menu(n) Tk Built-In Commands menu(n)
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NAME
menu, tk_menuSetFocus - Create and manipulate menu widgets
SYNOPSIS
menu pathName ?options?
tk_menuSetFocus pathName
STANDARD OPTIONS
-activebackground -borderwidth -foreground
-activeborderwidth -cursor -relief
-activeforeground -disabledforeground -takefocus
-background -font
See the options manual entry for details on the standard options.
WIDGET-SPECIFIC OPTIONS
Command-Line Name:-postcommand |
Database Name: postCommand |
Database Class: Command |
If this option is specified then it provides a Tcl command to execute each time the menu is |
posted. The command is invoked by the post widget command before posting the menu. Note that |
in 8.0 on Macintosh and Windows, all commands in a menu systems are executed before any are |
posted. This is due to the limitations in the individual platforms' menu managers.
Command-Line Name:-selectcolor
Database Name: selectColor
Database Class: Background
For menu entries that are check buttons or radio buttons, this option specifies the color to
display in the indicator when the check button or radio button is selected.
Command-Line Name:-tearoff
Database Name: tearOff
Database Class: TearOff
This option must have a proper boolean value, which specifies whether or not the menu should
include a tear-off entry at the top. If so, it will exist as entry 0 of the menu and the
other entries will number starting at 1. The default menu bindings arrange for the menu to be
torn off when the tear-off entry is invoked.
Command-Line Name:-tearoffcommand
Database Name: tearOffCommand
Database Class: TearOffCommand
If this option has a non-empty value, then it specifies a Tcl command to invoke whenever the
menu is torn off. The actual command will consist of the value of this option, followed by a
space, followed by the name of the menu window, followed by a space, followed by the name of
the name of the torn off menu window. For example, if the option's is ``a b'' and menu .x.y
is torn off to create a new menu .x.tearoff1, then the command ``a b .x.y .x.tearoff1'' will
be invoked. |
Command-Line Name:-title |
Database Name: title |
Database Class: Title |
The string will be used to title the window created when this menu is torn off. If the title |
is NULL, then the window will have the title of the menubutton or the text of the cascade item |
from which this menu was invoked. |
Command-Line Name:-type |
Database Name: type |
Database Class: Type |
This option can be one of menubar, tearoff, or normal, and is set when the menu is created. |
While the string returned by the configuration database will change if this option is changed, |
this does not affect the menu widget's behavior. This is used by the cloning mechanism and is |
not normally set outside of the Tk library.
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INTRODUCTION
The menu command creates a new top-level window (given by the pathName argument) and makes it into a
menu widget. Additional options, described above, may be specified on the command line or in the
option database to configure aspects of the menu such as its colors and font. The menu command
returns its pathName argument. At the time this command is invoked, there must not exist a window
named pathName, but pathName's parent must exist.
A menu is a widget that displays a collection of one-line entries arranged in one or more columns. |
There exist several different types of entries, each with different properties. Entries of different |
types may be combined in a single menu. Menu entries are not the same as entry widgets. In fact, |
menu entries are not even distinct widgets; the entire menu is one widget.
Menu entries are displayed with up to three separate fields. The main field is a label in the form
of a text string, a bitmap, or an image, controlled by the -label, -bitmap, and -image options for
the entry. If the -accelerator option is specified for an entry then a second textual field is dis-played displayed
played to the right of the label. The accelerator typically describes a keystroke sequence that may
be typed in the application to cause the same result as invoking the menu entry. The third field is
an indicator. The indicator is present only for checkbutton or radiobutton entries. It indicates
whether the entry is selected or not, and is displayed to the left of the entry's string.
In normal use, an entry becomes active (displays itself differently) whenever the mouse pointer is
over the entry. If a mouse button is released over the entry then the entry is invoked. The effect
of invocation is different for each type of entry; these effects are described below in the sections
on individual entries.
Entries may be disabled, which causes their labels and accelerators to be displayed with dimmer col-ors. colors.
ors. The default menu bindings will not allow a disabled entry to be activated or invoked. Disabled
entries may be re-enabled, at which point it becomes possible to activate and invoke them again. |
Whenever a menu's active entry is changed, a <<MenuSelect>> virtual event is send to the menu. The |
active item can then be queried from the menu, and an action can be taken, such as setting context- |
sensitive help text for the entry.
