/*
* tkGrab.c --
*
* This file provides procedures that implement grabs for Tk.
*
* Copyright (c) 1992-1994 The Regents of the University of California.
* Copyright (c) 1994-1997 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
* RCS: @(#) $Id: tkGrab.c,v 1.9 2002/08/31 06:12:20 das Exp $
*/
#include "tkPort.h"
#include "tkInt.h"
#if !(defined(__WIN32__) || defined(MAC_TCL) || defined(MAC_OSX_TK))
#include "tkUnixInt.h"
#endif
/*
* The grab state machine has four states: ungrabbed, button pressed,
* grabbed, and button pressed while grabbed. In addition, there are
* three pieces of grab state information: the current grab window,
* the current restrict window, and whether the mouse is captured.
*
* The current grab window specifies the point in the Tk window
* heirarchy above which pointer events will not be reported. Any
* window within the subtree below the grab window will continue to
* receive events as normal. Events outside of the grab tree will be
* reported to the grab window.
*
* If the current restrict window is set, then all pointer events will
* be reported only to the restrict window. The restrict window is
* normally set during an automatic button grab.
*
* The mouse capture state specifies whether the window system will
* report mouse events outside of any Tk toplevels. This is set
* during a global grab or an automatic button grab.
*
* The transitions between different states is given in the following
* table:
*
* Event\State U B G GB
* ----------- -- -- -- --
* FirstPress B B GB GB
* Press B B G GB
* Release U B G GB
* LastRelease U U G G
* Grab G G G G
* Ungrab U B U U
*
* Note: U=Ungrabbed, B=Button, G=Grabbed, GB=Grab and Button
*
* In addition, the following conditions are always true:
*
* State\Variable Grab Restrict Capture
* -------------- ---- -------- -------
* Ungrabbed 0 0 0
* Button 0 1 1
* Grabbed 1 0 b/g
* Grab and Button 1 1 1
*
* Note: 0 means variable is set to NULL, 1 means variable is set to
* some window, b/g means the variable is set to a window if a button
* is currently down or a global grab is in effect.
*
* The final complication to all of this is enter and leave events.
* In order to correctly handle all of the various cases, Tk cannot
* rely on X enter/leave events in all situations. The following
* describes the correct sequence of enter and leave events that
* should be observed by Tk scripts:
*
* Event(state) Enter/Leave From -> To
* ------------ ----------------------
* LastRelease(B | GB): restrict window -> anc(grab window, event window)
* Grab(U | B): event window -> anc(grab window, event window)
* Grab(G): anc(old grab window, event window) ->
* anc(new grab window, event window)
* Grab(GB): restrict window -> anc(new grab window, event window)
* Ungrab(G): anc(grab window, event window) -> event window
* Ungrab(GB): restrict window -> event window
*
* Note: anc(x,y) returns the least ancestor of y that is in the tree
* of x, terminating at toplevels.
*/
/*
* The following structure is used to pass information to
* GrabRestrictProc from EatGrabEvents.
*/
typedef struct {
Display *display; /* Display from which to discard events. */
unsigned int serial; /* Serial number with which to compare. */
} GrabInfo;
/*
* Bit definitions for grabFlags field of TkDisplay structures:
*
* GRAB_GLOBAL 1 means this is a global grab (we grabbed via
* the server so all applications are locked out).
* 0 means this is a local grab that affects
* only this application.
* GRAB_TEMP_GLOBAL 1 means we've temporarily grabbed via the
* server because a button is down and we want
* to make sure that we get the button-up
* event. The grab will be released when the
* last mouse button goes up.
*/
#define GRAB_GLOBAL 1
#define GRAB_TEMP_GLOBAL 4
/*
* The following structure is a Tcl_Event that triggers a change in
* the grabWinPtr field of a display. This event guarantees that
* the change occurs in the proper order relative to enter and leave
* events.
*/
typedef struct NewGrabWinEvent {
Tcl_Event header; /* Standard information for all Tcl events. */
TkDisplay *dispPtr; /* Display whose grab window is to change. */
Window grabWindow; /* New grab window for display. This is
* recorded instead of a (TkWindow *) because
* it will allow us to detect cases where
* the window is destroyed before this event
* is processed. */
} NewGrabWinEvent;
/*
* The following magic value is stored in the "send_event" field of
* EnterNotify and LeaveNotify events that are generated in this
* file. This allows us to separate "real" events coming from the
* server from those that we generated.
