MENU(9)MENU(9)NAMEmenu - Create and manipulate menu widgets
SYNOPSISmenu pathName ?options?
STANDARD OPTIONS-activebackground -borderwidth -foreground
-activeforeground -disabledcolor -relief
-background-font
WIDGET-SPECIFIC OPTIONS
-postcommand command
If this option is specified then it provides a Tk command to
execute each time the menu is posted. The command is invoked by
the post widget command before posting the menu.
-selectcolor colour
For menu entries that are check buttons or radio buttons, this
option specifies the colour to display in the indicator when the
check button or radio button is selected.
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 to configure
aspects of the menu such as its colours and font. The menu command
returns its pathName argument. At the time this command is invoked,
there must not exist a window named pathName.
A menu is a widget that displays a collection of one-line entries
arranged in a column. There exist several different types of entries,
each with different properties. Entries of different types may be com‐
bined in a single menu. Menu entries are not the same as entry wid‐
gets. 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.
The second field is a marker for cascade entries, showing that the
entry will post a cascade menu. It is displayed at the right-hand edge
of the 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 invo‐
cation 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 colours. 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.
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 Tk com‐
mand is executed. The Tk command 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 be‐
haviour 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 dese‐
lected states. When the entry is selected, the value ``1'' is stored
in a particular global variable (as determined by -variable option for
the entry); when the entry is deselected the value ``0'' 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 indi‐
cator's center is displayed in the colour given by the -selectcolor
option for the entry; otherwise the indicator's center is displayed in
the background colour for the menu. If a -command option is specified
for a checkbutton entry, then its value is evaluated as a Tk 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 deter‐
mined 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 colour given by the -selectcolor option for
the entry; otherwise the indicator's center is displayed in the back‐
ground colour for the menu. If a -command option is specified for a
radiobutton entry, then its value is evaluated as a Tk 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 asso‐
ciated menu just to the right 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 Tk command of
the form
menu post x y
where menu is the path name of the associated menu, and x and y are the
screen coordinates of the upper-right corner of the cascade entry. The
lower-level menu is unposted by executing a Tk command with the form
menu unpost
where menu is the name of the associated menu.
If a -command option is specified for a cascade entry then it is evalu‐
ated as a Tk command whenever the entry is invoked.
WIDGET COMMAND
The menu command creates a new Tk 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 behaviour of the command.
Many of the widget commands for a menu take as one argument an indica‐
tor 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.
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 closest to that y-coordinate is
used. For example, ``@0'' indicates the top-most entry in
the window.
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 colours. 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, com‐
mand, radiobutton, or separator. If additional arguments are
present, they specify any of the following options:
-activebackground value
Specifies a background colour to use for displaying this
entry when it is active. If this option is not specified
then the activebackground option for the overall menu is
used. This option is not available for separator
entries.
-activeforeground value
Specifies a foreground colour to use for displaying this
entry when it is active. If this option is not specified
then the activeforeground option for the overall menu is
used. This option is not available for separator
entries.
-background value
Specifies a background colour to use for displaying this
entry when it is in the normal state (neither active nor
disabled). If this option is not specified then the
background option for the overall menu is used. This
option is not available for separator entries.
-bitmap bitmap
Specifies a bitmap to display in the menu instead of a
textual label. 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 spec‐
ified, it overrides -bitmap. This option is not avail‐
able for separator entries.
-command value
Specifies a Tk command to execute when the menu entry is
invoked. Not available for separator entries.
-font value
Specifies the font to use when drawing the label or
accelerator string in this entry. If this option is not
specified then the font option for the overall menu is
used. This option is not available for separator
entries.
-foreground value
Specifies a foreground colour to use for displaying this
entry when it is in the normal state (neither active nor
disabled). If this option is not specified then the
foreground option for the overall menu is used. This
option is not available for separator entries.
-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
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
entries.
-label value
Specifies a string to display as an identifying label in
the menu entry. Not available for separator entries.
-menu value
Available only for cascade entries. Specifies the path
name of the submenu associated with this entry. The sub‐
menu must be a child of the menu.
-selectcolor value
Available only for checkbutton and radiobutton entries.
Specifies the colour to display in the indicator when the
entry is selected. If this option is not specified then
the selectcolor option for the menu determines the indi‐
cator colour.
-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 dis‐
played using the foreground and background colours. The
active state is typically used when the pointer is over
the entry. In active state the entry is displayed using
the activeforeground and activebackground colours. Dis‐
abled 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 accord‐
ing to the disabledcolor and background colours. 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
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 sep‐
arator 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 radiobut‐
ton 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 configure ?option? ?value option value ...?
Query or modify the configuration options of the widget. If no
option is specified, returns a list of all of the available
options for pathName. 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 values accepted by the
menu command.
pathName delete index1 ?index2?
Delete all of the menu entries between index1 and index2 inclu‐
sive. If index2 is omitted then it defaults to index1.
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 config‐
ure 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.
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.
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 screen
coordinates given by x and y. These coordinates are adjusted if
necessary to guarantee that the entire menu is visible on the
screen. This command normally returns an empty string. If the
postcommand option has been specified, then its value is exe‐
cuted as a Tk script before posting the menu and the result of
that script is returned as the result of the post widget com‐
mand. 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.
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.
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.
DEFAULT BINDINGS
Tk automatically creates bindings for menus that give them the follow‐
ing default behaviour:
[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] If any of the entries in a menu have letters underlined with
with -underline option, then pressing one of the underlined let‐
ters (or its upper-case or lower-case equivalent) invokes that
entry and unposts the menu.
Disabled menu entries are non-responsive: they don't activate and they
ignore mouse button presses and releases.
The behaviour of menus can be changed by defining new bindings for
individual widgets.
BUGS
The first time any colour option of an entry is configured, all of the
menu colour option values are captured and set in the entry. Any sub‐
sequent changes to the menu's colour options will not be reflected in
the entry.
SEE ALSOoptions(9), types(9)MENU(9)
