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.
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.
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