*/
#define GENERATED_EVENT_MAGIC ((Bool) 0x147321ac)
/*
* Mask that selects any of the state bits corresponding to buttons,
* plus masks that select individual buttons' bits:
*/
#define ALL_BUTTONS \
(Button1Mask|Button2Mask|Button3Mask|Button4Mask|Button5Mask)
static unsigned int buttonStates[] = {
Button1Mask, Button2Mask, Button3Mask, Button4Mask, Button5Mask
};
/*
* Forward declarations for procedures declared later in this file:
*/
static void EatGrabEvents _ANSI_ARGS_((TkDisplay *dispPtr,
unsigned int serial));
static TkWindow * FindCommonAncestor _ANSI_ARGS_((TkWindow *winPtr1,
TkWindow *winPtr2, int *countPtr1,
int *countPtr2));
static Tk_RestrictAction GrabRestrictProc _ANSI_ARGS_((ClientData arg,
XEvent *eventPtr));
static int GrabWinEventProc _ANSI_ARGS_((Tcl_Event *evPtr,
int flags));
static void MovePointer2 _ANSI_ARGS_((TkWindow *sourcePtr,
TkWindow *destPtr, int mode, int leaveEvents,
int EnterEvents));
static void QueueGrabWindowChange _ANSI_ARGS_((TkDisplay *dispPtr,
TkWindow *grabWinPtr));
static void ReleaseButtonGrab _ANSI_ARGS_((TkDisplay *dispPtr));
/*
*----------------------------------------------------------------------
*
* Tk_GrabObjCmd --
*
* This procedure is invoked to process the "grab" Tcl command.
* See the user documentation for details on what it does.
*
* Results:
* A standard Tcl result.
*
* Side effects:
* See the user documentation.
*
*----------------------------------------------------------------------
*/
/* ARGSUSED */
int
Tk_GrabObjCmd(clientData, interp, objc, objv)
ClientData clientData; /* Main window associated with
* interpreter. */
Tcl_Interp *interp; /* Current interpreter. */
int objc; /* Number of arguments. */
Tcl_Obj *CONST objv[]; /* Argument objects. */
{
int globalGrab;
Tk_Window tkwin;
TkDisplay *dispPtr;
char *arg;
int index;
int len;
static CONST char *optionStrings[] = { "current", "release",
"set", "status", (char *) NULL };
static CONST char *flagStrings[] = { "-global", (char *) NULL };
enum options { GRABCMD_CURRENT, GRABCMD_RELEASE,
GRABCMD_SET, GRABCMD_STATUS };
if (objc < 2) {
/*
* Can't use Tcl_WrongNumArgs here because we want the message to
* read:
* wrong # args: should be "cmd ?-global window" or "cmd option
* ?arg arg ...?"
* We can fake it with Tcl_WrongNumArgs if we assume the command name
* is "grab", but if it has been aliased, the message will be
* incorrect.
*/
Tcl_ResetResult(interp);
Tcl_AppendResult(interp, "wrong # args: should be \"",
Tcl_GetString(objv[0]), " ?-global? window\" or \"",
Tcl_GetString(objv[0]), " option ?arg arg ...?\"",
(char *) NULL);
return TCL_ERROR;
}
/*
* First check for a window name or "-global" as the first argument.
*/
arg = Tcl_GetStringFromObj(objv[1], &len);
if (arg[0] == '.') {
/* [grab window] */
if (objc != 2) {
Tcl_WrongNumArgs(interp, 1, objv, "?-global? window");
return TCL_ERROR;
}
tkwin = Tk_NameToWindow(interp, arg, (Tk_Window) clientData);
if (tkwin == NULL) {
return TCL_ERROR;
}
return Tk_Grab(interp, tkwin, 0);
} else if (arg[0] == '-' && len > 1) {
if (Tcl_GetIndexFromObj(interp, objv[1], flagStrings, "option", 0,
&index) != TCL_OK) {
return TCL_ERROR;
}
/* [grab -global window] */
if (objc != 3) {
Tcl_WrongNumArgs(interp, 1, objv, "?-global? window");
return TCL_ERROR;
}
tkwin = Tk_NameToWindow(interp, Tcl_GetString(objv[2]),
(Tk_Window) clientData);
if (tkwin == NULL) {
return TCL_ERROR;
}
return Tk_Grab(interp, tkwin, 1);
}
/*
* First argument is not a window name and not "-global", find out
* which option it is.
