menubar - Create and manipulate menubars

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# menubar(n) 0.5 tklib "Create and manipulate menubars"

## Name

menubar - Creates an instance of the menubar Class.

## Synopsis

- package require Tcl 8.6
- package require Tk 8.6
- package require menubar ?0.5?

- menubar new ?options?
- mBarInst define body
- mBarInst install pathName body
- mBarInst menu.configure option tag-settings ?option tag-settings ...?
- mBarInst menu.namespace tag namespace
- mBarInst menu.hide tag
- mBarInst menu.show tag
- mBarInst tag.add tag value
- mBarInst tag.configure pathName tag ?option value ...option value?
- mBarInst tag.cget pathName tag ?option?
- mBarInst group.add tag label ?cmd? ?accel? ?sequence? ?state?
- mBarInst group.delete tag label
- mBarInst group.move direction tag label
- mBarInst group.configure tag label ?option value ...option value?
- mBarInst group.serialize tag
- mBarInst group.deserialize tag stream
- mBarInst notebook.addTabStore pathname
- mBarInst notebook.deleteTabStore pathname
- mBarInst notebook.setTabValue pathname tag
- mBarInst notebook.restoreTabValues pathname

## Description

menubar new ?options?

Create and return a new instance of the menubar class. The menubar class encapsulates the definition, installation and dynamic behavior of a menubar. The class doesn't depend on a widget framework and therefore can be used with or without a framework (e.g. Bwidget, IWidget, Snit, etc.). Unlike other Tk widget commands, the menubar command doesn't have a pathName argument because menubars are handled by the window manager (i.e. wm) and not the application.

## Options

The following options can be passed to the menubar new command.

These options are inherited from the Tk menu command, their effect is platform specific.

-activebackground
-activeborderwidth
-activeforeground
-background
-borderwidth
-cursor
-disabledforeground
-font
-foreground
-relief

## Introduction

An instance of the menubar class provides methods for compiling a description of the menubar, configuring menu items and installing the menubar in toplevel windows.

A menubar can be thought of as a tree of cascading menus. Users define a menubar using a language that results in a human readable description of a menubar. The description of the menubar is then compiled by an instance of the menubar class after which it can be installed in one or more toplevel windows.

The menubar class provides many unique capabilities that are not found in other tcl/tk menubar implementation. Some of these are:

- A tagging system that simplifies access to menu entries in the menu tree.

- Support for user defined tags that depend on the toplevel window context.

- A simplified and uniform interface for all callback commands.

- Namespace support for all callback commands so callback commands can be easily grouped into namespaces.

- Support for hiding and exposing menus on the menubar.

- A simplified method for creating radiobutton groups.

- Automatic management of state variables for checkbuttons and radiobuttons.

- Scope control for the state variables of checkbuttons and radiobuttons.

- Tear-off menu management that ensures only one tearoff menu is created.

- Support for dynamic menu extension to simplify the creation of recent document menus.

- Support for saving and restoring dynamic menu extensions.

## Terminology

MENUBAR

  The visible rendering of a menubar in a toplevel window is a horizontally group of cascading Tk menus.

MENU

  A menu is an ordered list of items that is rendered vertically. Menus are not visible until a user preforms some action (normally a <ButtonPress-1> event). A menu may contain any number of child menus that are rendered as cascading menus. Cascading menus are rendered next to the parent menu when they are activated.

MENU ENTRY

  A menu contains an ordered list of items called entries. Menu entries have a type and the menubar class supports the following 6 entry types: Command, Checkbutton, Radiobutton, Separator, Group and Menu.

ENTRY LABEL

  Each menu entry has a visible string that is called the entry label.

TAG

  A tag is name that is normally used to referr to an item in a menu tree. A tag name is an alphanumeric character string that may include the underscore character. Menu tree tags are defined for all nodes and leafs in a menu tree. This provides a flat abstraction of the tree and simplifies item referencing in menubar methods. Without this abstraction it would be necessary to reference menu elements using a tree path which could change at run-time. The menubar class also has a method that can create a user defined tag. User defined tags store values that change based on the currently active toplevel window. User defined tags can be used to store widget pathnames use by callback code so that output can be routed to the appropriate toplevel window.

