checkbutton(n) Tk Built-In Commands checkbutton(n)_________________________________________________________________NAMEcheckbutton - Create and manipulate checkbutton widgets
SYNOPSIScheckbutton pathName ?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 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 but-
ton. 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 isn't 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:-offvalue
Tk 4.0 1
checkbutton(n) Tk Built-In Commands checkbutton(n)
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:-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
applicies to the indicator. If indicatorOn is
false, this color is used as the background for the
entire widget, in place of background or active-
Background, 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.
Tk 4.0 2
checkbutton(n) Tk Built-In Commands checkbutton(n)
Command-Line Name:-variable
Database Name: variable
Database Class: Variable
Specifies name of global variable to set to indi-
cate whether or not this button is selected.
Defaults to the name of the button within its par-
ent (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 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 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 path-
Name'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 new-
lines or if wrapping occurs because of the wrapLength
option) and one of the characters may optionally be under-
lined using the underline option. A checkbutton has all
of the behavior of a simple button, including the follow-
ing: 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 checkbut-
ton is selected then the indicator is normally drawn with
a sunken relief and a special color, and a Tcl variable
associated with the checkbutton is set to a particular
value (normally 1). If the checkbutton is not selected,
Tk 4.0 3
checkbutton(n) Tk Built-In Commands checkbutton(n)
then the indicator is drawn with a raised relief and no
special color, and the associated variable is set to a
different value (typically 0). 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 con-
figured to select and deselect itself on alternate button
clicks. In addition, each checkbutton monitors its asso-
ciated variable and automatically selects and deselects
itself when the variables value changes to and from the
button's ``on'' value.
WIDGET COMMAND
The checkbutton command creates a new Tcl command whose
name is pathName. This command may be used to invoke var-
ious operations on the widget. It has the following gen-
eral form:
pathName option ?arg arg ...?
Option and the args determine the exact behavior of the
command. The following commands are possible for check-
button 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 path-
Name (see Tk_ConfigureInfo for information on the
format of this list). If option is specified with
no value, then the command returns a list describ-
ing the one named option (this list will be identi-
cal 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
Tk 4.0 4
checkbutton(n) Tk Built-In Commands checkbutton(n)
redisplaying the checkbutton several times, alter-
nating 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 checkbut-
ton'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 com-
mand is ignored if the checkbutton's state is dis-
abled.
pathName select
Selects the checkbutton and sets the associated
variable to its ``on'' value.
pathName toggle
Toggles the selection state of the button, redis-
playing 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] A checkbutton activates whenever the mouse passes
over it and deactivates whenever the mouse leaves
the checkbutton.
[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.
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.
Tk 4.0 5
checkbutton(n) Tk Built-In Commands checkbutton(n)KEYWORDS
checkbutton, widget
Tk 4.0 6