*/
if (Tcl_GetIndexFromObj(interp, objv[1], optionStrings, "option", 0,
&index) != TCL_OK) {
return TCL_ERROR;
}
switch ((enum options) index) {
case GRABCMD_CURRENT: {
/* [grab current ?window?] */
if (objc > 3) {
Tcl_WrongNumArgs(interp, 1, objv, "current ?window?");
return TCL_ERROR;
}
if (objc == 3) {
tkwin = Tk_NameToWindow(interp,
Tcl_GetString(objv[2]), (Tk_Window) clientData);
if (tkwin == NULL) {
return TCL_ERROR;
}
dispPtr = ((TkWindow *) tkwin)->dispPtr;
if (dispPtr->eventualGrabWinPtr != NULL) {
Tcl_SetResult(interp,
dispPtr->eventualGrabWinPtr->pathName, TCL_STATIC);
}
} else {
for (dispPtr = TkGetDisplayList(); dispPtr != NULL;
dispPtr = dispPtr->nextPtr) {
if (dispPtr->eventualGrabWinPtr != NULL) {
Tcl_AppendElement(interp,
dispPtr->eventualGrabWinPtr->pathName);
}
}
}
return TCL_OK;
}
case GRABCMD_RELEASE: {
/* [grab release window] */
if (objc != 3) {
Tcl_WrongNumArgs(interp, 1, objv, "release window");
return TCL_ERROR;
}
tkwin = Tk_NameToWindow(interp,
Tcl_GetString(objv[2]), (Tk_Window) clientData);
if (tkwin == NULL) {
Tcl_ResetResult(interp);
} else {
Tk_Ungrab(tkwin);
}
break;
}
case GRABCMD_SET: {
/* [grab set ?-global? window] */
if ((objc != 3) && (objc != 4)) {
Tcl_WrongNumArgs(interp, 1, objv, "set ?-global? window");
return TCL_ERROR;
}
if (objc == 3) {
globalGrab = 0;
tkwin = Tk_NameToWindow(interp,
Tcl_GetString(objv[2]), (Tk_Window) clientData);
} else {
globalGrab = 1;
/*
* We could just test the argument by hand instead of using
* Tcl_GetIndexFromObj; the benefit of using the function is
* that it sets up the error message for us, so we are
* certain to be consistant with the rest of Tcl.
*/
if (Tcl_GetIndexFromObj(interp, objv[2], flagStrings, "option",
0, &index) != TCL_OK) {
return TCL_ERROR;
}
tkwin = Tk_NameToWindow(interp,
Tcl_GetString(objv[3]), (Tk_Window) clientData);
}
if (tkwin == NULL) {
return TCL_ERROR;
}
return Tk_Grab(interp, tkwin, globalGrab);
}
case GRABCMD_STATUS: {
/* [grab status window] */
TkWindow *winPtr;
if (objc != 3) {
Tcl_WrongNumArgs(interp, 1, objv, "status window");
return TCL_ERROR;
}
winPtr = (TkWindow *) Tk_NameToWindow(interp,
Tcl_GetString(objv[2]), (Tk_Window) clientData);
if (winPtr == NULL) {
return TCL_ERROR;
}
dispPtr = winPtr->dispPtr;
if (dispPtr->eventualGrabWinPtr != winPtr) {
Tcl_SetResult(interp, "none", TCL_STATIC);
} else if (dispPtr->grabFlags & GRAB_GLOBAL) {
Tcl_SetResult(interp, "global", TCL_STATIC);
} else {
Tcl_SetResult(interp, "local", TCL_STATIC);
}
break;
}
}
return TCL_OK;
}
/*
*----------------------------------------------------------------------
*
* Tk_Grab --
*
* Grabs the pointer and keyboard, so that mouse-related events are
* only reported relative to a given window and its descendants.
*
* Results:
* A standard Tcl result is returned. TCL_OK is the normal return
* value; if the grab could not be set then TCL_ERROR is returned
* and the interp's result will hold an error message.
*
* Side effects:
* Once this call completes successfully, no window outside the
* tree rooted at tkwin will receive pointer- or keyboard-related
* events until the next call to Tk_Ungrab. If a previous grab was
* in effect within this application, then it is replaced with a new
* one.
*
*----------------------------------------------------------------------
*/
int
Tk_Grab(interp, tkwin, grabGlobal)
Tcl_Interp *interp; /* Used for error reporting. */
Tk_Window tkwin; /* Window on whose behalf the pointer
* is to be grabbed. */
int grabGlobal; /* Non-zero means issue a grab to the
* server so that no other application
* gets mouse or keyboard events.
* Zero means the grab only applies
* within this application. */
{
int grabResult, numTries;
TkWindow *winPtr = (TkWindow *) tkwin;
TkDisplay *dispPtr = winPtr->dispPtr;
TkWindow *winPtr2;
unsigned int serial;
ReleaseButtonGrab(dispPtr);
if (dispPtr->eventualGrabWinPtr != NULL) {
if ((dispPtr->eventualGrabWinPtr == winPtr)
&& (grabGlobal == ((dispPtr->grabFlags & GRAB_GLOBAL) != 0))) {
return TCL_OK;
}
if (dispPtr->eventualGrabWinPtr->mainPtr != winPtr->mainPtr) {
alreadyGrabbed:
Tcl_SetResult(interp, "grab failed: another application has grab",
TCL_STATIC);
return TCL_ERROR;
}
Tk_Ungrab((Tk_Window) dispPtr->eventualGrabWinPtr);
}
Tk_MakeWindowExist(tkwin);
if (!grabGlobal) {
Window dummy1, dummy2;
int dummy3, dummy4, dummy5, dummy6;
unsigned int state;
/*
* Local grab. However, if any mouse buttons are down, turn
* it into a global grab temporarily, until the last button
* goes up. This does two things: (a) it makes sure that we
* 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,
winPtr->atts.cursor, CurrentTime);
if (grabResult != AlreadyGrabbed) {
break;
}
Tcl_Sleep(100);
}
if (grabResult != 0) {
grabError:
if (grabResult == GrabNotViewable) {
Tcl_SetResult(interp, "grab failed: window not viewable",
TCL_STATIC);
} else if (grabResult == AlreadyGrabbed) {
goto alreadyGrabbed;
} else if (grabResult == GrabFrozen) {
Tcl_SetResult(interp,
"grab failed: keyboard or pointer frozen", TCL_STATIC);
} else if (grabResult == GrabInvalidTime) {
Tcl_SetResult(interp, "grab failed: invalid time",
TCL_STATIC);
} else {
char msg[64 + TCL_INTEGER_SPACE];
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_HIERARCHY)) {
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.
