menu(3)
NAME
Tk::Menu - Create and manipulate Menu widgets
SYNOPSIS
$menu = $parent->Menu(?options?);
STANDARD OPTIONS
-activebackground -background -disabledfore
ground -relief -activeborderwidth -border
width -font -takefocus -activeforeground -cur
sor -foreground
See Tk::options for details of the standard options.
WIDGET-SPECIFIC OPTIONS
- Name: postCommand
Class: Command
Switch: -postcommand - If this option is specified then it provides a call
back to execute each time the menu is posted. The
callback is invoked by the post method 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. - Name: selectColor
Class: Background
Switch: -selectcolor - For menu entries that are check buttons or radio but
tons, this option specifies the color to display in
the indicator when the check button or radio button is
selected. - Name: tearOff
Class: TearOff
Switch: -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. - Name: tearOffCommand
Class: TearOffCommand
Switch: -tearoffcommand - If this option has a non-empty value, then it speci
fies a perl/Tk callback 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, fol
lowed 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. - Name: title
Class: Title
Switch: -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. - Name: type
Class: Type
Switch: -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 mecha
nism and is not normally set outside of the Tk
library.
DESCRIPTION
The Menu method creates a new top-level window (given by
the $widget 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 $widget argument. At the time this
command is invoked, there must not exist a window named
$widget, but $widget'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 sev
eral different types of entries, each with different prop
erties. Entries of different types may be combined in a
single menu. Menu entries are not the same as entry wid
gets. In fact, menu entries are not even distinct wid
gets; 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 sec
ond textual field is displayed 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 colors. 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 <<MenuSe
lect>> virtual event is sent 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 callback is executed. The callback is
specified with the -command 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 par
ticular global variable (as determined by the -onvalue and
-variable options for the entry); when the entry is dese
lected 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 checkbutton 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 dis
played in the background color for the menu. If a -com
mand option is specified for a checkbutton entry, then its
value is evaluated 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 vari
able then they are in the same group. An indicator dia
mond 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
-selectcolor option for the entry; otherwise the indica
tor'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 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 construc
tion of cascading menus. The postcascade method 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
- $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
$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 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 method
and cannot be deleted with the delete method. 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 the Toplevel constructor for syntax). On the Macin
tosh, whenever the toplevel is in front, this menu's cas
cade 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 win
dow. 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 "CLONES" for more
information. - 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 rightjustified help menu is provided. In all cases, these menus
must be created 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 Tkdefined 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 proce
dure 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 dis
played. 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 con
tents 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, col
ors, images, bitmaps, 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 justified. - SEPARATORS IN MENUBARS
- Separator entries are not displayed in menubars. The last
separator entry causes remaining entries to be right jus
tified. - 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 orig
inal are reflected in the clone. Additionally, any cas
cades 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 orig
inal menu is destroyed. - WIDGET METHODS
- The Menu method creates a widget object. This object sup
ports the configure and cget methods described in Tk::options which can be used to enquire and modify the
options described above. The widget also inherits all the
methods provided by the generic Tk::Widget class, and the
Tk::Wm class. - Many of the methods 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 equiva
lent to none. This form may not be abbreviated. - last
- Same as end.
- none
- Indicates ``no entry at all''; this is used most com
monly 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 method. This
form may not be abbreviated. - @number
- In this form, number is treated as a y-coordinate in
the menu's window; the entry closest to that y-coor
dinate 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.
(In perl/Tk the matching is under review, but exact
match should work.) - The following methods are possible for menu widgets:
- $menu->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 dis
abled, then the menu ends up with no active entry.
