How to convert plain text [Already know the alignment, font,size] to a RTF text using C#

I am in need to convert the plain text to a RTF text. I know the font ,size, alignment of the plain text. What i want is how to convert to the preformatted RTF text without using RichTextBox contr开发者_Go百科ol in windows forms, because i am going to implement this in a class library for 5 platforms.

I found this promising looking RTF writer:

http://netrtfwriter.sourceforge.net/