Provided by: tk8.5-doc_8.5.15-2ubuntu3_all 
NAME
button - Create and manipulate button 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.
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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 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.
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.
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
SEE ALSO
ttk::button(3tk)
KEYWORDS
button, widget