NAME
- menu - Create and manipulate menu widgets
SYNOPSIS
- menu 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 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. 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 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 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 command 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 behaviour 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, 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 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 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 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 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 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 associated 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
menu unpost
If a -command option is specified for a cascade entry then it is evaluated 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 ... ?
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 index es 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 , command , 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 specified, it overrides
-bitmap .
This option is not available 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 submenu 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 indicator 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 displayed 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.
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
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 separator 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 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 inclusive.
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 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.
- 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
executed as a Tk 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 .
- 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 following 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 letters (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 subsequent changes to the menu's colour options will not be reflected in the entry.
SEE ALSO
- options(9), types(9)
| MENU(9) | Rev: Tue Jan 29 13:12:04 GMT 2008 |