kscreensaver_vroot.h
/*****************************************************************************/
/*****************************************************************************/
/*
* vroot.h -- Virtual Root Window handling header file
*
* This header file redefines the X11 macros RootWindow and DefaultRootWindow,
* making them look for a virtual root window as provided by certain `virtual'
* window managers like swm and tvtwm. If none is found, the ordinary root
* window is returned, thus retaining backward compatibility with standard
* window managers.
* The function implementing the virtual root lookup remembers the result of
* its last invocation to avoid overhead in the case of repeated calls
* on the same display and screen arguments.
* The lookup code itself is taken from Tom LaStrange's ssetroot program.
*
* Most simple root window changing X programs can be converted to using
* virtual roots by just including
*
* #include <X11/vroot.h>
*
* after all the X11 header files. It has been tested on such popular
* X clients as xphoon, xfroot, xloadimage, and xaqua.
* It also works with the core clients xprop, xwininfo, xwd, and editres
* (and is necessary to get those clients working under tvtwm).
* It does NOT work with xsetroot; get the xsetroot replacement included in
* the tvtwm distribution instead.
*
* Andreas Stolcke <stolcke@ICSI.Berkeley.EDU>, 9/7/90
* - replaced all NULL's with properly cast 0's, 5/6/91
* - free children list (suggested by Mark Martin <mmm@cetia.fr>), 5/16/91
* - include X11/Xlib.h and support RootWindowOfScreen, too 9/17/91
*/
#ifndef _VROOT_H_
#define _VROOT_H_
#if !defined(lint) && !defined(SABER)
static const char vroot_rcsid[] = "#Id: vroot.h,v 1.4 1991/09/30 19:23:16 stolcke Exp stolcke #";
#endif
#include <qwidget.h>
#ifdef Q_WS_X11
#include <X11/X.h>
#include <X11/Xatom.h>
#include <X11/Xlib.h>
static Window
#if defined(__STDC__) || defined(__cplusplus) /* ANSIfication added by jwz, to avoid superfluous warnings. */
VirtualRootWindowOfScreen(Screen *screen)
#else /* !__STDC__ */
VirtualRootWindowOfScreen(screen) Screen *screen;
#endif /* !__STDC__ */
{
static Screen *save_screen = (Screen *)0;
static Window root = (Window)0;
if (screen != save_screen) {
Display *dpy = DisplayOfScreen(screen);
Atom __SWM_VROOT = None;
uint i;
Window rootReturn, parentReturn, *children;
unsigned int numChildren;
root = RootWindowOfScreen(screen);
/* go look for a virtual root */
__SWM_VROOT = XInternAtom(dpy, "__SWM_VROOT", False);
if (XQueryTree(dpy, root, &rootReturn, &parentReturn,
&children, &numChildren)) {
for (i = 0; i < numChildren; i++) {
Atom actual_type;
int actual_format;
unsigned long nitems, bytesafter;
unsigned char *newRoot = 0;
if (XGetWindowProperty(dpy, children[i],
__SWM_VROOT, 0, 1, False, XA_WINDOW,
&actual_type, &actual_format,
&nitems, &bytesafter,
&newRoot) == Success
&& newRoot)
{
void *tmpRoot = (void *) newRoot;
root = *(Window*) tmpRoot;
XFree( (char*) newRoot );
break;
}
}
if (children)
XFree((char *)children);
}
save_screen = screen;
}
return root;
}
#undef RootWindowOfScreen
#define RootWindowOfScreen(s) VirtualRootWindowOfScreen(s)
#undef RootWindow
#define RootWindow(dpy,screen) VirtualRootWindowOfScreen(ScreenOfDisplay(dpy,screen))
#undef DefaultRootWindow
#define DefaultRootWindow(dpy) VirtualRootWindowOfScreen(DefaultScreenOfDisplay(dpy))
#endif
#endif /* _VROOT_H_ */

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