COMMAND ENTRIES
The most common kind of menu entry is a command entry, which behaves much like a button widget. When
a command entry is invoked, a Tcl command is executed. The Tcl command is specified with the -com-mand -command
mand option.
SEPARATOR ENTRIES
A separator is an entry that is displayed as a horizontal dividing line. A separator may not be
activated or invoked, and it has no behavior other than its display appearance.
CHECKBUTTON ENTRIES
A checkbutton menu entry behaves much like a checkbutton widget. When it is invoked it toggles back
and forth between the selected and deselected states. When the entry is selected, a particular value
is stored in a particular global variable (as determined by the -onvalue and -variable options for
the entry); when the entry is deselected another value (determined by the -offvalue option) is
stored in the global variable. An indicator box is displayed to the left of the label in a checkbut-ton checkbutton
ton entry. If the entry is selected then the indicator's center is displayed in the color given by
the -selectcolor option for the entry; otherwise the indicator's center is displayed in the back-ground background
ground color for the menu. If a -command option is specified for a checkbutton entry, then its value
is evaluated as a Tcl command each time the entry is invoked; this happens after toggling the
entry's selected state.
RADIOBUTTON ENTRIES
A radiobutton menu entry behaves much like a radiobutton widget. Radiobutton entries are organized
in groups of which only one entry may be selected at a time. Whenever a particular entry becomes
selected it stores a particular value into a particular global variable (as determined by the -value
and -variable options for the entry). This action causes any previously-selected entry in the same
group to deselect itself. Once an entry has become selected, any change to the entry's associated
variable will cause the entry to deselect itself. Grouping of radiobutton entries is determined by
their associated variables: if two entries have the same associated variable then they are in the
same group. An indicator diamond is displayed to the left of the label in each radiobutton entry.
If the entry is selected then the indicator's center is displayed in the color given by the -select-color -selectcolor
color option for the entry; otherwise the indicator's center is displayed in the background color for
the menu. If a -command option is specified for a radiobutton entry, then its value is evaluated as
a Tcl command each time the entry is invoked; this happens after selecting the entry.
CASCADE ENTRIES
A cascade entry is one with an associated menu (determined by the -menu option). Cascade entries
allow the construction of cascading menus. The postcascade widget command can be used to post and
unpost the associated menu just next to of the cascade entry. The associated menu must be a child of
the menu containing the cascade entry (this is needed in order for menu traversal to work correctly).
A cascade entry posts its associated menu by invoking a Tcl command of the form
menu post x y
where menu is the path name of the associated menu, and x and y are the root-window coordinates of
the upper-right corner of the cascade entry. On Unix, the lower-level menu is unposted by executing |
a Tcl command with the form |
menu unpost |
where menu is the name of the associated menu. On other platforms, the platform's native code takes |
care of unposting the menu.
If a -command option is specified for a cascade entry then it is evaluated as a Tcl command whenever |
the entry is invoked. This is not supported on Windows.
TEAR-OFF ENTRIES
A tear-off entry appears at the top of the menu if enabled with the tearOff option. It is not like
other menu entries in that it cannot be created with the add widget command and cannot be deleted
with the delete widget command. When a tear-off entry is created it appears as a dashed line at the
top of the menu. Under the default bindings, invoking the tear-off entry causes a torn-off copy to
be made of the menu and all of its submenus.
MENUBARS |
Any menu can be set as a menubar for a toplevel window (see toplevel command for syntax). On the Mac- |
intosh, whenever the toplevel is in front, this menu's cascade items will appear in the menubar |
across the top of the main monitor. On Windows and Unix, this menu's items will be displayed in a |
menubar accross the top of the window. These menus will behave according to the interface guidelines |
of their platforms. For every menu set as a menubar, a clone menu is made. See the CLONES section for |
more information. |
As noted, menubars may behave differently on different platforms. One example of this concerns the |
handling of checkbuttons and radiobuttons within the menu. While it is permitted to put these menu |
elements on menubars, they may not be drawn with indicators on some platforms, due to system restric- |
tions.
