that's very easy. When your image with the chars is grayscale (background black and chars white), you can use the diffuse color of your vertices to give the characters a color.

I advice you to study clooties font code. If you don't understand things, use google to find out what they are about. I'm sure it will give you a good idea on how font rendering works.

If you happen to use ID3DXFont, i can tell you that there is a way to determine the text size. You have to call ID3DXFont:rawText with the DT_CALCRECT flag. It will not render anything, but instead it gives you the rectangle that will be occupied when rendering the text. Look at the following link for more info:


http://msdn2.microsoft.com/en-us/library/bb173962.aspx