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.so man.macros

.TH checkbutton n 4.4 Tk "Tk Built-In Commands"

.BS

'\" Note:  do not modify the .SH NAME line immediately below!

.SH NAME

checkbutton \- Create and manipulate checkbutton widgets

.SH SYNOPSIS

\fBcheckbutton\fI pathName \fR?\fIoptions\fR?

.SO

\-activebackground      \-cursor        \-highlightthickness    \-takefocus

\-activeforeground      \-disabledforeground    \-image \-text

\-anchor        \-font  \-justify       \-textvariable

\-background    \-foreground    \-padx  \-underline

\-bitmap        \-highlightbackground   \-pady  \-wraplength

\-borderwidth   \-highlightcolor        \-relief

.SE

.SH "WIDGET-SPECIFIC OPTIONS"

.OP \-command command 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 (\fB\-variable\fR option) will

be updated before the command is invoked.

.OP \-height height 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 \fBTk_GetPixels\fR);

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.

.OP \-indicatoron indicatorOn IndicatorOn

Specifies whether or not the indicator should be drawn.  Must be a

proper boolean value.  If false, the \fBrelief\fR option is

ignored and the widget's relief is always sunken if the widget is

selected and raised otherwise.

.OP \-offvalue offValue Value

Specifies value to store in the button's associated variable whenever

this button is deselected.  Defaults to ``0''.

.OP \-onvalue onValue Value

Specifies value to store in the button's associated variable whenever

this button is selected.  Defaults to ``1''.

.OP \-selectcolor selectColor Background

Specifies a background color to use when the button is selected.

If \fBindicatorOn\fR 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 \fBindicatorOn\fR is false, this color is used as the background

for the entire widget, in place of \fBbackground\fR or \fBactiveBackground\fR,

whenever the widget is selected.

If specified as an empty string then no special color is used for

displaying when the widget is selected.

.OP \-selectimage selectImage SelectImage

Specifies an image to display (in place of the \fBimage\fR option)

when the checkbutton is selected.

This option is ignored unless the \fBimage\fR option has been

specified.

.OP \-state state State

Specifies one of three states for the checkbutton:  \fBnormal\fR, \fBactive\fR,

or \fBdisabled\fR.  In normal state the checkbutton is displayed using the

\fBforeground\fR and \fBbackground\fR options.  The active state is

typically used when the pointer is over the checkbutton.  In active state

the checkbutton is displayed using the \fBactiveForeground\fR and

\fBactiveBackground\fR 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 \fBdisabledForeground\fR and

\fBbackground\fR options determine how the checkbutton is displayed.

.OP \-variable variable 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).

.OP \-width width 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 \fBTk_GetPixels\fR);

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.

.BE

.SH DESCRIPTION

.PP

The \fBcheckbutton\fR command creates a new window (given by the

\fIpathName\fR 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 \fBcheckbutton\fR command returns its

\fIpathName\fR argument.  At the time this command is invoked,

there must not exist a window named \fIpathName\fR, but

\fIpathName\fR's parent must exist.

.PP

A checkbutton is a widget

that displays a textual string, bitmap or image

and a square called an \fIindicator\fR.

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 \fBwrapLength\fR option) and

one of the characters may optionally be underlined using the

\fBunderline\fR 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 \fBstate\fR 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.

.PP

In addition, checkbuttons can be \fIselected\fR.

If a checkbutton is selected then the indicator is normally

.VS

drawn with a selected appearance, and

a Tcl variable associated with the checkbutton is set to a particular

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 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).

Under Unix, the indicator is drawn with a raised relief and no special

color.  Under Windows, the indicator is drawn without a check mark inside.

.VE

By default, the name of the variable associated with a checkbutton is the

same as the \fIname\fR 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.

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'' value.

.SH "WIDGET COMMAND"

.PP

The \fBcheckbutton\fR command creates a new Tcl command whose

name is \fIpathName\fR.  This

command may be used to invoke various

operations on the widget.  It has the following general form:

.CS

\fIpathName option \fR?\fIarg arg ...\fR?

.CE

\fIOption\fR and the \fIarg\fRs

determine the exact behavior of the command.  The following

commands are possible for checkbutton widgets:

.TP

\fIpathName \fBcget\fR \fIoption\fR

Returns the current value of the configuration option given

by \fIoption\fR.

\fIOption\fR may have any of the values accepted by the \fBcheckbutton\fR

command.

.TP

\fIpathName \fBconfigure\fR ?\fIoption\fR? ?\fIvalue option value ...\fR?

Query or modify the configuration options of the widget.

If no \fIoption\fR is specified, returns a list describing all of

the available options for \fIpathName\fR (see \fBTk_ConfigureInfo\fR for

information on the format of this list).  If \fIoption\fR is specified

with no \fIvalue\fR, 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 \fIoption\fR is specified).  If

one or more \fIoption\-value\fR 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.

\fIOption\fR may have any of the values accepted by the \fBcheckbutton\fR

command.

.TP

\fIpathName \fBdeselect\fR

Deselects the checkbutton and sets the associated variable to its ``off''

value.

.TP

\fIpathName \fBflash\fR

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 \fBdisabled\fR.

.TP

\fIpathName \fBinvoke\fR

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 \fBdisabled\fR.

.TP

\fIpathName \fBselect\fR

Selects the checkbutton and sets the associated variable to its ``on''

value.

.TP

\fIpathName \fBtoggle\fR

Toggles the selection state of the button, redisplaying it and

modifying its associated variable to reflect the new state.

.SH BINDINGS

.PP

Tk automatically creates class bindings for checkbuttons that give them

the following default behavior:

.VS

.IP [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.

.VE

.IP [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).

.VS

.IP [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.

.VE

.PP

If the checkbutton's state is \fBdisabled\fR then none of the above

actions occur:  the checkbutton is completely non-responsive.

.PP

The behavior of checkbuttons can be changed by defining new bindings for

individual widgets or by redefining the class bindings.

.SH KEYWORDS

checkbutton, widget