code: public void setFontAndSize(BaseFont bf, float size) {
          checkWriter();
          if (size < 0.0001f && size > -0.0001f)
              throw new IllegalArgumentException("Font size too small: " + size);
          state.size = size;
          state.fontDetails = writer.addSimple(bf);
          PageResources prs = getPageResources();
          PdfName name = state.fontDetails.getFontName();
          name = prs.addFont(name, state.fontDetails.getIndirectReference());
          content.append(name.getBytes()).append(' ').append(size).append(" Tf").append_i(separator);
      }
docs: Set the font and the size for the subsequent text writing.
  
  @param bf the font
  @param size the font size in points