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