tkgrab.c

linux系统下的音频通信

	 * see the button-up event;  and (b) it allows us to track mouse
	 * motion among all of the windows of this application.
	 */

	dispPtr->grabFlags &= ~(GRAB_GLOBAL|GRAB_TEMP_GLOBAL);
	XQueryPointer(dispPtr->display, winPtr->window, &dummy1,
		&dummy2, &dummy3, &dummy4, &dummy5, &dummy6, &state);
	if ((state & ALL_BUTTONS) != 0) {
	    dispPtr->grabFlags |= GRAB_TEMP_GLOBAL;
	    goto setGlobalGrab;
	}
    } else {
	dispPtr->grabFlags |= GRAB_GLOBAL;
	setGlobalGrab:

	/*
	 * Tricky point: must ungrab before grabbing.  This is needed
	 * in case there is a button auto-grab already in effect.  If
	 * there is, and the mouse has moved to a different window, X
	 * won't generate enter and leave events to move the mouse if
	 * we grab without ungrabbing.
	 */

	XUngrabPointer(dispPtr->display, CurrentTime);
	serial = NextRequest(dispPtr->display);

	/*
	 * Another tricky point: there are races with some window
	 * managers that can cause grabs to fail because the window
	 * manager hasn't released its grab quickly enough.  To work
	 * around this problem, retry a few times after AlreadyGrabbed
	 * errors to give the grab release enough time to register with
	 * the server.
	 */

	grabResult = 0;			/* Needed only to prevent gcc
					 * compiler warnings. */
	for (numTries = 0; numTries < 10; numTries++) {
	    grabResult = XGrabPointer(dispPtr->display, winPtr->window,
		    True, ButtonPressMask|ButtonReleaseMask|ButtonMotionMask
		    |PointerMotionMask, GrabModeAsync, GrabModeAsync, None,
		    None, CurrentTime);
	    if (grabResult != AlreadyGrabbed) {
		break;
	    }
	    Tcl_Sleep(100);
	}
	if (grabResult != 0) {
	    grabError:
	    if (grabResult == GrabNotViewable) {
		interp->result = "grab failed: window not viewable";
	    } else if (grabResult == AlreadyGrabbed) {
		goto alreadyGrabbed;
	    } else if (grabResult == GrabFrozen) {
		interp->result = "grab failed: keyboard or pointer frozen";
	    } else if (grabResult == GrabInvalidTime) {
		interp->result = "grab failed: invalid time";
	    } else {
		char msg[100];
	
		sprintf(msg, "grab failed for unknown reason (code %d)",
			grabResult);
		Tcl_AppendResult(interp, msg, (char *) NULL);
	    }
	    return TCL_ERROR;
	}
	grabResult = XGrabKeyboard(dispPtr->display, Tk_WindowId(tkwin),
		False, GrabModeAsync, GrabModeAsync, CurrentTime);
	if (grabResult != 0) {
	    XUngrabPointer(dispPtr->display, CurrentTime);
	    goto grabError;
	}

	/*
	 * Eat up any grab-related events generated by the server for the
	 * grab.  There are several reasons for doing this:
	 *
	 * 1. We have to synthesize the events for local grabs anyway, since
	 *    the server doesn't participate in them.
	 * 2. The server doesn't always generate the right events for global
	 *    grabs (e.g. it generates events even if the current window is
	 *    in the grab tree, which we don't want).
	 * 3. We want all the grab-related events to be processed immediately
	 *    (before other events that are already queued); events coming
	 *    from the server will be in the wrong place, but events we
	 *    synthesize here will go to the front of the queue.
	 */

	EatGrabEvents(dispPtr, serial);
    }

    /*
     * Synthesize leave events to move the pointer from its current window
     * up to the lowest ancestor that it has in common with the grab window.
     * However, only do this if the pointer is outside the grab window's
     * subtree but inside the grab window's application.
     */

    if ((dispPtr->serverWinPtr != NULL)
	    && (dispPtr->serverWinPtr->mainPtr == winPtr->mainPtr)) {
	for (winPtr2 = dispPtr->serverWinPtr; ; winPtr2 = winPtr2->parentPtr) {
	    if (winPtr2 == winPtr) {
		break;
	    }
	    if (winPtr2 == NULL) {
		MovePointer2(dispPtr->serverWinPtr, winPtr, NotifyGrab, 1, 0);
		break;
	    }
	}
    }
    QueueGrabWindowChange(dispPtr, winPtr);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * Tk_Ungrab --
 *
 *	Releases a grab on the mouse pointer and keyboard, if there
 *	is one set on the specified window.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Pointer and keyboard events will start being delivered to other
 *	windows again.
 *
 *----------------------------------------------------------------------
 */

