A display file consists of a set of commands to make an image. A display file interpreter is used to translate these commands and to make an actual image. User programs are fed in to the display file and commands are generated in the display file. Interpreter reads these commands and generates the output in a display.
Architecture of a display controller in Vector Scan display:
Many graphics systems use a display controller to interpret the commands in the display file. The display controller Is used for scan conversion. It actually digitizes a photo definition in an application program to a set of pixel values for frame buffer. It also generates line styles (dashed, dotted, etc.), shows colors, and does transformations and manipulations on the objects.