In summary, the program main$()($provided$)$ calls the parser $($provided$)$ which reads commands from a file and calls either routines in rd$\_$direct.h$($you implement$)$ or default routines in rd$\_$enginebase.h$($provided$).$ Your interface and rendering routines call the generic pixel plotting routines $($provided$)$ in rd$\_$display.h which call, depending on the chosen device, screen display routines $($provided$)$ or PPM display routines $($you$\_$implement$).$

When finished, your program will be able to handle the rd commands Display, using both Screen and PNM devices, Format, FrameBegin and FrameEnd, WorldBegin and WorldEnd, Background, Color, Point, Line, Circle, and Fill.

Important Operation Note: When displaying images on the screen, the program is set up to terminate when the image is clicked with the right mouse button. This is the best way to end the program.

As an additional aid, when displaying images on the screen, clicking the image with the left mouse button will give information about the pixel underneath the tip of the cursor.