SPECIAL MENUS IN MENUBARS |
Certain menus in a menubar will be treated specially. On the Macintosh, access to the special Apple |
and Help menus is provided. On Windows, access to the Windows System menu in each window is provided. |
On X Windows, a special right-justified help menu is provided. In all cases, these menus must be cre- |
ated with the command name of the menubar menu concatenated with the special name. So for a menubar |
named .menubar, on the Macintosh, the special menus would be .menubar.apple and .menubar.help; on |
Windows, the special menu would be .menubar.system; on X Windows, the help menu would be |
.menubar.help. |
When Tk sees an Apple menu on the Macintosh, that menu's contents make up the first items of the |
Apple menu on the screen whenever the window containing the menubar is in front. The menu is the |
first one that the user sees and has a title which is an Apple logo. After all of the Tk-defined |
items, the menu will have a separator, followed by all of the items in the user's Apple Menu Items |
folder. Since the System uses a different menu definition procedure for the Apple menu than Tk uses |
for its menus, and the system APIs do not fully support everything Tk tries to do, the menu item will |
only have its text displayed. No font attributes, images, bitmaps, or colors will be displayed. In |
addition, a menu with a tearoff item will have the tearoff item displayed as "(TearOff)". |
When Tk see a Help menu on the Macintosh, the menu's contents are appended to the standard help menu |
on the right of the user's menubar whenever the user's menubar is in front. The first items in the |
menu are provided by Apple. Similar to the Apple Menu, cusomization in this menu is limited to what |
the system provides. |
When Tk sees a System menu on Windows, its items are appended to the system menu that the menubar is |
attached to. This menu has an icon representing a spacebar, and can be invoked with the mouse or by |
typing Alt+Spacebar. Due to limitations in the Windows API, any font changes, colors, images, bit- |
maps, or tearoff images will not appear in the system menu. |
When Tk see a Help menu on X Windows, the menu is moved to be last in the menubar and is right justi- |
fied.
CLONES |
When a menu is set as a menubar for a toplevel window, or when a menu is torn off, a clone of the |
menu is made. This clone is a menu widget in its own right, but it is a child of the original. |
Changes in the configuration of the original are reflected in the clone. Additionally, any cascades |
that are pointed to are also cloned so that menu traversal will work right. Clones are destroyed when |
either the tearoff or menubar goes away, or when the original menu is destroyed.
WIDGET COMMAND
The menu command creates a new Tcl command whose name is pathName. This command may be used to
invoke various operations on the widget. It has the following general form:
pathName option ?arg arg ...?
Option and the args determine the exact behavior of the command.
Many of the widget commands for a menu take as one argument an indicator of which entry of the menu
to operate on. These indicators are called indexes and may be specified in any of the following
forms:
number Specifies the entry numerically, where 0 corresponds to the top-most entry of the menu, 1
to the entry below it, and so on.
active Indicates the entry that is currently active. If no entry is active then this form is
equivalent to none. This form may not be abbreviated.
end Indicates the bottommost entry in the menu. If there are no entries in the menu then
this form is equivalent to none. This form may not be abbreviated.
last Same as end.
none Indicates ``no entry at all''; this is used most commonly with the activate option to
deactivate all the entries in the menu. In most cases the specification of none causes
nothing to happen in the widget command. This form may not be abbreviated.
@number In this form, number is treated as a y-coordinate in the menu's window; the entry clos-est closest
est to that y-coordinate is used. For example, ``@0'' indicates the top-most entry in
the window.
pattern If the index doesn't satisfy one of the above forms then this form is used. Pattern is
pattern-matched against the label of each entry in the menu, in order from the top down,
until a matching entry is found. The rules of Tcl_StringMatch are used.
The following widget commands are possible for menu widgets:
pathName activate index
Change the state of the entry indicated by index to active and redisplay it using its active
colors. Any previously-active entry is deactivated. If index is specified as none, or if the
specified entry is disabled, then the menu ends up with no active entry. Returns an empty
string.
pathName add type ?option value option value ...?
Add a new entry to the bottom of the menu. The new entry's type is given by type and must be
one of cascade, checkbutton, command, radiobutton, or separator, or a unique abbreviation of
one of the above. If additional arguments are present, they specify any of the following
options:
-activebackground value
Specifies a background color to use for displaying this entry when it is active. If
this option is specified as an empty string (the default), then the activeBackground
option for the overall menu is used. If the tk_strictMotif variable has been set to
request strict Motif compliance, then this option is ignored and the -background option
is used in its place. This option is not available for separator or tear-off entries.
