iText - Get Font size and family of a text segment

Question

I'm currently trying to automatically extract important keywords from a PDF file. I am able to get the text information out of the PDF document. But now I need to know, which font size and font family these keywords have.

The following code I already have:

Main

public static void main(String[] args) throws IOException {
    String src = "SEM_081145.pdf";

    PdfReader reader = new PdfReader(src);

    SemTextExtractionStrategy semTextExtractionStrategy = new SemTextExtractionStrategy();

    PrintWriter out = new PrintWriter(new FileOutputStream(src + ".txt"));
    Rectangle rect = new Rectangle(70, 80, 490, 580);
    RenderFilter filter = new RegionTextRenderFilter(rect);

    for (int i = 1; i <= reader.getNumberOfPages(); i++) {
        // strategy = new FilteredTextRenderListener(new LocationTextExtractionStrategy(), filter);
        out.println(PdfTextExtractor.getTextFromPage(reader, i, semTextExtractionStrategy));
    }
    out.flush();
    out.close();
}

And I have implemented the TextExtraction Strategy SemTextExtractionStrategy which looks like this:

public class SemTextExtractionStrategy implements TextExtractionStrategy {

private String text;

@Override
public void beginTextBlock() {
}

@Override
public void renderText(TextRenderInfo renderInfo) {
    text = renderInfo.getText();

    System.out.println(renderInfo.getFont().getFontType());

    System.out.print(text);
}

@Override
public void endTextBlock() {
}

@Override
public void renderImage(ImageRenderInfo renderInfo) {
}

@Override
public String getResultantText() {
    return text;
}
}

I can get the FontType but there is no method to get the font size. Is there another way or how can I get the font size of the current text segment?

Or are there any other libraries which can fetch out the font size from TextSegments? I already had a look into PDFBox, and PDFTextStream. The PDF Shareware Library from Aspose would perfectly do the job. But it's very expensive and I need to use an open source project.

Answer 1

Thanks to Alexis I could convert his C# solution into Java code:

text = renderInfo.getText();

Vector curBaseline = renderInfo.getBaseline().getStartPoint();
Vector topRight = renderInfo.getAscentLine().getEndPoint();

Rectangle rect = new Rectangle(curBaseline.get(0), curBaseline.get(1), topRight.get(0), topRight.get(1));
float curFontSize = rect.getHeight();