[OpenSPARC-T2-SAM] / sam-t2 / devtools / v9 / man / mann / grab.n

'\"
'\" Copyright (c) 1992 The Regents of the University of California.
'\" Copyright (c) 1994-1996 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: grab.n,v 1.2.26.1 2004/10/28 10:19:29 dkf Exp $
'\" 
'\" The definitions below are for supplemental macros used in Tcl/Tk
'\" manual entries.
'\"
'\" .AP type name in/out ?indent?
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'\"	type is type of argument (int, etc.), in/out is either "in", "out",
'\"	or "in/out" to describe whether procedure reads or modifies arg,
'\"	and indent is equivalent to second arg of .IP (shouldn't ever be
'\"	needed;  use .AS below instead)
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'\" .AS ?type? ?name?
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'\"	name are examples of largest possible arguments that will be passed
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'\"	End of list of standard options for a Tk widget.
'\"
'\" .OP cmdName dbName dbClass
'\"	Start of description of a specific option.  cmdName gives the
'\"	option's name as specified in the class command, dbName gives
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.LP
See the \\fBoptions\\fR manual entry for details on the standard options.
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.TH grab n "" Tk "Tk Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
grab \- Confine pointer and keyboard events to a window sub-tree
.SH SYNOPSIS
\fBgrab \fR?\fB\-global\fR? \fIwindow\fR
.sp
\fBgrab \fIoption \fR?\fIarg arg \fR...?
.BE

.SH DESCRIPTION
.PP
This command implements simple pointer and keyboard grabs for Tk.
Tk's grabs are different than the grabs
described in the Xlib documentation.
When a grab is set for a particular window, Tk restricts all pointer
events to the grab window and its descendants in Tk's window hierarchy.
Whenever the pointer is within the grab window's subtree, the pointer
will behave exactly the same as if there had been no grab at all
and all events will be reported in the normal fashion.
When the pointer is outside \fIwindow\fR's tree, button presses and
releases and
mouse motion events are reported to \fIwindow\fR, and window entry
and window exit events are ignored.
The grab subtree ``owns'' the pointer:
windows outside the grab subtree will be visible on the screen
but they will be insensitive until the grab is released.
The tree of windows underneath the grab window can include top-level
windows, in which case all of those top-level windows
and their descendants will continue to receive mouse events
during the grab.
.PP
Two forms of grabs are possible:  local and global.
A local grab affects only the grabbing application:  events will
be reported to other applications as if the grab had never occurred.
Grabs are local by default.
A global grab locks out all applications on the screen,
so that only the given subtree of the grabbing application will be
sensitive to pointer events (mouse button presses, mouse button releases,
pointer motions, window entries, and window exits).
During global grabs the window manager will not receive pointer
events either.
.PP
During local grabs, keyboard events (key presses and key releases)
are delivered as usual:  the window
manager controls which application receives keyboard events, and
if they are sent to any window in the grabbing application then they are
redirected to the focus window.
During a global grab Tk grabs the keyboard so that all keyboard events
are always sent to the grabbing application.
The \fBfocus\fR command is still used to determine which window in the
application receives the keyboard events.
The keyboard grab is released when the grab is released.
.PP
Grabs apply to particular displays.  If an application has windows
on multiple displays then it can establish a separate grab on each
display.
The grab on a particular display affects only the windows on
that display.
It is possible for different applications on a single display to have
simultaneous local grabs, but only one application can have a global
grab on a given display at once.
.PP
The \fBgrab\fR command can take any of the following forms:
.TP
\fBgrab \fR?\fB\-global\fR? \fIwindow\fR
Same as \fBgrab set\fR, described below.
.TP
\fBgrab current \fR?\fIwindow\fR?
If \fIwindow\fR is specified, returns the name of the current grab
window in this application for \fIwindow\fR's display, or an empty
string if there is no such window.
If \fIwindow\fR is omitted, the command returns a list whose elements
are all of the windows grabbed by this application for all displays,
or an empty string if the application has no grabs.
.TP
\fBgrab release \fIwindow\fR
Releases the grab on \fIwindow\fR if there is one, otherwise does
nothing.  Returns an empty string.
.TP
\fBgrab set \fR?\fB\-global\fR? \fIwindow\fR
Sets a grab on \fIwindow\fR.  If \fB\-global\fR is specified then the
grab is global, otherwise it is local.
If a grab was already in effect for this application on
\fIwindow\fR's display then it is automatically released.
If there is already a grab on \fIwindow\fR and it has the same
global/local form as the requested grab, then the command
does nothing.  Returns an empty string.
.TP
\fBgrab status \fIwindow\fR
Returns \fBnone\fR if no grab is currently set on \fIwindow\fR,
\fBlocal\fR if a local grab is set on \fIwindow\fR, and
\fBglobal\fR if a global grab is set.
.SH WARNING
It is very easy to use global grabs to render a display completely
unusable (e.g. by setting a grab on a widget which does not respond to
events and not providing any mechanism for releasing the grab).  Take
\fIextreme\fR care when using them!