* 3. If a button press or release occurs outside the window where
* the first button was pressed, retarget the event so it's reported
* to the window where the first button was pressed.
* 4. If the last button is released in a window different than where
* the first button was pressed, generate Enter/Leave events to
* move the mouse from the button window to its current window.
* 5. If the grab is set at a time when a button is already down, or
* if the window where the button was pressed was deleted, then
* dispPtr->buttonWinPtr will stay NULL. Just forget about the
* auto-grab for the button press; events will go to whatever
* window contains the pointer. If this window isn't in the grab
* tree then redirect events to the grab window.
* 6. When a button is pressed during a local grab, the X server sets
* a grab of its own, since it doesn't even know about our local
* grab. This causes enter and leave events no longer to be
* generated in the same way as for global grabs. To eliminate this
* problem, set a temporary global grab when the first button goes
* down and release it when the last button comes up.
*/
if ((eventPtr->type == ButtonPress) || (eventPtr->type == ButtonRelease)) {
winPtr2 = dispPtr->buttonWinPtr;
if (winPtr2 == NULL) {
if (outsideGrabTree) {
winPtr2 = dispPtr->grabWinPtr; /* Note 5. */
} else {
winPtr2 = winPtr; /* Note 5. */
}
}
if (eventPtr->type == ButtonPress) {
if ((eventPtr->xbutton.state & ALL_BUTTONS) == 0) {
if (outsideGrabTree) {
TkChangeEventWindow(eventPtr, dispPtr->grabWinPtr);
Tk_QueueWindowEvent(eventPtr, TCL_QUEUE_HEAD);
return 0; /* Note 2. */
}
if (!(dispPtr->grabFlags & GRAB_GLOBAL)) { /* Note 6. */
serial = NextRequest(dispPtr->display);
if (XGrabPointer(dispPtr->display,
dispPtr->grabWinPtr->window, True,
ButtonPressMask|ButtonReleaseMask|ButtonMotionMask,
GrabModeAsync, GrabModeAsync, None, dispPtr->eventualGrabWinPtr->atts.cursor,
CurrentTime) == 0) {
EatGrabEvents(dispPtr, serial);
if (XGrabKeyboard(dispPtr->display, winPtr->window,
False, GrabModeAsync, GrabModeAsync,
CurrentTime) == 0) {
dispPtr->grabFlags |= GRAB_TEMP_GLOBAL;
} else {
XUngrabPointer(dispPtr->display, CurrentTime);
}
}
}
dispPtr->buttonWinPtr = winPtr;
return 1;
}
} else {
if ((eventPtr->xbutton.state & ALL_BUTTONS)
== buttonStates[eventPtr->xbutton.button - Button1]) {
ReleaseButtonGrab(dispPtr); /* Note 4. */
}
}
if (winPtr2 != winPtr) {
TkChangeEventWindow(eventPtr, winPtr2);
Tk_QueueWindowEvent(eventPtr, TCL_QUEUE_HEAD);
return 0; /* Note 3. */
}
}
return 1;
}
/*
*----------------------------------------------------------------------
*
* TkChangeEventWindow --
*
* Given an event and a new window to which the event should be
* retargeted, modify fields of the event so that the event is
* properly retargeted to the new window.
