Provided by: tk8.5-doc_8.5.19-3_all bug

NAME

       button - Create and manipulate button widgets

SYNOPSIS

       button pathName ?options?

STANDARD OPTIONS

       -activebackground     -font                -relief
       -activeforeground     -foreground          -repeatdelay
       -anchor               -highlightbackground -repeatinterval
       -background           -highlightcolor      -takefocus
       -bitmap               -highlightthickness  -text
       -borderwidth          -image               -textvariable
       -compound             -justify             -underline
       -cursor               -padx                -wraplength
       -disabledforeground   -pady

       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.

       Command-Line Name:-default
       Database Name:  default
       Database Class: 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  platform  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.

       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:-overrelief
       Database Name:  overRelief
       Database Class: OverRelief

              Specifies an alternative relief for the button, 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  button.   The
              empty string is the default value.

       Command-Line Name:-state
       Database Name:  state
       Database Class: 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.

       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 a text button (no image or with  -compound  none)  then  the
              width  specifies  how  much space in characters to allocate for the text label.  If
              the width is negative then this specifies a minimum width.  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 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 characters 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 original 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.

EXAMPLES

       This is the classic Tk “Hello, World!”  demonstration:

                  button .b -text "Hello, World!" -command exit
                  pack .b

       This example demonstrates how to handle button accelerators:

                  button .b1 -text Hello -underline 0
                  button .b2 -text World -underline 0
                  bind . <Key-h> {.b1 flash; .b1 invoke}
                  bind . <Key-w> {.b2 flash; .b2 invoke}
                  pack .b1 .b2

SEE ALSO

       ttk::button(3tk)

KEYWORDS

       button, widget