Provided by: perl-tk_804.036+dfsg1-1ubuntu3_amd64 
NAME
Tk::Checkbutton - Create and manipulate Checkbutton widgets
SYNOPSIS
$checkbutton = $parent->Checkbutton(?options?);
STANDARD OPTIONS
-activebackground -activeforeground -anchor -background -bitmap -borderwidth -compound -cursor
-disabledforeground -font -foreground -highlightbackground -highlightcolor -highlightthickness -image
-justify -padx -pady -relief -takefocus -text -textvariable -underline -wraplength
See Tk::options for details of the standard options.
WIDGET-SPECIFIC OPTIONS
Name: command
Class: Command
Switch: -command
Specifies a perl/Tk callback to associate with the button. This command is typically invoked when
mouse button 1 is released over the button window. The button's global variable (-variable option)
will be updated before the command is invoked.
Name: height
Class: Height
Switch: -height
Specifies a desired height for the button. If an image or bitmap is being displayed in the 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 button'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
Specifies whether or not the indicator should be drawn. Must be a proper boolean value. If false,
the relief option is ignored and the widget's relief is always sunken if the widget is selected and
raised otherwise.
Command-Line Name: -offrelief
Database Name: offRelief
Database Class: OffRelief
Specifies the relief for the checkbutton when the indicator is not drawn and the checkbutton is off.
The default value is raised. By setting this option to flat and setting -indicatoron false
-overrelief raised, the effect is achieved of having a flat button that raises on mouse-over and
which is depressed when activated. This is the behavior typically exhibited by the Bold, Italic, and
Underline checkbuttons on the toolbar of a word-processor, for example.
Name: offValue
Class: Value
Switch: -offvalue
Specifies value to store in the button's associated variable whenever this button is deselected.
Defaults to ``0''.
Name: onValue
Class: Value
Switch: -onvalue
Specifies value to store in the button's associated variable whenever this button is selected.
Defaults to ``1''.
Command-Line Name: -overrelief
Database Name: overRelief
Database Class: OverRelief
Specifies an alternative relief for the button, to be used when the mouse cursor is over the widget.
This option can be used to make toolbar buttons, by configuring -relief flat -overrelief raised.
If the value of this option is the empty string, then no alternative relief is used when the mouse
cursor is over the button. The empty string is the default value.
Name: selectColor
Class: Background
Switch: -selectcolor
Specifies a background color to use when the button is selected. If indicatorOn is true then the
color applies to the indicator. Under Windows, this color is used as the background for the
indicator regardless of the select state. If indicatorOn is false, this color is used as the
background for the entire widget, in place of background or activeBackground, whenever the widget is
selected. If specified as an empty string then no special color is used for displaying when the
widget is selected.
Name: selectImage
Class: SelectImage
Switch: -selectimage
Specifies an image to display (in place of the image option) when the checkbutton is selected. This
option is ignored unless the image option has been specified.
Name: state
Class: State
Switch: -state
Specifies one of three states for the checkbutton: normal, active, or disabled. In normal state the
checkbutton is displayed using the foreground and background options. The active state is typically
used when the pointer is over the checkbutton. In active state the checkbutton is displayed using
the activeForeground and activeBackground options. Disabled state means that the checkbutton 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 checkbutton
is displayed.
Name: variable
Class: Variable
Switch: -variable
Specifies reference to a variable to set to indicate whether or not this button is selected.
Defaults to "\$widget->{'Value'}" member of the widget's hash. In general perl variables are "undef"
unless specifically initialized which will not match either default -onvalue or default -offvalue.
Name: width
Class: Width
Switch: -width
Specifies a desired width for the button. If an image or bitmap is being displayed in the 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 button's desired width is computed from the size
of the image or bitmap or text being displayed in it.
DESCRIPTION
The Checkbutton method creates a new window (given by the $widget argument) and makes it into a
checkbutton widget. Additional options, described above, may be specified on the command line or in the
option database to configure aspects of the checkbutton such as its colors, font, text, and initial
relief. The checkbutton 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 checkbutton is a widget that displays a textual string, bitmap or image and a square called an
indicator. 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. A checkbutton has all of the
behavior of a simple button, including the following: it can display itself in either of three different
ways, according to the state option; it can be made to appear raised, sunken, or flat; it can be made to
flash; and it invokes a perl/Tk callback whenever mouse button 1 is clicked over the checkbutton.
In addition, checkbuttons can be selected. If a checkbutton is selected then the indicator is normally
drawn with a selected appearance, and a Tcl variable associated with the checkbutton is set to a
particular value (normally 1). Under Unix, the indicator is drawn with a sunken relief and a special
color. Under Windows, the indicator is drawn with a check mark inside. If the checkbutton is not
selected, then the indicator is drawn with a deselected appearance, and the associated variable is set to
a different value (typically 0). Under Unix, the indicator is drawn with a raised relief and no special
color. Under Windows, the indicator is drawn without a check mark inside. By default, the name of the
variable associated with a checkbutton is the same as the name used to create the checkbutton. The
variable name, and the ``on'' and ``off'' values stored in it, may be modified with options on the
command line or in the option database. Configuration options may also be used to modify the way the
indicator is displayed (or whether it is displayed at all). By default a checkbutton is configured to
select and deselect itself on alternate button clicks. In addition, each checkbutton monitors its
associated variable and automatically selects and deselects itself when the variables value changes to
and from the button's ``on'' value.
WIDGET METHODS
The Checkbutton 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 widget
also inherits all the methods provided by the generic Tk::Widget class.
The following additional methods are available for checkbutton widgets:
$checkbutton->deselect
Deselects the checkbutton and sets the associated variable to its ``off'' value.
$checkbutton->flash
Flashes the checkbutton. This is accomplished by redisplaying the checkbutton several times,
alternating between active and normal colors. At the end of the flash the checkbutton is left in the
same normal/active state as when the command was invoked. This command is ignored if the
checkbutton's state is disabled.
$checkbutton->invoke
Does just what would have happened if the user invoked the checkbutton with the mouse: toggle the
selection state of the button and invoke the perl/Tk callback associated with the checkbutton, if
there is one. The return value is the return value from the perl/Tk callback, or an empty string if
there is no command associated with the checkbutton. This command is ignored if the checkbutton's
state is disabled.
$checkbutton->select
Selects the checkbutton and sets the associated variable to its ``on'' value.
$checkbutton->toggle
Toggles the selection state of the button, redisplaying it and modifying its associated variable to
reflect the new state.
BINDINGS
Tk automatically creates class bindings for checkbuttons that give them the following default behavior:
[1] On Unix systems, a checkbutton activates whenever the mouse passes over it and deactivates whenever
the mouse leaves the checkbutton. On Mac and Windows systems, when mouse button 1 is pressed over a
checkbutton, the button activates whenever the mouse pointer is inside the button, and deactivates
whenever the mouse pointer leaves the button.
[2] When mouse button 1 is pressed over a checkbutton, it is invoked (its selection state toggles and the
command associated with the button is invoked, if there is one).
[3] When a checkbutton has the input focus, the space key causes the checkbutton to be invoked. Under
Windows, there are additional key bindings; plus (+) and equal (=) select the button, and minus (-)
deselects the button.
If the checkbutton's state is disabled then none of the above actions occur: the checkbutton is
completely non-responsive.
The behavior of checkbuttons can be changed by defining new bindings for individual widgets or by
redefining the class bindings.
KEYWORDS
checkbutton, widget
perl v5.38.2 2024-04-01 Checkbutton(3pm)