Why Does iTextSharp Fail to Extract Non-English Text from PDFs Correctly?

iTextSharp and Multilingual PDFs: Solving Non-English Text Extraction Issues

Extracting text from multilingual PDFs can be tricky. iTextSharp, while effective with English text, often struggles with non-English characters, resulting in corrupted or missing text. Let's examine the problem and its solution.

The Problem: Garbled Non-English Characters

A common scenario involves attempting to extract Persian or Arabic text from a PDF using iTextSharp. The code functions correctly for English, but non-English characters appear scrambled or incomplete.

The Root Cause: Encoding Errors

The core issue lies in how strings are handled and encoded within the .NET framework. .NET strings are inherently Unicode. Unnecessary encoding conversions lead to data corruption.

The problematic code snippet often looks like this:

currentText = Encoding.UTF8.GetString(Encoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.UTF8.GetBytes(currentText)));

This multiple encoding conversion process is the source of the problem.

The Solution: Simplify Encoding

The solution is remarkably simple: remove the redundant encoding conversion line:

currentText = Encoding.UTF8.GetString(Encoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.UTF8.GetBytes(currentText)));

By eliminating this line, the original Unicode representation is preserved. Additionally, ensure your application supports Unicode and you are using a current iTextSharp version.

Beyond Encoding: Text Order Considerations

While resolving encoding fixes the character corruption, it doesn't address potential text order issues. Right-to-left languages (like Arabic and Hebrew) might be rendered in reverse order within the PDF. Correctly handling this requires additional parsing logic to rearrange the text appropriately.

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