-activeforeground value
Specifies a foreground color to use for displaying this entry when it is active. If
this option is specified as an empty string (the default), then the activeForeground
option for the overall menu is used. This option is not available for separator or
tear-off entries.
-accelerator value
Specifies a string to display at the right side of the menu entry. Normally describes
an accelerator keystroke sequence that may be typed to invoke the same function as the
menu entry. This option is not available for separator or tear-off entries.
-background value
Specifies a background color to use for displaying this entry when it is in the normal
state (neither active nor disabled). If this option is specified as an empty string
(the default), then the background option for the overall menu is used. This option is
not available for separator or tear-off entries.
-bitmap value
Specifies a bitmap to display in the menu instead of a textual label, in any of the
forms accepted by Tk_GetBitmap. This option overrides the -label option but may be
reset to an empty string to enable a textual label to be displayed. If a -image option
has been specified, it overrides -bitmap. This option is not available for separator
or tear-off entries. |
-columnbreak |
value | |
When this option is zero, the appears below the previous entry. When this option is |
one, the menu appears at the top of a new column in the menu.
-command value
Specifies a Tcl command to execute when the menu entry is invoked. Not available for
separator or tear-off entries. |
-compound |
value | |
Specifies whether the menu entry should display both an image and text, and if so, |
where the image should be placed relative to the text. Valid values for this option |
are bottom, center, left, none, right and top. The default value is none, meaning that |
the button will display either an image or text, depending on the values of the -image |
and -bitmap options.
-font value
Specifies the font to use when drawing the label or accelerator string in this entry.
If this option is specified as an empty string (the default) then the font option for
the overall menu is used. This option is not available for separator or tear-off
entries.
-foreground value
Specifies a foreground color to use for displaying this entry when it is in the normal
state (neither active nor disabled). If this option is specified as an empty string
(the default), then the foreground option for the overall menu is used. This option is
not available for separator or tear-off entries. |
-hidemargin |
value | |
Specifies whether the standard margins should be drawn for this menu entry. This is |
useful when creating palette with images in them, i.e., color palettes, pattern |
palettes, etc. 1 indicates that the margin for the entry is hidden; 0 means that the |
margin is used.
-image value
Specifies an image to display in the menu instead of a text string or bitmap The image
must have been created by some previous invocation of image create. This option over-rides overrides
rides the -label and -bitmap options but may be reset to an empty string to enable a
textual or bitmap label to be displayed. This option is not available for separator or
tear-off entries.
-indicatoron value
Available only for checkbutton and radiobutton entries. Value is a boolean that deter-mines determines
mines whether or not the indicator should be displayed.
-label value
Specifies a string to display as an identifying label in the menu entry. Not available
for separator or tear-off entries.
-menu value
Available only for cascade entries. Specifies the path name of the submenu associated
with this entry. The submenu must be a child of the menu.
-offvalue value
Available only for checkbutton entries. Specifies the value to store in the entry's
associated variable when the entry is deselected.
-onvalue value
Available only for checkbutton entries. Specifies the value to store in the entry's
associated variable when the entry is selected.
-selectcolor value
Available only for checkbutton and radiobutton entries. Specifies the color to display
in the indicator when the entry is selected. If the value is an empty string (the
default) then the selectColor option for the menu determines the indicator color.
-selectimage value
Available only for checkbutton and radiobutton entries. Specifies an image to display
in the entry (in place of the -image option) when it is selected. Value is the name of
an image, which must have been created by some previous invocation of image create.
This option is ignored unless the -image option has been specified.
-state value
Specifies one of three states for the entry: normal, active, or disabled. In normal
state the entry is displayed using the foreground option for the menu and the back-ground background
ground option from the entry or the menu. The active state is typically used when the
pointer is over the entry. In active state the entry is displayed using the active-Foreground activeForeground
Foreground option for the menu along with the activebackground option from the entry.
Disabled state means that the entry should be insensitive: the default bindings will
refuse to activate or invoke the entry. In this state the entry is displayed according
to the disabledForeground option for the menu and the background option from the entry.