.SH BUGS
.PP
It took an incredibly complex and gross implementation to produce
the simple grab effect described above.
Given the current implementation, it isn't safe for applications
to use the Xlib grab facilities at all except through the Tk grab
procedures.
If applications try to manipulate X's grab mechanisms directly,
things will probably break.
.PP
If a single process is managing several different Tk applications,
only one of those applications can have a local grab for a given
display at any given time.  If the applications are in different
processes, this restriction doesn't exist.
.SH EXAMPLE
Set a grab so that only one button may be clicked out of a group.  The
other buttons are unresponsive to the mouse until the middle button is
clicked.
.CS
pack [button .b1 \-text "Click me! #1" \-command {destroy .b1}]
pack [button .b2 \-text "Click me! #2" \-command {destroy .b2}]
pack [button .b3 \-text "Click me! #3" \-command {destroy .b3}]
\fBgrab\fR .b2
.CE

.SH KEYWORDS
grab, keyboard events, pointer events, window
Commit	Line	Data
920dae64 AT	1	'\"
	2	'\" Copyright (c) 1992 The Regents of the University of California.
	3	'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
	4	'\"
	5	'\" See the file "license.terms" for information on usage and redistribution
	6	'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
	7	'\"
	8	'\" RCS: @(#) $Id: grab.n,v 1.2.26.1 2004/10/28 10:19:29 dkf Exp $
	9	'\"
	10	'\" The definitions below are for supplemental macros used in Tcl/Tk
	11	'\" manual entries.
	12	'\"
	13	'\" .AP type name in/out ?indent?
	14	'\" Start paragraph describing an argument to a library procedure.
	15	'\" type is type of argument (int, etc.), in/out is either "in", "out",
	16	'\" or "in/out" to describe whether procedure reads or modifies arg,
	17	'\" and indent is equivalent to second arg of .IP (shouldn't ever be
	18	'\" needed; use .AS below instead)
	19	'\"
	20	'\" .AS ?type? ?name?
	21	'\" Give maximum sizes of arguments for setting tab stops. Type and
	22	'\" name are examples of largest possible arguments that will be passed
	23	'\" to .AP later. If args are omitted, default tab stops are used.
	24	'\"
	25	'\" .BS
	26	'\" Start box enclosure. From here until next .BE, everything will be
	27	'\" enclosed in one large box.
	28	'\"
	29	'\" .BE
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	31	'\"
	32	'\" .CS
	33	'\" Begin code excerpt.
	34	'\"
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	37	'\"
	38	'\" .VS ?version? ?br?
	39	'\" Begin vertical sidebar, for use in marking newly-changed parts
	40	'\" of man pages. The first argument is ignored and used for recording
	41	'\" the version when the .VS was added, so that the sidebars can be
	42	'\" found and removed when they reach a certain age. If another argument
	43	'\" is present, then a line break is forced before starting the sidebar.
	44	'\"
	45	'\" .VE
	46	'\" End of vertical sidebar.
	47	'\"
	48	'\" .DS
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	52	'\" End of indented unfilled display.
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	54	'\" .SO
	55	'\" Start of list of standard options for a Tk widget. The
	56	'\" options follow on successive lines, in four columns separated
	57	'\" by tabs.
	58	'\"
	59	'\" .SE
	60	'\" End of list of standard options for a Tk widget.
	61	'\"
	62	'\" .OP cmdName dbName dbClass
	63	'\" Start of description of a specific option. cmdName gives the
	64	'\" option's name as specified in the class command, dbName gives
65	'\" the option's name in the option database, and dbClass gives
66	'\" the option's class in the option database.
67	'\"
68	'\" .UL arg1 arg2
69	'\" Print arg1 underlined, then print arg2 normally.
70	'\"
71	'\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $
72	'\"
73	'\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
74	.if t .wh -1.3i ^B
75	.nr ^l \n(.l
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79	.ie !"\\$4"" .TP \\$4
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81	. ie !"\\$2"" .TP \\n()Cu
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175	.\" draw two sides but no top otherwise.
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207	.de SO
208	.SH "STANDARD OPTIONS"
209	.LP
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213	..
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218	.LP
219	See the \\fBoptions\\fR manual entry for details on the standard options.
220	..
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222	.de OP
223	.LP
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226	Command-Line Name: \\fB\\$1\\fR
227	Database Name: \\fB\\$2\\fR
228	Database Class: \\fB\\$3\\fR
229	.fi
230	.IP
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242	..
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244	\\$1\l'\|0\(ul'\\$2
245	..
246	.TH grab n "" Tk "Tk Built-In Commands"
247	.BS
248	'\" Note: do not modify the .SH NAME line immediately below!
249	.SH NAME
250	grab \- Confine pointer and keyboard events to a window sub-tree
251	.SH SYNOPSIS
252	\fBgrab \fR?\fB\-global\fR? \fIwindow\fR
253	.sp
254	\fBgrab \fIoption \fR?\fIarg arg \fR...?
