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







button - Create and manipulate button widgets








button pathName ?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.








[-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 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. [-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 is not specified, the button's desired height
    is computed from the size of the image or bitmap or text being displayed in
    it. [-overrelief 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.
    [-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 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.












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.










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:


  

  
Returns the current value of the configuration option given by
      option. Option may have any of the values accepted by the
      button command.

  

  
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.

  

  
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.

  

  
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.
    

  










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.










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










ttk::button(n)








button, widget







  

    4.4
    Tk