Function TkPointerEvent

micropolis-activity/src/tk/tkgrab.c:488–719

(eventPtr, winPtr)

 * Side effects:
 *	Grab state information may be updated.
 *
 *----------------------------------------------------------------------
 */

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;
    int outsideGrabTree = 0;
    int originalFlags;
    int appGrabbed = 0;			/* Non-zero means event is being
					 * reported to an application that is
					 * affected by the grab. */
    static unsigned int state[] = {
	Button1Mask, Button2Mask, Button3Mask, Button4Mask, Button5Mask
    };

    /*
     * Don't do any filtering on events generated by the event-sharing code.
     */

    if (eventPtr == tkShareEventPtr) {
	return 1;
    }

    /*
     * If a grab is in effect, see if the event is being reported to
     * a window in the grab tree.  Also see if the event is being reported
     * to an application that is affected by the grab.
     */

    if (dispPtr->grabWinPtr != NULL) {
	if ((winPtr->mainPtr == dispPtr->grabWinPtr->mainPtr)
		|| (dispPtr->grabFlags & GRAB_GLOBAL)) {
	    appGrabbed = 1;
	}
	for (winPtr2 = winPtr; winPtr2 != dispPtr->grabWinPtr;
		winPtr2 = winPtr2->parentPtr) {
	    if (winPtr2 == NULL) {
		outsideGrabTree = 1;
		break;
	    }
	}
    }

    originalFlags = dispPtr->grabFlags;
    dispPtr->grabFlags &= ~GRAB_BUTTON_RELEASE;
    if ((eventPtr->type == EnterNotify) || (eventPtr->type == LeaveNotify)) {
	if ((eventPtr->type == EnterNotify)
		&& (eventPtr->xcrossing.detail != NotifyVirtual)
		&& (eventPtr->xcrossing.detail != NotifyNonlinearVirtual)) {
	    if ((dispPtr->grabWinPtr == NULL)
		    || (dispPtr->grabWinPtr->mainPtr == winPtr->mainPtr)) {
		dispPtr->ungrabWinPtr = winPtr;