| 1 | /* -*- Mode: C; tab-width: 2 -*- */ |
| 2 | /*****************************************************************************/ |
| 3 | /** Copyright 1991 by Andreas Stolcke **/ |
| 4 | /** Copyright 1990 by Solbourne Computer Inc. **/ |
| 5 | /** Longmont, Colorado **/ |
| 6 | /** **/ |
| 7 | /** All Rights Reserved **/ |
| 8 | /** **/ |
| 9 | /** Permission to use, copy, modify, and distribute this software and **/ |
| 10 | /** its documentation for any purpose and without fee is hereby **/ |
| 11 | /** granted, provided that the above copyright notice appear in all **/ |
| 12 | /** copies and that both that copyright notice and this permis- **/ |
| 13 | /** sion notice appear in supporting documentation, and that the **/ |
| 14 | /** name of Solbourne not be used in advertising **/ |
| 15 | /** in publicity pertaining to distribution of the software without **/ |
| 16 | /** specific, written prior permission. **/ |
| 17 | /** **/ |
| 18 | /** ANDREAS STOLCKE AND SOLBOURNE COMPUTER INC. DISCLAIMS ALL WARRANTIES **/ |
| 19 | /** WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF **/ |
| 20 | /** MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL ANDREAS STOLCKE **/ |
| 21 | /** OR SOLBOURNE BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL **/ |
| 22 | /** DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA **/ |
| 23 | /** OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER **/ |
| 24 | /** TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE **/ |
| 25 | /** OR PERFORMANCE OF THIS SOFTWARE. **/ |
| 26 | /*****************************************************************************/ |
| 27 | /* |
| 28 | * vroot.h -- Virtual Root Window handling header file |
| 29 | * |
| 30 | * This header file redefines the X11 macros RootWindow and DefaultRootWindow, |
| 31 | * making them look for a virtual root window as provided by certain `virtual' |
| 32 | * window managers like swm and tvtwm. If none is found, the ordinary root |
| 33 | * window is returned, thus retaining backward compatibility with standard |
| 34 | * window managers. |
| 35 | * The function implementing the virtual root lookup remembers the result of |
| 36 | * its last invocation to avoid overhead in the case of repeated calls |
| 37 | * on the same display and screen arguments. |
| 38 | * The lookup code itself is taken from Tom LaStrange's ssetroot program. |
| 39 | * |
| 40 | * Most simple root window changing X programs can be converted to using |
| 41 | * virtual roots by just including |
| 42 | * |
| 43 | * #include <X11/vroot.h> |
| 44 | * |
| 45 | * after all the X11 header files. It has been tested on such popular |
| 46 | * X clients as xphoon, xfroot, xloadimage, and xaqua. |
| 47 | * It also works with the core clients xprop, xwininfo, xwd, and editres |
| 48 | * (and is necessary to get those clients working under tvtwm). |
| 49 | * It does NOT work with xsetroot; get the xsetroot replacement included in |
| 50 | * the tvtwm distribution instead. |
| 51 | * |
| 52 | * Andreas Stolcke <stolcke@ICSI.Berkeley.EDU>, 9/7/90 |
| 53 | * - replaced all NULL's with properly cast 0's, 5/6/91 |
| 54 | * - free children list (suggested by Mark Martin <mmm@cetia.fr>), 5/16/91 |
| 55 | * - include X11/Xlib.h and support RootWindowOfScreen, too 9/17/91 |
| 56 | * |
| 57 | * Jamie Zawinski <jwz@jwz.org>, 28-Apr-1997 |
| 58 | * - use ANSI C |
