That's going to be a function of your display settings. On some systems, you can have any resolution stretched to fill the screen space available. On some systems, you can have a resolution use only the pixels required. The latter option results in a display that is smaller than the screen--usually with black borders around it. Best way to know for your particular system would be to create an image of a dark circle on light background (whatever pixel dimensions you like) and display it in DirectRT. You will see fairly easily if the circle is stretched, and if any black bands are surrounding the light background of the image. Does that make sense?