Ubuntu Manpage: button - Create and manipulate 'button' action widgets

NAME

       button - Create and manipulate 'button' action 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 the configured activebackground and background 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.

PLATFORM NOTES

       On Aqua/Mac OS X, some configuration options are ignored for the purpose of drawing of the
       widget because they would otherwise conflict with platform guidelines. The  configure  and
       cget  subcommands  can  still manipulate the values, but do not cause any variation to the
       look of the widget. The options affected notably include -background and -relief.

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

KEYWORDS

       button, widget