Provided by: tk8.6-doc_8.6.10-1_all 
NAME
checkbutton - Create and manipulate 'checkbutton' boolean selection widgets
SYNOPSIS
checkbutton pathName ?options?
STANDARD OPTIONS
-activebackground -disabledforeground -padx
-activeforeground -font -pady
-anchor -foreground -relief
-background -highlightbackground -takefocus
-bitmap -highlightcolor -text
-borderwidth -highlightthickness -textvariable
-compound -image -underline
-cursor -justify -wraplength
See the options manual entry for details on the standard options.
WIDGET-SPECIFIC OPTIONS
Command-Line Name:-command
Database Name: command
Database Class: Command
Specifies a Tcl command 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.
Command-Line Name:-height
Database Name: height
Database Class: 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 is
not specified, the button's desired height is computed from the size of the image
or bitmap or text being displayed in it.
Command-Line Name:-indicatoron
Database Name: indicatorOn
Database Class: 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 to false and -overrelief to “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.
Command-Line Name:-offvalue
Database Name: offValue
Database Class: Value
Specifies value to store in the button's associated variable whenever this button
is deselected. Defaults to “0”.
Command-Line Name:-onvalue
Database Name: onValue
Database Class: Value
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 checkbutton, 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
checkbutton. The empty string is the default value.
Command-Line Name:-selectcolor
Database Name: selectColor
Database Class: Background
Specifies a background color to use when the button is selected. If indicatorOn is
true then the 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.
Command-Line Name:-selectimage
Database Name: selectImage
Database Class: 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.
Command-Line Name:-state
Database Name: state
Database Class: 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.
Command-Line Name:-tristateimage
Database Name: tristateImage
Database Class: TristateImage
Specifies an image to display (in place of the -image option) when the checkbutton
is in tri-state mode. This option is ignored unless the -image option has been
specified.
Command-Line Name:-tristatevalue
Database Name: tristateValue
Database Class: Value
Specifies the value that causes the checkbutton to display the multi-value
selection, also known as the tri-state mode. Defaults to “”.
Command-Line Name:-variable
Database Name: variable
Database Class: Variable
Specifies the name of a global variable to set to indicate whether or not this
button is selected. Defaults to the name of the button within its parent (i.e. the
last element of the button window's path name).
Command-Line Name:-width
Database Name: width
Database Class: 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 is not 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 command creates a new window (given by the pathName 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 pathName
argument. At the time this command is invoked, there must not exist a window named
pathName, but pathName'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 Tcl command 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). 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). The indicator is drawn without a check mark inside. In the special case where the
variable (if specified) has a value that matches the tristatevalue, the indicator is drawn
with a tri-state appearance and is in the tri-state mode indicating mixed or multiple
values. (This is used when the check box represents the state of multiple items.) The
indicator is drawn in a platform dependent manner. Under Unix and Windows, the background
interior of the box is “grayed”. Under Mac, the indicator is drawn with a dash 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”, “off” and
“tristate” 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”, “off” and “tristate” values.
WIDGET COMMAND
The checkbutton 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 checkbutton widgets:
pathName cget option
Returns the current value of the configuration option given by option. Option may
have any of the values accepted by the checkbutton command.
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 checkbutton command.
pathName deselect
Deselects the checkbutton and sets the associated variable to its “off” value.
pathName 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.
pathName 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 Tcl command
associated with the checkbutton, if there is one. The return value is the return
value from the Tcl command, or an empty string if there is no command associated
with the checkbutton. This command is ignored if the checkbutton's state is
disabled.
pathName select
Selects the checkbutton and sets the associated variable to its “on” value.
pathName 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.
EXAMPLE
This example shows a group of uncoupled checkbuttons.
labelframe .lbl -text "Steps:"
checkbutton .c1 -text Lights -variable lights
checkbutton .c2 -text Cameras -variable cameras
checkbutton .c3 -text Action! -variable action
pack .c1 .c2 .c3 -in .lbl
pack .lbl
SEE ALSO
button(3tk), options(3tk), radiobutton(3tk), ttk::checkbutton(3tk)
KEYWORDS
checkbutton, widget