Button(3)						User Contributed Perl Documentation						 Button(3)

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

perl v5.12.1							    2007-07-30								 Button(3)