Returns an empty string. - $menu->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 cas cade, 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 dis
playing 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::strict Motif 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 sepa
rator or tear-off entries. - -activeforeground => value
- Specifies a foreground color to use for dis
playing 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 sepa
rator or tear-off entries. - -background => value
- Specifies a background color to use for dis
playing 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
- For command, checkbutton, and radiobutton
entries, specifies a callback to execute when
the menu entry is invoked. For cascade
entries, specifies a callback to execute when
the entry is activated (i.e. just before its
submenu is posted). Not available for separa
tor or tear-off entries. - -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 dis
playing 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 invo
cation of image create. This option overrides 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 determines
whether or not the indicator should be dis
played. - -label => value
- Specifies a string to display as an identify
ing 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. Spec
ifies the value to store in the entry's asso
ciated variable when the entry is deselected. - -onvalue => value
- Available only for checkbutton entries. Spec
ifies the value to store in the entry's asso
ciated 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 background 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 activeForeground 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 sepa
rator 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 corresponds
to the first character of the text displayed
in the entry, 1 to the next character, 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 tearoff entries. - -value => value
- Available only for radiobutton entries. Spec
ifies the value to store in the entry's asso
ciated 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 check
button entries the variable is also set when
the entry is deselected. For radiobutton
entries, changing the variable causes the cur
rently-selected entry to deselect itself. - The add method returns an empty string.
- $menu->clone($parent ?, cloneType?)
- Makes a clone of the current menu as a child of $par_
ent. 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 "CLONES" for more information. - $menu->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). - $menu->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 method. - $menu->entryconfigure(index ?,options?)
- This method is similar to the configure method, 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 val ues accepted by the add method. If options are speci fied, options are modified as indicated in the method
call and the method returns an empty string. If no
options are specified, returns a list describing the current options for entry index (see Tk::options for
information on the format of this list). - $menu->index(index)
- Returns the numerical index corresponding to index, or
none if index was specified as none. - $menu->insert(index, type?, -option=>value, ...?)
- Same as the add method 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 method. It is not possible to
insert new menu entries before the tear-off entry, if
the menu has one. - $menu->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 callback associated with
it then the result of that callback is returned as the
result of the invoke widget method. 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 method. - $menu->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 visible on the screen. This
method normally returns an empty string. If the post
Command option has been specified, then its value is executed before posting the menu and the result of
that callback is returned as the result of the post
widget method. If an error returns while executing
the method, then the error is returned without posting
the menu. - $menu->postcascade(index)
- Posts the submenu associated with the cascade entry
given by index, and unposts any previously posted sub
menu. If index doesn't correspond to a cascade entry,
or if $menu isn't posted, the method has no effect
except to unpost any currently posted submenu. - $menu->type(index)
- Returns the type of the menu entry given by index.
This is the type argument passed to the add widget
method when the entry was created, such as command or separator, or tearoff for a tear-off entry. - $menu->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 method does not
work on Windows and the Macintosh, as those platforms
have their own way of unposting menus. - $menu->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 wid
get that will become the menu bar. You then add cas
cade entries to this menu, specifying the pull down
menus you wish to use in your menu bar. You then cre
ate all of the pulldowns. Once you have done this,
specify the menu using the -menu option of the
toplevel's method. See the toplevel manual entry for details. - Pulldown Menus in Menu Buttons
- This is the compatable way to do menu bars. You cre
ate one menubutton widget for each top-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 documentation for details. - Popup Menus
- Popup menus typically post in response to a mouse but
ton press or keystroke. You create the popup menus
and any cascaded submenus, then you call the Post
method at the appropriate time to post the top-level
menu. - $menu->Post($x,$y?,$entry?)
- $x and $y are the root window coordinates at which the
$menu will be displayed. If $entry is specified then that entry is centred on that point, otherwise the
top-left corner of the $menu is placed at that point. - Menu also inherits methods from Tk::Wm and so the
method Popup can be used to position menu relative to
other windows, the mouse cursor or the screen. - Option Menus
- An option menu consists of a menubutton with an asso
ciated 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 class to create option menubut
tons 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 permanently posted as a
top-level window. The torn-off menu behaves just the
same as the original 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 under
- lined with with -underline option, then pressing one
of the underlined letters (or its upper-case or lowercase 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 sub
menu is unposted and the current menu entry becomes
the cascade entry in the parent. 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 deter
mined 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. - 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 individual entries.
SEE ALSO
Tk::callbacks
KEYWORDS
- menu, widget