Menubutton

Section: User Contributed Perl Documentation (3)
Updated: 2021-01-27
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NAME

Tk::Menubutton - Create and manipulate Menubutton widgets

SYNOPSIS

$menubutton = $parent->Menubutton(?options?);

STANDARD OPTIONS

-activebackground      -cursor -highlightthickness     -takefocus
-activeforeground       -disabledforeground     -image  -text
-anchor -font   -justify        -textvariable
-background     -foreground     -padx   -underline
-bitmap -highlightbackground    -pady   -wraplength
-borderwidth    -highlightcolor -relief

See Tk::options for details of the standard options.

WIDGET-SPECIFIC OPTIONS

Command-Line Name: -compound
Database Name: compound
Database Class: Compound: Specifies whether the button 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.
Name: direction
Class: Height
Switch: -direction: Specifies where the menu is going to be popup up. above tries to pop the menu above the menubutton. below tries to pop the menu below the menubutton. left tries to pop the menu to the left of the menubutton. right tries to pop the menu to the right of the menu button. flush pops the menu directly over the menubutton.
Name: height
Class: Height
Switch: -height: Specifies a desired height for the menubutton. If an image or bitmap is being displayed in the menubutton 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 menubutton's desired height is computed from the size of the image or bitmap or text being displayed in it.
Name: indicatorOn
Class: IndicatorOn
Switch: -indicatoron: The value must be a proper boolean value. If it is true then a small indicator rectangle will be displayed on the right side of the menubutton and the default menu bindings will treat this as an option menubutton. If false then no indicator will be displayed.
Name: menu
Class: MenuName
Switch: -menu: Specifies the path name of the menu associated with this menubutton. The menu must be a child of the menubutton.
Name: state
Class: State
Switch: -state: Specifies one of three states for the menubutton: normal, active, or disabled. In normal state the menubutton is displayed using the foreground and background options. The active state is typically used when the pointer is over the menubutton. In active state the menubutton is displayed using the activeForeground and activeBackground options. Disabled state means that the menubutton should be insensitive: the default bindings will refuse to activate the widget and will ignore mouse button presses. In this state the disabledForeground and background options determine how the button is displayed.
Name: width
Class: Width
Switch: -width: Specifies a desired width for the menubutton. If an image or bitmap is being displayed in the menubutton 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 menubutton's desired width is computed from the size of the image or bitmap or text being displayed in it.

DESCRIPTION

The Menubutton method creates a new window (given by the $widget 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 $widget argument. At the time this command is invoked, there must not exist a window named $widget, but $widget's parent must exist.

A menubutton is a widget that displays a textual string, bitmap, or image and is associated with a menu widget. If text is displayed, it must all be in a single font, but it can occupy multiple lines on the screen (if it contains newlines or if wrapping occurs because of the wrapLength option) and one of the characters may optionally be underlined using the underline option. 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.

There are several interactions between menubuttons and menus; see the menu manual entry for information on various menu configurations, such as pulldown menus and option menus.

WIDGET METHODS

The Menubutton method creates a widget object. This object supports the configure and cget methods described in Tk::options which can be used to enquire and modify the options described above. The menu method returns the menu associated with the widget. The widget also inherits all the methods provided by the generic Tk::Widget class.

DEFAULT BINDINGS

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

[1]

A menubutton activates whenever the mouse passes over it and deactivates whenever the mouse leaves it.

[2]

Pressing mouse button 1 over a menubutton posts the menubutton: its relief changes to raised and its associated menu is posted under the menubutton. If the mouse is dragged down into the menu with the button still down, and if the mouse button is then released over an entry in the menu, the menubutton is unposted and the menu entry is invoked.

[3]

If button 1 is pressed over a menubutton and then released over that menubutton, the menubutton stays posted: you can still move the mouse over the menu and click button 1 on an entry to invoke it. Once a menu entry has been invoked, the menubutton unposts itself.

[4]

If button 1 is pressed over a menubutton and then dragged over some other menubutton, the original menubutton unposts itself and the new menubutton posts.

[5]

If button 1 is pressed over a menubutton and released outside any menubutton or menu, the menubutton unposts without invoking any menu entry.

[6]

When a menubutton is posted, its associated menu claims the input focus to allow keyboard traversal of the menu and its submenus. See the menu documentation for details on these bindings.

[7]

If the underline option has been specified for a menubutton then keyboard traversal may be used to post the menubutton: Alt+x, where x is the underlined character (or its lower-case or upper-case equivalent), may be typed in any window under the menubutton's toplevel to post the menubutton.

[8]

The F10 key may be typed in any window to post the first menubutton under its toplevel window that isn't disabled.

[9]

If a menubutton has the input focus, the space and return keys post the menubutton.

If the menubutton's state is disabled then none of the above actions occur: the menubutton is completely non-responsive.

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

KEYWORDS

menubutton, widget