## Methods

mBarInst define body

  Compiles body into a tree of menu entries which define the visual layout of the menubar. The body argument describes the layout using the following syntax, where the elements of the syntax are described below.

  body == definitions

      definitions    ::= { <ignore> | <definition> | <definition> <definitions> }
      ignore         ::= { <nl> | <white-space> <nl> | # <comment> <nl> }
      definition     ::= { <command> | <checkbutton> | <radiobutton> | <separator> | <group> | <menu> }
      command        ::= <label> C <tag> <nl>
      checkbutton    ::= <label> X<scope> { <tag> | <tag>+ } <nl>
      radiobutton    ::= <label> R<scope> { <tag> | <tag>+ } <nl>
      separator      ::= <stext> S <tag> <nl>
      group          ::= <dummy> G <tag> <nl>
      menu           ::= <label> { M:<tag> | M:<tag>+ } <nl> <definitions>
      stext          ::= '--' | <label>
      scope          ::= '' | '@' | '='

  C - Command

    The C type entry is the most common type of entry. This entry executes a command when it is invoked.

  X - Checkbutton

    A X type entry behaves much like a Tk checkbutton widget. When it is invoked it toggles back and forth between a selected and deselected states. The value of a checkbutton is a boolean (i.e. 1 or 0). By default all checkbuttons are deselected. If you want the checkbutton to be initially selected then include a trailing plus (+) with the tag name. See SCOPE CONTROL below for a description of the scope indicator.

  R - Radiobutton

    A R type menu entry behaves much like a Tk radiobutton widget. Each radiobutton entry is a member of a radiobutton group that controls the behavior of the radiobuttons in the group. All radiobuttons in a group are given the same tag name. In the example below Red, Green and Blue all have the same tag and are therefore all in the same radiobutton group. A trailing plus (+) on the tag name of a radiobutton entry will cause the entry to be the initially selected entry. See SCOPE CONTROL below for a description of the scope indicator.

  S - Separator

    A S type menu entry is an entry that is displayed either as a horizontal dividing line or a label. Separators are not active elements of a menu and have no associated behavior if they are invoked. If <stext> is two dashes (i.e. '--') then the separator will be displayed as a horizontal line otherwise <stext> will be displayed as a bold label surrounded by double dashes (e.g. "-- <stext> --") with a lightgray background.

  G - Command Group

    The G type menu entry marks a location in the menu tree where entries can be dynamically added and removed. Menu extension can only occur at the end of a menu so G type entries must be the last item on a menu. A G type entry is rendered as a separator line. The group.<xxx> sub-commands are used to manipulate command group entries.

  M - Menu

    An M type entry is used to define both menubar menus and cascading menus. Menu entries are the most complicated of the 6 menu types. A menu entry is composed of three list elements. The first element of the list is its label. The second element of the list is a composite string consisting of a type identifier (M) followed by an optional tag (beginning with a ':' separator) and finally an optional plus (+) which indicates that the menu is a tear-off menu. The final element of the list is a LIST VALUE.

mBarInst install pathName body

  The install method installs the menubar created with the define method into toplevel window pathName. The body argument of the command contains a tcl script which is used to initialize the installed menubar. Normally the tcl script will contain calls to various menubar methods to perform the initialization. The initialization code is only run once when the menubar is installed. The namespace in which the install method is executed becomes the default namespace for callback commands (see menu.namespace below for more details).

## Methods - menu.xxx

mBarInst menu.configure option tag-settings ?option tag-settings ...?

  Configures the tags of a menubar and returns an empty string. This method provides a convenient way to configure a larger number of tags without the verbosity of using the tag.configure method.

  option

    Option may have any of the values accepted by the tag.configure method.

  tag-settings

    The tag-settings argument is a string that is converted to a list of tag-value pairs using the following syntax.

    Syntax for tag-settings.

        tag-settings ::= { <ignore> | <value> | <value> <tag-settings> }
        ignore       ::= { <nl> | <white-space> <nl> | # <comment> <nl> }
        value        ::= <tag> <option-value> <nl>

mBarInst menu.namespace tag namespace

  Change the namespace for a sub-tree of the menubar starting at entry tag. The new value will be namespace. Each entry in the menubar tree has an associated namespace which will be used for its callback procedure. The default namespace is the namespace where the install method was executed. The namespace method can be used to change the namespace that will be used for callbacks in a sub-tree of the menubar. This method can only be used in the context of an install script.

mBarInst menu.hide tag

  Remove (hide) a menubar entry. When a menubar tree is defined all entries are visible by default. This method can be used to hide a menubar entry. The hide methods can be used in the context of an install script so that a menu will be initially hidden at application start up. The tag argument is the tag name of the menu to be hidden.

mBarInst menu.show tag

  Exposes (shows) a hidden menubar entry. When a menubar tree is defined all entries are visible by default. If a entry is hidden from the user (using the menu.hide method) then it can be exposed again using the show method. The tag argument is the tag name of the menu to be shown.

