button(n) Tk Built-In Commands button(n) ______________________________________________________________________________
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 ...?
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/macOS, 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
SEE ALSO
ttk_button(n)
KEYWORDS
button, widget
Tk 4.4 button(n)
tk 8.6.15 - Generated Wed Dec 4 13:26:53 CST 2024