void
Tk_Ungrab(tkwin)
    Tk_Window tkwin;			/* Window whose grab should be
					 * released. */
{
    TkDisplay *dispPtr;
    TkWindow *grabWinPtr, *winPtr;
    unsigned int serial;

    grabWinPtr = (TkWindow *) tkwin;
    dispPtr = grabWinPtr->dispPtr;
    if (grabWinPtr != dispPtr->eventualGrabWinPtr) {
	return;
    }
    ReleaseButtonGrab(dispPtr);
    QueueGrabWindowChange(dispPtr, (TkWindow *) NULL);
    if (dispPtr->grabFlags & (GRAB_GLOBAL|GRAB_TEMP_GLOBAL)) {
	dispPtr->grabFlags &= ~(GRAB_GLOBAL|GRAB_TEMP_GLOBAL);
	serial = NextRequest(dispPtr->display);
	XUngrabPointer(dispPtr->display, CurrentTime);
	XUngrabKeyboard(dispPtr->display, CurrentTime);
	EatGrabEvents(dispPtr, serial);
    }

    /*
     * Generate events to move the pointer back to the window where it
     * really is.  Some notes:
     * 1. As with grabs, only do this if the "real" window is not a
     *    descendant of the grab window, since in this case the pointer
     *    is already where it's supposed to be.
     * 2. If the "real" window is in some other application then don't
     *    generate any events at all, since everything's already been
     *    reported correctly.
     * 3. Only generate enter events.  Don't generate leave events,
     *    because we never told the lower-level windows that they
     *    had the pointer in the first place.
     */

    for (winPtr = dispPtr->serverWinPtr; ; winPtr = winPtr->parentPtr) {
	if (winPtr == grabWinPtr) {
	    break;
	}
	if (winPtr == NULL) {
	    if ((dispPtr->serverWinPtr == NULL) ||
		    (dispPtr->serverWinPtr->mainPtr == grabWinPtr->mainPtr)) {
		MovePointer2(grabWinPtr, dispPtr->serverWinPtr,
			NotifyUngrab, 0, 1);
	    }
	    break;
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * ReleaseButtonGrab --
 *
 *	This procedure is called to release a simulated button grab, if
 *	there is one in effect.  A button grab is present whenever
 *	dispPtr->buttonWinPtr is non-NULL or when the GRAB_TEMP_GLOBAL
 *	flag is set.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	DispPtr->buttonWinPtr is reset to NULL, and enter and leave
 *	events are generated if necessary to move the pointer from
 *	the button grab window to its current window.
 *
 *----------------------------------------------------------------------
 */

static void
ReleaseButtonGrab(dispPtr)
    register TkDisplay *dispPtr;	/* Display whose button grab is to be
					 * released. */
{
    unsigned int serial;

    if (dispPtr->buttonWinPtr != NULL) {
	if (dispPtr->buttonWinPtr != dispPtr->serverWinPtr) {
	    MovePointer2(dispPtr->buttonWinPtr, dispPtr->serverWinPtr,
		    NotifyUngrab, 1, 1);
	}
	dispPtr->buttonWinPtr = NULL;
    }
    if (dispPtr->grabFlags & GRAB_TEMP_GLOBAL) {
	dispPtr->grabFlags &= ~GRAB_TEMP_GLOBAL;
	serial = NextRequest(dispPtr->display);
	XUngrabPointer(dispPtr->display, CurrentTime);
	XUngrabKeyboard(dispPtr->display, CurrentTime);
	EatGrabEvents(dispPtr, serial);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TkPointerEvent --
 *
 *	This procedure is called for each pointer-related event, before
 *	the event has been processed.  It does various things to make
 *	grabs work correctly.
 *
 * Results:
 *	If the return value is 1 it means the event should be processed
 *	(event handlers should be invoked).  If the return value is 0
 *	it means the event should be ignored in order to make grabs
 *	work correctly.  In some cases this procedure modifies the event.
 *
 * Side effects:
 *	Grab state information may be updated.  New events may also be
 *	pushed back onto the event queue to replace or augment the
 *	one passed in here.
 *
 *----------------------------------------------------------------------
 */

int
TkPointerEvent(eventPtr, winPtr)
    register XEvent *eventPtr;		/* Pointer to the event. */
    TkWindow *winPtr;			/* Tk's information for window
					 * where event was reported. */
{
    register TkWindow *winPtr2;
    TkDisplay *dispPtr = winPtr->dispPtr;
    unsigned int serial;
    int outsideGrabTree = 0;
    int ancestorOfGrab = 0;
    int appGrabbed = 0;			/* Non-zero means event is being
					 * reported to an application that is
					 * affected by the grab. */

