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menu \- Create and manipulate menu widgets
menu pathName ?options?
activeBackground background disabledForeground
activeBorderWidth borderWidth font
activeForeground cursor foreground
See section options, for more information.
:postcommand
-
Name="postCommand" 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.
:selector
-
Name="selector" Class="
Foreground"
For menu entries that are check buttons or radio buttons, this option
specifies the color to display in the selector when the check button
or radio button is selected.
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 a column. 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 text or
a bitmap, which is determined by the :label or :bitmap
option for the entry.
If the :accelerator option is specified for an entry then a second
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 a selector. The selector is present only for
check-button or radio-button 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. A disabled entry cannot be activated or invoked.
Disabled entries may be re-enabled, at which point it becomes
possible to activate and invoke them again.
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 :command option.
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.
A check-button menu entry behaves much like a check-button 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.
A selector box is displayed to the left of the label in a check-button
entry. If the entry is selected then the box's center is displayed
in the color given by the selector option for the menu;
otherwise the box's center is displayed in the background color for
the menu. If a :command option is specified for a check-button
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.
A radio-button menu entry behaves much like a radio-button widget.
Radio-button 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 radio-button entries is determined by their
associated variables: if two entries have the same associated
variable then they are in the same group.
A selector diamond is displayed to the left of the label in each
radio-button entry. If the entry is selected then the diamond's
center is displayed in the color given by the selector option
for the menu;
otherwise the diamond's center is displayed in the background color for
the menu. If a :command option is specified for a radio-button
entry, then its value is evaluated as a Tcl command each time the entry
is invoked; this happens after selecting the entry.
A cascade entry is one with an associated menu (determined
by the :menu option). Cascade entries allow the construction
of cascading menus. When the entry is activated, the
associated menu is posted just to the right of the entry;
that menu remains posted until the higher-level menu is unposted or
until some other entry is activated in the higher-level menu.
The associated menu should normally be a child of the menu containing
the cascade entry, 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, x
and y are the root-window coordinates of the upper-right
corner of the cascade entry, and group is the name of the
menu's group (as determined in its last post widget command).
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.
If a :command option is specified for a cascade entry then it is
evaluated as a Tcl command each time the associated menu is posted (the
evaluation occurs before the menu is posted).
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.
- last
-
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 spanning that y-coordinate is used.
For example, "@0" indicates the top-most entry in the
window. If number is outside the range of the window
then this form is equivalent to none.
- 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.
This option is not available for separator 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 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 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.
This option is not available for separator entries.
- :command value
-
For command, checkbutton, and radiobutton entries, specifies a
Tcl command to execute when the menu entry is invoked.
For cascade entries, specifies a Tcl command to execute
when the entry is activated (i.e. just before its submenu is
posted).
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 specified as an empty string (the default) then
the font option for the overall menu is used.
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 menu associated with this entry.
- :offvalue value
-
Available only for check-button entries. Specifies the value to
store in the entry's associated variable when the entry is
deselected.
- :onvalue value
-
Available only for check-button entries. Specifies the value to
store in the entry's associated variable when the entry is selected.
- :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 is insensitive: it doesn't activate
and doesn't respond to mouse button presses or releases.
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 typically used to indicate keyboard traversal characters.
0 corresponds to the first character of the text displayed in the entry,
1 to the next character, and so on.
If a bitmap is displayed in the entry then this option is ignored.
This option is not available for separator entries.
- :value value
-
Available only for radio-button entries. Specifies the value to
store in the entry's associated variable when the entry is selected.
- :variable value
-
Available only for check-button and radio-button 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 radio-button entries, changing the variable
causes the currently-selected entry to deselect itself.
The add widget command returns an empty string.
- 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
information 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 corresponding
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 values 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.
Returns an empty string.
- pathName :disable index
-
Change the state of the entry given by index to disabled
and redisplay the entry using its disabled colors.
Returns an empty string.
This command is obsolete and will eventually be removed;
use "pathName :entryconfigure index :state disabled" instead.
- pathName :enable index
-
Change the state of the entry given by index to normal
and redisplay the entry using its normal colors.
Returns an empty string.
This command is obsolete and will eventually be removed;
use "pathName :entryconfigure index :state normal" instead.
- 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 :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. Normally
the associated menubutton will take care of unposting the menu.
- 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 visible 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 :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.
Tk automatically creates class bindings for menus that give them
the following default behavior:
-
[1]
When the mouse cursor enters a menu, the entry underneath the mouse
cursor is activated; as the mouse moves around the menu, the active
entry changes to track the mouse.
-
[2]
When button 1 is released over a menu, the active entry (if any) is invoked.
-
[3]
A menu can be repositioned on the screen by dragging it with mouse
button 2.
-
[4]
A number of other bindings are created to support keyboard menu traversal.
See the manual entry for tk_bindForTraversal for details on these
bindings.
Disabled menu entries are non-responsive: they don't activate and
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.
At present it isn't possible to use the
option database to specify values for the options to individual
entries.
menu, widget
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