Ubuntu Manpage: menu, tk_menuSetFocus - Create and manipulate menu widgets

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

Command-Line Name:-postcommand
Database Name: postCommand
Database 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. 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.

Command-Line Name:-selectcolor
Database Name: selectColor
Database Class: Background

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.

Command-Line Name:-tearoff
Database Name: tearOff
Database Class: 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.

Command-Line Name:-tearoffcommand
Database Name: tearOffCommand
Database Class: 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.

Command-Line Name:-title
Database Name: title
Database Class: 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.

Command-Line Name:-type
Database Name: type
Database Class: 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

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 Tcl command is executed. The Tcl 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 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 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. 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 displayed in the background
color for the menu. If a -command option is specified for a checkbutton 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.

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 color
given by the -selectcolor option for the entry; otherwise the indicator'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 as a Tcl 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 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 a Tcl command of the form
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 a Tcl command with the form
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 as a Tcl
command 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 widget command and
cannot be deleted with the delete widget command. 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 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.

SPECIAL MENUS IN MENUBARS
Certain menus in a menubar will be treated specially. On the Macintosh, access to the
special Application and Help menus is provided. On Windows, access to the Windows System
menu in each window is provided. On X Windows, a special right-justified help menu may be
provided if Motif menu compatibility is enabled. 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 a .menubar.apple menu on the Macintosh, that menu's contents make up the
first items of the Application menu whenever the window containing the menubar is in
front. After all of the Tk-defined items, the menu will have a separator, followed by all
standard Application menu items.

When Tk sees a Help menu on the Macintosh, the menu's contents are appended to the
standard Help menu on the right of the user's menubar whenever the window's menubar is in
front. The first items in the menu are provided by Mac OS X.

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, colors, images, bitmaps, or tearoff images will not appear in the system menu.

When Tk sees a Help menu on X Windows and Motif menu compatibility is enabled the menu is
moved to be last in the menubar and is right justified. Motif menu compatibility is
enabled by setting the Tk option *Menu.useMotifHelp to true or by calling
tk::classic::restore menu.

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 ...?
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:

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.

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.

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.

If the index could match more than one of the above forms, then the form earlier in the
above list takes precedence.

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. If the
tk_strictMotif 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 separator or tear-off entries.

-activeforeground value
Specifies a foreground color to use for displaying 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 separator
or tear-off 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 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 (as controlled by the -compound 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 entry appears below the previous entry. When
this option is one, the entry appears at the top of a new column in the
menu.

-command value
Specifies a Tcl command to execute when the menu entry is invoked. Not
available for separator or tear-off entries.

-compound value
Specifies whether the menu entry should display both an image and text, and
if so, where the image should be placed relative to the text. Valid values
for this option are bottom, center, left, none, right and top. The default
value is none, meaning that the button will display either an image or text,
depending on the values of the -image and -bitmap options.

-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 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 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 invocation of
image create. This option overrides the -label and -bitmap options (as
controlled by the -compound option) 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 displayed.

-label value
Specifies a string to display as an identifying 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. Specifies the value to store in the
entry's associated variable when the entry is deselected.

-onvalue value
Available only for checkbutton entries. Specifies the value to store in the
entry's associated 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 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 or tear-off 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 variable 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 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.

KEYWORDS

       menu, widget