/*
* tkUnixFocus.c --
*
* This file contains platform specific functions that manage focus for
* Tk.
*
* Copyright (c) 1997 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*/
#include "tkUnixInt.h"
/*
*----------------------------------------------------------------------
*
* TkpChangeFocus --
*
* This function is invoked to move the official X focus from one window
* to another.
*
* Results:
* The return value is the serial number of the command that changed the
* focus. It may be needed by the caller to filter out focus change
* events that were queued before the command. If the function doesn't
* actually change the focus then it returns 0.
*
* Side effects:
* The official X focus window changes; the application's focus window
* isn't changed by this function.
*
*----------------------------------------------------------------------
*/
int
TkpChangeFocus(
TkWindow *winPtr, /* Window that is to receive the X focus. */
int force) /* Non-zero means claim the focus even if it
* didn't originally belong to topLevelPtr's
* application. */
{
TkDisplay *dispPtr = winPtr->dispPtr;
Tk_ErrorHandler errHandler;
Window window, root, parent, *children;
unsigned int numChildren, serial;
TkWindow *winPtr2;
int dummy;
/*
* Don't set the X focus to a window that's marked override-redirect.
* This is a hack to avoid problems with menus under olvwm: if we move
* the focus then the focus can get lost during keyboard traversal.
* Fortunately, we don't really need to move the focus for menus: events
* will still find their way to the focus window, and menus aren't
* decorated anyway so the window manager doesn't need to hear about the
* focus change in order to redecorate the menu.
*/
serial = 0;
if (winPtr->atts.override_redirect) {
return serial;
}
/*
* Check to make sure that the focus is still in one of the windows of
* this application or one of their descendants. Furthermore, grab the
* server to make sure that the focus doesn't change in the middle of this
* operation.
*/
XGrabServer(dispPtr->display);
if (!force) {
/*
* Find the focus window, then see if it or one of its ancestors is a
* window in our application (it's possible that the focus window is
* in an embedded application, which may or may not be in the same
* process.
*/
XGetInputFocus(dispPtr->display, &window, &dummy);
while (1) {
winPtr2 = (TkWindow *) Tk_IdToWindow(dispPtr->display, window);
if ((winPtr2 != NULL) && (winPtr2->mainPtr == winPtr->mainPtr)) {
break;
}
if ((window == PointerRoot) || (window == None)) {
goto done;
}
XQueryTree(dispPtr->display, window, &root, &parent, &children,
&numChildren);
if (children != NULL) {
XFree((void *) children);
}
if (parent == root) {
goto done;
}
window = parent;
}
}
/*
* Tell X to change the focus. Ignore errors that occur when changing the
* focus: it is still possible that the window we're focussing to could
* have gotten unmapped, which will generate an error.
*/
errHandler = Tk_CreateErrorHandler(dispPtr->display, -1,-1,-1, NULL,NULL);
if (winPtr->window == None) {
Tcl_Panic("ChangeXFocus got null X window");
}
XSetInputFocus(dispPtr->display, winPtr->window, RevertToParent,
CurrentTime);
Tk_DeleteErrorHandler(errHandler);
/*
* Remember the current serial number for the X server and issue a dummy
* server request. This marks the position at which we changed the focus,
* so we can distinguish FocusIn and FocusOut events on either side of the
* mark.
*/
serial = NextRequest(winPtr->display);
XNoOp(winPtr->display);
done:
XUngrabServer(dispPtr->display);
/*
* After ungrabbing the server, it's important to flush the output
* immediately so that the server sees the ungrab command. Otherwise we
* might do something else that needs to communicate with the server (such
* as invoking a subprocess that needs to do I/O to the screen); if the
* ungrab command is still sitting in our output buffer, we could
* deadlock.
*/
XFlush(dispPtr->display);
return serial;
}
/*
* Local Variables:
* mode: c
* c-basic-offset: 4
* fill-column: 78
* End:
*/
