XFree86-DGA 1.0

"($server_major, $server_minor) = $X->XF86DGAQueryVersion()"

Return the DGA protocol version implemented by the server.

"$flags = $X->XF86DGAQueryDirectVideo ($screen_num)"

Get flags describing direct video access on $screen_num (integer 0 upwards). The only flag bit is

    0x0001   direct video available
    

It's possible to have the extension available but no direct video on a particular screen, or even on no screens at all. When no direct video the requests below give protocol error "XF86DGANoDirectVideoMode".

"($address, $width, $bank_size_bytes, $ram_size_kbytes) = $X->XF86DGAGetVideoLL ($screen_num)"

Return the location and size of the video memory for $screen_num (integer 0 upwards).

$address is a raw physical 32-bit address as an integer. $width is in pixels.

$bank_size_bytes is the size in bytes accessible at a given time. $ram_size_kbytes is the total memory in 1024 byte blocks. If "$ram_size_kbytes*1024" is bigger than $bank_size_bytes then "$X->XF86DGASetVidPage()" below must be used to switch among the banks to access all the RAM.

"$X->XF86DGADirectVideo ($screen_num, $flags)"

Enable or disable direct video access on $screen_num (integer 0 upwards). $flags is bits

    0x0002    enable direct video graphics
    0x0004    enable mouse pointer reporting as relative
    0x0008    enable direct keyboard event reporting
    

When direct video graphics is enabled (bit 0x0002) the server gives up control to the client program.

If the graphics card doesn't have a direct video mode then an "XF86DGANoDirectVideoMode" error results, or if the screen is not active (eg. switched away to a different virtual terminal) then "XF86DGAScreenNotActive".

"($width, $height) = $X->XF86DGAGetViewPortSize ($screen_num)"

Get the size of the viewport on $screen_num (integer 0 upwards). This is the part of the video memory actually visible on the monitor. The memory might be bigger than the monitor.

"$X->XF86DGASetViewPort ($screen_num, $x, $y)"

Set the coordinates of the top-left corner of the visible part of the video memory on $screen_num (integer 0 upwards).

This can be used when the video memory is bigger than the monitor to pan around that bigger area. It can also be used for some double-buffering to display one part of memory while drawing to another.

"$vidpage = $X->XF86DGAGetVidPage ($screen_num)"

"$X->XF86DGASetVidPage ($screen_num, $vidpage)"

Get or set the video page (bank) on $screen_num (integer 0 upwards). $vidpage is an integer 0 upwards.

This is used to access all the RAM when when the bank size is less than the total memory size (per "XF86DGAGetVideoLL()" above).

"$vidpage = $X->XF86DGAInstallColormap ($screen_num, $colormap)"

Set the colormap on $screen_num to $colormap (integer XID).

This can only be used while direct video is enabled (per "XF86DGADirectVideo()" above) or an error "XF86DGAScreenNotActive" or "XF86DGADirectNotActivated" results.

"$bool = $X->XF86DGAViewPortChanged ($screen_num, $num_pages)"

Check whether a previous "XF86DGASetViewPort()" on $screen_num (integer 0 upwards) has completed, meaning a vertical retrace has occurred since that viewport location was set.

This is used for double-buffering (or N-multi-buffering) to check a viewport change has become visible. $num_pages should be 2 for double-buffering and can be higher for multi-buffering.