How do I change the weight of a simulated bold font using itext - itext

Question

I am using the iText library to generate text. I am loading the Arial Unicode MS font which does not contain a bold style so iText is simulating the bold. This works fine, but the weight of the bold font appears too heavy compared with text generated using the Java API or even using Microsoft Word.
I tried to get the weight from the FontDescriptor, but the value returned is always 0.0
float weight = font.getBaseFont().getFontDescriptor(BaseFont.FONT_WEIGHT, fontSize);
Is there a way I can change the weight of a simulated bold font?

Answer 1

As an addendum to #Chris' answer: You do not need to construct those Object[]s as there is a Chunk convenience method:
BaseFont arialUnicodeMs = BaseFont.createFont("c:\\Windows\\Fonts\\ARIALUNI.TTF", BaseFont.WINANSI, BaseFont.EMBEDDED);
Font arial12 = new Font(arialUnicodeMs, 12);
Paragraph p = new Paragraph();
for (int i = 1; i < 100; i++)
{
Chunk chunk = new Chunk(String.valueOf(i) + " ", arial12);
chunk.setTextRenderMode(PdfContentByte.TEXT_RENDER_MODE_FILL_STROKE, i/100f, null);
p.add(chunk);
}
document.add(p);
results in

Answer 2

EDIT
Sorry, I just realized after posting this that you're using iText but my answer is for iTextSharp. You should, however, be able to use most of the code below. I've updated the source code link to reference the appropriate Java source.
Bold simulation (faux bold) is done by drawing the text with a stroke. When iText is asked to draw bold text with a non-bold font it defaults to applying a stroke with a width of of the font's size divided by 30. You can see this in the current source code here. The magic part is setting the chunk's text rendering mode to a stroke of your choice:
//.Net code
myChunk.Attributes[Chunk.TEXTRENDERMODE] = new Object[] { PdfContentByte.TEXT_RENDER_MODE_FILL_STROKE, MAGIC_NUMBER_HERE, null };
//Java code
myChunk.attributes.put(Chunk.TEXTRENDERMODE, new Object[]{Integer.valueOf(PdfContentByte.TEXT_RENDER_MODE_FILL_STROKE), MAGIC_NUMBER_HERE, null});
Knowing that you can just apply the same logic but using your weight preference. The sample below creates four chunks, the first normal, the second faux-bold, the third ultra-heavy faux-bold and the fourth ultra-lite faux-bold.
//.Net code below but should be fairly easy to convert to Java
//Path to our PDF
var testFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "test.pdf");
//Path to our font
var ff = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Fonts), "ARIALUNI.TTF");
//Normal document setup, nothing special here
using (var fs = new FileStream(testFile, FileMode.Create, FileAccess.Write, FileShare.None)) {
using (var doc = new Document()) {
using (var writer = PdfWriter.GetInstance(doc, fs)) {
doc.Open();
//Register our font
FontFactory.Register(ff, "Arial Unicode MS");
//Declare a size to use throughout the demo
var size = 20;
//Get a normal and a faux-bold version of the font
var f = FontFactory.GetFont("Arial Unicode MS", BaseFont.IDENTITY_H, BaseFont.EMBEDDED, size, iTextSharp.text.Font.NORMAL);
var fb = FontFactory.GetFont("Arial Unicode MS", BaseFont.IDENTITY_H, BaseFont.EMBEDDED, size, iTextSharp.text.Font.BOLD);
//Create a normal chunk
var cNormal = new Chunk("Hello ", f);
//Create a faux-bold chunk
var cFauxBold = new Chunk("Hello ", fb);
//Create an ultra heavy faux-bold
var cHeavy = new Chunk("Hello ", f);
cHeavy.Attributes = new Dictionary<string, object>();
cHeavy.Attributes[Chunk.TEXTRENDERMODE] = new Object[] { PdfContentByte.TEXT_RENDER_MODE_FILL_STROKE, size / 10f, null };
//Create a lite faux-bold
var cLite = new Chunk("Hello ", f);
cLite.Attributes = new Dictionary<string, object>();
cLite.Attributes[Chunk.TEXTRENDERMODE] = new Object[] { PdfContentByte.TEXT_RENDER_MODE_FILL_STROKE, size / 50f, null };
//Add to document
var p = new Paragraph();
p.Add(cNormal);
p.Add(cFauxBold);
p.Add(cHeavy);
p.Add(cLite);
doc.Add(p);
doc.Close();
}
}
}