Problem with Print Preview

I have developed an object model to represent Printer, Page, Text, Image, Table etc. This model uses win api to render pages on given device context (hdc). I use printer dc as my measuring (or attribute) dc i.e. I use it for calculations. To get print preview, I render the object model on screen dc (actually a picture box dc). However, result is not WYSIWYG. To get WYSIWYG, I tried to create a printer compatible dc and then stretchblt the picture on screen dc. Although I have WYSIWYG preview, the quality is very bad due to aliasing effects caused by stretching it. Any solution to get good print preview? Thanx in advance.