XF86DGA(3X11)
NAME
XF86DGAQueryExtension, XF86DGAQueryVersion, XF86DGAQuery-
DirectVideo, XF86DGAGetVideo, XF86DGADirectVideo,
XF86DGASetVidPage, XF86DGASetViewPort, XF86DGAView-
PortChanged, XF86DGAGetViewPortSize, XF86DGAInstallCol-
ormap, XF86DGAForkApp - XFree86-DGA extension interface
functions
SYNTAX
#include <X11/extensions/xf86dga.h>
Bool XF86DGAQueryExtension(
Display *display,
int *event_base_return,
int *error_base_return);
Bool XF86DGAQueryVersion(
Display *display,
int *major_version_return,
int *minor_version_return);
Bool XF86DGAQueryDirectVideo(
Display *display,
int screen,
int *flags_return);
Bool XF86DGAGetVideo(
Display *display,
int screen,
char **addr_return,
int *width_return,
int *banksize_return,
int *memsize_return);
Bool XF86DGADirectVideo(
Display *display,
int screen,
int flags);
Bool XF86DGASetVidPage(
Display *display,
int screen,
int page);
Bool XF86DGASetViewPort(
Display *display,
int screen,
int x,
int y);
Bool XF86DGAViewPortChanged(
Display *display,
int screen,
int num_pages);
Bool XF86DGAGetViewPortSize(
Display *display,
int screen,
int *viewport_width_return,
int *viewport_height_return);
Bool XF86DGAInstallColormap(
Display *display,
int screen,
Colormap cmap);
int XF86DGAForkApp(
int screen);
ARGUMENTS
display Specifies the connection to the X
server.
screen Specifies which screen number the set-
ting apply to.
event_base_return Returns the base event number for the
extension.
error_base_return Returns the base error number for the
extension.
major_version_return
Returns the major version number of
the extension.
minor_version_return
Returns the minor version number of
the extension.
addr_return Returns a pointer to the start of the
video framebuffer.
width_return Returns the framebuffer line width.
banksize_return Returns the framebuffer bank size.
memsize_return Returns the size of the framebuffer
memory.
flags Sets the DirectVideo access features.
When zero, DirectVideo mode is dis-
abled. flags may be a a bit-wise com-
bination of the following values:
XF86DGADirectGraphics enable Direct Video mode
XF86DGADirectMouse enable reporting of pointer movement
as relative motion
XF86DGADirectKeyb enable direct reporting of keyboard events
flags_return Reports the DirectVideo features sup-
ported by the hardware. When zero,
the hardware does not support direct
video at all. flags may be a a bit-
wise combination of the following val-
ues:
XF86DGADirectPresent DirectVideo support is present
page Indicates the framebuffer page (bank)
to activate for read/write access.
x Incidates the x coordinate for the
upper-left corner of the view port.
y Incidates the y coordinate for the
upper-left corner of the view port.
viewport_width_return
Reports the width of the view port.
viewport_width_return
Reports the height of the view port.
num_pages Indicates the number of pages when
doing hardware multi-buffering.
cmap Indicates the colormap to install.
DESCRIPTION
These functions provide an interface to the server exten-
sion XFree86-DGA which allows a local client direct access
to the video framebuffer. Applications that use these
functions must be linked with -lXxf86dga
DGA FUNCTIONS
The function XF86DGAQueryDirectVideo returns the
DirectVideo capabilities supported by the graphics device.
The XF86DGAGetVideo function is used to get the parameters
for the framebuffer. The parameters returned are a
pointer to the start of the framebuffer, the framebuffer
line width, framebuffer bank size, and framebuffer memory
size.
XF86DGADirectVideo is used to enable or disable
DirectVideo mode.
The XF86DGASetVidPage function sets the currently active
framebuffer page (bank). This is only required for hard-
ware which has a banked memory layout (banksize < mem-
size).
The XF86DGASetViewPort function sets the framebuffer coor-
dinates to use for the upper-left corner of the view port.
The XF86DGAViewPortChanged function checks whether a pre-
vious XF86DGASetViewPort command has been completed by the
hardware, that is, whether a vertical retrace has occurred
since a previous XF86DGASetViewPort. This can (must, in
fact) be used with page-flipping; you can start writing to
the next page only when this function returns TRUE. For
some devices this will be the case immediately after
XF86DGASetViewPort, however this may be changed in the
future. The number of pages used is specified with
num_pages; it should be 2 for simple page flipping (double
buffering). If n is greater than two (triple or multi-
buffering), the function checks whether the (n -
2)-before-last SetViewPort has been completed.
The XF86DGAGetViewPortSize function returns the size of
the view port, which is the part of the framebuffer that
is visible on the screen.
The XF86DGAInstallColormap function is used to install a
colormap. This must be called after DirectVideo mode has
been enabled.
The XF86DGAForkApp function causes the client application
to fork, leaving the parent process to hang around and
return to non-DGA mode should the client exit for any rea-
son. This function returns 0 for success, or the error
condition returned by fork().
OTHER FUNCTIONS
The XF86DGAQueryVersion function can be used to determine
the version of the extension built into the server.
The function XF86DGAQueryExtension returns the lowest num-
bered error and event values assigned to the extension.
SEE ALSO
XFree86(1) XF86Config(4/5)
AUTHORS
Jon Tombs, Harm Hanemaayer, Mark Vojkovich.