| 59 | * |
| 60 | * Jamie Zawinski <jwz@jwz.org>, 3-Sep-2003 |
| 61 | * - if the environment variable "XSCREENSAVER_WINDOW" is set, use that |
| 62 | * as the root window instead of searching for __SWM_VROOT. |
| 63 | * |
| 64 | * Jamie Zawinski <jwz@jwz.org>, 14-Aug-2004 |
| 65 | * - changes to get gcc to stop whining about "type punning". |
| 66 | * |
| 67 | * Jamie Zawinski <jwz@jwz.org>, 16-Dec-2004 |
| 68 | * - fixed that last fix. |
| 69 | */ |
| 70 | |
| 71 | #ifndef _VROOT_H_ |
| 72 | #define _VROOT_H_ |
| 73 | #define _XSCREENSAVER_VROOT_H_ |
| 74 | |
| 75 | #if !defined(lint) && !defined(SABER) |
| 76 | static const char vroot_rcsid[] = |
| 77 | "#Id: vroot.h,v 1.8 2004/12/16 05:33:54 jwz Exp #" "\n" |
| 78 | "#Id: vroot.h,v 1.4 1991/09/30 19:23:16 stolcke Exp stolcke #"; |
| 79 | #endif |
| 80 | |
| 81 | #include <X11/X.h> |
| 82 | #include <X11/Xatom.h> |
| 83 | #include <X11/Xlib.h> |
| 84 | |
| 85 | static Window |
| 86 | #ifdef __STDC__ /* ANSIfication added by jwz, to avoid superfluous warnings. */ |
| 87 | VirtualRootWindowOfScreen(Screen *screen) |
| 88 | #else /* !__STDC__ */ |
| 89 | VirtualRootWindowOfScreen(screen) Screen *screen; |
| 90 | #endif /* !__STDC__ */ |
| 91 | { |
| 92 | static Screen *save_screen = (Screen *)0; |
| 93 | static Window root = (Window)0; |
| 94 | |
| 95 | if (screen != save_screen) { |
| 96 | Display *dpy = DisplayOfScreen(screen); |
| 97 | Atom __SWM_VROOT = None; |
| 98 | int i; |
| 99 | Window rootReturn, parentReturn, *children; |
| 100 | unsigned int numChildren; |
| 101 | |
| 102 | /* first check for a hex or decimal window ID in the environment */ |
| 103 | const char *xss_id = getenv("XSCREENSAVER_WINDOW"); |
| 104 | if (xss_id && *xss_id) { |
| 105 | unsigned long id = 0; |
| 106 | char c; |
| 107 | if (1 == sscanf (xss_id, " 0x%lx %c", &id, &c) || |
| 108 | 1 == sscanf (xss_id, " %lu %c", &id, &c)) { |
| 109 | root = (Window) id; |
| 110 | save_screen = screen; |
| 111 | return root; |
| 112 | } |
| 113 | } |
| 114 | |
| 115 | root = RootWindowOfScreen(screen); |
| 116 | |
| 117 | /* go look for a virtual root */ |
| 118 | __SWM_VROOT = XInternAtom(dpy, "__SWM_VROOT", False); |
| 119 | if (XQueryTree(dpy, root, &rootReturn, &parentReturn, |
| 120 | &children, &numChildren)) { |
| 121 | for (i = 0; i < numChildren; i++) { |
| 122 | Atom actual_type; |
| 123 | int actual_format; |
| 124 | unsigned long nitems, bytesafter; |
| 125 | unsigned char *newRoot = 0; |
| 126 | |
| 127 | if (XGetWindowProperty(dpy, children[i], |
| 128 | __SWM_VROOT, 0, 1, False, XA_WINDOW, |
| 129 | &actual_type, &actual_format, |
| 130 | &nitems, &bytesafter, |
| 131 | &newRoot) == Success |
| 132 | && newRoot) { |
| 133 | root = *((Window *) newRoot); |
| 134 | break; |
| 135 | } |
| 136 | } |
| 137 | if (children) |
| 138 | XFree((char *)children); |
| 139 | } |
| 140 | |
| 141 | save_screen = screen; |
| 142 | } |
| 143 | |
| 144 | return root; |
| 145 | } |
| 146 | |
| 147 | #undef RootWindowOfScreen |
| 148 | #define RootWindowOfScreen(s) VirtualRootWindowOfScreen(s) |
| 149 | |
| 150 | #undef RootWindow |
| 151 | #define RootWindow(dpy,screen) VirtualRootWindowOfScreen(ScreenOfDisplay(dpy,screen)) |
| 152 | |
| 153 | #undef DefaultRootWindow |
| 154 | #define DefaultRootWindow(dpy) VirtualRootWindowOfScreen(DefaultScreenOfDisplay(dpy)) |
| 155 | |
| 156 | #endif /* _VROOT_H_ */ |