= checkbutton: Create and manipulate checkbutton widgets     checkbutton 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. -offvalue string       Specifies  value  to  store in the button's associated       variable whenever this button is deselected.  Defaults       to ``0''. -onvalue string       Specifies  value  to  store in the button's associated       variable whenever this button is  selected.   Defaults       to ``1''. -selectcolor colour       Specifies  a  background colour to use when the button       is selected.  If indicatoron is true then  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  then no special colour is used for dis‐       playing when the widget is selected. -state 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.   Dis‐       abled  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  disabledcolor  and  back‐       ground  options  determine how the checkbutton is dis‐       played. -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. -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. The  checkbutton  command  creates a new window (given by thepathname argument) and makes it into  a  checkbutton  widget.Additional  options, described above, may be specified on thecommand line to configure aspects of the checkbutton such  asits colours, font, text, and initial relief.  The checkbuttoncommand returns its pathname argument.  At the time this com‐mand  is  invoked,  there must not exist a window named path‐name. A checkbutton is a widget that  displays  a  textual  string,bitmap or image and a square called an indicator.  If text isdisplayed, it must all be in a single font, but it can occupymultiple  lines  on  the screen (if it contains newlines) andone of the characters may optionally be underlined using  theunderline  option.  A checkbutton has all of the behaviour ofa simple button, including  the  following:  it  can  displayitself  in  either  of three different ways, according to thestate option; it can be made to  appear  raised,  sunken,  orflat;  and it invokes a Tk command whenever mouse button 1 isclicked over the checkbutton. In addition, checkbuttons can be selected.  If a  checkbuttonis  selected  then  the  indicator  is  normally drawn with asunken relief and a tick (check)  mark,  and  a  Tk  variableassociated  with  the checkbutton is set to the onvalue (nor‐mally 1).  If the checkbutton is not selected, then the indi‐cator  is  drawn  as an empty box with raised relief, and theassociated variable is set to the offvalue (normally 0).  Thevariable  name  may  be  modified with options on the commandline (-variable option).  Configuration options may  also  beused to modify the way the indicator is displayed (or whetherit is displayed at all).  By default a checkbutton is config‐ured  to  select  and  deselect  itself  on  alternate buttonclicks. == widget COMMANDThe checkbutton command creates a new Tk command  whose  nameis  pathname.   This  command  may  be used to invoke variousoperations on the widget.  It has the following general form:       pathname option ?arg arg ...?Option and the args determine the exact behaviour of the com‐mand.   The  following  commands are possible for checkbuttonwidgets: 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  wid‐       get.  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,  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 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 Tk command  associ‐       ated  with  the  checkbutton,  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 checkbutton.  This command is ignored if  the       checkbutton's state is disabled. pathname select       Selects  the checkbutton and sets the associated vari‐       able to 1. pathname toggle       Toggles the selection state of the button,  redisplay‐       ing  it  and  modifying  its  associated  variable  to       reflect the new state. == bindingsTk automatically creates bindings for checkbuttons that  givethem the following default behaviour: [1]    A checkbutton activates whenever the mouse passes over       it and  deactivates  whenever  the  mouse  leaves  the       checkbutton. [2]    When  mouse  button 1 is pressed over a checkbutton it       is invoked (its selection state toggles and  the  com‐       mand  associated  with the button is invoked, if there       is one). If the checkbutton's state is disabled then none of the aboveactions occur:  the checkbutton is completely non-responsive. The  behaviour of checkbuttons can be changed by defining newbindings for individual widgets. == see ALSObutton(9),   choicebutton(9),   options(9),   radiobutton(9),types(9)