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NAME

radiobutton - Create and manipulate radiobutton widgets

SYNOPSIS

radiobutton pathName ? options ?

STANDARD OPTIONS

-activebackground -disabledcolor      -justify
-activeforeground -font               -relief
-anchor           -foreground         -takefocus
-background       -highlightcolor     -text
-bitmap           -highlightthickness -underline
-borderwidth      -image

WIDGET-SPECIFIC OPTIONS

-command command
Specifies a Tk 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.
-height dist
Specifies a desired height for the button. 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.
-indicatoron boolean
Specifies whether or not the indicator should be drawn. If false, the relief option is ignored and the widget's relief is always sunken if the widget is selected and raised otherwise.
-selectcolor colour
Specifies a background colour to use when the button is selected. If indicatoron is true, the colour applies to the indicator. If indicatoron is false, this colour 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, no special colour is used for displaying when the widget is selected.
-selectimage image
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.
-state state
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 typically used when the pointer is over the radiobutton. In active state the radiobutton is displayed using the activeforeground and activebackground 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 disabledcolor and background options determine how the radiobutton is displayed.
-value string
Specifies value to store in the button's associated variable whenever this button is selected.
-variable string
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 .
-width dist
Specifies a desired width for the button. 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 to configure aspects of the radiobutton such as its colours, 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 .

A radiobutton is a widget that displays a textual string, bitmap or image and a diamond 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) and one of the characters may optionally be underlined using the underline option. A radiobutton has all of the behaviour 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; and it invokes a Tk 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 sunken relief and a special colour, and a Tk variable associated with the radiobutton is set to a particular value. If the radiobutton is not selected, the indicator is drawn with a raised relief and no special colour. 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. 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 Tk 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 arg s determine the exact behaviour 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 of all of the available options for pathName . 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 invoke
Does just what would have happened if the user invoked the radiobutton with the mouse: selects the button and invokes its associated Tk command, if there is one. The return value is the return value from the Tk command, or an empty string if there is no command associated with the radiobutton. This command 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 bindings for radiobuttons that give them the following default behaviour:

[1]
The radiobutton activates whenever the mouse passes over it and deactivates whenever the mouse leaves the radiobutton.

[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).

If the radiobutton's state is disabled then none of the above actions occur: the radiobutton is completely non-responsive.

The behaviour of radiobuttons can be changed by defining new bindings for individual widgets.

SEE ALSO

button(9), checkbutton(9), choicebutton(9), options(9), types(9)

RADIOBUTTON(9) Rev:  Tue Jan 29 13:12:04 GMT 2008