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