*
* Results:
* The following fields of eventPtr are modified: window,
* subwindow, x, y, same_screen.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
void
TkChangeEventWindow(eventPtr, winPtr)
register XEvent *eventPtr; /* Event to retarget. Must have
* type ButtonPress, ButtonRelease, KeyPress,
* KeyRelease, MotionNotify, EnterNotify,
* or LeaveNotify. */
TkWindow *winPtr; /* New target window for event. */
{
int x, y, sameScreen, bd;
register TkWindow *childPtr;
eventPtr->xmotion.window = Tk_WindowId(winPtr);
if (eventPtr->xmotion.root ==
RootWindow(winPtr->display, winPtr->screenNum)) {
Tk_GetRootCoords((Tk_Window) winPtr, &x, &y);
eventPtr->xmotion.x = eventPtr->xmotion.x_root - x;
eventPtr->xmotion.y = eventPtr->xmotion.y_root - y;
eventPtr->xmotion.subwindow = None;
for (childPtr = winPtr->childList; childPtr != NULL;
childPtr = childPtr->nextPtr) {
if (childPtr->flags & TK_TOP_HIERARCHY) {
continue;
}
x = eventPtr->xmotion.x - childPtr->changes.x;
y = eventPtr->xmotion.y - childPtr->changes.y;
bd = childPtr->changes.border_width;
if ((x >= -bd) && (y >= -bd)
&& (x < (childPtr->changes.width + bd))
&& (y < (childPtr->changes.height + bd))) {
eventPtr->xmotion.subwindow = childPtr->window;
}
}
sameScreen = 1;
} else {
eventPtr->xmotion.x = 0;
eventPtr->xmotion.y = 0;
eventPtr->xmotion.subwindow = None;
sameScreen = 0;
}
if (eventPtr->type == MotionNotify) {
eventPtr->xmotion.same_screen = sameScreen;
} else {
eventPtr->xbutton.same_screen = sameScreen;
}
}
/*
*----------------------------------------------------------------------
*
* TkInOutEvents --
*
* This procedure synthesizes EnterNotify and LeaveNotify events
* to correctly transfer the pointer from one window to another.
* It can also be used to generate FocusIn and FocusOut events
* to move the input focus.
*
* Results:
* None.
*
* Side effects:
* Synthesized events may be pushed back onto the event queue.
* The event pointed to by eventPtr is modified.
*
*----------------------------------------------------------------------
*/
void
TkInOutEvents(eventPtr, sourcePtr, destPtr, leaveType, enterType, position)
XEvent *eventPtr; /* A template X event. Must have all fields
* properly set except for type, window,
* subwindow, x, y, detail, and same_screen
* (Not all of these fields are valid for
* FocusIn/FocusOut events; x_root and y_root
* must be valid for Enter/Leave events, even
* though x and y needn't be valid). */
TkWindow *sourcePtr; /* Window that used to have the pointer or
* focus (NULL means it was not in a window
* managed by this process). */
TkWindow *destPtr; /* Window that is to end up with the pointer
* or focus (NULL means it's not one managed
* by this process). */
int leaveType; /* Type of events to generate for windows
* being left (LeaveNotify or FocusOut). 0
* means don't generate leave events. */
int enterType; /* Type of events to generate for windows
* being entered (EnterNotify or FocusIn). 0
* means don't generate enter events. */
Tcl_QueuePosition position; /* Position at which events are added to
* the system event queue. */
{
register TkWindow *winPtr;
int upLevels, downLevels, i, j, focus;
/*
* There are four possible cases to deal with:
*
* 1. SourcePtr and destPtr are the same. There's nothing to do in
* this case.
* 2. SourcePtr is an ancestor of destPtr in the same top-level
* window. Must generate events down the window tree from source
* to dest.
* 3. DestPtr is an ancestor of sourcePtr in the same top-level
* window. Must generate events up the window tree from sourcePtr
* to destPtr.
* 4. All other cases. Must first generate events up the window tree
* from sourcePtr to its top-level, then down from destPtr's
* top-level to destPtr. This form is called "non-linear."
*
* The call to FindCommonAncestor separates these four cases and decides
* how many levels up and down events have to be generated for.
*/
if (sourcePtr == destPtr) {
return;
}
if ((leaveType == FocusOut) || (enterType == FocusIn)) {
focus = 1;
} else {
focus = 0;
}
FindCommonAncestor(sourcePtr, destPtr, &upLevels, &downLevels);
/*
* Generate enter/leave events and add them to the grab event queue.
*/
#define QUEUE(w, t, d) \
if (w->window != None) { \
eventPtr->type = t; \
if (focus) { \
eventPtr->xfocus.window = w->window; \
eventPtr->xfocus.detail = d; \
} else { \
eventPtr->xcrossing.detail = d; \
TkChangeEventWindow(eventPtr, w); \
} \
Tk_QueueWindowEvent(eventPtr, position); \
}
if (downLevels == 0) {
/*
* SourcePtr is an inferior of destPtr.
*/
if (leaveType != 0) {
QUEUE(sourcePtr, leaveType, NotifyAncestor);
for (winPtr = sourcePtr->parentPtr, i = upLevels-1; i > 0;
winPtr = winPtr->parentPtr, i--) {
QUEUE(winPtr, leaveType, NotifyVirtual);
}
}
if ((enterType != 0) && (destPtr != NULL)) {
QUEUE(destPtr, enterType, NotifyInferior);
}
} else if (upLevels == 0) {
/*
* DestPtr is an inferior of sourcePtr.
*/
if ((leaveType != 0) && (sourcePtr != NULL)) {
QUEUE(sourcePtr, leaveType, NotifyInferior);
}
if (enterType != 0) {
for (i = downLevels-1; i > 0; i--) {
for (winPtr = destPtr->parentPtr, j = 1; j < i;
winPtr = winPtr->parentPtr, j++) {
}
QUEUE(winPtr, enterType, NotifyVirtual);
}
if (destPtr != NULL) {
QUEUE(destPtr, enterType, NotifyAncestor);
}
}
} else {
/*
* Non-linear: neither window is an inferior of the other.