    /*
     * Collect information about the grab (if any).
     */

    switch (TkGrabState(winPtr)) {
	case TK_GRAB_IN_TREE:
	    appGrabbed = 1;
	    break;
	case TK_GRAB_ANCESTOR:
	    appGrabbed = 1;
	    outsideGrabTree = 1;
	    ancestorOfGrab = 1;
	    break;
	case TK_GRAB_EXCLUDED:
	    appGrabbed = 1;
	    outsideGrabTree = 1;
	    break;
    }

    if ((eventPtr->type == EnterNotify) || (eventPtr->type == LeaveNotify)) {
	/*
	 * Keep track of what window the mouse is *really* over.
	 * Any events that we generate have a special send_event value,
	 * which is detected below and used to ignore the event for
	 * purposes of setting serverWinPtr.
	 */

	if (eventPtr->xcrossing.send_event != GENERATED_EVENT_MAGIC) {
	    if ((eventPtr->type == LeaveNotify) &&
		    (winPtr->flags & TK_TOP_LEVEL)) {
		dispPtr->serverWinPtr = NULL;
	    } else {
		dispPtr->serverWinPtr = winPtr;
	    }
	}

	/*
	 * When a grab is active, X continues to report enter and leave
	 * events for windows outside the tree of the grab window:
	 * 1. Detect these events and ignore them except for
	 *    windows above the grab window.
	 * 2. Allow Enter and Leave events to pass through the
	 *    windows above the grab window, but never let them
	 *    end up with the pointer *in* one of those windows.
	 */

	if (dispPtr->grabWinPtr != NULL) {
	    if (outsideGrabTree && appGrabbed) {
		if (!ancestorOfGrab) {
		    return 0;
		}
		switch (eventPtr->xcrossing.detail) {
		    case NotifyInferior:
			return 0;
		    case NotifyAncestor:
			eventPtr->xcrossing.detail = NotifyVirtual;
			break;
		    case NotifyNonlinear:
			eventPtr->xcrossing.detail = NotifyNonlinearVirtual;
			break;
		}
	    }

	    /*
	     * Make buttons have the same grab-like behavior inside a grab
	     * as they do outside a grab:  do this by ignoring enter and
	     * leave events except for the window in which the button was
	     * pressed.
	     */

	    if ((dispPtr->buttonWinPtr != NULL)
		    && (winPtr != dispPtr->buttonWinPtr)) {
		return 0;
	    }
	}
	return 1;
    }

    if (!appGrabbed) {
	return 1;
    }

    if (eventPtr->type == MotionNotify) {
	/*
	 * When grabs are active, X reports motion events relative to the
	 * window under the pointer.  Instead, it should report the events
	 * relative to the window the button went down in, if there is a
	 * button down.  Otherwise, if the pointer window is outside the
	 * subtree of the grab window, the events should be reported
	 * relative to the grab window.  Otherwise, the event should be
	 * reported to the pointer window.
	 */

	winPtr2 = winPtr;
	if (dispPtr->buttonWinPtr != NULL) {
	    winPtr2 = dispPtr->buttonWinPtr;
	} else if (outsideGrabTree || (dispPtr->serverWinPtr == NULL)) {
	    winPtr2 = dispPtr->grabWinPtr;
	}
	if (winPtr2 != winPtr) {
	    TkChangeEventWindow(eventPtr, winPtr2);
	    Tk_QueueWindowEvent(eventPtr, TCL_QUEUE_HEAD);
	    return 0;
	}
	return 1;
    }

    /*
     * Process ButtonPress and ButtonRelease events:
     * 1. Keep track of whether a button is down and what window it
     *    went down in.
     * 2. If the first button goes down outside the grab tree, pretend
     *    it went down in the grab window.  Note: it's important to
     *    redirect events to the grab window like this in order to make
     *    things like menus work, where button presses outside the
     *    grabbed menu need to be seen.  An application can always
     *    ignore the events if they occur outside its window.