Checkbutton(3pm) User Contributed Perl Documentation Checkbutton(3pm)
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 v5.40.1 2025-04-13 Checkbutton(3pm)
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