*/
if (leaveType != 0) {
QUEUE(sourcePtr, leaveType, NotifyNonlinear);
for (winPtr = sourcePtr->parentPtr, i = upLevels-1; i > 0;
winPtr = winPtr->parentPtr, i--) {
QUEUE(winPtr, leaveType, NotifyNonlinearVirtual);
}
}
if (enterType != 0) {
for (i = downLevels-1; i > 0; i--) {
for (winPtr = destPtr->parentPtr, j = 1; j < i;
winPtr = winPtr->parentPtr, j++) {
}
QUEUE(winPtr, enterType, NotifyNonlinearVirtual);
}
if (destPtr != NULL) {
QUEUE(destPtr, enterType, NotifyNonlinear);
}
}
}
}
/*
*----------------------------------------------------------------------
*
* MovePointer2 --
*
* This procedure synthesizes EnterNotify and LeaveNotify events
* to correctly transfer the pointer from one window to another.
* It is different from TkInOutEvents in that no template X event
* needs to be supplied; this procedure generates the template
* event and calls TkInOutEvents.
*
* Results:
* None.
*
* Side effects:
* Synthesized events may be pushed back onto the event queue.
*
*----------------------------------------------------------------------
*/
static void
MovePointer2(sourcePtr, destPtr, mode, leaveEvents, enterEvents)
TkWindow *sourcePtr; /* Window currently containing pointer (NULL
* means it's not one managed by this
* process). */
TkWindow *destPtr; /* Window that is to end up containing the
* pointer (NULL means it's not one managed
* by this process). */
int mode; /* Mode for enter/leave events, such as
* NotifyNormal or NotifyUngrab. */
int leaveEvents; /* Non-zero means generate leave events for the
* windows being left. Zero means don't
* generate leave events. */
int enterEvents; /* Non-zero means generate enter events for the
* windows being entered. Zero means don't
* generate enter events. */
{
XEvent event;
Window dummy1, dummy2;
int dummy3, dummy4;
TkWindow *winPtr;
winPtr = sourcePtr;
if ((winPtr == NULL) || (winPtr->window == None)) {
winPtr = destPtr;
if ((winPtr == NULL) || (winPtr->window == None)) {
return;
}
}
event.xcrossing.serial = LastKnownRequestProcessed(
winPtr->display);
event.xcrossing.send_event = GENERATED_EVENT_MAGIC;
event.xcrossing.display = winPtr->display;
event.xcrossing.root = RootWindow(winPtr->display,
winPtr->screenNum);
event.xcrossing.time = TkCurrentTime(winPtr->dispPtr, False);
/* FALSE because we want a real time (even an old one) not CurrentTime */
XQueryPointer(winPtr->display, winPtr->window, &dummy1, &dummy2,
&event.xcrossing.x_root, &event.xcrossing.y_root,
&dummy3, &dummy4, &event.xcrossing.state);
event.xcrossing.mode = mode;
event.xcrossing.focus = False;
TkInOutEvents(&event, sourcePtr, destPtr, (leaveEvents) ? LeaveNotify : 0,
(enterEvents) ? EnterNotify : 0, TCL_QUEUE_MARK);
}
/*
*----------------------------------------------------------------------
*
* TkGrabDeadWindow --
*
* This procedure is invoked whenever a window is deleted, so that
* grab-related cleanup can be performed.
*
* Results:
* None.
*
* Side effects:
* Various cleanups happen, such as generating events to move the
* pointer back to its "natural" window as if an ungrab had been
* done. See the code.
*
*----------------------------------------------------------------------
*/
void
TkGrabDeadWindow(winPtr)
register TkWindow *winPtr; /* Window that is in the process
* of being deleted. */
{
TkDisplay *dispPtr = winPtr->dispPtr;
if (dispPtr->eventualGrabWinPtr == winPtr) {
/*
* Grab window was deleted. Release the grab.
*/
Tk_Ungrab((Tk_Window) dispPtr->eventualGrabWinPtr);
} else if (dispPtr->buttonWinPtr == winPtr) {
ReleaseButtonGrab(dispPtr);
}
if (dispPtr->serverWinPtr == winPtr) {
if (winPtr->flags & TK_TOP_HIERARCHY) {
dispPtr->serverWinPtr = NULL;
} else {
dispPtr->serverWinPtr = winPtr->parentPtr;
}
}
if (dispPtr->grabWinPtr == winPtr) {
dispPtr->grabWinPtr = NULL;
}
}
/*
*----------------------------------------------------------------------
*
* EatGrabEvents --
*
* This procedure is called to eliminate any Enter, Leave,
* FocusIn, or FocusOut events in the event queue for a
* display that have mode NotifyGrab or NotifyUngrab and
* have a serial number no less than a given value and are not
* generated by the grab module.
*
* Results:
* None.
