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radiobutton(n) Tk Built-In Commands radiobutton(n)
NAME
radiobutton - Create and manipulate radiobutton widgets
SYNOPSIS
radiobutton pathName ?options? -activebackground -disabledfore-
ground -padx -activeforeground -font -pady -anchor -fore-
ground -relief -background -highlightbackground -takefocus
-bitmap -highlightcolor -text -borderwidth -highlightthick-
ness -textvariable -compound -image -underline -cursor -jus-
tify -wraplength
WIDGET-SPECIFIC OPTIONS
Specifies a Tcl command to associate with the button. This command is
typically invoked when mouse button 1 is released over the button win-
dow. The button's global variable (-variable option) will be updated
before the command is invoked. Specifies a desired height for the but-
ton. 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_Get-
Pixels); for text it is in lines of text. If this option isn't speci-
fied, the button's desired height is computed from the size of the
image or bitmap or text being displayed in it. 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. 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 back-
ground for the entire widget, in place of background or activeBack-
ground, whenever the widget is selected. If specified as an empty
string then no special color is used for displaying when the widget is
selected. 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 acti-
vated. This is the behavior typically exhibited by the Align-Left,
Align-Right, and Center radiobuttons on the toolbar of a word-proces-
sor, for example. Specifies an alternative relief for the radiobutton,
to be used when the mouse cursor is over the widget. This option can
be used to make toolbar buttons, by configuring -relief flat -overre-
lief raised. If the value of this option is the empty string, then no
alternative relief is used when the mouse cursor is over the radiobut-
ton. The empty string is the default value. Specifies an image to
display (in place of the image option) when the radiobutton is
selected. This option is ignored unless the image option has been
specified. Specifies one of three states for the radiobutton: normal,
active, or disabled. In normal state the radiobutton is displayed
using the foreground and background options. The active state is typi-
cally used when the pointer is over the radiobutton. In active state
the radiobutton is displayed using the activeForeground and activeBack-
ground options. Disabled state means that the radiobutton should be
insensitive: the default bindings will refuse to activate the widget
and will ignore mouse button presses. In this state the disabledFore-
ground and background options determine how the radiobutton is dis-
played. Specifies value to store in the button's associated variable
whenever this button is selected. Specifies name of global variable to
set whenever this button is selected. Changes in this variable also
cause the button to select or deselect itself. Defaults to the value
selectedButton. Specifies a desired width for the button. If an image
or bitmap is being displayed in the button, 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 radiobutton command creates a new window (given by the pathName
argument) and makes it into a radiobutton widget. Additional options,
described above, may be specified on the command line or in the option
database to configure aspects of the radiobutton such as its colors,
font, text, and initial relief. The radiobutton 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 radiobutton is a widget that displays a textual string, bitmap or
image and a diamond or circle called an indicator. If text is dis-
played, 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 option-
ally be underlined using the underline option. A radiobutton has all
of the behavior of a simple button: 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 check button.
In addition, radiobuttons can be selected. If a radiobutton is
selected, the indicator is normally drawn with a selected appearance,
and a Tcl variable associated with the radiobutton is set to a particu-
lar 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 round mark inside. If the radiobutton is not selected,
then the indicator is drawn with a deselected appearance, and the asso-
ciated 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 round mark inside.
Typically, several radiobuttons share a single variable and the value
of the variable indicates which radiobutton is to be selected. When a
radiobutton is selected it sets the value of the variable to indicate
that fact; each radiobutton also monitors the value of the variable
and automatically selects and deselects itself when the variable's
value changes. By default the variable selectedButton is used; its
contents give the name of the button that is selected, or the empty
string if no button associated with that variable is selected. The
name of the variable for a radiobutton, plus the variable to be stored
into 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 radiobutton is configured to select itself on button clicks.
WIDGET COMMAND
The radiobutton command creates a new Tcl command whose name is path-
Name. 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 radiobutton 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
radiobutton 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 avail-
able options for pathName (see Tk_ConfigureInfo for information
on the format of this list). If option is specified with no
value, 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, 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 radiobutton command.
pathName deselect
Deselects the radiobutton and sets the associated variable to an
empty string. If this radiobutton was not currently selected,
the command has no effect.
pathName flash
Flashes the radiobutton. This is accomplished by redisplaying
the radiobutton several times, alternating between active and
normal colors. At the end of the flash the radiobutton is left
in the same normal/active state as when the command was invoked.
This command is ignored if the radiobutton's state is disabled.
pathName invoke
Does just what would have happened if the user invoked the
radiobutton with the mouse: selects the button and invokes its
associated Tcl command, 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 radiobutton. This com-
mand is ignored if the radiobutton's state is disabled.
pathName select
Selects the radiobutton and sets the associated variable to the
value corresponding to this widget.
BINDINGS
Tk automatically creates class bindings for radiobuttons that give them
the following default behavior:
[1] On Unix systems, a radiobutton activates whenever the mouse
passes over it and deactivates whenever the mouse leaves the
radiobutton. On Mac and Windows systems, when mouse button 1 is
pressed over a radiobutton, 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 radiobutton it is invoked
(it becomes selected and the command associated with the button
is invoked, if there is one).
[3] When a radiobutton has the input focus, the space key causes the
radiobutton to be invoked.
If the radiobutton's state is disabled then none of the above actions
occur: the radiobutton is completely non-responsive.
The behavior of radiobuttons can be changed by defining new bindings
for individual widgets or by redefining the class bindings.
SEE ALSO
checkbutton(n), labelframe(n), listbox(n), options(n), scale(n)
KEYWORDS
radiobutton, widget
Tk 4.4 radiobutton(n)
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