How to avoid spurious spaces in words when reading PDF using iText for .NET

Using iText7 (v8.0.0) I am attempting to parse a (non-PDF/A) PDF. The code is as follows:

using iText.Kernel.Pdf;
using iText.Kernel.Pdf.Canvas.Parser;

var pdfDocument = new PdfDocument(new PdfReader("TestFile.pdf"));

var page = pdfDocument.GetPage(1);

var text = PdfTextExtractor.GetTextFromPage(page);

All is well in terms of the output except that certain words in the output text have spurious spaces in them. I understand that this is to do with the way text is rendered into the PDF. The GetTextFromPage method has an overload that takes a text extraction strategy; I tried both the default strategy implementations LocationTextExtractionStrategy and SimpleTextExtractionStrategy but neither dealt with the issue.

I am guessing that I need to define my own text extraction strategy but it isn't very obvious how to go about doing this.

(In case readers are interested, I tried the same with IronPDF and that was no better.)

Although I have subsequently decided not to use the iText library due to the licensing costs, as I managed to fix the issue, I thought I'd share my findings. Aside from the many helpful comments above, I got the base information I needed from answers to this question: https://stackoverflow.com/questions/16398483/how-can-we-extract-text-from-pdf-using-itextsharp-with-spaces.

Here is the easiest way to address this issue. Add the following class:

using iText.Kernel.Pdf.Canvas.Parser.Listener;

internal class MyStrategy : LocationTextExtractionStrategy
{
    protected override bool IsChunkAtWordBoundary(TextChunk chunk, TextChunk previousChunk)
    {
        var chunkLocation = chunk.GetLocation();
        var previousChunkLocation = previousChunk.GetLocation();
        var chunkCharSpaceWidth = chunkLocation.GetCharSpaceWidth();

        float dist = chunkLocation.DistanceFromEndOf(previousChunkLocation);
        if (dist < -chunkCharSpaceWidth || dist > chunkCharSpaceWidth / 1.5f)
            return true;
        return false;
    }
}

I found the value 1.5f gave the best results (the default is 2.0f); your mileage may vary.

It is then a simple matter to supply the custom strategy to the processing thus:

var text = PdfTextExtractor.GetTextFromPage(page, new MyStrategy());

Note that if you need to do the same thing with the SimpleTextExtractionStrategy you pretty much have to copy and paste the entire original class, as it uses a bunch of private members which you don't have access to when inheriting.