Carlos Alfonso Maya created PDFBOX-5529:
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Summary: Wrong Text Extraction - Unwanted Extra Spaces in the
middle of words
Key: PDFBOX-5529
URL: https://issues.apache.org/jira/browse/PDFBOX-5529
Project: PDFBox
Issue Type: Bug
Components: Text extraction
Affects Versions: 2.0.27, 2.0.26, 2.0.25, 2.0.24, 2.0.23, 2.0.22, 2.0.21,
2.0.20, 2.0.19, 2.0.18, 2.0.17, 2.0.16, 2.0.15, 2.0.14, 2.0.13, 2.0.12, 2.0.11,
2.0.10, 2.0.9, 2.0.8, 2.0.7, 2.0.6, 2.0.5, 2.0.4, 2.0.3, 2.0.2, 2.0.1, 2.0.0
Reporter: Carlos Alfonso Maya
Attachments: image-2022-10-18-15-53-06-512.png,
image-2022-10-18-16-23-00-123.png, image-2022-10-18-16-26-15-001.png
*Overview:*
We are using PDFBOX as a third party API to extract text from financial PDF
documents.
We have been using PDFBox since a long time back, and we have detected a
problem related to a bad text extraction on PDFs from a Customer.
Since we worked with Customer Data we cannot shared the PDF besides that are
signed and we cannot even edit them.
*Description of the problem:*
By opening the PDF in Adobe Reader we can see several cases like the following
screenshot:
!image-2022-10-18-15-53-06-512.png|width=221,height=211!
Visually it appears to have spaces between words, but if we copy the text from
Adobe Reader and paste it into a text editor there is no extra spaces.
The following is the output that PDFBOX generates at the moment of doing text
extraction:
{code:java}
Da te
In v oice number
Ou r r eference
You r reference
Con tact person{code}
(!) *Important note: this behavior is present in all the versions of PDFBox.*
*Analysis:*
By downloading the PDFBOX source code 2.0.27 (this was checked as well in
2.0.26, 2.0.25 and 2.0.24) and testing/debugging we detected that the method
_*writePage()* inside *PDFTextStripper.java*_ declared a list of objects:
{code:java}
List<LineItem> line = new ArrayList<LineItem>();{code}
Which subsequently the code add elements into the list:
{code:java}
line.add(LineItem.getWordSeparator());
.
.
.
line.add(new LineItem(position));{code}
And at some point it passes the list as a parameter into the following
statement:
{code:java}
writeLine(normalize(line));{code}
(!) *The important about this list called "line" is that somehow the "LineItem"
objects are having NULL values inserted into it, and this values are at some
point interpreted as "blank spaces" causing the behavior described above.*
Here is an screenshot of how it is showed in the debugger:
!image-2022-10-18-16-23-00-123.png|width=621,height=195!
!image-2022-10-18-16-26-15-001.png|width=620,height=431!
We tried to look for a method that manipulates this list and that we can
override, but all of these methods that modified or access the list are
protected.
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