NAME

       DMXGetWindowAttributes - determine back-end window attributes

SYNOPSIS

       #include <X11/extensions/dmxext.h>

       Bool DMXGetWindowAttributes(Display *dpy,
                                   Window window,
                                   int *screen_count,
                                   int available_count,
                                   DMXWindowAttributes *attr);

DESCRIPTION

       When  calling  DMXGetWindowAttributes(), window specifies the window ID of a window on the Xdmx(1) server
       and available_count specifies the length of attr.

       The number of screens for which information is available will be returned in screen_count and information
       about  those  screen  will  be  returned  in  attr.   If  screen_count is less than available_count, then
       information  for  all  of  the  screens  will  be  returned.   Otherwise,  information  for   the   first
       available_count screens will be returned.

       The DMXWindowAttributes structure is:

       typedef struct {
           int          screen;
           Window       window;
           XRectangle   pos, vis;
       } DMXWindowAttributes;

       For each back-end X server that displays a portion of window, this structure contains the physical screen
       containing that portion, the window ID on the back-end X server of the window  containing  that  portion,
       the  position  and dimensions of the window on the back-end (pos, in screen coordinates), and the visible
       area of the window on the back-end (vis, in window-relative coordinates -- all zeros if the window is not
       visible on the backend).

       To obtain more information about the physical screen use the DMXGetScreenAttributes(3) call.

       Note  that  DMX  allows  multiple  back-end  windows  to overlap in their view of the DMX logical window.
       Further, a logical window does not have to be completely covered by back-end  windows  --  there  may  be
       gaps.

       As an example, consider a 500x500 window that spans the top two 1024x768 back-end displays (A and B) of a
       2048x1536 DMX display composed of 4 1024x768 back-end displays arranged in a cube:

           A B
           C D

       In this case, the DMXGetWindowAttributes call would return the  following  information  for  the  500x500
       window:

       display A: 500x500 window at 1024-250,0 (relative to back end)
                  with 250x500 visible at 0,0 (relative to window origin)

       display B: 500x500 window at -250,0 (relative to back end)
                  with 250x500 visible at 250,0 (relative to window origin)

       display C: 500x500 window at 1024-250,-768 with 0x0 visible at 0,0

       display D: 500x500 window at -250,-768 with 0x0 visible at 0,0

RETURN VALUE

       DMXGetWindowAttributes() returns True unless there is a protocol error.

       DMXGetWindowAttributes() can generate BadWindow and BadAlloc errors.

NOTES

       Because  this call transports a great deal of information over the wire, please call DMXGetScreenCount(3)
       first, and make sure attr is sufficiently large.

       On a particular back-end server, it is possible that the  associated  window  has  not  yet  been  mapped
       because  the  XMapWindow(3)  call  that will eventually map the window had been buffered by Xlib's normal
       buffering system.  To avoid this race condition, please call  DMXSync(3)  before  communicating  directly
       with the back-end X server.

SEE ALSO

       DMXGetScreenCount(3), DMXSync(3), DMXGetScreenAttributes(3), DMX(3), Xdmx(1)