.0.4 PDFBox, 4.0.0
>
> Attachments: EmptyActualText_poppler.txt,
> EmptyActualText_reduced_poppler.txt, Main.java,
> PDFBOX-5868-7FHMU2HNOUUPENUPKZDGD2V65YEVABRS-EmptyActualText.pdf,
> PDFBOX-5868-SI5K4X4Z55SQAUPLAUP6QRRWT3UD3LAA-EmptyActualText.pdf,
> PDFBOX-5868-SI5K4X4Z55SQAUPLAUP6QRRWT3UD3LAA-EmptyActualText_reduced.pdf,
> Tilman's_solution_out.txt, adobe_out.txt,
> content_diffs_with_exceptions-ActualText.xlsx,
> image-2024-08-19-10-38-13-472.png, multilingual_test.pdf, okular_out.txt,
> page.pdf, pdfbox_out.txt, poppler_out.txt, screenshot-1.png,
> screenshot-2.png, suppressDuplicateOverlapping_out.txt
>
>
> I downloaded the latest executable jar of pdfbox (3.0.3) for testing and used
> the export:text command line tool to obtain the results
> * the multilingual_test.pdf is the original pdf i made to test multilingual
> text extraction.
> * the pdfbox_out.txt is the text file produced by pdfbox
> * the adobe_out.txt is the text file created by adobe reader's save as text
> feature
>
> Observation:
> as you can see in the attachment the text file obtained by pdfbox shows weird
> unicodes for tamil and bengali (for hindi the charecters are extracted but
> not overlapped; japanese seems fine to me). in contrast the text file file
> obtained from adobe reader's save as text feature seems fine and copy pasting
> the text from my document viewer(evince) also works.
> Questions:
> # why are the outputs from pdfbox and adobe different?
> # what can i do to extract the text from a multilingual pdf correctly?
> # Is there a way to apply pattern matching to text in pdf file and declare
> matches without extracting the text first? (say if the problem is with fonts
> and glyphs)
> —
> My Usecase fyi:
> i am trying to extract text from files and run pattern matching. I am using
> apache tika for parsing documents. I noticed problem with extracted PDF text
> (other filetypes parse fine). used executable pdfbox jar to conclude that the
> _problem is in pdfbox and not in tika._ tested with adobe reader's extract
> text to confirm the problem is not with the pdf. i want to extract these
> multilingual text to run pattern matching on them alone and do not need to
> display the content but only if the pattern is present or not (say if the
> problem is with fonts and glyphs)
>
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