*
* Side effects:
* DispPtr's display gets sync-ed, and some of the events get
* removed from the Tk event queue.
*
*----------------------------------------------------------------------
*/
static void
EatGrabEvents(dispPtr, serial)
TkDisplay *dispPtr; /* Display from which to consume events. */
unsigned int serial; /* Only discard events that have a serial
* number at least this great. */
{
Tk_RestrictProc *oldProc;
GrabInfo info;
ClientData oldArg, dummy;
info.display = dispPtr->display;
info.serial = serial;
TkpSync(info.display);
oldProc = Tk_RestrictEvents(GrabRestrictProc, (ClientData)&info, &oldArg);
while (Tcl_ServiceEvent(TCL_WINDOW_EVENTS)) {
}
Tk_RestrictEvents(oldProc, oldArg, &dummy);
}
/*
*----------------------------------------------------------------------
*
* GrabRestrictProc --
*
* A Tk_RestrictProc used by EatGrabEvents to eliminate any
* Enter, Leave, FocusIn, or FocusOut events in the event queue
* for a display that has mode NotifyGrab or NotifyUngrab and
* have a serial number no less than a given value.
*
* Results:
* Returns either TK_DISCARD_EVENT or TK_DEFER_EVENT.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
static Tk_RestrictAction
GrabRestrictProc(arg, eventPtr)
ClientData arg;
XEvent *eventPtr;
{
GrabInfo *info = (GrabInfo *) arg;
int mode, diff;
/*
* The diff caculation is trickier than it may seem. Don't forget
* that serial numbers can wrap around, so can't compare the two
* serial numbers directly.
*/
diff = eventPtr->xany.serial - info->serial;
if ((eventPtr->type == EnterNotify)
|| (eventPtr->type == LeaveNotify)) {
mode = eventPtr->xcrossing.mode;
} else if ((eventPtr->type == FocusIn)
|| (eventPtr->type == FocusOut)) {
mode = eventPtr->xfocus.mode;
} else {
mode = NotifyNormal;
}
if ((info->display != eventPtr->xany.display) || (mode == NotifyNormal)
|| (diff < 0)) {
return TK_DEFER_EVENT;
} else {
return TK_DISCARD_EVENT;
}
}
/*
*----------------------------------------------------------------------
*
* QueueGrabWindowChange --
*
* This procedure queues a special event in the Tcl event queue,
* which will cause the "grabWinPtr" field for the display to get
* modified when the event is processed. This is needed to make
* sure that the grab window changes at the proper time relative
* to grab-related enter and leave events that are also in the
* queue. In particular, this approach works even when multiple
* grabs and ungrabs happen back-to-back.
*
* Results:
* None.
*
* Side effects:
* DispPtr->grabWinPtr will be modified later (by GrabWinEventProc)
* when the event is removed from the grab event queue.
*
*----------------------------------------------------------------------
*/
static void
QueueGrabWindowChange(dispPtr, grabWinPtr)
TkDisplay *dispPtr; /* Display on which to change the grab
* window. */
TkWindow *grabWinPtr; /* Window that is to become the new grab
* window (may be NULL). */
{
NewGrabWinEvent *grabEvPtr;
grabEvPtr = (NewGrabWinEvent *) ckalloc(sizeof(NewGrabWinEvent));
grabEvPtr->dispPtr = dispPtr;
if (grabWinPtr == NULL) {
grabEvPtr->grabWindow = None;
} else {
grabEvPtr->grabWindow = grabWinPtr->window;
}
Tcl_QueueProcEvent(GrabWinEventProc, &grabEvPtr->header, TCL_QUEUE_MARK);
dispPtr->eventualGrabWinPtr = grabWinPtr;
}
/*
*----------------------------------------------------------------------
*
* GrabWinEventProc --
*
* This procedure is invoked as a handler for Tcl_Events of type
* NewGrabWinEvent. It updates the current grab window field in
* a display.
*
* Results:
* Returns 1 if the event was processed, 0 if it should be deferred
* for processing later.
*
* Side effects:
* The grabWinPtr field is modified in the display associated with
* the event.
*
*----------------------------------------------------------------------
*/
static int
GrabWinEventProc(evPtr, flags)
Tcl_Event *evPtr; /* Event of type NewGrabWinEvent. */
int flags; /* Flags argument to Tk_DoOneEvent: indicates
* what kinds of events are being processed
* right now. */
{
NewGrabWinEvent *grabEvPtr = (NewGrabWinEvent *) evPtr;
grabEvPtr->dispPtr->grabWinPtr = (TkWindow *) Tk_IdToWindow(
grabEvPtr->dispPtr->display, grabEvPtr->grabWindow);
return 1;
}
/*
*----------------------------------------------------------------------
*
* FindCommonAncestor --
*
* Given two windows, this procedure finds their least common
* ancestor and also computes how many levels up this ancestor
* is from each of the original windows.
