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Graphics drivers are linked to the X server with the X Server Link Kit. Each routine in this section is prefixed with a 2-6 character prefix that uniquely describes this graphics driver. The Synopsis sections of these manual pages use the xxx string to represent this prefix. Most of these routines are called by pointers in a structure documented in the D4nfb manual page section.
Many of these functions have multiple forms, such as nfbTileRects( ) and miTileRects( ) as well as the form that is specific for this driver. The xxkddx command sets up the initial source directory with all the functions satisfied by calls to equivalent NFB functions. If you do not supply your own routine, the NFB layers provide the functionality. You may also be able to call another form, such as mfb (monoframe buffers), cfb (colorframe buffers), or gen (generic).
The functions that must be written by the driver writer are included as stubs with empty code; you must fill in the proper code for your hardware. When writing your own function, yo can take advantage of other layers of the X server to help with the function. For example, if your video hardware is optimized to do TileRects( ) for 8-bit color displays, you can write an xxxTileREcts( ) routine to do that case, and for the other cases use the nfbTileRects( ) or miTileRects( ) functionality.
For more information about using the NFB API, see ``Writing NFB graphical adapter drivers'' in Developing NFB graphics adapter drivers.
For a quick reference of terminology used with graphical adapter drivers and the X Link Kit, see ``Terminology for graphics driver writers'' in Developing NFB graphics adapter drivers.