NAME¶
checkbutton - Create and manipulate checkbutton widgets
SYNOPSIS¶
checkbutton pathName ?
options?
STANDARD OPTIONS¶
-activebackground -disabledforeground -padx
-activeforeground -font -pady
-anchor -foreground -relief
-background -highlightbackground -takefocus
-bitmap -highlightcolor -text
-borderwidth -highlightthickness -textvariable
-compound -image -underline
-cursor -justify -wraplength
See the
options manual entry for details on the standard 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 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 is not 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: -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 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 activated. This is the
behavior typically exhibited by the Bold, Italic, and Underline
checkbuttons on the toolbar of a word-processor, for example.
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: -overrelief
Database Name: overRelief
Database Class: OverRelief
- Specifies an alternative relief for the checkbutton, 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 checkbutton.
The empty string is the default value.
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 is used as the
background for the indicator 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.
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.
Command-Line Name: -tristateimage
Database Name: tristateImage
Database Class: TristateImage
- Specifies an image to display (in place of the image
option) when the checkbutton is in tri-state mode. This option is ignored
unless the image option has been specified.
Command-Line Name: -tristatevalue
Database Name: tristateValue
Database Class: Value
- Specifies the value that causes the checkbutton to display
the multi-value selection, also known as the tri-state mode. Defaults to
“”.
Command-Line Name: -variable
Database Name: variable
Database Class: Variable
- Specifies the name of a 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 acceptable to Tk_GetPixels); for text it is
in characters. If this option is not 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
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 selected appearance, and a Tcl
variable associated with the checkbutton is set to a particular value
(normally 1). The indicator is drawn with a check mark inside. If the
checkbutton is not selected, then the indicator is drawn with a deselected
appearance, and the associated variable is set to a different value (typically
0). The indicator is drawn without a check mark inside. In the special case
where the variable (if specified) has a value that matches the tristatevalue,
the indicator is drawn with a tri-state appearance and is in the tri-state
mode indicating mixed or multiple values. (This is used when the check box
represents the state of multiple items.) The indicator is drawn in a platform
dependent manner. Under Unix and Windows, the background interior of the box
is “grayed”. Under Mac, the indicator is drawn with a dash mark
inside. 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”, “off” and “tristate” 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 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 variables value changes to
and from the button's “on”, “off” and
“tristate” values.
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 command.
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 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
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 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
command is ignored if the checkbutton's state is disabled.
- pathName select
- Selects the checkbutton and sets the associated variable 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]
- On Unix systems, a checkbutton activates whenever the mouse
passes over it and deactivates whenever the mouse leaves the checkbutton.
On Mac and Windows systems, when mouse button 1 is pressed over a
checkbutton, 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 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. Under Windows, there are additional
key bindings; plus (+) and equal (=) select the button, and minus (-)
deselects the button.
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.
EXAMPLE¶
This example shows a group of uncoupled checkbuttons.
labelframe .lbl -text "Steps:"
checkbutton .c1 -text Lights -variable lights
checkbutton .c2 -text Cameras -variable cameras
checkbutton .c3 -text Action! -variable action
pack .c1 .c2 .c3 -in .lbl
pack .lbl
SEE ALSO¶
button(3tk), options(3tk), radiobutton(3tk), ttk::checkbutton(3tk)
KEYWORDS¶
checkbutton, widget