*
* Results:
* If the windows are in different applications or top-level
* windows, then NULL is returned and *countPtr1 and *countPtr2
* are set to the depths of the two windows in their respective
* top-level windows (1 means the window is a top-level, 2 means
* its parent is a top-level, and so on). Otherwise, the return
* value is a pointer to the common ancestor and the counts are
* set to the distance of winPtr1 and winPtr2 from this ancestor
* (1 means they're children, 2 means grand-children, etc.).
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
static TkWindow *
FindCommonAncestor(winPtr1, winPtr2, countPtr1, countPtr2)
TkWindow *winPtr1; /* First window. May be NULL. */
TkWindow *winPtr2; /* Second window. May be NULL. */
int *countPtr1; /* Store nesting level of winPtr1 within
* common ancestor here. */
int *countPtr2; /* Store nesting level of winPtr2 within
* common ancestor here. */
{
register TkWindow *winPtr;
TkWindow *ancestorPtr;
int count1, count2, i;
/*
* Mark winPtr1 and all of its ancestors with a special flag bit.
*/
if (winPtr1 != NULL) {
for (winPtr = winPtr1; winPtr != NULL; winPtr = winPtr->parentPtr) {
winPtr->flags |= TK_GRAB_FLAG;
if (winPtr->flags & TK_TOP_HIERARCHY) {
break;
}
}
}
/*
* Search upwards from winPtr2 until an ancestor of winPtr1 is
* found or a top-level window is reached.
*/
winPtr = winPtr2;
count2 = 0;
ancestorPtr = NULL;
if (winPtr2 != NULL) {
for (; winPtr != NULL; count2++, winPtr = winPtr->parentPtr) {
if (winPtr->flags & TK_GRAB_FLAG) {
ancestorPtr = winPtr;
break;
}
if (winPtr->flags & TK_TOP_HIERARCHY) {
count2++;
break;
}
}
}
/*
* Search upwards from winPtr1 again, clearing the flag bits and
* remembering how many levels up we had to go.
*/
if (winPtr1 == NULL) {
count1 = 0;
} else {
count1 = -1;
for (i = 0, winPtr = winPtr1; winPtr != NULL;
i++, winPtr = winPtr->parentPtr) {
winPtr->flags &= ~TK_GRAB_FLAG;
if (winPtr == ancestorPtr) {
count1 = i;
}
if (winPtr->flags & TK_TOP_HIERARCHY) {
if (count1 == -1) {
count1 = i+1;
}
break;
}
}
}
*countPtr1 = count1;
*countPtr2 = count2;
return ancestorPtr;
}
/*
*----------------------------------------------------------------------
*
* TkPositionInTree --
*
* Compute where the given window is relative to a particular
* subtree of the window hierarchy.
*
* Results:
*
* Returns TK_GRAB_IN_TREE if the window is contained in the
* subtree. Returns TK_GRAB_ANCESTOR if the window is an
* ancestor of the subtree, in the same toplevel. Otherwise
* it returns TK_GRAB_EXCLUDED.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
int
TkPositionInTree(winPtr, treePtr)
TkWindow *winPtr; /* Window to be checked. */
TkWindow *treePtr; /* Root of tree to compare against. */
{
TkWindow *winPtr2;
for (winPtr2 = winPtr; winPtr2 != treePtr;
winPtr2 = winPtr2->parentPtr) {
if (winPtr2 == NULL) {
for (winPtr2 = treePtr; winPtr2 != NULL;
winPtr2 = winPtr2->parentPtr) {
if (winPtr2 == winPtr) {
return TK_GRAB_ANCESTOR;
}
if (winPtr2->flags & TK_TOP_HIERARCHY) {
break;
}
}
return TK_GRAB_EXCLUDED;
}
}
return TK_GRAB_IN_TREE;
}
/*
*----------------------------------------------------------------------
*
* TkGrabState --
*
* Given a window, this procedure returns a value that indicates
* the grab state of the application relative to the window.
*
* Results:
* The return value is one of three things:
* TK_GRAB_NONE - no grab is in effect.
* TK_GRAB_IN_TREE - there is a grab in effect, and winPtr
* is in the grabbed subtree.
* TK_GRAB_ANCESTOR - there is a grab in effect; winPtr is
* an ancestor of the grabbed window, in
* the same toplevel.
* TK_GRAB_EXCLUDED - there is a grab in effect; winPtr is
* outside the tree of the grab and is not
* an ancestor of the grabbed window in the
* same toplevel.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
int
TkGrabState(winPtr)
TkWindow *winPtr; /* Window for which grab information is
* needed. */
{
TkWindow *grabWinPtr = winPtr->dispPtr->grabWinPtr;
if (grabWinPtr == NULL) {
return TK_GRAB_NONE;
}
if ((winPtr->mainPtr != grabWinPtr->mainPtr)
&& !(winPtr->dispPtr->grabFlags & GRAB_GLOBAL)) {
return TK_GRAB_NONE;
}
return TkPositionInTree(winPtr, grabWinPtr);
}