Radiobutton(3) User Contributed Perl Documentation Radiobutton(3)NAMETk::Radiobutton - Create and manipulate Radiobutton widgets
SYNOPSIS
$radiobutton = $parent->Radiobutton(?options?);
STANDARD OPTIONS-activebackground-cursor-highlightthickness -takefocus -active‐
foreground -disabledforeground -image -text
-anchor-font-justify-textvariable -background -fore‐
ground -padx-underline -bitmap -highlightback‐
ground -pady-wraplength -borderwidth -highlight‐
color -relief
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 -overre‐
lief 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 Under‐
line checkbuttons on the toolbar of a word-processor, for example.
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 but‐
ton. 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 indica‐
tor 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 radiobutton 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 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
activeBackground options. Disabled state means that the radiobut‐
ton 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 radiobutton is displayed.
Name: value
Class: Value
Switch: -value
Specifies value to store in the button's associated variable when‐
ever this button is selected.
Name: variable
Class: Variable
Switch: -variable
Specifies reference to a 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 "\$Tk::selectedButton".
Name: width
Class: Width
Switch: -width
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 method creates a new window (given by the $widget argu‐
ment) 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
$widget argument. At the time this command is invoked, there must not
exist a window named $widget, but $widget'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 perl/Tk callback 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 METHODS
The Radiobutton 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 radiobutton widgets:
$radiobutton->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.
$radiobutton->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.
$radiobutton->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 command is
ignored if the radiobutton's state is disabled.
$radiobutton->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 bind‐
ings for individual widgets or by redefining the class bindings.
KEYWORDS
radiobutton, widget
perl v5.8.8 2004-02-28 Radiobutton(3)
