Q:

How can I test if my font is rendered correctly in pdf?

When using different fonts in jasper report, you need to use font-extensions.
However if the font is not rendered correctly is there a way that I can test if the font is supported by pdf so that I can understand if the problem is related to my font-extensions or to my .ttf font?
The incorrect rendering of font when exporting to pdf from jasper reports is a common problem example Jasper Reports PDF doesn't export cyrillic values, as seen in checklist point 1 using font-extensions are not always enough, the font need's also to be supported by pdf generating library and able to render the actual character. This is why I have decided to pass this Q-A style questions, so that future user when hitting checklist 1 can have a reference on how to quickly test the font.

A:

Since jasper report use the itext library the easiest way to test if your font will be rendered correctly in pdf is to test it directly with itext.
Example program*, adapted from iText: Chapter 11: Choosing the right font
import java.io.FileOutputStream;
import java.io.IOException;

import com.lowagie.text.Document;
import com.lowagie.text.DocumentException;
import com.lowagie.text.Font;
import com.lowagie.text.Paragraph;
import com.lowagie.text.pdf.BaseFont;
import com.lowagie.text.pdf.ColumnText;
import com.lowagie.text.pdf.PdfWriter;

public class FontTest {

    /** The resulting PDF file. */
    public static final String RESULT = "fontTest.pdf";
    /** the text to render. */
    public static final String TEST = "Test to render this text with the turkish lira character \u20BA";

    public void createPdf(String filename) throws IOException, DocumentException {
        Document document = new Document();
        PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(filename));
        document.open();
        BaseFont bf = BaseFont.createFont(
            "pathToMyFont/myFont.ttf", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
        Font font = new Font(bf, 20);
        ColumnText column = new ColumnText(writer.getDirectContent());
        column.setSimpleColumn(36, 730, 569, 36);
        column.addElement(new Paragraph(TEST, font));
        column.go();
        document.close();
    }

    public static void main(String[] args) throws IOException, DocumentException {
        new FontTest().createPdf(RESULT);
    }
}

Some notes (seen in example):

To render special characters use it's encoded value example
\u20BA to avoid problems of encoding type on your file.
Consider to always use Unicode encoding, this is recommended approach
in the newer PDF standard (PDF/A, PDF/UA) and gives you the possibility to mix
different encoding types, with the only dis-advantage of slightly
larger file size.

Conclusion:

If your font is rendered correctly in the "fontTest.pdf", you have a
  problem with your font-extensions in jasper report.
If you font is not rendered correctly in the "fontTest.pdf", there is
  nothing you can do in jasper reports, you need to find another font.

*Latest jasper-reports distribution use a special version itext-2.1.7, the imports in this version is com.lowagie.text, if you are using later version the imports are com.itextpdf.text as in adapted example.

