GCL TK Manual: menubutton

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### 2.8 menubutton

menubutton \- Create and manipulate menubutton widgets

#### Synopsis

menubutton pathName ?options?

#### Standard Options

    activeBackground  bitmap              font        relief
    activeForeground  borderWidth         foreground  text
    anchor            cursor              padX        textVariable
    background        disabledForeground  padY        underline

See options, for more information.

#### Arguments for Menubutton

`:height`

  Name=`"height" Class=`"`Height"`

  Specifies a desired height for the menu button. If a bitmap is being displayed in the menu button then the value is in screen units (i.e. any of the forms acceptable to Tk_GetPixels); for text it is in lines of text. If this option isn’t specified, the menu button’s desired height is computed from the size of the bitmap or text being displayed in it.

`:menu`

  Name=`"menu" Class=`"`MenuName"`

  Specifies the path name of the menu associated with this menubutton. The menu must be a descendant of the menubutton in order for normal pull-down operation to work via the mouse.

`:state`

  Name=`"state" Class=`"`State"`

  Specifies one of three states for the menu button: normal, active, or disabled. In normal state the menu button is displayed using the foreground and background options. The active state is typically used when the pointer is over the menu button. In active state the menu button is displayed using the activeForeground and activeBackground options. Disabled state means that the menu button is insensitive: it doesn’t activate and doesn’t respond to mouse button presses. In this state the disabledForeground and background options determine how the button is displayed.

`:width`

  Name=`"width" Class=`"`Width"`

  Specifies a desired width for the menu button. If a bitmap is being displayed in the menu button then the value is in screen units (i.e. any of the forms acceptable to Tk_GetPixels); for text it is in characters. If this option isn’t specified, the menu button’s desired width is computed from the size of the bitmap or text being displayed in it.

#### Introduction

The menubutton command creates a new window (given by the pathName argument) and makes it into a menubutton widget. Additional options, described above, may be specified on the command line or in the option database to configure aspects of the menubutton such as its colors, font, text, and initial relief. The menubutton 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 menubutton is a widget that displays a textual string or bitmap and is associated with a menu widget. In normal usage, pressing mouse button 1 over the menubutton causes the associated menu to be posted just underneath the menubutton. If the mouse is moved over the menu before releasing the mouse button, the button release causes the underlying menu entry to be invoked. When the button is released, the menu is unposted.

Menubuttons are typically organized into groups called menu bars that allow scanning: if the mouse button is pressed over one menubutton (causing it to post its menu) and the mouse is moved over another menubutton in the same menu bar without releasing the mouse button, then the menu of the first menubutton is unposted and the menu of the new menubutton is posted instead. The tk-menu-bar procedure is used to set up menu bars for scanning; see that procedure for more details.

#### A Menubutton Widget’s Arguments

The menubutton 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. The following commands are possible for menubutton widgets:

pathName :activate

  Change the menu button’s state to active and redisplay the menu button using its active foreground and background colors instead of normal colors. The command returns an empty string. This command is ignored if the menu button’s state is disabled. This command is obsolete and will eventually be removed; use “pathName :configure :state active” instead.

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 menubutton command.

pathName :deactivate

  Change the menu button’s state to normal and redisplay the menu button using its normal foreground and background colors. The command returns an empty string. This command is ignored if the menu button’s state is disabled. This command is obsolete and will eventually be removed; use “pathName :configure :state normal” instead.

#### "Default Bindings"

Tk automatically creates class bindings for menu buttons that give them the following default behavior:

- [1] A menu button activates whenever the mouse passes over it and deactivates whenever the mouse leaves it.
- [2] A menu button’s relief is changed to raised whenever mouse button 1 is pressed over it, and the relief is restored to its original value when button 1 is later released or the mouse is dragged into another menu button in the same menu bar.
- [3] When mouse button 1 is pressed over a menu button, or when the mouse is dragged into a menu button with mouse button 1 pressed, the associated menu is posted; the mouse can be dragged across the menu and released over an entry in the menu to invoke that entry. The menu is unposted when button 1 is released outside either the menu or the menu button. The menu is also unposted when the mouse is dragged into another menu button in the same menu bar.
- [4] If mouse button 1 is pressed and released within the menu button, then the menu stays posted and keyboard traversal is possible as described in the manual entry for tk-menu-bar.
- [5] Menubuttons may also be posted by typing characters on the keyboard. See the manual entry for tk-menu-bar for full details on keyboard menu traversal.
- [6] If mouse button 2 is pressed over a menu button then the associated menu is posted and also torn off: it can then be dragged around on the screen with button 2 and the menu will not automatically unpost when entries in it are invoked. To close a torn off menu, click mouse button 1 over the associated menu button.

If the menu button’s state is disabled then none of the above actions occur: the menu button is completely non-responsive.

The behavior of menu buttons can be changed by defining new bindings for individual widgets or by redefining the class bindings.

#### Keywords

menubutton, widget

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