NAME

       Tk::Button - Create and manipulate Button widgets

SYNOPSIS

       $button = $parent->Button(?options?);

STANDARD OPTIONS

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

       See Tk::options for details of the standard options.

WIDGET-SPECIFIC OPTIONS

       Name:     command
       Class:    Command
       Switch:   -command
           Specifies a Perl/Tk callback to associate with the button.  This command is typically invoked when
           mouse button 1 is released over the button window.

       Command-Line Name: -compound
       Database Name:  compound
       Database Class: Compound
           Specifies whether the button should display both an image and text, and if so, where the image should
           be placed relative to the text.  Valid values for this option are bottom, center, left, none, right
           and top.  The default value is none, meaning that the button will display either an image or text,
           depending on the values of the -image and -bitmap options.

       Name:     default
       Class:    Default
       Switch:   -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.  ring.

       Name:     height
       Class:    Height
       Switch:   -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 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.

       Name:     state
       Class:    State
       Switch:   -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.

       Name:     width
       Class:    Width
       Switch:   -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.

DESCRIPTION

       The Button method creates a new window (given by the $widget 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 $widget argument.  At the time this command is invoked, there must not exist a window named
       $widget, but $widget'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 perl/Tk
       callback specified in the -command option is invoked.

WIDGET METHODS

       The Button method creates a widget object.  This object supports the configure and cget methods described
       in Tk::options which can be used to enquire and modify the options described above.  The widget also
       inherits all the methods provided by the generic Tk::Widget class.

       The following additional methods are available for button widgets:

       $button->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.

       $button->invoke
           Invoke the callback associated with the buttons -command option, if there is one.  The return value
           is the return value from the callback, or the undefined value if there is no callback 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.

KEYWORDS

       button, widget