| '\" |
| '\" 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 1998/09/14 18:22:56 stanton Exp $ |
| '\" |
| '\" The definitions below are for supplemental macros used in Tcl/Tk |
| '\" manual entries. |
| '\" |
| '\" .AP type name in/out ?indent? |
| '\" Start paragraph describing an argument to a library procedure. |
| '\" 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) |
| '\" |
| '\" .AS ?type? ?name? |
| '\" Give maximum sizes of arguments for setting tab stops. Type and |
| '\" name are examples of largest possible arguments that will be passed |
| '\" to .AP later. If args are omitted, default tab stops are used. |
| '\" |
| '\" .BS |
| '\" Start box enclosure. From here until next .BE, everything will be |
| '\" enclosed in one large box. |
| '\" |
| '\" .BE |
| '\" End of box enclosure. |
| '\" |
| '\" .CS |
| '\" Begin code excerpt. |
| '\" |
| '\" .CE |
| '\" End code excerpt. |
| '\" |
| '\" .VS ?version? ?br? |
| '\" Begin vertical sidebar, for use in marking newly-changed parts |
| '\" of man pages. The first argument is ignored and used for recording |
| '\" the version when the .VS was added, so that the sidebars can be |
| '\" found and removed when they reach a certain age. If another argument |
| '\" is present, then a line break is forced before starting the sidebar. |
| '\" |
| '\" .VE |
| '\" End of vertical sidebar. |
| '\" |
| '\" .DS |
| '\" Begin an indented unfilled display. |
| '\" |
| '\" .DE |
| '\" End of indented unfilled display. |
| '\" |
| '\" .SO |
| '\" Start of list of standard options for a Tk widget. The |
| '\" options follow on successive lines, in four columns separated |
| '\" by tabs. |
| '\" |
| '\" .SE |
| '\" 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 |
| '\" the option's name in the option database, and dbClass gives |
| '\" the option's class in the option database. |
| '\" |
| '\" .UL arg1 arg2 |
| '\" Print arg1 underlined, then print arg2 normally. |
| '\" |
| '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ |
| '\" |
| '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. |
| .if t .wh -1.3i ^B |
| .nr ^l \n(.l |
| .ad b |
| '\" # Start an argument description |
| .de AP |
| .ie !"\\$4"" .TP \\$4 |
| .el \{\ |
| . ie !"\\$2"" .TP \\n()Cu |
| . el .TP 15 |
| .\} |
| .ta \\n()Au \\n()Bu |
| .ie !"\\$3"" \{\ |
| \&\\$1 \\fI\\$2\\fP (\\$3) |
| .\".b |
| .\} |
| .el \{\ |
| .br |
| .ie !"\\$2"" \{\ |
| \&\\$1 \\fI\\$2\\fP |
| .\} |
| .el \{\ |
| \&\\fI\\$1\\fP |
| .\} |
| .\} |
| .. |
| '\" # define tabbing values for .AP |
| .de AS |
| .nr )A 10n |
| .if !"\\$1"" .nr )A \\w'\\$1'u+3n |
| .nr )B \\n()Au+15n |
| .\" |
| .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n |
| .nr )C \\n()Bu+\\w'(in/out)'u+2n |
| .. |
| .AS Tcl_Interp Tcl_CreateInterp in/out |
| '\" # BS - start boxed text |
| '\" # ^y = starting y location |
| '\" # ^b = 1 |
| .de BS |
| .br |
| .mk ^y |
| .nr ^b 1u |
| .if n .nf |
| .if n .ti 0 |
| .if n \l'\\n(.lu\(ul' |
| .if n .fi |
| .. |
| '\" # BE - end boxed text (draw box now) |
| .de BE |
| .nf |
| .ti 0 |
| .mk ^t |
| .ie n \l'\\n(^lu\(ul' |
| .el \{\ |
| .\" Draw four-sided box normally, but don't draw top of |
| .\" box if the box started on an earlier page. |
| .ie !\\n(^b-1 \{\ |
| \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| .\} |
| .el \}\ |
| \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| .\} |
| .\} |
| .fi |
| .br |
| .nr ^b 0 |
| .. |
| '\" # VS - start vertical sidebar |
| '\" # ^Y = starting y location |
| '\" # ^v = 1 (for troff; for nroff this doesn't matter) |
| .de VS |
| .if !"\\$2"" .br |
| .mk ^Y |
| .ie n 'mc \s12\(br\s0 |
| .el .nr ^v 1u |
| .. |
| '\" # VE - end of vertical sidebar |
| .de VE |
| .ie n 'mc |
| .el \{\ |
| .ev 2 |
| .nf |
| .ti 0 |
| .mk ^t |
| \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' |
| .sp -1 |
| .fi |
| .ev |
| .\} |
| .nr ^v 0 |
| .. |
| '\" # Special macro to handle page bottom: finish off current |
| '\" # box/sidebar if in box/sidebar mode, then invoked standard |
| '\" # page bottom macro. |
| .de ^B |
| .ev 2 |
| 'ti 0 |
| 'nf |
| .mk ^t |
| .if \\n(^b \{\ |
| .\" Draw three-sided box if this is the box's first page, |
| .\" draw two sides but no top otherwise. |
| .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| .\} |
| .if \\n(^v \{\ |
| .nr ^x \\n(^tu+1v-\\n(^Yu |
| \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c |
| .\} |
| .bp |
| 'fi |
| .ev |
| .if \\n(^b \{\ |
| .mk ^y |
| .nr ^b 2 |
| .\} |
| .if \\n(^v \{\ |
| .mk ^Y |
| .\} |
| .. |
| '\" # DS - begin display |
| .de DS |
| .RS |
| .nf |
| .sp |
| .. |
| '\" # DE - end display |
| .de DE |
| .fi |
| .RE |
| .sp |
| .. |
| '\" # SO - start of list of standard options |
| .de SO |
| .SH "STANDARD OPTIONS" |
| .LP |
| .nf |
| .ta 5.5c 11c |
| .ft B |
| .. |
| '\" # SE - end of list of standard options |
| .de SE |
| .fi |
| .ft R |
| .LP |
| See the \\fBoptions\\fR manual entry for details on the standard options. |
| .. |
| '\" # OP - start of full description for a single option |
| .de OP |
| .LP |
| .nf |
| .ta 4c |
| Command-Line Name: \\fB\\$1\\fR |
| Database Name: \\fB\\$2\\fR |
| Database Class: \\fB\\$3\\fR |
| .fi |
| .IP |
| .. |
| '\" # CS - begin code excerpt |
| .de CS |
| .RS |
| .nf |
| .ta .25i .5i .75i 1i |
| .. |
| '\" # CE - end code excerpt |
| .de CE |
| .fi |
| .RE |
| .. |
| .de UL |
| \\$1\l'|0\(ul'\\$2 |
| .. |
| .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 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 KEYWORDS |
| grab, keyboard events, pointer events, window |