255	.BE
256
257	.SH DESCRIPTION
258	.PP
259	This command implements simple pointer and keyboard grabs for Tk.
260	Tk's grabs are different than the grabs
261	described in the Xlib documentation.
262	When a grab is set for a particular window, Tk restricts all pointer
263	events to the grab window and its descendants in Tk's window hierarchy.
264	Whenever the pointer is within the grab window's subtree, the pointer
265	will behave exactly the same as if there had been no grab at all
266	and all events will be reported in the normal fashion.
267	When the pointer is outside \fIwindow\fR's tree, button presses and
268	releases and
269	mouse motion events are reported to \fIwindow\fR, and window entry
270	and window exit events are ignored.
271	The grab subtree ``owns'' the pointer:
272	windows outside the grab subtree will be visible on the screen
273	but they will be insensitive until the grab is released.
274	The tree of windows underneath the grab window can include top-level
275	windows, in which case all of those top-level windows
276	and their descendants will continue to receive mouse events
277	during the grab.
278	.PP
279	Two forms of grabs are possible: local and global.
280	A local grab affects only the grabbing application: events will
281	be reported to other applications as if the grab had never occurred.
282	Grabs are local by default.
283	A global grab locks out all applications on the screen,
284	so that only the given subtree of the grabbing application will be
285	sensitive to pointer events (mouse button presses, mouse button releases,
286	pointer motions, window entries, and window exits).
287	During global grabs the window manager will not receive pointer
288	events either.
289	.PP
290	During local grabs, keyboard events (key presses and key releases)
291	are delivered as usual: the window
292	manager controls which application receives keyboard events, and
293	if they are sent to any window in the grabbing application then they are
294	redirected to the focus window.
295	During a global grab Tk grabs the keyboard so that all keyboard events
296	are always sent to the grabbing application.
297	The \fBfocus\fR command is still used to determine which window in the
298	application receives the keyboard events.
299	The keyboard grab is released when the grab is released.
300	.PP
301	Grabs apply to particular displays. If an application has windows
302	on multiple displays then it can establish a separate grab on each
303	display.
304	The grab on a particular display affects only the windows on
305	that display.
306	It is possible for different applications on a single display to have
307	simultaneous local grabs, but only one application can have a global
308	grab on a given display at once.
309	.PP
310	The \fBgrab\fR command can take any of the following forms:
311	.TP
312	\fBgrab \fR?\fB\-global\fR? \fIwindow\fR
313	Same as \fBgrab set\fR, described below.
314	.TP
315	\fBgrab current \fR?\fIwindow\fR?
316	If \fIwindow\fR is specified, returns the name of the current grab
317	window in this application for \fIwindow\fR's display, or an empty
318	string if there is no such window.
319	If \fIwindow\fR is omitted, the command returns a list whose elements
320	are all of the windows grabbed by this application for all displays,
321	or an empty string if the application has no grabs.
322	.TP
323	\fBgrab release \fIwindow\fR
324	Releases the grab on \fIwindow\fR if there is one, otherwise does
325	nothing. Returns an empty string.
326	.TP
327	\fBgrab set \fR?\fB\-global\fR? \fIwindow\fR
328	Sets a grab on \fIwindow\fR. If \fB\-global\fR is specified then the
329	grab is global, otherwise it is local.
330	If a grab was already in effect for this application on
331	\fIwindow\fR's display then it is automatically released.
332	If there is already a grab on \fIwindow\fR and it has the same
333	global/local form as the requested grab, then the command
334	does nothing. Returns an empty string.
335	.TP
336	\fBgrab status \fIwindow\fR
337	Returns \fBnone\fR if no grab is currently set on \fIwindow\fR,
338	\fBlocal\fR if a local grab is set on \fIwindow\fR, and
339	\fBglobal\fR if a global grab is set.
340	.SH WARNING
341	It is very easy to use global grabs to render a display completely
342	unusable (e.g. by setting a grab on a widget which does not respond to
343	events and not providing any mechanism for releasing the grab). Take
344	\fIextreme\fR care when using them!
345	.SH BUGS
346	.PP
347	It took an incredibly complex and gross implementation to produce
348	the simple grab effect described above.
349	Given the current implementation, it isn't safe for applications
350	to use the Xlib grab facilities at all except through the Tk grab
351	procedures.
352	If applications try to manipulate X's grab mechanisms directly,
353	things will probably break.
354	.PP
355	If a single process is managing several different Tk applications,
356	only one of those applications can have a local grab for a given
357	display at any given time. If the applications are in different
358	processes, this restriction doesn't exist.
359	.SH EXAMPLE
360	Set a grab so that only one button may be clicked out of a group. The
361	other buttons are unresponsive to the mouse until the middle button is
362	clicked.
363	.CS
364	pack [button .b1 \-text "Click me! #1" \-command {destroy .b1}]
365	pack [button .b2 \-text "Click me! #2" \-command {destroy .b2}]
366	pack [button .b3 \-text "Click me! #3" \-command {destroy .b3}]
367	\fBgrab\fR .b2
368	.CE
369
370	.SH KEYWORDS
371	grab, keyboard events, pointer events, window