## Methods - tag.xxx

mBarInst tag.add tag value

  Add a user defined tag value. The tag.add method adds a new tag-value pair to the the tags defined for a menubar. User defined tags are different from the tags created by the define method. The tag.add method can only be used in an install script and its value is associated with the toplevel where the menubar is installed. This makes the tag context sensitive so callback code that queries the tag value will receive a value that is associated with the window that performed the callback.

mBarInst tag.configure pathName tag ?option value ...option value?

  Given the pathName of a toplevel window and a tag this method configures the menu entry associated with the tag and return an empty string.

  Standard Options

    These option are the same as those described for menu entries in the Tk menu documentation.

    -activebackground
    -activeforeground
    -background
    -bitmap
    -columnbreak
    -compound
    -font
    -foreground
    -hidemargin
    -image
    -indicatoron
    -label
    -selectcolor
    -selectimage
    -state

  Class Specific Options
    -bind {uline accel sequence}

      The value of the -bind option is three element list where the values are as follows.

      uline

        An integer index of a character to underline in the entry. This value performs the same function as the Tk menu -underline option. If this value is an empty string then no underlining is performed.

      accel

        A string to display at the right side of the menu entry. The string normally describes an accelerator keystroke sequence that may be typed to invoke the same function as the menu entry. This value performs the same function as the Tk menu -accelerator option. If this value is an empty string then no accelerator is displayed.

      sequence

        A bind sequence that will cause the entries associated command to fire.

    -command cmdprefix

      The value of the -command option a command prefix that is evaluated when the menu entry is invoked. By default the callback is evaluate in the namespace where the install method was executed. Additional values are appended to the cmdprefix and are thus passed to the callback command as argument. These additional arguments are described in the list below.

      command entry

        1) The pathname of the toplevel window that invoked the callback.

      checkbutton entry

        1) The pathname of the toplevel window that invoked the callback.

        2) The checkbutton's tag name

        3) The new value for the checkbutton

      radiobutton entry

        1) The pathname of the toplevel window that invoked the callback.

        2) The radiobutton's tag name

        3) The label of the button that was selected

      group entry

        1) The pathname of the toplevel window that invoked the callback.

mBarInst tag.cget pathName tag ?option?

  Returns the value of the configuration option given by option or the value of a user defined tag. The option argument may be any of the options accepted by the tag.configure method for the tag type. User defined tags are queried without an option value.

## Methods - group.xxx

mBarInst group.add tag label ?cmd? ?accel? ?sequence? ?state?

  Add a command to the group with tag name tag. This method appends a new command entry to the end of a command group. The order of the arguments is fixed but arguments to the right can be ignored. Arguments to this method have the following meaning.

  tag (string)

    The tag name of the command group.

  label (string)

    The displayed label for the menu entry.

  cmd (string)

    A command prefix that will be used for callback command.

  accel (string)

    An accelerator string that will be displayed next to the entry label.

  sequence (string)

    A bind sequence that will be bound to the callback command.

  state (enum)

    Sets the active state of the command. One of: normal, disabled, active

mBarInst group.delete tag label

  Delete a command from a group with tag name tag. This method deletes command label from a command group.

mBarInst group.move direction tag label

  Change the position of an entry in a group with tag name tag. The direction argument is the direction ('up' or 'down') the entry will be moved. The entry that is moved has the name label.

mBarInst group.configure tag label ?option value ...option value?

  Configure the options of an entry in the command group with tag name tag. This method is similar to the tag.configure method except that it works on entries in a command group. Set documentation for the tag.configure method (above) for more details on command entry options.

mBarInst group.serialize tag

  Return a string serialization of the entries in a command group. The argument tag is the tag name for the group that is to be serialized. The resulting serialization is a list containing three element (1) the tag name of the group (2) a dictionary containing group level options (3) a list of zero or more similar three element lists that describe the entries in the group.

mBarInst group.deserialize tag stream

  Replace the contents of group tag tag with the commands defined in the serialization stream. The original contents of the group are lost.