This option is not available for separator entries.
-underline value
Specifies the integer index of a character to underline in the entry. This option is
also queried by the default bindings and used to implement keyboard traversal. 0 cor-responds corresponds
responds to the first character of the text displayed in the entry, 1 to the next char-acter, character,
acter, and so on. If a bitmap or image is displayed in the entry then this option is
ignored. This option is not available for separator or tear-off entries.
-value value
Available only for radiobutton entries. Specifies the value to store in the entry's
associated variable when the entry is selected. If an empty string is specified, then
the -label option for the entry as the value to store in the variable.
-variable value
Available only for checkbutton and radiobutton entries. Specifies the name of a global
value to set when the entry is selected. For checkbutton entries the variable is also
set when the entry is deselected. For radiobutton entries, changing the variable
causes the currently-selected entry to deselect itself.
The add widget command returns an empty string.
pathName cget option
Returns the current value of the configuration option given by option. Option may have any of
the values accepted by the menu command. |
pathName clone newPathname ?clone- |
Type? | |
Makes a clone of the current menu named newPathName. This clone is a menu in its own right, |
but any changes to the clone are propogated to the original menu and vice versa. cloneType can |
be normal, menubar, or tearoff. Should not normally be called outside of the Tk library. See |
the CLONES section for more information.
pathName configure ?option? ?value option value ...?
Query or modify the configuration options of the widget. If no option is specified, returns a
list describing all of the available options for pathName (see Tk_ConfigureInfo for informa-tion information
tion on the format of this list). If option is specified with no value, then the command
returns a list describing the one named option (this list will be identical to the correspond-ing corresponding
ing sublist of the value returned if no option is specified). If one or more option-value
pairs are specified, then the command modifies the given widget option(s) to have the given
value(s); in this case the command returns an empty string. Option may have any of the val-ues values
ues accepted by the menu command.
pathName delete index1 ?index2?
Delete all of the menu entries between index1 and index2 inclusive. If index2 is omitted then
it defaults to index1. Attempts to delete a tear-off menu entry are ignored (instead, you
should change the tearOff option to remove the tear-off entry).
pathName entrycget index option
Returns the current value of a configuration option for the entry given by index. Option may
have any of the values accepted by the add widget command.
pathName entryconfigure index ?options?
This command is similar to the configure command, except that it applies to the options for an
individual entry, whereas configure applies to the options for the menu as a whole. Options
may have any of the values accepted by the add widget command. If options are specified,
options are modified as indicated in the command and the command returns an empty string. If
no options are specified, returns a list describing the current options for entry index (see
Tk_ConfigureInfo for information on the format of this list).
pathName index index
Returns the numerical index corresponding to index, or none if index was specified as none.
pathName insert index type ?option value option value ...?
Same as the add widget command except that it inserts the new entry just before the entry
given by index, instead of appending to the end of the menu. The type, option, and value
arguments have the same interpretation as for the add widget command. It is not possible to
insert new menu entries before the tear-off entry, if the menu has one.
pathName invoke index
Invoke the action of the menu entry. See the sections on the individual entries above for
details on what happens. If the menu entry is disabled then nothing happens. If the entry
has a command associated with it then the result of that command is returned as the result of
the invoke widget command. Otherwise the result is an empty string. Note: invoking a menu
entry does not automatically unpost the menu; the default bindings normally take care of this
before invoking the invoke widget command.
pathName post x y
Arrange for the menu to be displayed on the screen at the root-window coordinates given by x
and y. These coordinates are adjusted if necessary to guarantee that the entire menu is visi-ble visible
ble on the screen. This command normally returns an empty string. If the postCommand option
has been specified, then its value is executed as a Tcl script before posting the menu and the
result of that script is returned as the result of the post widget command. If an error
returns while executing the command, then the error is returned without posting the menu.
pathName postcascade index
Posts the submenu associated with the cascade entry given by index, and unposts any previously
posted submenu. If index doesn't correspond to a cascade entry, or if pathName isn't posted,
the command has no effect except to unpost any currently posted submenu.
pathName type index
Returns the type of the menu entry given by index. This is the type argument passed to the
add widget command when the entry was created, such as command or separator, or tearoff for a
tear-off entry.
pathName |
unpost | |
Unmap the window so that it is no longer displayed. If a lower-level cascaded menu is posted, |
unpost that menu. Returns an empty string. This subcommand does not work on Windows and the |
Macintosh, as those platforms have their own way of unposting menus.
pathName yposition index
Returns a decimal string giving the y-coordinate within the menu window of the topmost pixel
in the entry specified by index.
