button(n)						       Tk Built-In Commands							 button(n)

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NAME

       button - Create and manipulate button widgets

SYNOPSIS

       button 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 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.	[-default default] Specifies one of three states for the default ring: normal, active,	or  disabled.	In  active |
       state, the button is drawn with the platform specific appearance for a default button.  In normal state, the button is drawn with the plat- |
       form specific appearance for a non-default button, leaving enough space to draw the default  button  appearance.   The  normal  and  active |
       states  will  result  in  buttons  of the same size.  In disabled state, the button is drawn with the non-default button appearance without |
       leaving space for  the  default	appearance.   The  disabled  state  may  result  in  a	smaller  button  than  the  active  state.   ring.
       [-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 Tk_GetPixels); for text it is in lines of text.  If this option isn't specified, the but-
       ton's desired height is computed from the size of the image or bitmap or text being displayed in it.  [-state state] Specifies one of three
       states for the button:  normal, active, or disabled.  In normal state the button is displayed using the foreground and background  options.
       The active state is typically used when the pointer is over the button.	In active state the button is displayed using the activeForeground
       and activeBackground options.  Disabled state means that the button 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 button is
       displayed.  [-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 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.
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DESCRIPTION

       The button command creates a new window (given by the pathName argument) and makes it into a button widget.  Additional options,  described
       above,  may  be	specified on the command line or in the option database to configure aspects of the button such as its colors, font, text,
       and initial relief.  The button 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  button  is  a widget that displays a textual string, bitmap or image.  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 charac-
       ters  may  optionally  be underlined using the underline option.  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; and it can be made to flash.  When a user invokes the button  (by  pressing
       mouse button 1 with the cursor over the button), then the Tcl command specified in the -command option is invoked.

WIDGET COMMAND

       The  button 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 button 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  button
	      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 button command.

       pathName flash
	      Flash the button.  This is accomplished by redisplaying the button several times, alternating between active and normal colors.	At
	      the end of the flash the button is left in the same normal/active state as when the command was invoked.	This command is ignored if
	      the button's state is disabled.

       pathName invoke
	      Invoke the Tcl command associated with the button, 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 button.  This command is ignored if the button's state is disabled.

DEFAULT BINDINGS

       Tk automatically creates class bindings for buttons that give them default behavior:

       [1]    A  button  activates  whenever  the  mouse passes over it and deactivates whenever the mouse leaves the button.  Under Windows, this |
	      binding is only active when mouse button 1 has been pressed over the button.

       [2]    A button's relief is changed to sunken whenever mouse button 1 is pressed over the button, and the relief is restored to its  origi-
	      nal value when button 1 is later released.

       [3]    If  mouse button 1 is pressed over a button and later released over the button, the button is invoked.  However, if the mouse is not
	      over the button when button 1 is released, then no invocation occurs.

       [4]    When a button has the input focus, the space key causes the button to be invoked.

       If the button's state is disabled then none of the above actions occur:	the button is completely non-responsive.

       The behavior of buttons can be changed by defining new bindings for individual widgets or by redefining the class bindings.

KEYWORDS

       button, widget

Tk									4.4								 button(n)