## Methods - notebook.xxx

mBarInst notebook.addTabStore pathname

  This method should be used in code that creates a new notebook tab. Execution of this method will cause state storage to be allocated for the new notebook tab. The pathname for the notebook tab is passed as an argument to the method.

mBarInst notebook.deleteTabStore pathname

  This command deallocates the state store for a notebook tab. The pathname for the notebook tab is passed as an argument to the method.

mBarInst notebook.setTabValue pathname tag

  This method should be used in the callback for menubar checkbuttons or radiobuttons that have notebook tab scope control. When this method is executed it will move the value associated with tag into the tab store for the tab identified by pathname.

mBarInst notebook.restoreTabValues pathname

  This method should be place in a bind script that is triggered by a notebooks <<NotebookTabChanged>> event.

## Scope Control

By default a menubar instance looks the same in all installed toplevel windows. As changes are made to one instance of a menubar all the other instances are immediately updated. This means the internal state of all the menu entries for the instances are synchronized. This behavior is called global scope control of the menubar state.

The menubar class allows finer scope control on check and radio buttons. The scope of these entry types can be modified by adding a modifier character to their type character. Two modifier characters are supported as show in the table below.

    ''  ::= global scope (no character)
    '@' ::= local scope modifier
    '=' ::= notebook tab scope modifier

When the local scope character (@) is added to the definition of a button, the button is given a new variable for each installed toplevel window. This has the effect of making the button's state local to the window (i.e. local scope). An example use case for this behavior might be a status bar that can be toggled on an off by a checkbutton. The developer may want to allow the user to control the visibility of the status bar on a per window basis. In this case a local modifier would be added to the status bar selector so the callback code would receive an appropriate value based on the current toplevel window.

The notebook tab scope character (=) is similar in effect to the local scope character but it allows a notebook tab selection to also manage the state of of a button. Adding the notebook tab scope modifier enables notebook tab scope control but the developer must then make use of the notebook.xxxx sub-commands to actively manage state values as tabs are added, deleted and selected.

## Example

    package require Tcl
    package require Tk
    package require menubar
    set tout [text .t -width 25 -height 12]
    pack ${tout} -expand 1 -fill both
    set mbar [menubar new \
        -borderwidth 4 \
        -relief groove  \
        -foreground black \
        -background tan \
        ]
    ${mbar} define {
        File M:file {
            Exit                 C      exit
        }
        Edit M:items+ {
        #   Label               Type    Tag Name(s)
        #   -----------------   ----    ---------
            "Cut"               C       cut
            "Copy"              C       copy
            "Paste"             C       paste
            --                  S       s2
            "Options" M:opts {
                "CheckList" M:chx+ {
                    Coffee      X       coffee+
                    Donut       X       donut
                    Eggs        X       eggs
                    }
                "RadioButtons" M:btn+ {
                    "Red"       R       color
                    "Green"     R       color+
                    "Blue"      R       color
                    }
            }
        }
        Help M:help {
            About               C       about
        }
    }
    ${mbar} install . {
        ${mbar} tag.add tout ${tout}
        ${mbar} menu.configure -command {
            # file menu
            exit            {Exit}
            # Item menu
            cut             {CB Edit cut}
            copy            {CB Edit copy}
            paste           {CB Edit paste}
            # boolean menu
            coffee          {CB CheckButton}
            donut           {CB CheckButton}
            eggs            {CB CheckButton}
            # radio menu
            color           {CB RadioButton}
            # Help menu
            about           {CB About}
        } -bind {
            exit        {1 Cntl+Q  Control-Key-q}
            cut         {2 Cntl+X  Control-Key-x}
            copy        {0 Cntl+C  Control-Key-c}
            paste       {0 Cntl+V  Control-Key-v}
            coffee      {0 Cntl+A  Control-Key-a}
            donut       {0 Cntl+B  Control-Key-b}
            eggs        {0 Cntl+C  Control-Key-c}
            about       0
        } -background {
            exit red
        } -foreground {
            exit white
        }
    }
    proc pout { txt } {
        global mbar
        set tout [${mbar} tag.cget . tout]
        ${tout} insert end "${txt}\n"
    }
    proc Exit { args } {
        puts "Goodbye"
        exit
    }
    proc CB { args } {
        set alist [lassign ${args} cmd]
        pout "${cmd}: [join ${alist} {, }]"
    }
    wm minsize . 300 300
    wm geometry . +4+4
    wm protocol . WM_DELETE_WINDOW exit
    wm title . "Example"
    wm focusmodel . active
    pout "Example started ..."

## Caveats

This implementation uses TclOO so it requires 8.6. The code has been tested on Windows (Vista), Linux and OSX (10.4).

## References

See also

1. menu

2. A command that creates menubar objects

## Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category menubar of the Tklib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

## Copyright

Copyright © 2009 Tom Krehbiel <krehbiel.tom@gmail.com> All rights reserved.