tk4.2 User Commands - checkbutton
NAME
checkbutton - Create and manipulate checkbutton widgets
SYNOPSIS
checkbutton 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 button.
This command is typically invoked when mouse button 1
is released over the button window. The button's glo-
bal 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 accept-
able 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
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 appli-
cies to the indicator. 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 back-
ground 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. Dis-
abled state means that the checkbutton should be insen-
sitive: 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:-variable
Database Name: variable
Database Class: Variable
Specifies name of 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 accept-
able 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 ini-
tial 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
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, 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. Con-
figuration 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 vari-
ables 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 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 com-
mand. 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 correspond-
ing 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 vari-
able 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 associ-
ated 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 vari-
able 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] A checkbutton activates whenever the mouse passes over
it and deactivates whenever the mouse leaves the check-
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.
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.
KEYWORDS
checkbutton, widget