ddxScreenInfo(D4nfb)

ddxScreenInfo -- adapter initialization structure

Synopsis

#include "ddxScreen.h"

Description

The common layer (../X11/server/sys/common) of the X server uses the ddxScreenInfo structure to initialize each adapter. The ddxScreenInfo structure is loaded dynamically at runtime and kept in the ddxActiveScreens structure.

Structure definition

struct _ddxScreenInfo {
	ddxProbeFunc	screenProbe;
	Bool		(* screenInit)();

	char *screenName ;
	unsigned short screenWidth ;
	unsigned short screenHeight ;
	struct _Screen *protoScreenRec ;

	int numvisuals ;
	struct _Visual *visuals ;
	VisualID *VIDs ;
	int defaultVisualClass ;
	int defaultVisualDepth ;

	ddxScreenRequest *pRequest;
	pointer		  osPriv;
};
typedef struct _ddxScreenInfo ddxScreenInfo;

Structure members

The members are:

screenProbe: probe for formats used by the ddx layer.
(* screenInit): initializes the screen and gets it ready for drawing. This is different than SetGraphics(D3nfb) because it is called only once per ServerGeneration by the InitOutput routine. Also, any scratch memory needed by the display driver should be allocated here.
*screenName: display driver name. This must be a 3-5 character string.
screenWidth: width of the screen, in pixels.
screenHeight: height of the screen, in pixels. This value is not initialized and is usually obtained from the grafinfo(DSP/4dsp) file.
*protoScreenRec: prototype ScreenRec(D4nfb) structure to be used by nfbScreenInit(D3nfb). If the driver does not use nfb, protoScreenRec is not needed.
numvisuals: number of visual types supported by the screen.
*visuals: pointer to the list of visuals.
*VIDs: pointer to a list of visual IDs.
defaultVisualClass: default Visual used by the server.
defaultVisualDepth: depth of the default Visual.
*pRequest: pointer to the ddxScreenRequest(D4nfb) structure built by the SYS common layer using the command line arguments.
osPriv: reserved for future use.

Usage

The graphics driver code must set up this structure; it is created by the nfb layer. If the driver uses nfbScreenInit(D3nfb), then only the first three members of this structure need to be initialized; this is the recommended way to initialize the screen. If one of the other ScreenInit(D3nfb) functions are used, then the entire structure must be initialized.

Version applicability

This structure is supported for NFB drivers on all releases of SCO OpenServer 5, SVR5, and AIX 5L.

References

nfbScreenInit(D3nfb), ddxScreenRequest(D4nfb)

``Initializing the hardware'' in Developing NFB graphics adapter drivers