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

[-postcommand postCommand] 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 Tk 8.0 on Macintosh and Windows, all post-commands in a system of menus are executed before any of those menus are posted. This is due to the limitations in the individual platforms' menu managers. [-selectcolor selectColor] 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. [-tearoff 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. [-tearoffcommand 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 value 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. [-title 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. [-type 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.

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 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 <<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.

TYPES OF ENTRIES

menu post x y

menu unpost

MENUBARS

Any menu can be set as a menubar for a toplevel window (see toplevel command for syntax). On the Macintosh, 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 across 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 restrictions.

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 ...?

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 closest to that y-coordinate is used. For example, “@0” indicates the top-most entry in the window.

pattern

If the index does not 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:

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 ?cloneType?

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 propagated 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 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. 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 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 postcascade index

Posts the submenu associated with the cascade entry given by index, and unposts any previously posted submenu. If index does not correspond to a cascade entry, or if pathName is not 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 xposition index

Returns a decimal string giving the x-coordinate within the menu window of the leftmost pixel in the entry specified by index.

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 common 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 compatible way to do menu bars. You create 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 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 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 underlined with the -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 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 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 do not 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 is not possible to use the option database to specify values for the options to individual entries.

SEE ALSO

bind(n), menubutton(n), ttk::menubutton(n), toplevel(n)

KEYWORDS

menu, widget