MENU CONFIGURATIONS
The default bindings support four different ways of using menus: |
Pulldown Menus in |
Menubar | |
This is the most command case. You create a menu widget that will become the menu bar. You |
then add cascade entries to this menu, specifying the pull down menus you wish to use in your |
menu bar. You then create all of the pulldowns. Once you have done this, specify the menu |
using the -menu option of the toplevel's widget command. See the toplevel manual entry for |
details.
Pulldown Menus in Menu Buttons
This is the compatable way to do menu bars. You create one menubutton widget for each top-level toplevel
level menu, and typically you arrange a series of menubuttons in a row in a menubar window.
You also create the top-level menus and any cascaded submenus, and tie them together with
-menu options in menubuttons and cascade menu entries. The top-level menu must be a child of
the menubutton, and each submenu must be a child of the menu that refers to it. Once you have
done this, the default bindings will allow users to traverse and invoke the tree of menus via
its menubutton; see the menubutton manual entry for details.
Popup Menus
Popup menus typically post in response to a mouse button press or keystroke. You create the
popup menus and any cascaded submenus, then you call the tk_popup procedure at the appropriate
time to post the top-level menu.
Option Menus
An option menu consists of a menubutton with an associated menu that allows you to select one
of several values. The current value is displayed in the menubutton and is also stored in a
global variable. Use the tk_optionMenu procedure to create option menubuttons and their
menus.
Torn-off Menus
You create a torn-off menu by invoking the tear-off entry at the top of an existing menu. The
default bindings will create a new menu that is a copy of the original menu and leave it per-manently permanently
manently posted as a top-level window. The torn-off menu behaves just the same as the origi-nal original
nal menu.
DEFAULT BINDINGS
Tk automatically creates class bindings for menus that give them the following default behavior:
[1] When the mouse enters a menu, the entry underneath the mouse cursor activates; as the mouse
moves around the menu, the active entry changes to track the mouse.
[2] When the mouse leaves a menu all of the entries in the menu deactivate, except in the special
case where the mouse moves from a menu to a cascaded submenu.
[3] When a button is released over a menu, the active entry (if any) is invoked. The menu also
unposts unless it is a torn-off menu.
[4] The Space and Return keys invoke the active entry and unpost the menu.
[5] If any of the entries in a menu have letters underlined with with -underline option, then
pressing one of the underlined letters (or its upper-case or lower-case equivalent) invokes
that entry and unposts the menu.
[6] The Escape key aborts a menu selection in progress without invoking any entry. It also
unposts the menu unless it is a torn-off menu.
[7] The Up and Down keys activate the next higher or lower entry in the menu. When one end of the
menu is reached, the active entry wraps around to the other end.
[8] The Left key moves to the next menu to the left. If the current menu is a cascaded submenu,
then the submenu is unposted and the current menu entry becomes the cascade entry in the par-ent. parent.
ent. If the current menu is a top-level menu posted from a menubutton, then the current
menubutton is unposted and the next menubutton to the left is posted. Otherwise the key has
no effect. The left-right order of menubuttons is determined by their stacking order: Tk
assumes that the lowest menubutton (which by default is the first one created) is on the left.
[9] The Right key moves to the next menu to the right. If the current entry is a cascade entry,
then the submenu is posted and the current menu entry becomes the first entry in the submenu.
Otherwise, if the current menu was posted from a menubutton, then the current menubutton is
unposted and the next menubutton to the right is posted.
Disabled menu entries are non-responsive: they don't activate and they ignore mouse button presses
and releases.
Several of the bindings make use of the command tk_menuSetFocus. It saves the current focus and sets |
the focus to its pathName argument, which is a menu widget.
The behavior of menus can be changed by defining new bindings for individual widgets or by redefining
the class bindings.
BUGS
At present it isn't possible to use the option database to specify values for the options to individ-ual individual
ual entries.
KEYWORDS
menu, widget
Tk 4.1 menu(n)
|